CA1041365A - Dehydrated granular potato product and process for production of same - Google Patents
Dehydrated granular potato product and process for production of sameInfo
- Publication number
- CA1041365A CA1041365A CA195,199A CA195199A CA1041365A CA 1041365 A CA1041365 A CA 1041365A CA 195199 A CA195199 A CA 195199A CA 1041365 A CA1041365 A CA 1041365A
- Authority
- CA
- Canada
- Prior art keywords
- cells
- potato
- potatoes
- emulsifier
- agglomerates
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D9/00—Level control, e.g. controlling quantity of material stored in vessel
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
- A23L19/10—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops
- A23L19/12—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops of potatoes
- A23L19/15—Unshaped dry products, e.g. powders, flakes, granules or agglomerates
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Health & Medical Sciences (AREA)
- Nutrition Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Preparation Of Fruits And Vegetables (AREA)
- Storage Of Fruits Or Vegetables (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A dehydrated potato product is produced in a single-pass, non-addbeck process by preparing and cooking potatoes, mixing the cooked potatoes with a starch complexing emulsifier in the range of 0.3 to 2.0% by weight of solids to coat the surface of the potato cells, and mixing the resulting mash while directly subjecting the mash to a high velocity heated air stream to dry the mash to a point at which partially dried particles are airlifted and removed from the mixer-dryer.
The partially dried cells are then dried to completion by conventional means. The starch complexing emulsifier reduces the adhesive characteristics of the mash, allowing separation of intact cells without damage after reducing the mash moisture to the range of about 30 to 50%. The dehydrated cooked potato product consists of intact potato cells in granular form sub-stantially passing through a standard 60 mesh screen with high cold water absorption characteristics and rehydratable in hot water into mealy mashed potatoes.
A dehydrated potato product is produced in a single-pass, non-addbeck process by preparing and cooking potatoes, mixing the cooked potatoes with a starch complexing emulsifier in the range of 0.3 to 2.0% by weight of solids to coat the surface of the potato cells, and mixing the resulting mash while directly subjecting the mash to a high velocity heated air stream to dry the mash to a point at which partially dried particles are airlifted and removed from the mixer-dryer.
The partially dried cells are then dried to completion by conventional means. The starch complexing emulsifier reduces the adhesive characteristics of the mash, allowing separation of intact cells without damage after reducing the mash moisture to the range of about 30 to 50%. The dehydrated cooked potato product consists of intact potato cells in granular form sub-stantially passing through a standard 60 mesh screen with high cold water absorption characteristics and rehydratable in hot water into mealy mashed potatoes.
Description
The invention relates to tne production of dehydrated intact cooked po-tato cells~ i3 e. potato granules Further, the invention relates to a single-pass~ continuous process not requiring the addback of the ~lnal product to the starting 5 materials as required in prior art potato granule processes.
There are numerous disclosure~; in the prior art for processes -to produce by a direct process dehydr&ted potato pieces capable o~ reconstitution to a mashed potato~
Great Britain Patent No. 542,125 discloses a process 10 wherein mashed potatoes are dried at a temperature o~ 50-60C.
~or two hours to reach a moisture content of 40 to 60~. The partially dried mash is then compressed and conditioned ~or 6 to 24 hours, a~ter which it is divided by rubbing through a ~ieve, and the divided pieces are then dried to completion.
15United States Patent No. 2,750~295 discloses a process in which mashed potatoesare mixed with ethyl alcohol and 60~ o~ the moisture is removed by distillation. Additional alcohol is mixed with the partiall~ dried potatoes to remove - an additional 35~ o~ the water, and a~ter ~iltration, the 20 unicellular granules are dried conventionally. This process is too costly and leaves an undesirable residual ~lavor Also there are man~ prior art processes based on ;
the 'l~reeze-squeeze" approach in which mashed potatoes are ~rozen; thawed; and dewatered to produce a ~riable damp ;;
25 powder which can be dried conventionally. However, such processes are not satis~actory because o~ economic reasons coupled with unacceptably large losses o~ solids and nutrients and resulting sandy texture.
Great Britain Patent No. 740~711 to Templeton 30 discloses a non-addback process ~or making dehydrated potato ; ,
There are numerous disclosure~; in the prior art for processes -to produce by a direct process dehydr&ted potato pieces capable o~ reconstitution to a mashed potato~
Great Britain Patent No. 542,125 discloses a process 10 wherein mashed potatoes are dried at a temperature o~ 50-60C.
~or two hours to reach a moisture content of 40 to 60~. The partially dried mash is then compressed and conditioned ~or 6 to 24 hours, a~ter which it is divided by rubbing through a ~ieve, and the divided pieces are then dried to completion.
15United States Patent No. 2,750~295 discloses a process in which mashed potatoesare mixed with ethyl alcohol and 60~ o~ the moisture is removed by distillation. Additional alcohol is mixed with the partiall~ dried potatoes to remove - an additional 35~ o~ the water, and a~ter ~iltration, the 20 unicellular granules are dried conventionally. This process is too costly and leaves an undesirable residual ~lavor Also there are man~ prior art processes based on ;
the 'l~reeze-squeeze" approach in which mashed potatoes are ~rozen; thawed; and dewatered to produce a ~riable damp ;;
25 powder which can be dried conventionally. However, such processes are not satis~actory because o~ economic reasons coupled with unacceptably large losses o~ solids and nutrients and resulting sandy texture.
Great Britain Patent No. 740~711 to Templeton 30 discloses a non-addback process ~or making dehydrated potato ; ,
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;5 powder except that addback ls initially used during start-up7 Templeton adds coo~ed potatoes having up to 60~ moisture to the inlet end of a three trough mixer-evaporator, Each trough is surrounded by a steam ~acket to keep the product 5 at about 50~C. maximum. Counter-current alr is blown over the product to evaporate the water as the product progresses through the mixer. At the outlet end a moist powder is discharged having below 30~ moisture which is then ~inal dried, The process is either a batch process or can be run -10 continuously by adjusting the rate o~ input with the rate o~ ;~
output so that a certain level is maintained in the mixer.
There is no disclosure of the use o~ monoglycerides nor is there a disclosure that the powder is granulated without excessive dam~ge during mixing and entrained by the air Plow.
U. S, Patent No. 3,133,797 to Pierson discloses a ; non-addback process ~or dehydrating potatoes in which the cooked potatoes are mechanicall~ ~orced by a roller through screen openings separating the mash into aggregates and are then blown of~ o~ the screen by an air blast. The 20 particles ~all through a d~hy~ r counter-current to a warm i;
air ~low and are then ~inish dried. The end product i8 a ;
mixture o~ granules and powder. A similar process is dis-closed in U. $, Patent No. 3~517,716 to Carlsen which includes additional baf~le means and counter-current air flow means 25 to retard the free ~all o~ the comminuted particles through ~ '" , the dryer and permit adequate drying thereo~, Neither o~
. . .
these processes disclose the use o~ monoglycerides nor the granulation o~ the moist mash by passing it through the dryer and entraining the granulated particles in the air flow , .
30 to r~move them from the system, ''':;
~ 3.
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.. .... . . .. . . .
U~S. Patent No. 3,009,817 to Hendel discloses a non-addback process for making dehydrated potato granules. Raw potatoes are washed, peeled, trimmed, cut and dipped in soaium bisulphite solution and cooked, The cooked potatoes are mashed, blended with optional additives which include edible dispersing agents such as monoglycerly esters of long chamn fatty acids to increase the ability to absorb water and to reduce stickiness, and then conditioned by cooling for several hours either at room temperature or for shorter periods at down to sub-freezing temperatures. The conditioned, cooked potatoes are then granulated by subdividing the mash into single cells without ; rupturing the cells by gently mixing in a granulator while subjecting the mix to a hot air stream to reduae moisture.
Thereafter, the temperature and velocity of the air is increased and the granulated particles are entrained by the air stream and carried into a collector and then finally dried. The process ; - is long, requiring asaa minimum 2 to 3 hours from the time the conditioning step begins. Hendel teaches the elimination of or shortening the duration of his conditioning step but only in a ` 20 process where portions of the final product are added back to the ! starting materials and even then a cooling step is required. See also, U.S. Patent 3,009,816 to Hendel for a generally similar .
disclosure but teaching the addition of a 1-4 hour soaking step prior to coo~ing in order to increase the water absorption ~; characteristics of the dehydrated granules.
Applicants have found, through the proper use of monoglycerides to coat the individual intact cooked potato ; cells, a unique process by which ~endel's conditioning step can be eliminated without the need to use either a cooling .:
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. .
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. .
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step or the step of adding back final product to the startlng materials and applicants achieve impro~ed water absorption characteristics over prior art granules wlthout a soaking step. Applicants' process iB quick and 5 effective and a distinct improvement over Hendel's teachings. -~ .
Cooked potato cells are extremelg fraglle and if - ruptured during processing, the end products are too rubbery or stick~ to be utilized in making mealy mashed potatoes. 2~ ' This accounts for the failure of prior art single-pass 10 potato granules processes to make a product of acceptable quality. In contrast, the product of this invention has a , ~ .;.. ..
~ more natural, freshly cooked potato flavor. The product is ` ~ ~
.. ~
not sub~ected to repeated handllng and heating and does not require the protectlve additives necessary in some prior 15 art processe~. The texture is mealy when reconstituted in contrast to stickiness or a sandy quality characteristic of prior art products~ In addition, the product of the invention has improved cold water absorption qualities and is especially desirable in ~ormulation of fabricated potato 20 snack products such as those described in United States Patents 3,539,356 and 3,576,647.
The invention includes a process for making a dehydrated potato product having unique characterlstics in which raw potatoes are ~irst prepared for cooking in 25 the usual manner by washing, peeling, trimming and cutting.
Optionally, the cut potatoes are dipped in a sodium bisulphite solution to prevent discoloration and are then -; cooked co~ventionally. The cooked potatoes are mixed with a starch complexing emulsifier in order to separate the 30 cooked potato cells and uniformly coat the separ&ted ce~ls ', ; 5-. ~ :
.. . .
;` . . .... . . ... . .
~ 4~36S
with a ~ilm of the emulsi~ier. This separating and coat-lng action reduces the cohesiveness o~ the freshly mashed potatoas and lubricates the sur~ace o~ the cells to prevent rupture during subsequent processing. The potato-5 emulsi~ier mixture is then granulated in a mixer-dryer by mixing the mixture to expose new moist sur~aces f~or drying without rupture o~' the cells while drying the surfaces by injecting high velocity hot air directly onto the surfaces. When the moisture content of the mixture is 10 appro~imately 25-30~ by weight~ intact potato cells and small agglomerates thereo~ are automatlcally separated from the mixture and alrli~ted out of the mixer-dryer where they are separated ~rom the air stream and then conventionally ~; dried to about 8a/Omolsture content", These granules are of a ; .
15 particle size that will substantially pass a 4rO mesh '~ screen?havé high cold water absorption characteristlcs and produce a mealy mashed potato when rehydrated in water.
It is an ob~act of this invention to produce de-~,~ hydrated potato granules without the use o~ addback and 20 without the necessity ~or conditioning the starting j~ materials. It is an ob~ect o~ this invention to use whole '~r potatoes without the necessity o~ precooking and cooling.
It is an ob~ect o~ this invention to use a process which can produce granules suitable ~or ~inal drying within 25 45 minutes a~ter the mashed potatoes a,re ready ~or granu-lation and drying.
It is an ob~ect o~ ~is inventlon to provide a ;
,t~,',',.,~ product that is 1QW in additives and has unusually high cold water absorption characteristics.
Other ob~ects will be clear from the description . :
,,~. i , :
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. . ,, , ~ . : . .-. .
' ;,:
' ~
,, :
-. ... . : . .. . .
;5 powder except that addback ls initially used during start-up7 Templeton adds coo~ed potatoes having up to 60~ moisture to the inlet end of a three trough mixer-evaporator, Each trough is surrounded by a steam ~acket to keep the product 5 at about 50~C. maximum. Counter-current alr is blown over the product to evaporate the water as the product progresses through the mixer. At the outlet end a moist powder is discharged having below 30~ moisture which is then ~inal dried, The process is either a batch process or can be run -10 continuously by adjusting the rate o~ input with the rate o~ ;~
output so that a certain level is maintained in the mixer.
There is no disclosure of the use o~ monoglycerides nor is there a disclosure that the powder is granulated without excessive dam~ge during mixing and entrained by the air Plow.
U. S, Patent No. 3,133,797 to Pierson discloses a ; non-addback process ~or dehydrating potatoes in which the cooked potatoes are mechanicall~ ~orced by a roller through screen openings separating the mash into aggregates and are then blown of~ o~ the screen by an air blast. The 20 particles ~all through a d~hy~ r counter-current to a warm i;
air ~low and are then ~inish dried. The end product i8 a ;
mixture o~ granules and powder. A similar process is dis-closed in U. $, Patent No. 3~517,716 to Carlsen which includes additional baf~le means and counter-current air flow means 25 to retard the free ~all o~ the comminuted particles through ~ '" , the dryer and permit adequate drying thereo~, Neither o~
. . .
these processes disclose the use o~ monoglycerides nor the granulation o~ the moist mash by passing it through the dryer and entraining the granulated particles in the air flow , .
30 to r~move them from the system, ''':;
~ 3.
'''~
.. .... . . .. . . .
U~S. Patent No. 3,009,817 to Hendel discloses a non-addback process for making dehydrated potato granules. Raw potatoes are washed, peeled, trimmed, cut and dipped in soaium bisulphite solution and cooked, The cooked potatoes are mashed, blended with optional additives which include edible dispersing agents such as monoglycerly esters of long chamn fatty acids to increase the ability to absorb water and to reduce stickiness, and then conditioned by cooling for several hours either at room temperature or for shorter periods at down to sub-freezing temperatures. The conditioned, cooked potatoes are then granulated by subdividing the mash into single cells without ; rupturing the cells by gently mixing in a granulator while subjecting the mix to a hot air stream to reduae moisture.
Thereafter, the temperature and velocity of the air is increased and the granulated particles are entrained by the air stream and carried into a collector and then finally dried. The process ; - is long, requiring asaa minimum 2 to 3 hours from the time the conditioning step begins. Hendel teaches the elimination of or shortening the duration of his conditioning step but only in a ` 20 process where portions of the final product are added back to the ! starting materials and even then a cooling step is required. See also, U.S. Patent 3,009,816 to Hendel for a generally similar .
disclosure but teaching the addition of a 1-4 hour soaking step prior to coo~ing in order to increase the water absorption ~; characteristics of the dehydrated granules.
Applicants have found, through the proper use of monoglycerides to coat the individual intact cooked potato ; cells, a unique process by which ~endel's conditioning step can be eliminated without the need to use either a cooling .:
: . !
. .
~ -4_ . .
. .
10~1l3~;S ~
step or the step of adding back final product to the startlng materials and applicants achieve impro~ed water absorption characteristics over prior art granules wlthout a soaking step. Applicants' process iB quick and 5 effective and a distinct improvement over Hendel's teachings. -~ .
Cooked potato cells are extremelg fraglle and if - ruptured during processing, the end products are too rubbery or stick~ to be utilized in making mealy mashed potatoes. 2~ ' This accounts for the failure of prior art single-pass 10 potato granules processes to make a product of acceptable quality. In contrast, the product of this invention has a , ~ .;.. ..
~ more natural, freshly cooked potato flavor. The product is ` ~ ~
.. ~
not sub~ected to repeated handllng and heating and does not require the protectlve additives necessary in some prior 15 art processe~. The texture is mealy when reconstituted in contrast to stickiness or a sandy quality characteristic of prior art products~ In addition, the product of the invention has improved cold water absorption qualities and is especially desirable in ~ormulation of fabricated potato 20 snack products such as those described in United States Patents 3,539,356 and 3,576,647.
The invention includes a process for making a dehydrated potato product having unique characterlstics in which raw potatoes are ~irst prepared for cooking in 25 the usual manner by washing, peeling, trimming and cutting.
Optionally, the cut potatoes are dipped in a sodium bisulphite solution to prevent discoloration and are then -; cooked co~ventionally. The cooked potatoes are mixed with a starch complexing emulsifier in order to separate the 30 cooked potato cells and uniformly coat the separ&ted ce~ls ', ; 5-. ~ :
.. . .
;` . . .... . . ... . .
~ 4~36S
with a ~ilm of the emulsi~ier. This separating and coat-lng action reduces the cohesiveness o~ the freshly mashed potatoas and lubricates the sur~ace o~ the cells to prevent rupture during subsequent processing. The potato-5 emulsi~ier mixture is then granulated in a mixer-dryer by mixing the mixture to expose new moist sur~aces f~or drying without rupture o~' the cells while drying the surfaces by injecting high velocity hot air directly onto the surfaces. When the moisture content of the mixture is 10 appro~imately 25-30~ by weight~ intact potato cells and small agglomerates thereo~ are automatlcally separated from the mixture and alrli~ted out of the mixer-dryer where they are separated ~rom the air stream and then conventionally ~; dried to about 8a/Omolsture content", These granules are of a ; .
15 particle size that will substantially pass a 4rO mesh '~ screen?havé high cold water absorption characteristlcs and produce a mealy mashed potato when rehydrated in water.
It is an ob~act of this invention to produce de-~,~ hydrated potato granules without the use o~ addback and 20 without the necessity ~or conditioning the starting j~ materials. It is an ob~ect o~ this invention to use whole '~r potatoes without the necessity o~ precooking and cooling.
It is an ob~ect o~ this invention to use a process which can produce granules suitable ~or ~inal drying within 25 45 minutes a~ter the mashed potatoes a,re ready ~or granu-lation and drying.
It is an ob~ect o~ ~is inventlon to provide a ;
,t~,',',.,~ product that is 1QW in additives and has unusually high cold water absorption characteristics.
Other ob~ects will be clear from the description . :
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and claims that follow. ,~
The present invention in one aspect, resides in a direct process for the production of dehyd~a~ed;potato produ~t comprising the steps of: (a) preparing potatoes for cooking; i:
~b~ cooking the prepared potatoes; (c) mixing uniformly with the cooked potatoes a starch complexing emulsifier in the ',' ' .
concentration of about 0~30-2.0% by weight of the total solid .,~
matter, said emulsifie~ added to said mixed cooked potatoes in .' ~:
a form such that it is dispersed throughout said mixed cooked , ~', .
. 10 potatoes whereby it complexes the soluble amylose starch frac-~.~ . ..
tion of said cooked potatoes ther~by reducing the cohesiveness of said potatoes, and lubricates and coats the surface of the cells of the cooked potatoes with the emulsifier such that they ', are not ruptured during the subsequent granulating step, and directly (d) granulating khe mixture of step (c) by ~1) mixing the mixture using sufficient mixing action to expose continually , , new surfaces for drying without rupturing the coated cells and by (2) reducing the moisture of the mixture to about 25-30% ,' by injecting heated air on the surfaces of the mixture so that ,~
intact potato cells and agglomerates of intact cells are , ', separated from the mixture; performing steps (c) and (d) before o, ?
an~ significant conditioning of a,aid mixture can take place whereby the conversion of amylose to its insoluble retrograded ,"
.... .
'' form is prevented; ~e) airlifting the granulated cells and agglomerates by entrainment in the hea~ed air; (f) separating the airlifted materials from the heated air; and (g) drying .
'.~ the separated materials to a final moisture content of about .. 7-8% by weight.
,~ In a further aspect this invention resides in a ;
granular dehydrated instant mashed potato product with unaltered '' natural flavor consisting essentially of single intact cooked ..
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-36~
potato cells and small agglomerates t~ereof coated wlth starch complexing emulsifier and containing amylose in unretrograded soluble form and suitable for rapid reconstitution in hot or cold water to form a mealy mashed potato, said product being characterized by being reconstitutable to a non-pourable mix when rehydrated with about 4.85 parts by weight of cold water per 1 part of said product.
In another aspect the invention resides in a direct process for the production of dehydrated intact cooked potato cells and small agglomerates thereof comprising the steps of: :
~a) preparing potatoes by washing and trimming; (b) cooking the prepared potatoes to completion; (c) admixing a starch complexing emulsifier uniformly with said cooked potatoes at a temperature above the melting point of said emulsifier and in a concentration so that said.emulsiier comprises about 1.0~ of the total solid matter present, said emulsifier dispersed throughout said mixed cooked potatoes whereby it complexes the soluble amylose starch fraction of said cooked potatoes thereby reducing the cohesive-ness of said potatoes, and thereby lubricating and coating the cells of said cooked potato with said emulsifier such that they are not ruptured during the subsequent steps (d) - (f); (d) :
mixing said coated potato cells in a mixer-dryer using ::
, sufficient mixing action to expose continuously new large drying : surface areas without rupturing the cells while simultaneously .. ~e~ injecting high velocity heated air onto the surface areas of -the mixture to lower the moisture content of the coated cells;
(f) granulating the coated cells when the moisture content has :
;~ been reduced to the range of about 25-30%, thereby separating . single cells and agglomerates; performing steps (c), (d), (e) ~.
and (f~ before any significant conditioning of said mixt~re can take place; (g) entraining peel particles along with the separ-ated single cells and agglomerates from.the mixer-~ryer in . :......... , ~ 7 . ,, , :.
, ,.. -: .: , . . . . - . :
i365 heated air;
~h~ reducing the velocity of the air ~arrying entrained ; material to a point at which the larger of the entrained agglo-merates above the size that will pass a 40 mesh screen fall from entrainment back into the mixer-dryer while the peel particles along ~ith the single cells and the smaller o~ the entrained agglomerates remain entrained and are removed from the system; ~`
(i) separating the solid matter from the entraining air; `~
(j) drying the solid matter to a moisture content of about 7-8~;
and (k) separating the peel particles from the dried solid matter, ~hereby isolating the dried intact cells and small agglomerates.
In the drawings which are annexed hereto and illustrate by way of example particular aspects of the present invention:
Fig. 1 is a cross sectional view o the mixer-dryer taken along the lines 1-1 of Fig. 3.
Fig. 2 is a cross sectional plan view of the mixer-dryer showing air distribution means and mixing paddle structure taken along the line 2-2 of Fig. 1.
- Fig. 3 is a cross section end view of the mixer-dryer taken along the line 3-3 of Fig. 1 and showing the expansion hood and mixer paddles.
The production of potato granules requires preparing and cooking potatoes, separating intact potato cells without ;~
rupturing them and then drying the separated cells. Ruptured cells liberate free starch which makes the resulting dried product unacceptable in that when it is rehydrated with water to form mashed potatoes, the potatoes are sticky or gummy.
In this description, the term "agglomerate" is applied s to a group of intact po$ato cells which have been separated but which adhere in loose random fashion. In contrast, the term "aggregate" is applied to particles of potato comprising ~ ~`
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intact cells which ha~e not been previously separated, such as would be formed by forcing cooked potato through a screen aperture followed by drying. The particles would be dense and would rehydrate poorly, The first stage of processing is to prepare the potatoes. Raw potatoes are lye peeled, washed and trimmed as usual, The potatoes are then dipped into a sodium bisulfite solution (1/2% as S02) to neutralize any residual lye prior to cooking, This results in a S02 content in the finished product which is far below the amount normally found ' , .~, '. ,.
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in dehydrated instant mashed potato products The process o~ this invention ls a low additive process. It is not necessary to add large amounts o~
additives, such as S02-containing salts, chelating agents, `- ~;
antioxidants and the like~ to prokect the product during the process. Normally, commercial potato granules contain 200-500 ppm S02 in addition to antioxidants and other pre-servatives which are necessary to prei~ent oxidation and discoloration during repeated and lengthy heating~ standing~ -and drying periods. All o~ these additives are eliminated in the present process. ~ndeed but for the trace of S02 and the starch complexing emulsi~ier, described below, there are no other additlves necessary to the process.
,;, . .
; Although the pre~erre~ embodiment uses completely prepared 15 potatoes, we have operated the process success~ully, with minor alterations~ on unpeeled potatoes. Large peel pieces are quickly entrained in the mixer-dryer described below and can be separated subsequently ~rom the intact . ;............ . .
cells by screenlng. ;
.... .
` 20 The next stage of processing is cooking the pre-pared potatoes. It will be obvious to one skilled in the art that an~ method o~ cooking potatces to completion can be employed in the inventive process. Although we pre~er .
to cook with atmospheric steam, hot oil or hot water 25 cooking are likewise satis~actory.
, ~ .
The next stage of processing is separating the cooked potato cells and uniformly coating the separated cell ;~
; sur~aces with a ~ilm o~ starch complexing emulsifier. This ; :, step is pre~erably accomplished by partially mashing the 30 cooked potatoes as by ricing and immediately mixing with a 8.
,' ,~ ;.
.','~
~4~3~S : -starch complexing emulsifier, such as glyceryl monostearate at a temperature above its melting point. During the mixing, which is necessary to accomplish complete cell separation, the emulsifier is uniformly distributed and the surfaces of the separated cells are uniformly coated with a thin film of the melted emulsifier. This coating accomplishes two functions. As is known in the prior art, starch complexing emulsifiers complex with the soluble amylose starch fraction that is at least partially responsible for the cohesiveness of freshly mashed potatoes. Such emulsifiers also appear to lubricate the potato cell surfaces so that they are not ruptured during subsequent moderate mixing and drying.
As one example we have successfully mixed the potatoes at a temperature of about 190F using a distilled glyceryl monostearate at a concentration of 1~0% by wei~ht ba~ed upon potato solids, to coat the intact potato cells with a film of monoglyceride.
; The coating action can also be accomplished by adding the emulsifier in dispersed form, but this technique introduces into the system appreciable additional water which must be :; :
removed in the drying step. However, the advantage of this ;
alternative is that the coating action takes place below the melting point of the emulsifier, An example of a suitable dispersed emulsifier is one made by mixing 1.1 parts of weight of glyceryl monostearate with 25 parts of water at 160~F. to `
form a stable creamy colloid.
~ lthough we prefer to use monoglyceridès sùch~Sas glyceryl monostearate as the starch complexing emulsifier, test runs were successfully conducted using other starch complexing , i- ~9--!:
, - . .~ ~ , , ~` ~ . .
, . .. . . . .
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emulsifiers. Sodium stearyl fumarate, calcium stearoyl *~
lactylate, sodium stearoyl-2-lactylate, and propylene glycol monoesters were all effective in the same concentration as used for the monoglycerides -- 0.3-2.0~. Commercial propylene glycol monoester contains about 11% monoglycerides.
The concentration of the starch complexing emulsifier was found to be very importa~t. When the process was conducted using the emulsifier at a concentration below 0.3~ by weight based on total solid matter, the mash became progressively more rubbery during subsequent mixing and eventually formed an unmanageable ball with no trace of granulation. At the other extreme, there was no advantage in adding more than ~% on a solids basis, It appears that adequate "lubrication" and complexing of the soluble amylose are accomplished in the range of .3 - 2~.
The temperature of the mashed potato-emulsifier mix was likewise found to be very important. When the potatoes are allowed to cool before the addition of the emulsifier resulting in a mix temperature below the melting point of the emulsifier, the separated intact potato cells are not adequately ;
coated or lubricated and the soluble amylose is nok complexed.
As a result, the mix contains unmelted emulsifier particles and does not granulate properly, and a product comparable in particle ,j , : .. .
size to potato granules cah~t be-produced. G~yceryl monostearate, the monoglyceride used in the preferred embodiment, has a melting point of 65-70C. (149.0 -- 158.0F.) When the -^' temperature of the mix is maintained above this value, uniform ;
.
;~ distribution of the monoglyceride can be accomplished without damage. We prefer to mix at a temperature of at least 160F. ~- -3Q to assure complete coating of the potato cells. Monoylycerides of o~her comparable fatty acids, such as of lauric and-palmitic ;,: , :
" 10 '~ ' .. ; .
' ~4~65 acids, have lower melting points and could undoubtPdly be distributed at temperatures below 150F. but abo~e~their melting points. It is essential that the monoglycerides or , .
other starch complexing emulsifier employed, be uniformly distributed. The mixing steps ou~lined above accomplished this, although any other non-damaging means of distribution would be equally sati~factory. -In an alternative embodiment, the cooked potatoes are slurried and defective portions, such as peel and eye fragments, are removed by screening to produce a defect-free slurry of intact potato cells consisting of about 18% potato solids. The slurry is then intimately mixed hot with mono-glycserides and may be added to the mixer-dryer ~desaribed below) as the sole source of potato solids. The dry end product is substantially defect-free. Of course, the extra water added to form the slurry has to be additionally removed during drying , .,, ~.
~ of the product. `;
f~ . The ~ext stage of processing is granulating the cooked ;~
potatoes by mixing and drying them in the mixer-dryer and then airlifting the granulated particles out of the system for final treatment.
One apparatus for performing these steps is shown in , Figs. 1, 2 and 3 and will be first described. It ls understood ~5 that additional apparatus may be ~mployed to perform these same steps.
~` Referring to Fig. 1, the inlet end of the mixer-.
dryer is shown generally at 12. Inside the mixer-dryer -., ., , , :
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3~5 ~-are located two parallel shafts 8 which rotate (drive means not shown) in the same direction and carry intermeshing paddles 9 with a cross-of-Lorraine con~iguration. As shown in Fig. 2, hot air enters the air distribution header 1 and ~ 5 is controllably mixed with cold air through dampers 2;-~ and ; is then led through outlets 3 and tubes 4 where it is sent at high velocity directly into the troughs 5 o~ the mixer-dryer. As best shown in Fig. 3, a hood I0 with 20 diverging sides 11 sits atop the mixer-dryer. The angled sides 11 10 function to prevent product buildup thereon and also ~unction as a di~fuser to reduce air velocity as air progresses toward the top 6 of the hood and out the exhaust duct 7~
In the operation o~ the mixer-dryer, it ~as been ~ound that i~ high velocity heated air is directed onto the 15 mashed potato - emulsi~ier mixture, the moisture content which was initially about 80~ can be lowered without the rupture of cells or the formation o~ a hard, horny crust known as case hardening. The mixing constantly exposes new drying sur-faces to the heated air. `~
~ The mashed potato-emulsi~ier mixture is continuously ~ed into the mixer-dryer at the inlet end 12 at the rate o~
about 24 pounds per minute. At this location the mixture resembles a dough and has a moisture content initially at about 80~. As the mix progresses (rightward in Fig. 1~ in ;~
25 the mixer~dryer, the dough begins to separate into small particles when the moisture content has been reduced to about % under the drying action of the high velocity hot airO
Farther rightward in the mixer-dryer where the moisture `
` content is reduced to about 25-30~, the mix begins to 30 granulate to particles which are then entrained in the air .
::
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: .. ~ ~ ., , , . . : . : . : : , , ~04~3~5 flow. The air velocity is ad~usted so that single intact cells or small agglomerates of' about 40 mesh consistin~
of several intact cells are alr llfted and carried out of the system along with smaller quantitie3 o~ larger ~ractiorls, ;5 such as na-tural ~ibers and small pieces of residual peel.
This granulation is sudden and unexpected and does not start until the moisture level is near 25-30C~. Mos-t of the entrained agglomerates larger than about 40 mesh remain in the system by ~alling back into the trough 5 and are ~urther 10 granulated and dried. This separation o~ larger particles is accomplished by expanding the area of hood 10 above the mixer~dryer to reduce the air velocity rapidly, (see Fig. 3) Single cells and small ag~lomerates remain entra~ned and are removed ln the exhaust air through exhaust duct 7 ~or -15 subsequent collection and final drying.
The process is made continuous by adding potato solids in the ~orm o~ mashed potato-emulsi~ier mixture at the inlet end 12 o~ the mixer roughly equivalent in weight to the - potato solids which are separated ~rom the system. ;-The optimum speed of the mixing means would undoubtedly be di~erent ~or each di~ferent piece o~ mixing equipment, A rotational speed must be chosen which will be slow enough not to throw the potato mix out o~ contact with the mixing means and not to rupture the tender potato cells , 25 by impact or abrasion and yet will be ~ast enough to expose , continuously enough new moist sur~aces to allow rapid drying.
We pre~er the mixer shown in Figs. 1-3 which is used in commercial potato granule operations to blend cooked potatoes and addback uni~ormly to a damp powder. On this mixing 30 equipment a rotational speed o~ 100-120 rpm is optimum and ~ -`
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was found to be e~ficient and non-damagln~. 60 rpm does .~ not expose suf~icient new drying surfaces and 160 rpm~throws the product excessively.
rrhe location, temperature and velocity o~
. 5 in~ection of the hot air is important to satis~actory - results and drying e~ficiency.
. ,: .
As is evident ~rom Figs. 1 and 2, we in~ect hot . air dow~ward through the multiple tubes 4 along the entire - ~
length o~ the mixer-dryer, although other methods of air ~ `
10 addition will be obvious to one skilled in the art ~ It is desirable to use temperatures as high as ; possible without resulting in scorched material. We have ~ound temperatures o~ 500~ to be damagin~ but no damage resulted when air was applied at 470F. It will be 15 obvious that the use o~ higher temperature~ would reduce .
; the required residence time in the mixer and would reduce ~. ~
. any possible physical damage due to the action o~ the mixer . ~.
s;¦ itsal~ We have also ~ound that higher air temperatures can :
be applied at the inlet end where moistures are abo~e 50~
20 than can be applied at the exhaust end where moistures are about 30~. For example, we have ~ound that temperatures at :~
the outlets o~ tubes 4 o~ 420F. at the inlet end, 400 in ~ the center section and 350F. at the downstream end are satis~
,,,,.,,.1 ~actory.
Air velocities must be selected within a range in which single cells and small agglomerates are removed from ~ the system by entrainment but larger agglomerates are .:. continually contacted by the mixing means until granulation ~` is essentially complete. In our equipment, velocities above ~ 30 9000 feet per minute at point o~ in~ection had the same i . ' ~' .~; 14.
~ .
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, . . .
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; detrim~ntal effect as excessive mixer speed -- the product was suspended and did not mix properly. At the other extreme, velocities below 4000 feet per minute at point of injection resulted in unsatisfactory drying. We have found an air velocity of 6400 fpm in the tubes 4 to be satisfactory. This resulted in an upward air velocity of about 400 fpm at the top of the mixer dryer 5 and of about 160 fpm at the top of mixer hood 6.
Certain precautions must be taken in the handling of the cells and agglomerates which are entrained. If all material entrained from the mixing area is removed from the system, the end product is too moist, too coarse in particle size, and does not rehydrate quickly and completely after drying. As mentioned above, in the expanding area of hood 10, air velocities at the widest point reduce to about 160 fpm. This assures that large dense agglomerates - su~stantially larger than 40 mesh -- will drop back into the mixer to undergo further granulation and not ~
be removed from the system. Since the exhaust duct 7 is located -~-toward the inlet end 12, this allows the large agglomerates which are dropped from entrainment in the expanded hood to be deposited into the mix nearer the inlet end where moistures a~e higher.
Thus, after arriving at equilibrium conditions, the product at the inlet end of the mixer-dryer is about 65% - 75% in moisture; the product in the center is about 35~45% in moisture;
.~ .
and the product in the opposite end has a moisture content of ~
.. .
about 25-30%o The product temperature throughout the mixer-dryer is about 115-120 F. The rotational speed of paddle shafts ..
8 was about 100 rpm, and the level of product at rest in the ; mixeF-dryer stabiliZed at a point .,.,. ~.
. :
~.
' -1~ -~0~3~5 about rnidway between sha~ts ~
1`he mixing means utilized in the mixer-dryer gave satis~actory results. Other mixing devices would likewise be e~pected to give comparable results i~ the mixing action during the time the product is exposed to mixing is not damaging to the tender intact potato cells and yet the action is sufficient to constantl~ expose new high moisture sur~aces and to break up agglomerates too large to be ~ removed by entralnment in the heated airO For example, - 10 initial drying can be further accelerated by substituting closely set pin paddles in the first third of the mixer-dryer where moistures are high.
; The time necessary to convert the hot mashed potato- `
emulsi~ier mix to a ~inc granulate ready ~or ~inal drying is approximately 30-45 minutes, This is only a ~raction o~
the time required in prior art potato granule processes `~ ~
The brevity of the process inherently results not only in ~ -improved quality but in novel physical characteristics Due to the rapid completion of drying, natural ~lavor is retained and the soluble am~lose fraction o~ the starch is not appreciably retrograded to its insoluble ~orm prior to .
; drying By retention o~ amylose in its soluble ~orm, the product of the lnvention rapidly absorbs appreciably more i` cold water than commercial potato granu]es. In contrast, commercial potato granule processes require length~ holding periods prior to drying ~or the purpose o~ accomplishing retrogradation or insolubilization o~ amylose since this toughens potato cells and aids in their separation in intact ~orm. Such a retrograded product, although capable o~
~orming excellent mashed potatoes when reconstituted in very j .,,,, , ' .
. .
. .
` 16 .
. :, 1~4~13~S `~
hot water, does not absorb cold water appreciably7thereby limiting its appllcations.
The ~inal stage o~ processing is ~inal drying and dehydratlng the granulated particles The intact cells and small agglomerates entrained in the exhaust air duct 7 have a moisture content o~ about 16-2~o and are separated by conventional means, such as, b~ a low velocity cyclone - collector ~not shown) which does not sub~ect the particles to forces which would result in cell breakage during collection. At the collector discharge, the moisture content is about 12-18~, and the product is easil~ dried ~i to the desired ~inal moisture content o~ about 7-80,~ by conventional mean~, 5uch as a hot air ~luid bed dr~er, The dried product had a particle size substantially passing a standard 40 mesh screen and about 70~ by weight ; passing through a standard 60 mesh screen. The small plus 40 mesh fractlon comprises ~ibers and other undesirable particles and is discarded. The dried product is made into mashed potatoes ~y rehydrating in 5 parts by weight o~
salted water-milk mixture heated to boiling The texture and appearance are excellent and the product is judged to .,.~ .... .
have a more natural potato ~lavor than other commercial instant mashed potato products This is attributed to ,. .,~ .
such ~actors as lack o~ additives, short processing time and low product temperature during processing.
Although exact parameters have been determined ~or our specially designed equipment, it will be obvlous that adjustments would undoubtedly be required ~or other equipment designs.
Another embodiment of the lnvention u~ilizes a ':
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predrying step which is optional. The uniform hot mashed potato-monoglyceride mix with completely coated potato cells is riced onto a perforated screen drying sur~ace and predried until about 75~ o~ the moisture is removed by 5 passing air heated to about 140-150F. over the mix for about five minutes. The predried mash is then ~ed into the mixer-dryer operated in the manner previously described. `
The predried mash granulates in about 4 minutes. The ~inal product is good in quali~y ~ut contains a higher 10 percentage of larger agglomerates. When the predrying step is used to remove up to 56-68~ of the moisture ln the mash, the predried mash granulates in 6-12 minutes. The dry ~inished product is excellent in quality and comparable in granulation to the product produced by utilizing the pre-15 ~erred embodiment, 1.1 In recent years, processes ~or making instant mashed ., .
potato products, such as potato granules and potato flakes, have incorporated precooking and cooling steps prior to cooking. This sequence of steps results in a tougher cell -25 that resists rupture during processing and makes a more mealy ~inished mash However, these steps require additional equipment and greater water usage and result in appreciable solids loss. We have operated our inventive process both ways and have ~ound no advantages( to either.
25 Thus, our process, by eliminating the necessity o~ the ^`~ precook-cool steps prior to cooking, is simplified and gives increased yields with less water usage.
- Additional research has shown that the cold waterabsorption and other physical characteristics o~ the de-.. .
30 hydrated granules o~ this invention can be var:Led by ~-. . .
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18.
,. , .~
. ;
. . .
, . ~ ~ . .. . . . . . : .
,. . ~ ~ . : . .. :
s adjustment of feed rates and air temperatures. Of course, higher feed rates require hotter air to accomplish equivalent drying in a given piece of e~uipment. As feed rate increases, `~ the residence time within the mixer~dryer decreases and the cold water absorption of the resulting end product increases.
When the feed rate is decreased, the time :in the undried state ;
is increased, apparently allowing retrogradation of soluble amylose to take place, resulting in an end product with reduced cold water absorption--closer to that of conventional potato granules. T~erefore, within limits, the inventive process allows one to produce end products having different physical character-s istics wh~ch cannot be duplicated by potato granules produced by prior art proces~es and which give the product of the invention utility in specialized applications in which potato granules are not satisfactory.
In arriving at the preferred embodiment, objective tests were developed or utillzed to advantage. For example, an estimation of cell rupture can be obtained by a variation of the Blue Value Test in which free starch is reacted with iddine and the depth of the blue color is measured objectively by light ; transmission. By varying only the percentage of monoglycerides, .,. ~
for example, and testing the product periodically for cell rupture during mixing, it was determin~d that mixes containing 0.75% glyceryl monostearate or higher by weight of solids showed no evidence of cell rupture (decrease of light transmission) even after 25 minutes of mixing. In contrast, mixes with 0.50% -monostearate showed no rupture after 15 minutes, but some rupture resulted from prolonged mixing. When cooked mashed ,~ " ~ . .
; potatoes with no monoglyceride were used, appreciable rupt~re , -, , :;,.
f --1 9--;' ~
." ~'''' : . ' ' "' '' ', .' .'' , . ' ','' ' ' "
3~5 was detectable in less than 5 minutes and shortly thereafter an .. ; .
unmanageable mass resulted. .
In a further aspect of our studies, an attempt was made to substitute oil for monoglyceride on the theory that lubrication alone might prevent cell rupture during the mixing~
: . . .
drying operation. It was found that the required granulation ~ ~
could not be obtained with oil alone, although oil in the ~: .
concentration of a . 1 to 1.0% of the solids in combination with . :.
monoglycexide promoted granulation. This substantiates the .~: :
.
theory that the starch complexing emulsifier complexes the soluble amylose in the hot mash, thereby reducing the cohesive-ness sufficiently 50 that the tender intact potato cells when coated with additional emulsifier are lubricated sufficiently so that they do not rupture during the mixing-drying steps.
Although it has been long appreciated that these emulsifiers ;
complex soluble amylose, it has not been known prior to appli~a ;:
cants' invention that these starch complexing emulsifiers could be incorporatêd into mashed potatoes in a way which would allow separation and drying of intact cells to produce a new product with the appearance of conventional potato granules but having new and useful characteristics completely different from potato granules of the prior art. ~he greatly sho.rtened processing time at low product temperatures from starting mashed potatoes to .,. ~ .
finished dried product (approximately 30-45 minutes) apparently , obviates the necessity to add preservatives and antioxi~ants :.. , during processing as is required in commercial prior art instant .', , .~
'~
~ -2Q--~4~3~5 mashed potato processes both to protect the product during processing and to impart stability during storage. This is a distinct advance in the art~sinGe such additives are restricted in many countries and are b~comin~ less 5 acceptable e~erywhere. -~
Comparative analysis o~ applicants' product with typical commercial potato granules and potato flakes are shown in the ~ollowing table:
Commercial Commercial Appllcants' PotatoPotato 10 Procedure Product GranulesFlakes Soluble Starch ; Hot Extraction (1) 50.5 5200 4.o Cold Extraction (2) 100.0 100.0 56.5 S2 (ppm) o-80.0 380.0 375-5 BHT (antioxidant-ppm)(3)o O ~ o 14 2 15 Recipe Rehydration Ratio(4) 5.5:1 4 8:1 6 0:1 Cold Water Absorption (5) 4.85:1 3.2:1 5.75:1 Amylograph Units Cold (6) 2300 545 33 Hot (7) 54 650 1~50 20 Flavor Evaluation ~resh Potato Bland~tarchy Texture Evaluation Verg good Ver~ good $1ightly Sticky (1) ~ transmisslon, 185F. extract, 0.1~ solution with iodine added (2) ~ transmission, 70F. extract, 0.1~ solution with iodine ~ `
added. -(3) Butylated hydroxytoluene 25 ~4) Parts o~ boiling liquid per part of product required to ~ make mashed potatoes ~-i~ (5) Parts o~ water at 70F. absorbed by 1 part by weight product I (6) 100 parts product, 400 parts water, 10 minutes at o-4c.
(7) 75 parts product, 450 parts water, 45 minutes star-ting ` 30 at 25C. and ending at 92 5C
21.
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The above data show that the product o~ the invention is comparable to potato granules in soluble starch and far less than pot~-to ~lakes.
The sul~ur dioxide value of the product is much 5 lower than fl~kes and granules which are comparable. ;
The product is far above potato granules and slightly below potato flakes in the ability to absorb hot and cold liquid.
- The product has a cold amylograph viscosity ~ar ., .
10 higher than potato granules and slightly lower than potato -flakes. The hot amylograph viscosity is higher than potato flakes and half way between flakes and potato granules.
The product was ~udged to have superior flavor and texture when compared to potato flakes and a superior ~lavor 15 to conventional pota-to granules.
' Unless otherwise stated herein all percentages are by weight, :. .
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and claims that follow. ,~
The present invention in one aspect, resides in a direct process for the production of dehyd~a~ed;potato produ~t comprising the steps of: (a) preparing potatoes for cooking; i:
~b~ cooking the prepared potatoes; (c) mixing uniformly with the cooked potatoes a starch complexing emulsifier in the ',' ' .
concentration of about 0~30-2.0% by weight of the total solid .,~
matter, said emulsifie~ added to said mixed cooked potatoes in .' ~:
a form such that it is dispersed throughout said mixed cooked , ~', .
. 10 potatoes whereby it complexes the soluble amylose starch frac-~.~ . ..
tion of said cooked potatoes ther~by reducing the cohesiveness of said potatoes, and lubricates and coats the surface of the cells of the cooked potatoes with the emulsifier such that they ', are not ruptured during the subsequent granulating step, and directly (d) granulating khe mixture of step (c) by ~1) mixing the mixture using sufficient mixing action to expose continually , , new surfaces for drying without rupturing the coated cells and by (2) reducing the moisture of the mixture to about 25-30% ,' by injecting heated air on the surfaces of the mixture so that ,~
intact potato cells and agglomerates of intact cells are , ', separated from the mixture; performing steps (c) and (d) before o, ?
an~ significant conditioning of a,aid mixture can take place whereby the conversion of amylose to its insoluble retrograded ,"
.... .
'' form is prevented; ~e) airlifting the granulated cells and agglomerates by entrainment in the hea~ed air; (f) separating the airlifted materials from the heated air; and (g) drying .
'.~ the separated materials to a final moisture content of about .. 7-8% by weight.
,~ In a further aspect this invention resides in a ;
granular dehydrated instant mashed potato product with unaltered '' natural flavor consisting essentially of single intact cooked ..
:`:
`' .
-36~
potato cells and small agglomerates t~ereof coated wlth starch complexing emulsifier and containing amylose in unretrograded soluble form and suitable for rapid reconstitution in hot or cold water to form a mealy mashed potato, said product being characterized by being reconstitutable to a non-pourable mix when rehydrated with about 4.85 parts by weight of cold water per 1 part of said product.
In another aspect the invention resides in a direct process for the production of dehydrated intact cooked potato cells and small agglomerates thereof comprising the steps of: :
~a) preparing potatoes by washing and trimming; (b) cooking the prepared potatoes to completion; (c) admixing a starch complexing emulsifier uniformly with said cooked potatoes at a temperature above the melting point of said emulsifier and in a concentration so that said.emulsiier comprises about 1.0~ of the total solid matter present, said emulsifier dispersed throughout said mixed cooked potatoes whereby it complexes the soluble amylose starch fraction of said cooked potatoes thereby reducing the cohesive-ness of said potatoes, and thereby lubricating and coating the cells of said cooked potato with said emulsifier such that they are not ruptured during the subsequent steps (d) - (f); (d) :
mixing said coated potato cells in a mixer-dryer using ::
, sufficient mixing action to expose continuously new large drying : surface areas without rupturing the cells while simultaneously .. ~e~ injecting high velocity heated air onto the surface areas of -the mixture to lower the moisture content of the coated cells;
(f) granulating the coated cells when the moisture content has :
;~ been reduced to the range of about 25-30%, thereby separating . single cells and agglomerates; performing steps (c), (d), (e) ~.
and (f~ before any significant conditioning of said mixt~re can take place; (g) entraining peel particles along with the separ-ated single cells and agglomerates from.the mixer-~ryer in . :......... , ~ 7 . ,, , :.
, ,.. -: .: , . . . . - . :
i365 heated air;
~h~ reducing the velocity of the air ~arrying entrained ; material to a point at which the larger of the entrained agglo-merates above the size that will pass a 40 mesh screen fall from entrainment back into the mixer-dryer while the peel particles along ~ith the single cells and the smaller o~ the entrained agglomerates remain entrained and are removed from the system; ~`
(i) separating the solid matter from the entraining air; `~
(j) drying the solid matter to a moisture content of about 7-8~;
and (k) separating the peel particles from the dried solid matter, ~hereby isolating the dried intact cells and small agglomerates.
In the drawings which are annexed hereto and illustrate by way of example particular aspects of the present invention:
Fig. 1 is a cross sectional view o the mixer-dryer taken along the lines 1-1 of Fig. 3.
Fig. 2 is a cross sectional plan view of the mixer-dryer showing air distribution means and mixing paddle structure taken along the line 2-2 of Fig. 1.
- Fig. 3 is a cross section end view of the mixer-dryer taken along the line 3-3 of Fig. 1 and showing the expansion hood and mixer paddles.
The production of potato granules requires preparing and cooking potatoes, separating intact potato cells without ;~
rupturing them and then drying the separated cells. Ruptured cells liberate free starch which makes the resulting dried product unacceptable in that when it is rehydrated with water to form mashed potatoes, the potatoes are sticky or gummy.
In this description, the term "agglomerate" is applied s to a group of intact po$ato cells which have been separated but which adhere in loose random fashion. In contrast, the term "aggregate" is applied to particles of potato comprising ~ ~`
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intact cells which ha~e not been previously separated, such as would be formed by forcing cooked potato through a screen aperture followed by drying. The particles would be dense and would rehydrate poorly, The first stage of processing is to prepare the potatoes. Raw potatoes are lye peeled, washed and trimmed as usual, The potatoes are then dipped into a sodium bisulfite solution (1/2% as S02) to neutralize any residual lye prior to cooking, This results in a S02 content in the finished product which is far below the amount normally found ' , .~, '. ,.
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in dehydrated instant mashed potato products The process o~ this invention ls a low additive process. It is not necessary to add large amounts o~
additives, such as S02-containing salts, chelating agents, `- ~;
antioxidants and the like~ to prokect the product during the process. Normally, commercial potato granules contain 200-500 ppm S02 in addition to antioxidants and other pre-servatives which are necessary to prei~ent oxidation and discoloration during repeated and lengthy heating~ standing~ -and drying periods. All o~ these additives are eliminated in the present process. ~ndeed but for the trace of S02 and the starch complexing emulsi~ier, described below, there are no other additlves necessary to the process.
,;, . .
; Although the pre~erre~ embodiment uses completely prepared 15 potatoes, we have operated the process success~ully, with minor alterations~ on unpeeled potatoes. Large peel pieces are quickly entrained in the mixer-dryer described below and can be separated subsequently ~rom the intact . ;............ . .
cells by screenlng. ;
.... .
` 20 The next stage of processing is cooking the pre-pared potatoes. It will be obvious to one skilled in the art that an~ method o~ cooking potatces to completion can be employed in the inventive process. Although we pre~er .
to cook with atmospheric steam, hot oil or hot water 25 cooking are likewise satis~actory.
, ~ .
The next stage of processing is separating the cooked potato cells and uniformly coating the separated cell ;~
; sur~aces with a ~ilm o~ starch complexing emulsifier. This ; :, step is pre~erably accomplished by partially mashing the 30 cooked potatoes as by ricing and immediately mixing with a 8.
,' ,~ ;.
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~4~3~S : -starch complexing emulsifier, such as glyceryl monostearate at a temperature above its melting point. During the mixing, which is necessary to accomplish complete cell separation, the emulsifier is uniformly distributed and the surfaces of the separated cells are uniformly coated with a thin film of the melted emulsifier. This coating accomplishes two functions. As is known in the prior art, starch complexing emulsifiers complex with the soluble amylose starch fraction that is at least partially responsible for the cohesiveness of freshly mashed potatoes. Such emulsifiers also appear to lubricate the potato cell surfaces so that they are not ruptured during subsequent moderate mixing and drying.
As one example we have successfully mixed the potatoes at a temperature of about 190F using a distilled glyceryl monostearate at a concentration of 1~0% by wei~ht ba~ed upon potato solids, to coat the intact potato cells with a film of monoglyceride.
; The coating action can also be accomplished by adding the emulsifier in dispersed form, but this technique introduces into the system appreciable additional water which must be :; :
removed in the drying step. However, the advantage of this ;
alternative is that the coating action takes place below the melting point of the emulsifier, An example of a suitable dispersed emulsifier is one made by mixing 1.1 parts of weight of glyceryl monostearate with 25 parts of water at 160~F. to `
form a stable creamy colloid.
~ lthough we prefer to use monoglyceridès sùch~Sas glyceryl monostearate as the starch complexing emulsifier, test runs were successfully conducted using other starch complexing , i- ~9--!:
, - . .~ ~ , , ~` ~ . .
, . .. . . . .
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emulsifiers. Sodium stearyl fumarate, calcium stearoyl *~
lactylate, sodium stearoyl-2-lactylate, and propylene glycol monoesters were all effective in the same concentration as used for the monoglycerides -- 0.3-2.0~. Commercial propylene glycol monoester contains about 11% monoglycerides.
The concentration of the starch complexing emulsifier was found to be very importa~t. When the process was conducted using the emulsifier at a concentration below 0.3~ by weight based on total solid matter, the mash became progressively more rubbery during subsequent mixing and eventually formed an unmanageable ball with no trace of granulation. At the other extreme, there was no advantage in adding more than ~% on a solids basis, It appears that adequate "lubrication" and complexing of the soluble amylose are accomplished in the range of .3 - 2~.
The temperature of the mashed potato-emulsifier mix was likewise found to be very important. When the potatoes are allowed to cool before the addition of the emulsifier resulting in a mix temperature below the melting point of the emulsifier, the separated intact potato cells are not adequately ;
coated or lubricated and the soluble amylose is nok complexed.
As a result, the mix contains unmelted emulsifier particles and does not granulate properly, and a product comparable in particle ,j , : .. .
size to potato granules cah~t be-produced. G~yceryl monostearate, the monoglyceride used in the preferred embodiment, has a melting point of 65-70C. (149.0 -- 158.0F.) When the -^' temperature of the mix is maintained above this value, uniform ;
.
;~ distribution of the monoglyceride can be accomplished without damage. We prefer to mix at a temperature of at least 160F. ~- -3Q to assure complete coating of the potato cells. Monoylycerides of o~her comparable fatty acids, such as of lauric and-palmitic ;,: , :
" 10 '~ ' .. ; .
' ~4~65 acids, have lower melting points and could undoubtPdly be distributed at temperatures below 150F. but abo~e~their melting points. It is essential that the monoglycerides or , .
other starch complexing emulsifier employed, be uniformly distributed. The mixing steps ou~lined above accomplished this, although any other non-damaging means of distribution would be equally sati~factory. -In an alternative embodiment, the cooked potatoes are slurried and defective portions, such as peel and eye fragments, are removed by screening to produce a defect-free slurry of intact potato cells consisting of about 18% potato solids. The slurry is then intimately mixed hot with mono-glycserides and may be added to the mixer-dryer ~desaribed below) as the sole source of potato solids. The dry end product is substantially defect-free. Of course, the extra water added to form the slurry has to be additionally removed during drying , .,, ~.
~ of the product. `;
f~ . The ~ext stage of processing is granulating the cooked ;~
potatoes by mixing and drying them in the mixer-dryer and then airlifting the granulated particles out of the system for final treatment.
One apparatus for performing these steps is shown in , Figs. 1, 2 and 3 and will be first described. It ls understood ~5 that additional apparatus may be ~mployed to perform these same steps.
~` Referring to Fig. 1, the inlet end of the mixer-.
dryer is shown generally at 12. Inside the mixer-dryer -., ., , , :
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3~5 ~-are located two parallel shafts 8 which rotate (drive means not shown) in the same direction and carry intermeshing paddles 9 with a cross-of-Lorraine con~iguration. As shown in Fig. 2, hot air enters the air distribution header 1 and ~ 5 is controllably mixed with cold air through dampers 2;-~ and ; is then led through outlets 3 and tubes 4 where it is sent at high velocity directly into the troughs 5 o~ the mixer-dryer. As best shown in Fig. 3, a hood I0 with 20 diverging sides 11 sits atop the mixer-dryer. The angled sides 11 10 function to prevent product buildup thereon and also ~unction as a di~fuser to reduce air velocity as air progresses toward the top 6 of the hood and out the exhaust duct 7~
In the operation o~ the mixer-dryer, it ~as been ~ound that i~ high velocity heated air is directed onto the 15 mashed potato - emulsi~ier mixture, the moisture content which was initially about 80~ can be lowered without the rupture of cells or the formation o~ a hard, horny crust known as case hardening. The mixing constantly exposes new drying sur-faces to the heated air. `~
~ The mashed potato-emulsi~ier mixture is continuously ~ed into the mixer-dryer at the inlet end 12 at the rate o~
about 24 pounds per minute. At this location the mixture resembles a dough and has a moisture content initially at about 80~. As the mix progresses (rightward in Fig. 1~ in ;~
25 the mixer~dryer, the dough begins to separate into small particles when the moisture content has been reduced to about % under the drying action of the high velocity hot airO
Farther rightward in the mixer-dryer where the moisture `
` content is reduced to about 25-30~, the mix begins to 30 granulate to particles which are then entrained in the air .
::
12.
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: .. ~ ~ ., , , . . : . : . : : , , ~04~3~5 flow. The air velocity is ad~usted so that single intact cells or small agglomerates of' about 40 mesh consistin~
of several intact cells are alr llfted and carried out of the system along with smaller quantitie3 o~ larger ~ractiorls, ;5 such as na-tural ~ibers and small pieces of residual peel.
This granulation is sudden and unexpected and does not start until the moisture level is near 25-30C~. Mos-t of the entrained agglomerates larger than about 40 mesh remain in the system by ~alling back into the trough 5 and are ~urther 10 granulated and dried. This separation o~ larger particles is accomplished by expanding the area of hood 10 above the mixer~dryer to reduce the air velocity rapidly, (see Fig. 3) Single cells and small ag~lomerates remain entra~ned and are removed ln the exhaust air through exhaust duct 7 ~or -15 subsequent collection and final drying.
The process is made continuous by adding potato solids in the ~orm o~ mashed potato-emulsi~ier mixture at the inlet end 12 o~ the mixer roughly equivalent in weight to the - potato solids which are separated ~rom the system. ;-The optimum speed of the mixing means would undoubtedly be di~erent ~or each di~ferent piece o~ mixing equipment, A rotational speed must be chosen which will be slow enough not to throw the potato mix out o~ contact with the mixing means and not to rupture the tender potato cells , 25 by impact or abrasion and yet will be ~ast enough to expose , continuously enough new moist sur~aces to allow rapid drying.
We pre~er the mixer shown in Figs. 1-3 which is used in commercial potato granule operations to blend cooked potatoes and addback uni~ormly to a damp powder. On this mixing 30 equipment a rotational speed o~ 100-120 rpm is optimum and ~ -`
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was found to be e~ficient and non-damagln~. 60 rpm does .~ not expose suf~icient new drying surfaces and 160 rpm~throws the product excessively.
rrhe location, temperature and velocity o~
. 5 in~ection of the hot air is important to satis~actory - results and drying e~ficiency.
. ,: .
As is evident ~rom Figs. 1 and 2, we in~ect hot . air dow~ward through the multiple tubes 4 along the entire - ~
length o~ the mixer-dryer, although other methods of air ~ `
10 addition will be obvious to one skilled in the art ~ It is desirable to use temperatures as high as ; possible without resulting in scorched material. We have ~ound temperatures o~ 500~ to be damagin~ but no damage resulted when air was applied at 470F. It will be 15 obvious that the use o~ higher temperature~ would reduce .
; the required residence time in the mixer and would reduce ~. ~
. any possible physical damage due to the action o~ the mixer . ~.
s;¦ itsal~ We have also ~ound that higher air temperatures can :
be applied at the inlet end where moistures are abo~e 50~
20 than can be applied at the exhaust end where moistures are about 30~. For example, we have ~ound that temperatures at :~
the outlets o~ tubes 4 o~ 420F. at the inlet end, 400 in ~ the center section and 350F. at the downstream end are satis~
,,,,.,,.1 ~actory.
Air velocities must be selected within a range in which single cells and small agglomerates are removed from ~ the system by entrainment but larger agglomerates are .:. continually contacted by the mixing means until granulation ~` is essentially complete. In our equipment, velocities above ~ 30 9000 feet per minute at point o~ in~ection had the same i . ' ~' .~; 14.
~ .
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, . . .
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; detrim~ntal effect as excessive mixer speed -- the product was suspended and did not mix properly. At the other extreme, velocities below 4000 feet per minute at point of injection resulted in unsatisfactory drying. We have found an air velocity of 6400 fpm in the tubes 4 to be satisfactory. This resulted in an upward air velocity of about 400 fpm at the top of the mixer dryer 5 and of about 160 fpm at the top of mixer hood 6.
Certain precautions must be taken in the handling of the cells and agglomerates which are entrained. If all material entrained from the mixing area is removed from the system, the end product is too moist, too coarse in particle size, and does not rehydrate quickly and completely after drying. As mentioned above, in the expanding area of hood 10, air velocities at the widest point reduce to about 160 fpm. This assures that large dense agglomerates - su~stantially larger than 40 mesh -- will drop back into the mixer to undergo further granulation and not ~
be removed from the system. Since the exhaust duct 7 is located -~-toward the inlet end 12, this allows the large agglomerates which are dropped from entrainment in the expanded hood to be deposited into the mix nearer the inlet end where moistures a~e higher.
Thus, after arriving at equilibrium conditions, the product at the inlet end of the mixer-dryer is about 65% - 75% in moisture; the product in the center is about 35~45% in moisture;
.~ .
and the product in the opposite end has a moisture content of ~
.. .
about 25-30%o The product temperature throughout the mixer-dryer is about 115-120 F. The rotational speed of paddle shafts ..
8 was about 100 rpm, and the level of product at rest in the ; mixeF-dryer stabiliZed at a point .,.,. ~.
. :
~.
' -1~ -~0~3~5 about rnidway between sha~ts ~
1`he mixing means utilized in the mixer-dryer gave satis~actory results. Other mixing devices would likewise be e~pected to give comparable results i~ the mixing action during the time the product is exposed to mixing is not damaging to the tender intact potato cells and yet the action is sufficient to constantl~ expose new high moisture sur~aces and to break up agglomerates too large to be ~ removed by entralnment in the heated airO For example, - 10 initial drying can be further accelerated by substituting closely set pin paddles in the first third of the mixer-dryer where moistures are high.
; The time necessary to convert the hot mashed potato- `
emulsi~ier mix to a ~inc granulate ready ~or ~inal drying is approximately 30-45 minutes, This is only a ~raction o~
the time required in prior art potato granule processes `~ ~
The brevity of the process inherently results not only in ~ -improved quality but in novel physical characteristics Due to the rapid completion of drying, natural ~lavor is retained and the soluble am~lose fraction o~ the starch is not appreciably retrograded to its insoluble ~orm prior to .
; drying By retention o~ amylose in its soluble ~orm, the product of the lnvention rapidly absorbs appreciably more i` cold water than commercial potato granu]es. In contrast, commercial potato granule processes require length~ holding periods prior to drying ~or the purpose o~ accomplishing retrogradation or insolubilization o~ amylose since this toughens potato cells and aids in their separation in intact ~orm. Such a retrograded product, although capable o~
~orming excellent mashed potatoes when reconstituted in very j .,,,, , ' .
. .
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hot water, does not absorb cold water appreciably7thereby limiting its appllcations.
The ~inal stage o~ processing is ~inal drying and dehydratlng the granulated particles The intact cells and small agglomerates entrained in the exhaust air duct 7 have a moisture content o~ about 16-2~o and are separated by conventional means, such as, b~ a low velocity cyclone - collector ~not shown) which does not sub~ect the particles to forces which would result in cell breakage during collection. At the collector discharge, the moisture content is about 12-18~, and the product is easil~ dried ~i to the desired ~inal moisture content o~ about 7-80,~ by conventional mean~, 5uch as a hot air ~luid bed dr~er, The dried product had a particle size substantially passing a standard 40 mesh screen and about 70~ by weight ; passing through a standard 60 mesh screen. The small plus 40 mesh fractlon comprises ~ibers and other undesirable particles and is discarded. The dried product is made into mashed potatoes ~y rehydrating in 5 parts by weight o~
salted water-milk mixture heated to boiling The texture and appearance are excellent and the product is judged to .,.~ .... .
have a more natural potato ~lavor than other commercial instant mashed potato products This is attributed to ,. .,~ .
such ~actors as lack o~ additives, short processing time and low product temperature during processing.
Although exact parameters have been determined ~or our specially designed equipment, it will be obvlous that adjustments would undoubtedly be required ~or other equipment designs.
Another embodiment of the lnvention u~ilizes a ':
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predrying step which is optional. The uniform hot mashed potato-monoglyceride mix with completely coated potato cells is riced onto a perforated screen drying sur~ace and predried until about 75~ o~ the moisture is removed by 5 passing air heated to about 140-150F. over the mix for about five minutes. The predried mash is then ~ed into the mixer-dryer operated in the manner previously described. `
The predried mash granulates in about 4 minutes. The ~inal product is good in quali~y ~ut contains a higher 10 percentage of larger agglomerates. When the predrying step is used to remove up to 56-68~ of the moisture ln the mash, the predried mash granulates in 6-12 minutes. The dry ~inished product is excellent in quality and comparable in granulation to the product produced by utilizing the pre-15 ~erred embodiment, 1.1 In recent years, processes ~or making instant mashed ., .
potato products, such as potato granules and potato flakes, have incorporated precooking and cooling steps prior to cooking. This sequence of steps results in a tougher cell -25 that resists rupture during processing and makes a more mealy ~inished mash However, these steps require additional equipment and greater water usage and result in appreciable solids loss. We have operated our inventive process both ways and have ~ound no advantages( to either.
25 Thus, our process, by eliminating the necessity o~ the ^`~ precook-cool steps prior to cooking, is simplified and gives increased yields with less water usage.
- Additional research has shown that the cold waterabsorption and other physical characteristics o~ the de-.. .
30 hydrated granules o~ this invention can be var:Led by ~-. . .
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18.
,. , .~
. ;
. . .
, . ~ ~ . .. . . . . . : .
,. . ~ ~ . : . .. :
s adjustment of feed rates and air temperatures. Of course, higher feed rates require hotter air to accomplish equivalent drying in a given piece of e~uipment. As feed rate increases, `~ the residence time within the mixer~dryer decreases and the cold water absorption of the resulting end product increases.
When the feed rate is decreased, the time :in the undried state ;
is increased, apparently allowing retrogradation of soluble amylose to take place, resulting in an end product with reduced cold water absorption--closer to that of conventional potato granules. T~erefore, within limits, the inventive process allows one to produce end products having different physical character-s istics wh~ch cannot be duplicated by potato granules produced by prior art proces~es and which give the product of the invention utility in specialized applications in which potato granules are not satisfactory.
In arriving at the preferred embodiment, objective tests were developed or utillzed to advantage. For example, an estimation of cell rupture can be obtained by a variation of the Blue Value Test in which free starch is reacted with iddine and the depth of the blue color is measured objectively by light ; transmission. By varying only the percentage of monoglycerides, .,. ~
for example, and testing the product periodically for cell rupture during mixing, it was determin~d that mixes containing 0.75% glyceryl monostearate or higher by weight of solids showed no evidence of cell rupture (decrease of light transmission) even after 25 minutes of mixing. In contrast, mixes with 0.50% -monostearate showed no rupture after 15 minutes, but some rupture resulted from prolonged mixing. When cooked mashed ,~ " ~ . .
; potatoes with no monoglyceride were used, appreciable rupt~re , -, , :;,.
f --1 9--;' ~
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3~5 was detectable in less than 5 minutes and shortly thereafter an .. ; .
unmanageable mass resulted. .
In a further aspect of our studies, an attempt was made to substitute oil for monoglyceride on the theory that lubrication alone might prevent cell rupture during the mixing~
: . . .
drying operation. It was found that the required granulation ~ ~
could not be obtained with oil alone, although oil in the ~: .
concentration of a . 1 to 1.0% of the solids in combination with . :.
monoglycexide promoted granulation. This substantiates the .~: :
.
theory that the starch complexing emulsifier complexes the soluble amylose in the hot mash, thereby reducing the cohesive-ness sufficiently 50 that the tender intact potato cells when coated with additional emulsifier are lubricated sufficiently so that they do not rupture during the mixing-drying steps.
Although it has been long appreciated that these emulsifiers ;
complex soluble amylose, it has not been known prior to appli~a ;:
cants' invention that these starch complexing emulsifiers could be incorporatêd into mashed potatoes in a way which would allow separation and drying of intact cells to produce a new product with the appearance of conventional potato granules but having new and useful characteristics completely different from potato granules of the prior art. ~he greatly sho.rtened processing time at low product temperatures from starting mashed potatoes to .,. ~ .
finished dried product (approximately 30-45 minutes) apparently , obviates the necessity to add preservatives and antioxi~ants :.. , during processing as is required in commercial prior art instant .', , .~
'~
~ -2Q--~4~3~5 mashed potato processes both to protect the product during processing and to impart stability during storage. This is a distinct advance in the art~sinGe such additives are restricted in many countries and are b~comin~ less 5 acceptable e~erywhere. -~
Comparative analysis o~ applicants' product with typical commercial potato granules and potato flakes are shown in the ~ollowing table:
Commercial Commercial Appllcants' PotatoPotato 10 Procedure Product GranulesFlakes Soluble Starch ; Hot Extraction (1) 50.5 5200 4.o Cold Extraction (2) 100.0 100.0 56.5 S2 (ppm) o-80.0 380.0 375-5 BHT (antioxidant-ppm)(3)o O ~ o 14 2 15 Recipe Rehydration Ratio(4) 5.5:1 4 8:1 6 0:1 Cold Water Absorption (5) 4.85:1 3.2:1 5.75:1 Amylograph Units Cold (6) 2300 545 33 Hot (7) 54 650 1~50 20 Flavor Evaluation ~resh Potato Bland~tarchy Texture Evaluation Verg good Ver~ good $1ightly Sticky (1) ~ transmisslon, 185F. extract, 0.1~ solution with iodine added (2) ~ transmission, 70F. extract, 0.1~ solution with iodine ~ `
added. -(3) Butylated hydroxytoluene 25 ~4) Parts o~ boiling liquid per part of product required to ~ make mashed potatoes ~-i~ (5) Parts o~ water at 70F. absorbed by 1 part by weight product I (6) 100 parts product, 400 parts water, 10 minutes at o-4c.
(7) 75 parts product, 450 parts water, 45 minutes star-ting ` 30 at 25C. and ending at 92 5C
21.
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The above data show that the product o~ the invention is comparable to potato granules in soluble starch and far less than pot~-to ~lakes.
The sul~ur dioxide value of the product is much 5 lower than fl~kes and granules which are comparable. ;
The product is far above potato granules and slightly below potato flakes in the ability to absorb hot and cold liquid.
- The product has a cold amylograph viscosity ~ar ., .
10 higher than potato granules and slightly lower than potato -flakes. The hot amylograph viscosity is higher than potato flakes and half way between flakes and potato granules.
The product was ~udged to have superior flavor and texture when compared to potato flakes and a superior ~lavor 15 to conventional pota-to granules.
' Unless otherwise stated herein all percentages are by weight, :. .
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Claims (31)
1. A direct process for the production of dehydrated potato product comprising the steps of:
(a) preparing potatoes for cooking;
(b) cooking the prepared potatoes;
(c) mixing uniformly with the cooked potatoes a starch complexing emulsifier in the concentration of about 0.30-2.0% by weight of the total solid matter, said emulsifier added to said mixed cooked potatoes in a form such that it is dispersed throughout said mixed cooked potatoes whereby it complexes the soluble amylose starch fraction of said cooked potatoes thereby reducing the cohesiveness of said potatoes, and lubricates and coats the surface of the cells of the cooked potatoes with the emulsifier such that they are not ruptured during the subsequent granulating step, and directly (d) granulating the mixture of step (c) by (1) mixing the mixture using sufficient mixing action to expose continually new surfaces for drying without rupturing the coated cells and by (2) reducing the moisture of the mixture to about 25-30% by injecting heated air on the surfaces of the mixture so that intact potato cells and agglomerates of intact cells are separated from the mixture;
performing steps (c) and (d) before any significant conditioning of said mixture can take place, whereby the conversion of amylose to its insoluble retrograded form is prevented;
(e) airlifting the granulated cells and agglomerates by entrainment in the heated air;
(f) separating the airlifted materials from the heated air; and (g) drying the separated materials to a final moisture content of about 7-8% by weight.
(a) preparing potatoes for cooking;
(b) cooking the prepared potatoes;
(c) mixing uniformly with the cooked potatoes a starch complexing emulsifier in the concentration of about 0.30-2.0% by weight of the total solid matter, said emulsifier added to said mixed cooked potatoes in a form such that it is dispersed throughout said mixed cooked potatoes whereby it complexes the soluble amylose starch fraction of said cooked potatoes thereby reducing the cohesiveness of said potatoes, and lubricates and coats the surface of the cells of the cooked potatoes with the emulsifier such that they are not ruptured during the subsequent granulating step, and directly (d) granulating the mixture of step (c) by (1) mixing the mixture using sufficient mixing action to expose continually new surfaces for drying without rupturing the coated cells and by (2) reducing the moisture of the mixture to about 25-30% by injecting heated air on the surfaces of the mixture so that intact potato cells and agglomerates of intact cells are separated from the mixture;
performing steps (c) and (d) before any significant conditioning of said mixture can take place, whereby the conversion of amylose to its insoluble retrograded form is prevented;
(e) airlifting the granulated cells and agglomerates by entrainment in the heated air;
(f) separating the airlifted materials from the heated air; and (g) drying the separated materials to a final moisture content of about 7-8% by weight.
2. The process of claim 1 in which the starch com-plexing emulsifier is glyceryl monostearate.
3. The process of claim 1 in which the starch com-plexing emulsifier is selected from a group consisting of monoglycerides of fatty acids, sodium stearyl fumarate, calcium stearoyl-2-lactylate, sodium stearoyl-2-lactylate, and propyl-ene glycol monoesters.
4. The process of claim 1 wherein the granulating step is performed in a mixer-dryer and the heated air is injected directly onto the surfaces of the mixture at a tem-perature which is sufficient to reduce the moisture content of the coated cells to the desired level without scorching, the temperature of the injected air being reduced as the point of injection is farther removed from the inlet of the mixer-dryer so that the highest temperature air is applied to the highest moisture mix, and the lowest temperature air is applied to the lowest moisture mix.
5. The process of claim 1 wherein steps d(1) and d(2) are performed simultaneously.
6. The process of claim 1 wherein the temperature of the injected air is in the range of 500°F and the velocity of the injected air is above 4000 fpm.
7. The process of claim 6 wherein the velocity at the point of injection onto the surfaces is about 6400 fpm.
8. The process of claim 1 in which the product maintained in entrainment is in the moisture range of about 16-20%.
9. The process of claim 8 in which the separated cells and smaller agglomerates are in the approximate moisture range of 12-18%.
10. The process of claim 9 further comprising the step of, following the airlifting step, (a) returning the larger of the agglomerates to the mixture from entrainment in the air by expanding the cross-sectional area of flow above the mixture sufficiently to reduce the velocity of the heated air sufficiently to deposit the larger agglomerates back into the mixture while still maintaining the granulated cells and the smaller of the agglomerates in entrainment in the heated air, and wherein the separating step includes separating the granulated cells and smaller agglomerates from the heated air.
11. The process of claim 10 wherein the reduced velocity is approximately 160 fpm, the dried separated material has a particle size substantially passing a standard 40 mesh screen and the fraction failing to pass is discarded.
12. The process of claim 11 wherein about 70% by weight of the isolated cells and agglomerates have a particle size which substantially passes a standard 60 mesh screen and the small plus 40 mesh fraction comprises mostly fibers and other undesirable particles.
13. The process of claim 1 in which the dried separated material is dried in a fluid bed dryer to a moisture content of about 7-8%.
14. The process of claim 1 in which processing steps (d) through (f) are completed in a total time of about 30-45 minutes.
15. The process of claim 1 in which the direct process is made continuous by adding continuously to step (d) mashed potato-starch complexing emulsifier mixture from step (c) in an amount roughly equal in solid matter to the potato solids separated continuously from the entraining air in step (f).
16. The process of claim 1 in which the mixing step (c) takes place at a temperature above the melting point of-said starch complexing emulsifier.
17. The process of claim 1 in which said starch complexing emulsifier is colloidally dispersed in water prior to said mixing step.
18. The process of claim 1 in which said preparing step further comprises lye peeling and dipping the lye peeled potatoes into a sulfur dioxide-containing solution prior to cooking.
19. The process of claim 18 in which said solution contains about 0.5% sulfur dioxide.
20. The process of claim 1 further comprising the steps of conventional precooking and cooling prior to cooking
21. The process of claim 1 in which the cooked prepared potatoes are mixed with water to produce a slurry of about 18% solids followed by removal of defective portions to produce a defect-free slurry prior to the mixing step (c).
22. The process of claim 1 in which the cooked potato-starch complexing emulsifier admixture as produced in step (c) is predried by heated air to remove up to about 75%
of the moisture content of the mixture prior to introduction into the granulating step as recited in step (d).
of the moisture content of the mixture prior to introduction into the granulating step as recited in step (d).
23. The process of claim 1 in which the method of cooking is selected from a group consisting of steam, hot water and hot oil.
24. The process of claim 3 in which oil in the concentration of 0.1 to 1.0% by weight of the solids present is incorporated in the mixing step (c).
25. A direct process for the production of dehy-drated intact cooked potato cells and small agglomerates thereof comprising the steps of:
(a) preparing potatoes by washing and trimming;
(b) cooking the prepared potatoes to completion;
(c) admixing a starch complexing emulsifier uniformly with said cooked potatoes at a temperature above the melting point of said emulsifier and in a concentration so that said emulsifier comprises about 1.0% of the total solid matter present, said emulsifier dispersed throughout said mixed cooked potatoes whereby it complexes the soluble amylose starch fraction of said cooked potatoes thereby reducing the cohesiveness of said potatoes, and thereby lub-ricating and coating the cells of said cooked potato with said emulsifier such that they are not ruptured during the subsequent steps (d)-(f);
(d) mixing said coated potato cells in a mixer-dryer using sufficient mixing action to expose continuously new large drying surface areas without rupturing the cells while simultaneously (e) injecting high velocity heated air onto the surface areas of the mixture to lower the moisture content of the coated cells;
(f) granulating the coated cells when the moisture content has been reduced to the range of about 25-30%, there-by separating single cells and agglomerates; performing steps (c), (d), (e) and (f) before any significant conditioning of said mixture can take place;
(g) entraining peel particles along with the separated single cells and agglomerates from the mixer-dryer in heated air;
(h) reducing the velocity of the air carrying entrained material to a point at which the larger of the entrained agglomerates above the size that will pass a 40 mesh screen fall from entrainment back into the mixer-dryer while the peel particles along with the single cells and the smaller of the entrained agglomerates remain entrained and are removed from the system;
(i) separating the solid matter from the entraining air;
(j) drying the solid matter to a moisture content of about 7-8%; and (k) separating the peel particles from the dried solid matter, thereby isolating the dried intact cells and small agglomerates.
(a) preparing potatoes by washing and trimming;
(b) cooking the prepared potatoes to completion;
(c) admixing a starch complexing emulsifier uniformly with said cooked potatoes at a temperature above the melting point of said emulsifier and in a concentration so that said emulsifier comprises about 1.0% of the total solid matter present, said emulsifier dispersed throughout said mixed cooked potatoes whereby it complexes the soluble amylose starch fraction of said cooked potatoes thereby reducing the cohesiveness of said potatoes, and thereby lub-ricating and coating the cells of said cooked potato with said emulsifier such that they are not ruptured during the subsequent steps (d)-(f);
(d) mixing said coated potato cells in a mixer-dryer using sufficient mixing action to expose continuously new large drying surface areas without rupturing the cells while simultaneously (e) injecting high velocity heated air onto the surface areas of the mixture to lower the moisture content of the coated cells;
(f) granulating the coated cells when the moisture content has been reduced to the range of about 25-30%, there-by separating single cells and agglomerates; performing steps (c), (d), (e) and (f) before any significant conditioning of said mixture can take place;
(g) entraining peel particles along with the separated single cells and agglomerates from the mixer-dryer in heated air;
(h) reducing the velocity of the air carrying entrained material to a point at which the larger of the entrained agglomerates above the size that will pass a 40 mesh screen fall from entrainment back into the mixer-dryer while the peel particles along with the single cells and the smaller of the entrained agglomerates remain entrained and are removed from the system;
(i) separating the solid matter from the entraining air;
(j) drying the solid matter to a moisture content of about 7-8%; and (k) separating the peel particles from the dried solid matter, thereby isolating the dried intact cells and small agglomerates.
26. A composition of matter comprising single intact cooked potato cells and agglomerates of separated but intact dehydrated cooked potato cells, said potato cells being coated with starch complexing emulsifier, said single potato cells and said agglomerates being readily rehydratable in hot water to form a mealy mashed potato and which are capable of absorbing about 4.85 parts by weight of cold water, said composition being prepared by the process of claim 1 or claim 25.
27. A stable antioxidant-free dehydrated granular potato product comprising essentially single intact cooked potato cells and small agglomerates of the cells with a particle size substantially finer than a standard 40 mesh and about 70%
by weight finer than standard 60 mesh, said potato cells being coated with starch complexing emulsifier, characterized by the ability to form a mealy mashed potato when reconstituted with about 5 parts by weight of hot water and further charac-terized by having a cold water absorption of about 4.85:1 and a sulfur dioxide content of less than about 80 ppm, said product being prepared by the process of claim 1 or claim 25.
by weight finer than standard 60 mesh, said potato cells being coated with starch complexing emulsifier, characterized by the ability to form a mealy mashed potato when reconstituted with about 5 parts by weight of hot water and further charac-terized by having a cold water absorption of about 4.85:1 and a sulfur dioxide content of less than about 80 ppm, said product being prepared by the process of claim 1 or claim 25.
28. A granular dehydrated instant mashed potato product with unaltered natural flavor consisting essentially of single intact cooked potato cells and small agglomerates thereof coated with starch complexing emulsifier and containing amylose in unretrograded soluble form and suitable for rapid reconstitution in hot or cold water to form a mealy mashed potato, said product being characterized by being reconstitutable to a non-pourable mix when rehydrated with about 4.85 parts by weight of cold water per 1 part of said product, said product being prepared by the process of claim 1.
29. The product as claimed in claim 28 in which the solubility of said amylose is preserved by having dried the product to completion in about 30 to 45 minutes, thereby pre-venting conversion of the amylose to its insoluble retrograded form.
30. The product as claimed in claim 28 in which the emulsifier is glyceryl monostearate and comprises 0.30-2.0 by weight of the cells.
31. The product as claimed in claim 28 in which the dehydrated product consists essentially of particles having a size which can pass through a standard 40 mesh screen and at least about 70% by weight can pass through a standard 60 mesh screen.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US34405273A | 1973-03-22 | 1973-03-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041365A true CA1041365A (en) | 1978-10-31 |
Family
ID=23348832
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA195,199A Expired CA1041365A (en) | 1973-03-22 | 1974-03-18 | Dehydrated granular potato product and process for production of same |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS49134865A (en) |
| BE (1) | BE812739A (en) |
| CA (1) | CA1041365A (en) |
| DE (1) | DE2413693A1 (en) |
| ES (1) | ES424484A1 (en) |
| FR (1) | FR2222028B1 (en) |
| GB (1) | GB1456749A (en) |
| NL (1) | NL7403887A (en) |
| ZA (1) | ZA741480B (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3031314A (en) * | 1960-03-16 | 1962-04-24 | Carl E Hendel | Preparation of dehydrated potatoes |
-
1974
- 1974-03-07 ZA ZA00741480A patent/ZA741480B/en unknown
- 1974-03-18 CA CA195,199A patent/CA1041365A/en not_active Expired
- 1974-03-21 GB GB1257174A patent/GB1456749A/en not_active Expired
- 1974-03-21 FR FR747409719A patent/FR2222028B1/fr not_active Expired
- 1974-03-21 DE DE2413693A patent/DE2413693A1/en active Pending
- 1974-03-21 ES ES424484A patent/ES424484A1/en not_active Expired
- 1974-03-22 JP JP3158074A patent/JPS49134865A/ja active Pending
- 1974-03-22 NL NL7403887A patent/NL7403887A/xx not_active Application Discontinuation
- 1974-03-22 BE BE142379A patent/BE812739A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS49134865A (en) | 1974-12-25 |
| NL7403887A (en) | 1974-09-24 |
| BE812739A (en) | 1974-07-15 |
| ZA741480B (en) | 1975-02-26 |
| DE2413693A1 (en) | 1974-10-17 |
| FR2222028B1 (en) | 1979-02-09 |
| AU6704174A (en) | 1975-09-25 |
| GB1456749A (en) | 1976-11-24 |
| FR2222028A1 (en) | 1974-10-18 |
| ES424484A1 (en) | 1976-06-01 |
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