CA2249167A1 - Microwave-expandable snack food product - Google Patents

Abstract

The present invention is directed to a method for producing a shelf-stable, flavored extruded product having a moisture content of not more than 18% by weight, whichhalf-product upon microwaving can be expanded into a flavored expanded snack food The process comprises forming a dough within an extruder by introducing and mixing flour not having more than 10% by weight total protein content, adding 1 to 7%
flavoring, adding 3 to 5% by weight oil, and adding sufficient water to form a dough having a total moisture content of 20 to 45% by weight; advancing and cooking the dough to gelatinize the starch contained in the flours, at a temperature between 100°C
to 120°C for approximately 30 to 60 seconds, cooling the cooked dough and extruding it through an appropriate shaped extruder die opening of an appropriate shape and cutting, without causing any expansion, thereby producing a cold extrudate of flavored cooked dough in an appropriate shape and size; and drying the extrudate to a moisture content of less than 18% to yield a shelf-stable flavored, half-product which can be formed into a puffed flavored snack product.

Description

Microwave-Expandable Snack Food Product Field of the Invention This invention relates to snack foods and more particularly to a snack food which is microwave expandable and a process for making such.

Back~round of the Invention Extrusion cooking is a known process for making a variety of food products which are preferably expanded. Within the realm of extrusion cooking there are different methods to produce an expanded, extruded product. In one method, puffed products are prepared by extruding a cooked dough at high moisture content, hightemperature and high pressure. As the product escapes from the die into atmospheric pressure, the sudden pressure reduction causes excess moisture to flash off and the product to puff. The product is then allowed to sufficiently dry. Alternatively, "half products" are cooked and extruded. Such "half products" require additional cooking of the extruded product in order to produce a puffed, edible product. Cooking the dough by rapid heating or depressurizing such as by deep frying or heating in a convection oven causes such "halfproducts'7 to puffout or expand. ~ltt~ tively, the dough can be "gun puffed" by rotating precut pieces in a sealed, heated drum under p1es7~u1~;. Upon a release of the pressure inside the drum, the precut dough pieces expand or puff up.
Another method by which "half products" can be expanded or puffed is by microwaving. Microwaving is a highly desirable cooking method because it is veryrapid. U.S. Patent 4,950,492 describes a method for making microwave puffed or expanded snack product in which no fats or oils are used. A flour-free dough is made, shaped into desired pieces and then steamed for several hours. Once sufficientlysteamed, the dough is then cooled by refrigeration and finally frozen. The resultant frozen product is then microwaved to puff the product. While this patent does describe a method for producing a microwavable snack food, the method requires several steps and therefore is very time consuming and also very costly from a production stand point. The half-product is not shelf stable at room temperature and requires refrigeration until microwaving.
U.S. Patent 4,990,348 describes a method for making a microwave-puffable snack food which is extruded as a hot melt from an extruder die. The hot extrudate may be then coated with flavorings such as sugar coating compositions before it is allowed to cool. The cooled product is then microwaved to produce a puffed snackfood product. The method of this patent does not however, produce a product which adequately and consistently puffs during microwaving and thus is not as highly desired as an instant type of snack food. Furthermore, flavoring is added to thesurface of the product resulting in a coated puffed snack food which makes handsgreasy, sticky and smelly as the coated flavoring rubs off onto the hands when eating.
There is therefore a need to develop an improved method for the production of a microwave-expanded snack food product which obviates the problems associated with the methods of the prior art and which also produces a better product with more desired characteristics and more consistent puffing qualities than microwave-puffed snack foods pre$ently known and available.

Summ~rv of the Invention In accordance with the present invention there is provided a novel method for the production of a microwave-expanded snack food product that is rapid and economical and which produces a product that consistently puffs up when microwaved. Furthermore, the method of the present invention consistently produces a flavored microwave snack food which after microwaving does not lose its flavor, nor does the flavoring rub off onto the hands when eaten.
According to an object of the present invention there is provided an improved method for producing a shelf-stable, flavored extruded product having a moisturecontent of not more than 18% by weight, which half-product upon microwaving can be expanded into a flavored expanded snack food, the process comprising: --(a) forming a dough within an extruder by introducing and mixing flour not having more than 10% by weight total protein content, adding 1 to 7% by weight flavoring or seasoning, adding 3 to 5% by weight oil, and adding sufficient water to form a dough having a total moisture content of 20 to 45% by weight;

(b) advancing and cooking the dough to gelatinize the starch contained in the flours, at a temperature between 100~C to 120~C for approximately 30 to 60 seconds;
(c) cooling the cooked dough and extruding it through an ~pl'upliate shaped extruder die opening of an applo~liate shape and cutting, without c~ ing any expansion, thereby producing a cold extrudate of flavored cooked dough in an ap~ iate shape and size; and (d) drying the extrudate to a moisture content of less than 18% to yield a shelf-stable flavored, half-product which can be forrned into a puffed flavored snack product.
According to another object of the present invention is a microwave puffed flavored snack product which has a flavoring encapsulated within the product.

Detailed Description of the Preferred Embodiments The present invention relates to snack foods which upon microwaving form a puffed, crisp, flavored product. The present invention also relates to an improved process for making such a product.
The flavored snack food is prepared by mixing and forming a dough comprising flour, edible oil and flavorings. Flour suitable for use in the present invention can be any variety of flours having a protein content of less than about 10%
by weight. More proteinaceous flours produce a product which does not sufficiently puffupon microwaving. Flours suitable for use include but are not restricted to wheat, corn, rice, tapioca, rye, potato, soy and other vegetable flours and Illi~lulc;s thereof.
Edible oil is added to the flour in an amount of about 3 to 5% by weight. Any vegetable or animal oil is suitable for use in the present invention. Alternatively, lecithin can be used as a substitute for the oil, however, in smaller quantities. The amount of lecithin should not exceed 1% by weight as it may create an off-flavor in the final microwaved product. Both the oil and the lecithin act as a binder and help hold the flavoring within the gel~tini7e~1 starch upon extrusion cooking.
Flavorings and other taste-imparting or improving compositions are added to the extruder in an amount of 1 to 7% by weight and incorporated into the dough and hence do not escape or are volatilized, since they will be "encapsulated" within the final puffed product. Since the flavors are "encapsulated" within the final unpuffed product (and not coated like in other processes), several different flavored products can be added into a final retail pack. On microwaving, the pack will yield different flavored puffed pieces, without creating any "mixed-up" flavors. Since the flavors are encapsulated within the product, they will not coat the hands when being eaten.
Flavourings suitable for use in the present invention include, but are not iimited to, sugar cont~ining compositions, salt, bacon or simulated bacon, sour cream and onion, barbecue, salt and vinegar, hickory smoked, ranch, jalapeno, dill pickle, ketchup and cheese. Several flavorings can also be incorporated into the dough at one time.
Other ingredients may also be added to the dough during the short extrusion cooking process. Such ingredients include, but are not restricted to preservatives andlor food colourings and leavening agents.
Water is added to the extruder in order to form a dough having a moisture content of about 20 to 40% by weight. The dough is then heated within the extruder barrel to a temperature of about 110~C to 120~C while the dough is being massaged in order to gelatinize the starch within the flours which helps to encapsulate the flavoring components. This results in the formation of a plastic type of dough. The residence time inside the extruder is only about 30 to 60 seconds. The cooked dough is extruded at a pressure of approximately 5 to 15 psi through a cooling end of theextruder into an appropriate shaped die opening, without causing any expansion, thereby producing a cold extrudate of flavored cooked dough in an ~propl;ate shape which is cut into a suitable size through the use of a rotary cutting knife attached at the die opening.
It is to be understood by those skilled in the art that any type of extruder, including single and double (twin) screw types, can be used in the method of thepresent invention. When using a twin screw extruder, it is not necessary to form a dough with 30 to 45% moisture. Instead a drier loose, crumbly dough mixture may be formed with a lower amount of total moisture (20 to 30%).
The drying process for the wet dough takes about 5 to 7 hours under a controlled temperature and humidity or up to 48 hours under normal room tempel~u.es and humidities. The extruded product is allowed to dry to a final moisture content of about 12 to 18% and preferably from about 11 to 13%. If the final moisture content exceeds 13%, antimicrobial agents may be required to be added to address the potential for microbial spoilage. This final half product with 1 1 to 13% is shelf stable with no subsequent loss in moisture content upon proper storage.
In order to puff the product, about SO to 1 OOg of the half product is placed, preferably in a packaging material suitable for microwaving (similar to ones currently used for Microwave Popcorn), and then microwaved for about 1 to 3 minutes depending on the type and style of microwave oven used. The time required for microwaving also depends on the quantity of product being puffed at one time. It is to be understood that any commercially available microwave is suitable to use to puff the flavored half product of the present invention. It is also understood by those skilled in the art that any type of expansion cooking can be used to puff the produce in addition to microwaving.
The resultant flavored puffed product is light and crispy. In addition, since the flavor is incorporated and encapsulated within the product, it does not rub offon the hands when being consumed. As a microwaved snack, the puffed product is suitablefor calorie-sensitive consumers.
The shape of the half product plays an important role in its microwaveability.
The best results were obtained using half products of continuous shape such as round balls 0.5" (11 mm) diameter sphere, or round wafers 1-1.5" (22-33 mm) diameter and 0.1" (2.2 mm) thick or an "onion ring" shape. Square, rectangular or cube shapedproducts may also be extruded, although the corners generally do not microwave as well.
The product can also be puffed up (expanded) when subjected to deep fat frying.
The method of the present invention can be used to produce a packaged line of microwave snack foods of various flavors in separate individual packages or a combination of different flavored products within the same package, which can bedistributed to retail stores. The packages can be sold as individual packages or in multiples suitably packaged as multipacks. Alternatively, the products can be packaged and sold already expanded.

In summary, the present invention provides a method which, is both rapid and economical and produces a microwavable flavored half product. Once microwaved, the product puffs to form a crispy snack food that is both, light textured and with an encapsulated flavor such that the flavoring does not rub off on to the hands when eaten.
The following examples are provided for a better understanding of the present invention and are not intended to limit the invention.

Example 1 A 4,000 g dry mix containing the following:
Potato flour 1,520g Rice flour 1,400g Wheat flour (all purpose) 960g *Seasoning mix 120g was used to prepare a uniform, non-sticky dough, by mixing and adding gradually

2,200g of cold water in a Hobart mixer, at medium speed.
The dough was then processed through a pilot plant, single screw extruder 2"
(44mm) diameter screw equipped with four equal zones each connected to either steam or cold water. The cooker extruder was operated to mix the material further under low shear and subject the mix to a higher temperature (110~C) in Zone 1 - the first zone from the input end of the barrel of the extruder barrel, and cool towards Zones 3 and 4 - the output end of the barrel. For the best results, the product was cooked to 110~C (using steam) in Zone 1 and cooled to 60~C or less (using cold water) in Zone 4; Zones 2 and 3 were neither heated or cooled. The cooked dough emerging from 0.5" (1 lmm) round die at the output end of the extruder was cut into 0.5" (1 lmm) length (almost round, ball-shaped pieces) by a rotary knife. The half product extrudate had the appearance of a semi-translucent, dense unexpanded 1/2'' (1 lmm) diameter balls.
After being discharged from the extruder, the formed pieces were slowly dried at 50 to 55~C (relative humidity 40 to 50%) for about 7 hours or until the moisture content of 12-13% range was reached.

When 50g sample of the dry half product was placed in an empty 'popcorn"
bag and microwaved (770 W, Panasonic Genius Oven) for 2 minute~, the product puffed up to about 4 times its original volume, with a typical snack-like, puffy light and yet crispy texture with a pleasant sourcream and onion flavor. The product was neither sticky or oily to touch and did not leave any residue or flavoring onto the hands when eaten.
*Sourcream and onion seasoning mix comprising of salt, monosodium glut~m~te, sugar, salt, citric acid, sourcream powder, black pepper garlic and onion powders.

Example 2 A 4,000 g dry mix cont~ining the following Potato flour 1,500g Rice flour 1,300g Corn starch (redried) 920g **Seasoning mix 280g was used to prepare a uniform, non-sticky dough, using 2,400 g of cold water andextruded and further dried as described in Example 1. The normal operating temperature in Zone 1 was m~int~ined at 100~C (using steam) and Zone 4 was cooled by cold water; Zones 2 and 3 again, were neither heated or cooled.
**Ranch seasoning mix #NP49440R24 ~ 7% from Flavorite Laboratories Inc.

Example 3 The procedure of Example 1 was repeated by using 4,000 g dry mix con~ining the following Rice flour 3,000g Wheat flour (all purpose) 600g Soy flour 320g ***Seasoning mix 80g was used to prepare a uniform, non-sticky dough, using 2,350g of cold water and extruded and further dried as described in Example 1. The normal operating temperature in Zone 1 was m:~int:lined at 110~C (using steam) however Zones 2, 3 and 4 were neither heated or cooled.

***Hickory barbecue seasoning mix #NP54989Rl (~ 2% from Flavorite Laboratories Inc.

Example 4 Experimental details are as follows:
6920 - Recipe Reference Number Customer recipe Ref: 4 Dry mix for snack Kilo~rams Pounds Percent In~redient Supplier FurnishedBy 35.23 77.65 38.70 Potato Starch Avebe W
32.42 71.44 35.69 Rice Flour Rivland W
22.25 40.03 24.49 SoftWheatFlour SoftAs Silk W
0.94 2.06 1.03 Salt Totals: 90.84 200.18 100.00 6919 - Recipe Reference Number Customer Recipe Ref: 3 SlurrY for Snack Kilo~rams Pounds Percent In~redient Supplier FurnishedBy 1.14 2.50 25.00 Barbecue Flavour C

3.41 7.50 75.00 Vegetable Oil W
Totals: 4.55 10.00 100.00 Comments:
In the above recipe, the total starch level is m~int~ined above 80% and hence the final microwaved product gives lighter and softer textures.
Vegetable oil is included in the recipe as a processing aid to reduce stickiness, control expansion and to impart a more uniform cellular structure in the final product.

Extruder Model:TX57 from Wenger Manufacturing Run Number 980625.104 980625.105 980625.106 Process details Dry Recipe Moisture %wb DryRecipe Density kg/m3 804 604 604 Dry Recipe Rate kg/hr 148 158 155 Feed Screw Speed rpm 21 18 21 PRECONDITIONING INFORMATION:
Preconditioner Speed rpm 300 300 300 Steam Flow to Preconditioner kg/hr 17 15 15 Water Flow to Preconditioner kg~r 17 15 15 Preconditioner Discharge Temp. ~ C 81 81 81 Moisture Entering Extruder % wb E~TRUSION ~FORMATION:
Extruder Shaft Speed rpm 199 199 200 Extruder Motor Load % 67 65 65 Steam Flow to Extruder kg/hr 4 4 5 Water Flow to Extruder kg/hr ExtruderAdditiveRate kg/hr 6 6 6 Control/Temperature lstHead ~C 60/65 60/65 60/65 Control/Temperature 2nd Head ~ C 100/101 100/100 100/101 Control/Temperature 3rd Head ~ C 100/102 100/103 100/102 ControVTemperature 4th Head ~ C 80/79 80/81 80/81 Control/Temperature 5~ Head ~ C 70/70 70/71 70/71 Control/Temperature 6~ Head ~ C
Control/Temperature 7th Head Control/Temperature 8th Head Control/Temperature 9~ Head HeadlPressure kPa5/62705/5880 5/6050 Knife Drive Speed rpm1128 591 303 FINAL PRODUCT INFORMATION:
Extruder Discharge Moisture % wb Extruder Discharge Rate kg/hr Extruder Discharge Density kg/m3 Dryer Discharge Density kg/m3 Extruder Performance Stable Stable Stable Duration of Run min Final Product Description Round Customer Recipe Number 4 4 4 Run Rating Good Good Good REFERENCE NI~MBERS: s Main Recipe 6920 6920 6920 Precond. Additive 1 Recipe Extruder Additive 1 Recipe 6919 6919 6919 Preconditioner Configuration 109 109 109 Extruder Configuration 818 818 818 Die and Knife Configuration 3862 3862 3862 Product Analysis (shown below)9456 9457 9458 Three samples with different widths were prepared:
980625-104: Thin cut DS/600psi 980625-105: Same product with thicker cut: DS/510 psi 980625-106: Thickerproduct, same conditions: DS/500 psi CO = Cooling Oil CW = Cooling Water S - Steam N = No Thermal Fluid HO = Hot Oil HW = Hot WaterPSIG = Pressure Product Analysis:
Number 9456 9457 9458 PRODUCT MOISTURES
Dryer discharge %wb 12.09 12.61 13.02 Comments:
Properly dried snack pellets expand better following a stabilization period of approximately one or two days during which time the moisture migrates from the interior of the product and eventually an equilibrium within the final product.

Example 5 Consideration must be given in the selection of cereal grains, starches, proteins and other minor ingredients when this snack food is designed. For example, a potato snack will puff at a lower temperature or cook in a shorter time in the microwave oven than a rice or wheat snack of the same thickness and shape. After puffing, different ingredients have a different finished color. Rice is whitish, corn-yellow and potato is golden brown.
In the following example, a higher level of potato flour is used giving a final product that is softer in texture with a delicate potato flavor.

6955 - Recipe Reference Number Customer Recipe Ref: 2 Drv mix for snack Kilo~rams Pounds Percent In~redient Supplier FurnishedBY
113.50 250.15 67.08 Potato Granules Idaho Pacific W
52.51 115.07 30.86 Soft Wheat Flour Soft As Silk W
3.50 7.70 2.06 Salt Totals: 169.21 372.92 100.00 6957 - Recipe Reference Number Customer Recipe Ref: 4 Slurry for snack Kilo~rams Pounds Percent In~redient Supplier Furnished By 3.63 8.00 40.00 B.B.Q. flavor TFF C
5.45 12.01 60.00 Vegetable Oil W
Totals: 9.08 20.01 100.00 Extruder Model:TX57from Wenger Manufacturing Rurl Number 980727.104980727.105 DRY RECIPE INFORMATION:
Dry Recipe Moisture %wb 8.81 DryRecipe Density kg/m3 762 762 Dry Recipe Rate kglhr 150 150 Feed Screw Speed rpm 35 36 -PRECONDITIONING INFORMATION:
Preconditioner Speed rpm 300 300 Steam Flow to Preconditioner kg/hr 17 17 Water Flow to Preconditioner kg/hr 17 17 Preconditioner Discharge Temp. ~ C 80 79 Moisture Entering Extruder % wb 24.02 24.71 EXTRUSION INFORMATION:
Extruder Shaft Speed rpm 199 199 Extruder Motor Load % 47 46 Steam Flow to Extruder kglhr WaterFlowto Extruder kg/hr 5 5 Extruder Additive Rate kg/hr 5.5 5.5 Control/Temperature lstHead ~C 60/65 60/65 Control/Temperature 2nd Head ~ C 100/100 100/100 Control/Temperature 3rd Head ~ C 100/105 100/103 Control/Temperature 4tll Head ~ C 50/57 50/59 Control/Temperature 5th Head ~ C 50/50 50/50 Control/Temperature 6th Head ~ C
Control/Temperature 7th Head Control/Temperature 8~ Head Control/Temperature gth Head Head/Pressure kPa Knife Drive Speed rpm FINAL PRODUCT INFORMATION:
Extruder Discharge Moisture % wb 22.98 20.83 Extruder Discharge Rate kglhr Extruder Discharge Density kg/m3 Dryer Discharge Density kg/m3 Extruder Performance Stable Stable Duration of Run min 15 15 Final Product Description Round CustomerRecipe Number 2 3 Run Rating Good Good REFERENCE NUMBERS:
MainRecipe (as shown above) 6955 6956 Precond. Additive 1 Recipe ExtruderAdditive 1 Recipe (above) 6957 6967 Preconditioner Configuration 108 108 Extruder Configuration 818 818 Die and Knife Configuration 3903 3903 Dryer Formula 9457 9458 Product Analysis 9550 9551 980727-104: Tried to run with the same conditions as previous runs from 980626-104.
Had problems with product being top hot and bubbling off extruder. Lowered head temps on Zones 4 and 5 and took all steam out of extruder barrel and added 4% water to barrel. Made good product aQer.
980727-105: Preconditioner water temp ambient > Extruder water temp ambient >
Knife drive speed 676.

CO = Cooling Oil CW = Cooling Water S - Steam N = No Thermal Fluid HO = Hot Oil HW = Hot Water PSIG = Pressure Product Analysis:
Number 9550 9551 PRODUCT MOISTURES
Dry recipe %wb 8.61 Preconditioner discharge %wb 24.02 24.71 Extruder Discharge %wb 22.9820.83 Dryer Discharge %wb 12.2011.80 In summary, the present invention provides a method which is both rapid and economical and produces a microwavable flavored half product. Once microwaved, the product puffs to form a tasty crispy snack food with both a light and flavored texture.
Although preferred embodiments have been described herein in detail, it is understood by those skilled in the art that variations may be made thereto without departing from the scope of the invention.

Claims (19)

CLAIMS:

1. A method for producing a shelf-stable, flavored extruded product having a moisture content of not more than 18% by weight, which half-product upon microwaving can be expanded into a flavored expanded snack food, the process comprising:
(a) forming a dough within an extruder by introducing and mixing flour not having more than 10% by weight total protein content, adding 1 to 7% flavoring, adding 3 to 5% by weight oil, and adding sufficient water to form a dough having a total moisture content of 20 to 45% by weight;
(b) advancing and cooking the dough to gelatinize the starch contained in the flours, at a temperature between 100°C to 120°C for approximately 30 to 60 seconds;
(c) cooling the cooked dough and extruding it through an appropriate shaped extruder die opening of an appropriate shape and cutting, without causing any expansion, thereby producing a cold extrudate of flavored cooked dough in an appropriate shape and size; and (d) drying the extrudate to a moisture content of less than 18% to yield a shelf-stable flavored, half-product which can be formed into a puffed flavored snack product.

2. The method of claim 1, wherein said total moisture content is 30 to 45% by weight.

3. The method of claim 1, wherein said total moisture content is 20-30% by weight.

4. The method of claim 1, wherein said cooked dough is extruded at a pressure ofapproximately 5 to 15 psi through a cooling end of the extruder.

5. The method of claim 1, wherein said extrudate is dried to a moisture content of about 11 to 13%.

6. The method of claim 1, wherein said flour is selected from the group consisting of wheat, corn, rice, tapioca, rye, potato, soy and mixtures thereof.

7. The method of claim 1, wherein said oil is selected from the group consistingof vegetable and animal oil.

8. The method of claim 1, wherein said flavoring is selected from the group consisting of sugar compositions, salt, bacon or simulated bacon, sour cream andonion, barbecue, salt and vinegar, hickory smoked, ranch, jalapeno, dill pickle,ketchup, cheese and mixtures thereof.

9. The method of claim 1, wherein said dough may additionally comprise preservatives, food colourings, leavening agents and mixtures thereof.

10. The method of claim 1, wherein said extrudate is dried for a period of about 5 to 7 hours.

11. The method of claim 1, wherein said oil is substituted with lecithin which does not exceed 1% by weight.

12. The method of claim 1, wherein antimicrobial agents are added to said dough when said extrudate has a moisture content of about 13% to 18%.

13. The method of claim 1, wherein said half-product is formed into a puffed flavored snack product by microwaving, deep-frying or dry expansion cooking.

14. The method of claim 1, wherein said flavoring is encapsulated within said dough.

15. A puffed, flavor-encapsulated snack food made by the process of claim 1.

16. A shelf-stable, flavoured extruded food product which upon microwaving is expanded into a flavored expanded snack food wherein the flavoring is encapsulated within said snack food, said food product comprising a dough not having more than 10% by weight total protein content and a total moisture content of 30% to 45% by weight, said dough additionally comprising 1% to 7% by weight flavoring and 3% to 5% by weight oil, wherein said dough is cooked, extruded and dried to a moisturecontent of less than 18%.

17. The food product of claim 16, wherein said product is packaged as individualmicrowavable portions.

18. The food product of claim 16, wherein said individual microwavable portions are packaged as multipacks.

19. The food product of claim 16, wherein said product is microwaved to form a puffed snack food.