GB1575089A - Process for the treatment of whey and whey permeate and products resulting therefrom - Google Patents

Description

(54) PROCESS FOR THE TREATMENT OF WHEY AND WHEY PERMEATE AND PRODUCTS RESULTING THEREFROM (71) We, PATENT TECHNOLOGY, INC., a corporation organised and existing under the laws of the State of California, United States of America, of One Post Street, San Francisco, State of California 94104, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a process for the treatment of whey and to the products obtained thereby.

Processes are presently in commercial use which treat whey for the separation and production of various useful products, including whey protein products and lactose. One such process makes use of membrane ultrafiltration which serves to separate the whey into two fractions, one being a protein-rich fraction, and the other being a permeate rich in lactose. Such a process is disclosed in Canadian Patent 966,361 dated April 22, 1975. The composition of a typical whey permeate obtained by application of membrane ultrafiltration depends upon a number of factors, including the character and source of the whey, and the manner in which the membrane ultrafiltration is carried out. The principal constituents include lactose, mineral salts, protein, non-protein nitrogen (NPN), and a small amount of fat. The mineral salts include both the natural buffer salts of milk, and also mineral salts resulting from the cheese making process from which the whey is derived. A general composition range (dry solids basis) for permeate derived from acid and sweet wheys is as follows: o Lactose 68.0 to 87.0 Protein 3.0 to 5.5 NPN 0.4 to 0.8 Fat 0.1 to 0.2 Ash 8.5 to 14.0 Titratable acidity 2.0 to 14.0 The high level of mineral salts tends to impart undesirable flavor characteristics.

When processed for the removal of lactose by crystallization, which involves concentration of the permeate, certain of the salts precipitate out, together with crystallization of the lactose, and this tends to reduce the lactose yield and decrease its purity. While the permeates include substances of value, their disposal without processing poses a serious problem since it is an ecological pollutant.

Commercial processes for the manufacture of lactose generally remove lactose from whey concentrate by crystallization (see U.S. Patent 2,439,612 dated April 13, 1948). Such lactose is relatively impure, since it contains some whey protein and mineral salts. Resolution and recrystallization is employed to obtain products of higher purity. The remaining mother liquor is not suitable for human consumption and cannot be discarded to waste because of adverse ecological effects.

This invention relates generally to the treatment of cheese whey to produce various usable products, and more particularly to processes making use of membrane ultrafiltration and to the treatment of the resulting whey permeate.

An object of the invention is to provide a process capable of converting whey permeate into one or more prdducts of marketable value without undue expense.

Another object is to provide a process for the treatment of whey permeate which will produce a high yield of relatively pure lactose.

Another object is to provide a process which yields one or more mineral salt products of marketable value.

Another object is to provide a permeate treatment process which facilitates elimination of disposable materials which are objectionable as ecological pollutants.

According to the present invention there is provided a process for the treatment of whey, comprising the steps of subjecting the whey to membrane ultrafiltration to form a protein rich fraction and a permeate, the permeate having a lactose content of from 68 to 870/n (dry solids basis), a protein content of not more than 6 /^ of the total solids content and a mineral salt content, precipitating a portion of the mineral salt content of the permeate, removing the precipitate from the permeate, concentrating the permeate and removing a portion of the lactose content by crystallization. The permeate, after ultrafiltration and before concentration, may have a protein content of from 3.0 to 5.5 of the total solids content.

The present invention also provides a process for the treatment of whey comprising subjecting the whey to membrane ultrafiltration to produce a protein rich fraction and a lactose permeate, adding an alkali to the permeate to adjust its pH to 7 to 10, heating the permeate to a temperature level of from 180 to 200"F and holding the same at such temperature for a period from 1 to 2 hours, removing precipitated material from the heat treated permeate, cooling the material to 90 to 1100 F, acidifying the material to adjust the pH to 4 to 5, concentrating the material and then spray drying the material to produce a product having flavor properties comparable to soy sauce.

Additional objects and features of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings in which: Figure 1 is a flow diagram illustrating one embodiment of the process.

Figure 2 is a flow diagram illustrating another embodiment of the process making use of alkaline precipitation.

Figure 3 is a flow diagram illustrating another embodiment in which lactose is purified in two stages.

Figure 4 is a flow diagram illustrating another embodiment.

Figure 5 is a flow diagram illustrating a procedure for manufacturing a flavoring material like soy sauce.

In Figure 1 it is assumed that the whey being treated is an edible grade acid cheese whey, although the process is deemed applicable to other types of wheys, such as Cheddar cheese whey. Preliminary to its processing, the whey may be treated in any one of various ways, as for example by pasteurization or chemical treatment to control bacterial contamination. The whey is shown being subjected to membrane ultrafiltration in step 10, thereby producing a protein-rich fraction and a whey permeate. Ultrafiltration may be carried out in a single stage, or in more than one stage, depending upon the protein level desired for the protein fraction. In any event ultrafiltration is carried out in such a manner that the residual protein in the permeate does not amount to more than 6.0 /n of the total solids content. The permeate is shown being subjected to a precipitating step 11 which serves to selectively precipitate certain of the mineral salts. More specifically, in this instance precipitation is carried out by heating the permeate, which as it is obtained from step 10 has a solids content of 5.0 to 7.5%, to a temperature level of from 180 to 200"F, and concentrating the permeate by evaporation to a solids content of 40 to 45%. The sequence of these steps can be altered by first concentrating the ~ permeate by vacuum evaporation and then heating and holding for promoting precipitation. For example, the material may be held at the indicated temperature level and concentration for a period of 30 to 90 minutes. As a result of this treatment, certain of the mineral salts are selectively precipitated, including particularly the natural buffer salts of the whey. More particularly, the calcium and citrate salts of the buffering system are precipitated, whereas the phosphate salts of the buffering system do not tend to be precipitated by this treatment. Likewise, this treatment does not precipitate the simpler monovalent salts such as sodium chloride.

By application of the treatment described above, from 5.0 to 15.0% of the total mineral salts of the permeate are precipitated. The precipitate is removed in step 12 and the remaining permeate is clarified and treated for the removal of lactose. Step 12 preferably is carried out while the permeate is at an elevated temperature of 180 to 200"F. The filter medium may be iron free or reduced diatomaceous earth (e.g., acid washed Celite), which serves to remove precipitate and to clarify the material. In step 13 the lactose is crystallized from the mother liquor, collected, and subsequently subjected to washing in step 14. The crystallizing step 13 can be carried out with the permeate at a sufficient concentration for effective crystallization, as for example, a concentration of 50 to 60% total solids.

Concentration to higher levels which cause further precipitation of mineral salts should be avoided. Thus concentration of the permeate following the filtering step 12 is carried out within the range of total solids previously mentioned without further precipitation of salts, and serves to provide an effective yield of lactose in the crystallizing operation. The lactose crystals from washing step 14 may be subjected to drying by conventional methods to produce the lactose product A.

Water of proper purity may be used for washing in step 14, although we prefer to use acidified water. For example, the wash water may contain a small amount of hydrochloric or other acid, whereby the wash is slightly acid at a pH of from 2.5 to 3.5. It has been found that this serves to more effectively remove protein and other impurities from the collected lactose crystals.

The process as described above produces lactose of a purity of 99.1 /n or better. The lactose yield may be of 35 to 55%. The mother liquor from step 13, with or without being blended with wash water from step 14, may be subjected to further treatment to increase the yield of lactose and to provide another lactose product of high purity.

Thus the liquor from step 13 is shown being subjected to a further precipitating step 15 which in this instance is preferably carried out by adjusting the pH to a value of 7 to 10, by adding an alkali neutralizing agent such as sodium or potassium hydroxide.

Following or at the time the neutralizing agent is added, the material is heated to a temperature of 140 to 1500F, whereby a substantial percentage of the mineral salts present, which are not precipitated and removed in steps 11 and 12, are precipitated. The solids concentration at the time of this treatment may be 20 to 30%.

The salts precipitated in this manner are mainly salts other than the natural buffering salts. However, the phosphate buffer salts are precipitated and also a substantial amount of non-protein nitrogen. Following step 15 the material is treated for the removal of the precipitate as by the step 16 carried out like step 12 of Figure 1. Both steps 12 and 16 may also be carried out by centrifuging to remove the precipitate followed by decolorizing by passing the material through a decolorizing carbon filter while at a temperature of 180 to 2000F.

Lactose is then removed by crystallizing and collecting in step 17, with or without further washing, to produce the lactose product B Here again it may be necessary to further concentrate the material (e.g., 48 to 65 /n solids) following the filtering step 16 and before crystallizing in step 17, taking care to avoid concentrating to a solids level sufficient to cause further precipitation of residual mineral salts.

Assuming that the process includes the second stage of lactose crystallization and removal, the overall yield of lactose for the process may be 80 or higher. Also the product B may have a purity of 97% or higher.

In some instances it may be desirable to spray dry the filtered permeate from step 12.

Thus, the permeate may be concentrated and spray dried in step 21 to produce the spray dried lactose product C. Because of the removal of whey protein and a substantial amount of buffer salts in the precipitating step 11, the flavor of the spray dried product is superior to that of untreated spray dried whey permeate, and therefore product C can be used in formulating various food and feed products.

The buffer salts removed in the filtering step 12 may be subjected to drying 22 to produce the dry product D. This is a high calcium and mineral salt content product which has value as an additive to various formulations including animal feeds. An analysis of a typical product D is as follows: Water 5.805% Total nitrogen 0.23% Ash 31.09 Calcium 14.3% Phosphorous 0.43% Magnesium 0.07% Sodium 0.25 /n Potassium 0.8% Citrate 43.4% Lactose 25.5 /n Titratable acidity 2.0% pH 5.3 According to the process of Figure 2, the whey is subjected to ultrafiltration 31 as in Figure 1, and the permeate is then subjected in step 32 to precipitation at an adjusted pH of 7 to 10. This step is carried out like step 15 of Figure 1 by introducing a suitable neutralizing alkali such as sodium hydroxide. After or at the time the pH is adjusted, the material is heated to a temperature level of from 180 to 2000F and held at this temperature level for a time sufficient to substantially complete precipitation, as for example from 30 to 90 minutes. The precipitate is then removed in the clarifying or filtering step 33, which preferably is carried out as described for step 16 of Figure 1 with the material at an elevated temperature of 180 to 2000F. For the purpose of producing products of varying purity, some of the material after filtering in step 33 is shown being concentrated in step 34 to a solids content of from 20 to 30 /n and then being subjected to a demineralizing step 35; which can be carried out by any one of several known methods, including contact with ion exchange resins, or preferably by electrodialysis. By such treatment a desired amount (e.g., 10 to 90%) of the residual mineral is removed. The demineralized permeate is shown being further concentrated in step 36, after which it is shown being spray dried in step 37 to produce the spray dried product E. This product may have a lactose content of 90 to 98%, and the lactose yield for the process may be from 70 to 85%. Electrodialysis is effective for the removal of from 10 to 90% of the mineral salt content. Ion exchange resins are effective to remove up to 98 /n of the salt content.

Instead of directly spray drying the material from the demineralizing step 35, some of the concentrated and demineralized permeate is shown being subjected to the crystallizing and collecting step 38, with the collected lactose crystals being subjected to washing in step 39, followed by drying 40 to produce the lactose product F. This product may have a purity of 99%. As disclosed in connection with Figure 1, the wash employed in step 39 may be slightly acidified water at a pH of from 2.5 to 3.5.

Some clarified permeate from step 33 of Figure 2 is shown being concentrated in step 41 and subjected to spray drying 42 to produce the product G. Also a concentrate of the clarified permeate is shown being subjected to a lactose crystallizing and collecting step 43, with the collected crystals being subjected to washing in step 44, and drying 45 to produce the purified lactose product H. This product has a purity similar to product A of Figure 1, and this procedure provides a lactose yield of from 50 to 60%.

The process of Figure 3 employs a precipitating step together with lactose removal by crystallization and refining.

Thus in this instance whey is subjected to membrane ultrafiltration 51 to remove a whey protein fraction, and the resulting permeate is subjected to the precipitating step 52 which is carried out by heating and concentrating in the manner described in connection with step 11 of Figure 1. After step 52 the material is subjected to step 53 which can be carried out by filtering and clarifying the material while it is at an elevated temperature of 180 to 2000F to remove precipitate and to clarify the permeate. The clarified permeate is then concentated in step 54 to a solids content of 50 to 60% and subjected to the lactose crystallizing step 55. The lactose crystals collected in step 56 are subjected to washing, which can be carried out by acidified wash water at a pH of from 2.5 to 3.5. The lactose from step 56 may be dried in step 57 to produce the dry lactose.

product I. The mother liquor from step 56 is shown being subjected to pH adjustment and precipitating in step 58 which can be carried out in the same manner as step 32 of Figure 2. After filtering and clarifying in step 59 the material is shown being concentrated at 60 (e.g., to 50 to 60% solids), subjected to crystallizing 61, and the crystals collected and washed in step 62, preferably with acidified wash water.

Drying 63 provides the lactose product J.

Precipitate from step 53 is shown being dried at 64 to provide the mineral salt product K. Likewise precipitate from step 59 is shown being dried at 66 to produce the mineral salt product L. Concentrated liquor from step 60 is shown being directly dried at 67 to produce the lactose product M.

The process described in connection with Figure 3 produces lactose products of high purity, and in addition, lactose yields can be obtained of 70% or higher. Lactose products I and J may have purities of about 99% and 97% respectively.

Some of the concentrate from 54 can be spray dried at 68 to produce the dry lactose product N which is relatively impure compared to lactose products produced by further processing according to the present invention.

In the various embodiments of the invention described above, removal of whey protein and precipitation and removal of precipitated salts is carried out before removal of lactose by concentration and crystallization. To effect crystallization of a substantial amount of the lactose present (e.g., 40 to 60%) the permeate should be concentrated by evaporation to solids contents of 48 to 65%. Since evaporation to such concentrations requires some heat treatment, some of the mineral salts, if not previously removed, precipitate and are removed with the collected lactose crystals, thus reducing the purity of the lactose product. By previous removal of a substantial amount of the mineral salts (e.g., 10% or more) such contamination of the recovered lactose is avoided. In addition, when precipitation of mineral salts is carried out in the manners and under the conditions described, lactose remains in solution and therefore no appreciable amount of lactose is removed with the precipitated salts.

The process shown in Figure 4 employs both precipitation of mineral salts and electrodialysis. The permeate from ultrafiltration step 71 is subjected to preciptation step 72 carried out by heating and concentation as for step 11 of Figure 1.

This serves to precipitate particularly the calcium and citrate salts of the buffering system. The partially demineralized permeate is then treated in step 73 for removal of the precipitate and clarification, as described for step 12 of Figure 1. Further mineral salts are removed to the extent desired in the electroldialyzing step 74.

Before electrodialyzing, the pH and concentration may be adjusted for optimum operation (e.g., to pH 3.9 to 4.2 and 30% solids). Thereafter some of the material may be further concentrated at 75 and spray dried at 76 to produce the dry lactose product 0. According to the present invention a purer lactose product is obtained by concentrating 77, crystallizing and collecting lactose crystals 78, washing of the crystals 79 and drying 80 to produce the lactose product P. It should be noted that electrodialysis operates more effectively on monovalent salts, which are not removed by the precipitating steps 72 and 73.

All of the above procedures first remove the whey protein and then a substantial portion of the mineral salt content, leaving a material consisting mainly of lactose. This is exemplified in its simplest form by steps 10, 11 and 12 of Figure 1, which remove whey protein and reduce the ash content, leaving a material comprising mainly lactose which can be concentrated and spray dried.

Precipitation in such a simplified process can be carried out either by step 11 or step 32 of Figure 2.

Figure 5 illustrates a treatment process which produces a product having the flavor characteristics of soy sauce. Here the permeate produced by ultrafiltration 81 of whey is neutralized at 82 by the addition of an alkali to pH 7 to 10.5. It is then subjected to heat treatment 83 at an elevated temperature of the order of from 180 to 200"F for an extended period of time of the order of 2 to 3 hours or more. During this time certain changes in composition take place due to the alkali treatment at the elevated temperature, and a substantial amount of the mineral salts is precipitated.

The heat treated permeate is then subjected to filtering 84 carried out at an elevated temperature of the order of 180"F, after which it is cooled in step 85 as by flashing in a partial vacuum. The cooled material, which may be at a temperature level of from 90 to 1100F, is then re-acidifed at 86 as by the addition of any edible acids, such as hydrochloric, to a pH level of 4.0 to 5.0 pH.

Thereafter it is concentrated in step 87 and spray dried at 88 to produce the dry product Q. This material has unique flavor characteristics, and when slurried with water it is suitable for use in place of soy sauce. The composition of the dry product in a typical instance is as follows: 0 n Moisture 3.2 Protein 4.08 Non-protein nitrogen 0.66 Ash 20.45 Titratable acidity 2.44 Lactose 66.64 The precise reasons for the flavor characteristics cannot be adequately explained, but are presumably due to the alkali treatment at an elevated temperature which causes certain complex changes to take place.

Examples of the process are as follows: EXAMPLE 1 The procedure was generally as shown in Figure 1. The source whey was an acid whey produced by the manufacture of cottage cheese. The whey was subjected to membrane ultrafiltration, making use of equipment manufactured by Westinghouse Company. The resulting permeate had a total solids content of 6.6% and analyzed as follows (dry solids basis) O/o Protein 6.3 Ash 11.1 Titratable acidity 10.0 Lactose 70.0 With respect to the ash content, 13.34% of the ash comprised calcium. The permeate was first passed through a filter of activated carbon while at a temperature of 120 to 1300F, to decolorize the material and to remove a part of the protein.

Thereafter the permeate was heated to 180 to 2000F, and concentrated to 40 /n solids.

This treatment caused a floc to be precipitated. The material was then filtered making use of acid-washed diatomaceous earth filter medium (Celite). At the time of filtering the material was at a temperature of 180"F, which served to maintain the lactose in solution. The filtrate was then further concentrated to 48 /n solids, and cooled to effect crystallization of lactose.

The resulting crystals were collected and subjected to washing in a basket centrifuge.

The resulting lactose crystals were dried to produce the lactose product A of Figure 1.

The filtrate from step 12 of Figure 1 had a total solids content of 46.46% which analyzed as follows: O/o Nitrogen 0.37 Ash 5.15 Lactose 33.95 Titratable acidity 0.35 The reduced acidity was due to the removal of buffer salts.

The purity of the lactose crystals collected in step 13, without washing, was 98.30/,. After washing with acidified water, the purity was 99.30/,.

Some of the filtrate from step 12 was subjected to spray drying to produce a product C. Also it was confirmed that the precipitate from step 12 could be dried to produce a mineral salt product D suitable for use as an animal feed supplement.

Mother liquor from the crystallizing step 13 of Figure 1 and wash effluent from the washing step 14 were merged, concentrated to 20.5% solids, and sodium hydroxide added to adjust the pH to the level of 9. This resulted in some further precipitation after which the material was filtered in step 16, the filtrate acidified to pH 4.5 and after further concentration to 68% solids, was cooled to produce crystallization of lactose in step 17. The collected lactose crystals were washed to produce product B, which was lactose having a purity of 89%.

It was confirmed by analysis that the treatment in step 11 served to precipitate the calcium and citrate buffer salts and that the product D was a mineral product comprising mainly the calcium and citrate buffering compounds. Also it was confirmed that additional mineral salts were removed in step 15, including the buffer phosphates.

The foregoing example was repeated using sweet whey as a source material. This gave a product B having a purity of 97%.

Example 2 The permeate employed was one resulting from the membrane ultrafiltration of acid cottage cheese whey. It had a total solids content of 6.3% and analyzed (dry solids basis) as follows: n Protein 6.3 Ash 11.07 Titratable acidity 10.0 Lactose 70.7 Following generally the procedure of Figure 3, the permeate was heated to 1800F, and evaporated to 20% total solids. While being maintained at 1800 F, sodium hydroxide was added sufficient to adjust the pH to 9. After holding at 1800 F, for a period of about 60 minutes, precipitated solids were removed in step 33 by passing through an acid washed diatomaceous earth filter medium (Celite). Likewise while at about 1800 F the material was passed through an activated carbon filtering medium for decolorizing. The filtrate was then concentrated to 68% solids, and lactose crystals removed as indicated in step 43 of Figure 2. The lactose crystals were collected and subjected to washing and drying to produce the product H. This product had a purity of 99.8. It was found that the same procedure, but without using a carbon filter, provided a product H having a purity of 98%. Some of the filtrate was concentrated and spray dried as indicated by steps 41 and 42 of Figure 2 to produce product G. This product was estimated to contain 85 /n lactose, the remainder being mainly mineral salt.

To produce a spray dried product having a higher level of lactose and reduced mineral salt content, a portion of the effluent from step 33 was concentrated to about 25% solids and subjected to demineralization by electrodialysis to remove about 90% of the mineral salt content. The resulting partially demineralized material was concentrated to about 50 /n solids, and then spray dried, as indicated by step 36 and 37 of Figure 2, to produce the product E. This product contained about 98% lactose, the remaining solids being mineral salt.

To produce a lactose of higher purity than product H, some of the partially demineralized permeate. from step 35 was concentrated to 65% solids, and lactose removed by crystallization, as indicated by steps 38, 39 and 40 of Figure 1 to produce the dry lactose product F. This product had a purity of 99.9%.

Example 3 The procedure was generally that of Figure 3. Acid whey was subjected to membrane ultrafiltration to produce a permeate analyzing generally the same as in Example 2. The permeate was then treated to heating and concentrating for precipitating buffer salts (calcium and citrate), followed by clarifying in step 53, substantially as explained in Example 1.

Following this treatment the permeate, after concentrating to 50% solids, was subjected to crystallizing 55, collection and washing of the crystals in step 56 and drying 57 to provide a lactose product corresponding generally to product A of Figure 1 and Example 1. To attain a product of higher purity and to increase the yield of lactose, the mother liquor from 56 may be subjected to the further steps 58, 59, 60, 61 and 62, and the collected crystals dried to provide product J. Washing in step 62 may employ acidulated water (pH 2.5). Product J produced in this manner may be a lactose having an estimated purity of 97%.

Some of the clarified concentrated filtrate from step 59 may be spray dried as indicated by step 67 of Figure 3 to produce the spray dried product K, which may contain 90% lactose.

Example 4 This example illustrates the process of Figure 5 which produces a product having flavor characteristics like soy sauce. Acid whey was subjected to ultrafiltration and mineral salts precipitated by adjusting the pH to 10.5 and by holding at a temperature of 180"F, as indicated by steps 72 and 73 of Figure 5, for a period of 90 minutes.

Precipitate was then removed by filtering as indicated by step 74, the filtrate cooled to 105"F, and sufficient hydrochloric acid added to adjust the pH to 4.5. This was then concentrated to 40 /n solids, and may be used as such or spray dried to produce the product Q. This product could be slurried with water to produce a material having the flavor properties of soy sauce.

WHAT WE CLAIM IS: 1. A process for the treatment of whey, comprising the steps of subjecting the whey to membrane ultrafiltration to form a protein rich fraction and a permeate, the permeate having a lactose content of from 68 to 87% (dry solids basis), a protein content of not more than 6% of the total solids content and a mineral salt content, precipitating a portion of the mineral salt content of the permeate, removing the precipitate from the permeate, concentrating the permeate and removing a portion of the lactose content by crystallization.

2. A process as claimed in Claim 1 in which mineral salts are precipitated by heating the permeate to a temperature of 180 to 2000F while at a concentration of the order of 40 to 45% total solids.

3. A process as claimed in Claim 2 in which the mineral salt content of the permeate fraction produced by ultrafiltration includes calcium and citrate salts together with phosphate and monovalent salts, the precipitation of mineral salts serving to precipitate calcium and citrate salts without substantial precipitation of phosphate salts.

4. A process as claimed in Claim 1 in which mineral salts are precipitated from the permeate by adjusting the pH to 7 to 10 by addition of a neutralizing agent, and holding the neutralized material at a temperature of 180"F for a period of 60 minutes or more.

5. A process as claimed in any one of the preceding claims in which the permeate after removal of a portion of the lactose content by crystallization is subjected to spray drying.

6. A process as claimed in any one of the preceding claims in which the permeate, after precipitation and removal of a portion of the mineral salt content, is subjected to further treatment for removal of a portion of the remaining salt content.

7. A process as claimed in Claim 6 in which the further treatment is carried out by electrodialysis.

8. A process for the treatment of whey comprising subjecting the whey to membrane ultrafiltration to produce a protein rich fraction and a lactose permeate, adding an alkali to the permeate to adjust its pH to 7 to 10, heating the permeate to a temperature level of from 180 to 2000F and holding the same at such temperature for a period from 1 to 2 hours, removing precipitated material from the heat treated permeate, cooling the material to 90 to 1100 F, acidifying the material to adjust the pH to 4 to 5, concentrating the material and then spray drying the material to produce a product having flavor properties comparable to soy sauce.

9. A process for the treatment of whey substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

10. A process for the treatment of whey as set forth in any of the foregoing Examples.

11. A product of a process as claimed in any one of the preceding claims.

12. Protein obtained by a process as claimed in any one of Claims 1 to 10.

13. Lactose obtained by a process as claimed in any one of Claims 1 to 10.

14. A mineral salt obtained by a process as claimed in any one of Claims I to 10.

15. A food or feed product which comprises a product as claimed in Claim 11.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (15)

**WARNING** start of CLMS field may overlap end of DESC **. Precipitate was then removed by filtering as indicated by step 74, the filtrate cooled to 105"F, and sufficient hydrochloric acid added to adjust the pH to 4.5. This was then concentrated to 40 /n solids, and may be used as such or spray dried to produce the product Q. This product could be slurried with water to produce a material having the flavor properties of soy sauce. WHAT WE CLAIM IS:

1. A process for the treatment of whey, comprising the steps of subjecting the whey to membrane ultrafiltration to form a protein rich fraction and a permeate, the permeate having a lactose content of from 68 to 87% (dry solids basis), a protein content of not more than 6% of the total solids content and a mineral salt content, precipitating a portion of the mineral salt content of the permeate, removing the precipitate from the permeate, concentrating the permeate and removing a portion of the lactose content by crystallization.

2. A process as claimed in Claim 1 in which mineral salts are precipitated by heating the permeate to a temperature of 180 to 2000F while at a concentration of the order of 40 to 45% total solids.

3. A process as claimed in Claim 2 in which the mineral salt content of the permeate fraction produced by ultrafiltration includes calcium and citrate salts together with phosphate and monovalent salts, the precipitation of mineral salts serving to precipitate calcium and citrate salts without substantial precipitation of phosphate salts.

4. A process as claimed in Claim 1 in which mineral salts are precipitated from the permeate by adjusting the pH to 7 to 10 by addition of a neutralizing agent, and holding the neutralized material at a temperature of 180"F for a period of 60 minutes or more.

5. A process as claimed in any one of the preceding claims in which the permeate after removal of a portion of the lactose content by crystallization is subjected to spray drying.

6. A process as claimed in any one of the preceding claims in which the permeate, after precipitation and removal of a portion of the mineral salt content, is subjected to further treatment for removal of a portion of the remaining salt content.

7. A process as claimed in Claim 6 in which the further treatment is carried out by electrodialysis.

8. A process for the treatment of whey comprising subjecting the whey to membrane ultrafiltration to produce a protein rich fraction and a lactose permeate, adding an alkali to the permeate to adjust its pH to 7 to 10, heating the permeate to a temperature level of from 180 to 2000F and holding the same at such temperature for a period from 1 to 2 hours, removing precipitated material from the heat treated permeate, cooling the material to 90 to 1100 F, acidifying the material to adjust the pH to 4 to 5, concentrating the material and then spray drying the material to produce a product having flavor properties comparable to soy sauce.

9. A process for the treatment of whey substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

10. A process for the treatment of whey as set forth in any of the foregoing Examples.

11. A product of a process as claimed in any one of the preceding claims.

12. Protein obtained by a process as claimed in any one of Claims 1 to 10.

13. Lactose obtained by a process as claimed in any one of Claims 1 to 10.

14. A mineral salt obtained by a process as claimed in any one of Claims I to 10.

15. A food or feed product which comprises a product as claimed in Claim 11.