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An Improved Method for Brine Salting Cheese1
TECHNICAL NOTES
An Improved Method for Brine Salting Cheese1 G. W. REINBOLD~ and E. G. HAMMOND Department of Food Technology Iowa State University Ames 50010 Abstract
according to the method described for Iowa style Swiss cheese by Reinbold (3). Salt and mois~tre determinations of the cheese were made by the Official Methods of the AOAC (1). The cheese was examined at 60 days after manufacture for eye formation, surface al3normalities, and flavor by two judges experienced with Swiss cheese. The salt added to the cheese was computed by multiplying the weight of the block of cheese by the percentage of salt desired in the final product, usually about 1.55. If the amount of salt was added as brine, it was assumed that the saturated brine was 26.5~ salt by weight at room temperature and that the specific gravity was 1.2.
Cheese varieties, such as Swiss, which are salted by soaking for a day or more after make in saturated brine, may be salted more simply and conveniently by including brine solution in the plastic bags in which the cheese is normally wrapped for curing. To insure even distribution of the brine, it is necessary to include a porous layer like sheets of sponge, cloth, paper toweling, or similar material. The flavor and eye formation of Swiss cheese salted in this way was not adversely affected but did tend to have softer surfaces with a slightly lighter color than the interior. Yields can be improved because the significant amounts of water lost by osmosis during conventional brining of cheese are avoided. Moisture control can be achieved by varying the ratio of salt to water added to the curing bag. Salts other than sodium chloride, which may improve the flavor or texture of the cheese, can be included in the added brine.
Results and Discussion
Introduction
Several varieties of cheese, notably Swiss cheese, are salted by soaking the fresh blocks of curd in a concentrated brine solution for a day or more. Salting cheese in this way involves extra handling of the cheese b~oeks, considerable drip loss of brine when the blocks are removed from brine tanks, and frequently unaesthetic and unappetizing brine tanks. We report an improved method for brine salting cheese which involves adding the correct amount of salt to the pouches in which rindless blocks are cured. Methods
Swiss cheese was made in 9-kg blocks Received April 22, 1974. 1Journal Paper No. J-7884 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project 1839. ~Present address: Leprino Cheese Company, Denver, CO 80211.
Our first and many of our subsequent experiments were with saturated brine held in cellulose sponges from the O'Cello Division of General Mills. These sponges covered the two major surfaces of the cheese blocks and were 34 x 26 x .6 era. They would easily hold the necessary amounts of saturated brine when lying flat but not when suspended by an edge. A cheese block would not press the brine from such a sponge when lying fiat on it. The appropriate amount of brine was added to the sponges and the block of cheese was placed between them. Then the cheese and sponges were wrapped with a Saran-film or placed in a Cryovac bag and sealed. The rate of salt enetration of the cheese was not measured, ut was essentially complete at the end of the w a r m room treatment w i t h only a small portion of the salt left in the sponge. The sponges could be removed and the cheese few-rapped at this time; however, it is more advantageous to leave the sponges on the cheese until it is ready to be cut as this is just as satisfactory and eliminates extra handling. Cheese brined in this way had salt contents proportional to the amounts of salt added to the sponge. Moisture contents were significantly higher than controls brined by the conventional method. Part of the difference .in moisture is from moisture loss of cheese brined in a conventional brine tank, and part is caused by gain of moisture of cheese
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1254
TECHNICAL
salted with brine-soaked sponges. Mthough the cheese may gain over 1% by weight of salt while being soaked in a brine tank, the high osmotic value of the brine solution pulls water from the cheese into the brine tank. The loss of water more than makes up for the gain in salt. The magnitude of this loss will depend on the ratio of surface to volume of the cheese block, the saturation of the brine and the length of the soaking period. Water loss is undoubtedly accentuated by the custom of sprinkling dry salt on the surfaces of the floating cheese blocks in the brine tank. For small 9-kg blocks of Iowa style Swiss (36)K 26 X 12 cm) the loss ranged from 2.2 to 3.3%. Measurements in commercial plants making 37-kg and 45-kg blocks revealed weight losses of 1.5 and 1.4%, but there was a net weight gain of 2.5 to 2.8% by 9-kg blocks cheese brine salted by our method. About haft o1 this gain is salt and about half is moisture. This net weight gain could be translated into a net gain in yield by the manufacturer. In the past it has been impractical to exercise close control of the moisture of Swiss cheese. Federal standards indicate Swiss cheese should contain no more than 41% moisture (2), but most conventionally salted Swiss contains considerably less. Aside from an increase in yield, salting cheese in the curing bag gives the possibility of better control over moisture. Diluted brine, a mixture of brine and suspended salt, or dry salt may be used instead of saturated brine. It is not satisfactory to place dry salt directly in contact with the cheese during curing as this causes a hard and nonuniform surface; however, it is possible to place a slightly damp sponge in contact with the cheese and to place dry salt on the side of the sponge away from the cheese. The salt will be transferred through the damp sponge into the cheese. Many ways of holding and distributing the brine solution besides sponges may be used. Sponges are relatively expensive but may be recycled. In general, any porous permeable layer may be used that will be compatible with cheese and brine. We have used successfully cloth, paper towels, sheets of filter paper, spun Pyrex glass fiber pads, blotting paper, and agar gels saturated with brine. It is desirable to select a material coherent enough to peel off the cheese surface without leaving a residue because the porous material will be pressed into the cheese during curing. Certain paper products of high wet-strength may prove the most ecgnomical material to use.
NOTE
1255
Although the material used to distribute the salt may be thin and porous, it is not satisfactory simply to put a brine solution into the curing bag. This is because the cheese is fluid enough to creep during curing. It must be supported by some sort of rigid container. As the cheese presses against its supporting container, the brine solution will be trapped in certain portions of the bag. Some parts of the cheese will get too much salt; others will get an insufficient amount. This will cause uneven fermentation, undesirable flavors and nonuniform eye development. The flavor of cheese salted in the curing bag has generally been clean and Swiss-like. Our simple taste tests have not revealed that cheese salted in this way differed significantly from controls salted in the usual way. Evidently the higher moisture and more leisurely penetration of salt into the cheese have not had an adverse effect on the flavor. Eye formation and interior texture of Swiss cheese salted in the curing bag was not significantly different from controls salted by the usual procedure; however, cheese salted in the curing bag tended to have softer surfaces than cheese salted in brine tanks, and there was a significant increase in the incidence of blocks with surfaces lighter in color than the interior. This surface bleaching was slight in most instances. The small volumes of brine needed to salt cheese in the curing bag made it possible to try additives along with the salt to see what effect they would have on the cheese. The addition of calcium chloride sufficient to give .3% and magnesium sulfate sufficient to give .5% in the cheese tended to reduce the incidence of bleach and gave firmer surfaces. Phosphate and acetate buffers and traces of iron and copper were added to the brine without marked effect except that the copper accumulated at the cheese surfaces and turned them blue-green. Brine made up in whey and milk with and without added yeast extract w~.~ tried without obvious effect. If the porous layer used to distribute the salt is very thick, a significant amount of liquid may be recovered from it at the end of the ripening period. This liquid has a clean Swiss-like flavor and may be useful as a flavoring. References
(1) Association of Official Analytical Chemists. 1970. Official methods of analysis. Washington, D.C. IOURNAL OF DAIRY SCIENCE VOL. 57. NO, 10
1256
J O U R N A L O F DAIRY S C I E N C E
(2) Definitions and Standards. 1959. Cheese and cheese products. Code of Federal Reg~flations. Part 19, Title 21. Food and Drug Ad-
ministration. (3) Reinbold, G. W. 1972. Swiss cheese varieties. Pfizer, Inc.
ContinuousVacuum Foam-Drying of Whole Milk. VI. Iron Enrichment E. F. SCHOPPET, C. C. PANZER, F. B. TALLEY, and H. I. SlNNAMON U.S. Department of Agriculture Eastern Regional Research Center Philadelphia, PA 19118 Abstract
With the growing interest in iron fortifieati0n of foods, particularly milk, we studied the processing and keeping qualifies of vacuum foam-dried whole milk after the addition of 10.6 mg per liter of iron in the folm of ferric ammonium citrate. Added iron had no adverse effects on the dehydration process, initial flavor and dispersibility, or flavor and dispersibility after extended storage.
Introduction
Investigators agree that the American diet is nutritionally deficient in iron (3, 8, 16). Foods in the diets of infants, adolescents, and women do not provide enough iron to prevent iron deficiency anemia. The amount of iron that a person should ingest has not been established definitely (9); however, the problem has not been ignored. Amounts of iron fortification for proper nutrition have been suggested (7). Iron enrichment of milk is one approach to decreasing the hazard of iron deficiency anemia, since milk is an important commodity in the American diet (10, 11). Many states now permit iron fortification with proper labeling and/or specified limits (6). Unfortunately, iron catalyzes the development of oxidative-type off-flavors in milk. To determine the extent of off-flavor development in fluid milk, investigators have studied effects of added iron from both ferrous and ferric forms (4, 5, 12). Their conclusions indicate either form is Received April 2, 1974. JOURNAL OF DAIRY SCIENCE VOL. 37, NO, 10
acceptable, but modifications in pasteurization should be made to inhibit the oxidative catalyzing effect of added iron. This report summarizes effects of added iron on processing and storage behavior of whole milk dried by the vacuum foam process developed in our laboratory (13). Procedure
1. Preparation o~ dry milk. A supply of raw clarified whole milk, representative of a large pool supply, was purchased from a local dairy. The milk was divided into two lots with one lot having the equivalent of 10.6 mg of iron per liter from ferric ammonium citrate, and the other representative of a typical feed for the process. Ferric ammonium citrate has little effect on flavor and nutritive value of milk and very favorable biological adsorption as compared to other supplemental sources of iron (14, 15). The two lots of milk then were processed successively in the same day in accordance with the method established for vacuum foam-dried whole milk (13). One exception was in the pasteurization step to aecommodate recommendations when iron is added, i.e., pasteurize at 81 C instead of 78 C (5). Products of the process were packed in cans under nitrogen in the usual manner and stored at 3.3 C. 2. Taste panel evaluation. Samples were withdrawn from storage at intervals up to 40 wk and judged by triangle tests and by absolute scoring by a trained panel of judges. The objective of the triangle taste tests was to reveal differences in flavor due to iron only. Some samples were evaluated further in an absolute scoring method (2). Absolute scoring evaluations of typical products of the process
An Improved Method for Brine Salting Cheese1 G. W. REINBOLD~ and E. G. HAMMOND Department of Food Technology Iowa State University Ames 50010 Abstract
according to the method described for Iowa style Swiss cheese by Reinbold (3). Salt and mois~tre determinations of the cheese were made by the Official Methods of the AOAC (1). The cheese was examined at 60 days after manufacture for eye formation, surface al3normalities, and flavor by two judges experienced with Swiss cheese. The salt added to the cheese was computed by multiplying the weight of the block of cheese by the percentage of salt desired in the final product, usually about 1.55. If the amount of salt was added as brine, it was assumed that the saturated brine was 26.5~ salt by weight at room temperature and that the specific gravity was 1.2.
Cheese varieties, such as Swiss, which are salted by soaking for a day or more after make in saturated brine, may be salted more simply and conveniently by including brine solution in the plastic bags in which the cheese is normally wrapped for curing. To insure even distribution of the brine, it is necessary to include a porous layer like sheets of sponge, cloth, paper toweling, or similar material. The flavor and eye formation of Swiss cheese salted in this way was not adversely affected but did tend to have softer surfaces with a slightly lighter color than the interior. Yields can be improved because the significant amounts of water lost by osmosis during conventional brining of cheese are avoided. Moisture control can be achieved by varying the ratio of salt to water added to the curing bag. Salts other than sodium chloride, which may improve the flavor or texture of the cheese, can be included in the added brine.
Results and Discussion
Introduction
Several varieties of cheese, notably Swiss cheese, are salted by soaking the fresh blocks of curd in a concentrated brine solution for a day or more. Salting cheese in this way involves extra handling of the cheese b~oeks, considerable drip loss of brine when the blocks are removed from brine tanks, and frequently unaesthetic and unappetizing brine tanks. We report an improved method for brine salting cheese which involves adding the correct amount of salt to the pouches in which rindless blocks are cured. Methods
Swiss cheese was made in 9-kg blocks Received April 22, 1974. 1Journal Paper No. J-7884 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project 1839. ~Present address: Leprino Cheese Company, Denver, CO 80211.
Our first and many of our subsequent experiments were with saturated brine held in cellulose sponges from the O'Cello Division of General Mills. These sponges covered the two major surfaces of the cheese blocks and were 34 x 26 x .6 era. They would easily hold the necessary amounts of saturated brine when lying flat but not when suspended by an edge. A cheese block would not press the brine from such a sponge when lying fiat on it. The appropriate amount of brine was added to the sponges and the block of cheese was placed between them. Then the cheese and sponges were wrapped with a Saran-film or placed in a Cryovac bag and sealed. The rate of salt enetration of the cheese was not measured, ut was essentially complete at the end of the w a r m room treatment w i t h only a small portion of the salt left in the sponge. The sponges could be removed and the cheese few-rapped at this time; however, it is more advantageous to leave the sponges on the cheese until it is ready to be cut as this is just as satisfactory and eliminates extra handling. Cheese brined in this way had salt contents proportional to the amounts of salt added to the sponge. Moisture contents were significantly higher than controls brined by the conventional method. Part of the difference .in moisture is from moisture loss of cheese brined in a conventional brine tank, and part is caused by gain of moisture of cheese
R
1254
TECHNICAL
salted with brine-soaked sponges. Mthough the cheese may gain over 1% by weight of salt while being soaked in a brine tank, the high osmotic value of the brine solution pulls water from the cheese into the brine tank. The loss of water more than makes up for the gain in salt. The magnitude of this loss will depend on the ratio of surface to volume of the cheese block, the saturation of the brine and the length of the soaking period. Water loss is undoubtedly accentuated by the custom of sprinkling dry salt on the surfaces of the floating cheese blocks in the brine tank. For small 9-kg blocks of Iowa style Swiss (36)K 26 X 12 cm) the loss ranged from 2.2 to 3.3%. Measurements in commercial plants making 37-kg and 45-kg blocks revealed weight losses of 1.5 and 1.4%, but there was a net weight gain of 2.5 to 2.8% by 9-kg blocks cheese brine salted by our method. About haft o1 this gain is salt and about half is moisture. This net weight gain could be translated into a net gain in yield by the manufacturer. In the past it has been impractical to exercise close control of the moisture of Swiss cheese. Federal standards indicate Swiss cheese should contain no more than 41% moisture (2), but most conventionally salted Swiss contains considerably less. Aside from an increase in yield, salting cheese in the curing bag gives the possibility of better control over moisture. Diluted brine, a mixture of brine and suspended salt, or dry salt may be used instead of saturated brine. It is not satisfactory to place dry salt directly in contact with the cheese during curing as this causes a hard and nonuniform surface; however, it is possible to place a slightly damp sponge in contact with the cheese and to place dry salt on the side of the sponge away from the cheese. The salt will be transferred through the damp sponge into the cheese. Many ways of holding and distributing the brine solution besides sponges may be used. Sponges are relatively expensive but may be recycled. In general, any porous permeable layer may be used that will be compatible with cheese and brine. We have used successfully cloth, paper towels, sheets of filter paper, spun Pyrex glass fiber pads, blotting paper, and agar gels saturated with brine. It is desirable to select a material coherent enough to peel off the cheese surface without leaving a residue because the porous material will be pressed into the cheese during curing. Certain paper products of high wet-strength may prove the most ecgnomical material to use.
NOTE
1255
Although the material used to distribute the salt may be thin and porous, it is not satisfactory simply to put a brine solution into the curing bag. This is because the cheese is fluid enough to creep during curing. It must be supported by some sort of rigid container. As the cheese presses against its supporting container, the brine solution will be trapped in certain portions of the bag. Some parts of the cheese will get too much salt; others will get an insufficient amount. This will cause uneven fermentation, undesirable flavors and nonuniform eye development. The flavor of cheese salted in the curing bag has generally been clean and Swiss-like. Our simple taste tests have not revealed that cheese salted in this way differed significantly from controls salted in the usual way. Evidently the higher moisture and more leisurely penetration of salt into the cheese have not had an adverse effect on the flavor. Eye formation and interior texture of Swiss cheese salted in the curing bag was not significantly different from controls salted by the usual procedure; however, cheese salted in the curing bag tended to have softer surfaces than cheese salted in brine tanks, and there was a significant increase in the incidence of blocks with surfaces lighter in color than the interior. This surface bleaching was slight in most instances. The small volumes of brine needed to salt cheese in the curing bag made it possible to try additives along with the salt to see what effect they would have on the cheese. The addition of calcium chloride sufficient to give .3% and magnesium sulfate sufficient to give .5% in the cheese tended to reduce the incidence of bleach and gave firmer surfaces. Phosphate and acetate buffers and traces of iron and copper were added to the brine without marked effect except that the copper accumulated at the cheese surfaces and turned them blue-green. Brine made up in whey and milk with and without added yeast extract w~.~ tried without obvious effect. If the porous layer used to distribute the salt is very thick, a significant amount of liquid may be recovered from it at the end of the ripening period. This liquid has a clean Swiss-like flavor and may be useful as a flavoring. References
(1) Association of Official Analytical Chemists. 1970. Official methods of analysis. Washington, D.C. IOURNAL OF DAIRY SCIENCE VOL. 57. NO, 10
1256
J O U R N A L O F DAIRY S C I E N C E
(2) Definitions and Standards. 1959. Cheese and cheese products. Code of Federal Reg~flations. Part 19, Title 21. Food and Drug Ad-
ministration. (3) Reinbold, G. W. 1972. Swiss cheese varieties. Pfizer, Inc.
ContinuousVacuum Foam-Drying of Whole Milk. VI. Iron Enrichment E. F. SCHOPPET, C. C. PANZER, F. B. TALLEY, and H. I. SlNNAMON U.S. Department of Agriculture Eastern Regional Research Center Philadelphia, PA 19118 Abstract
With the growing interest in iron fortifieati0n of foods, particularly milk, we studied the processing and keeping qualifies of vacuum foam-dried whole milk after the addition of 10.6 mg per liter of iron in the folm of ferric ammonium citrate. Added iron had no adverse effects on the dehydration process, initial flavor and dispersibility, or flavor and dispersibility after extended storage.
Introduction
Investigators agree that the American diet is nutritionally deficient in iron (3, 8, 16). Foods in the diets of infants, adolescents, and women do not provide enough iron to prevent iron deficiency anemia. The amount of iron that a person should ingest has not been established definitely (9); however, the problem has not been ignored. Amounts of iron fortification for proper nutrition have been suggested (7). Iron enrichment of milk is one approach to decreasing the hazard of iron deficiency anemia, since milk is an important commodity in the American diet (10, 11). Many states now permit iron fortification with proper labeling and/or specified limits (6). Unfortunately, iron catalyzes the development of oxidative-type off-flavors in milk. To determine the extent of off-flavor development in fluid milk, investigators have studied effects of added iron from both ferrous and ferric forms (4, 5, 12). Their conclusions indicate either form is Received April 2, 1974. JOURNAL OF DAIRY SCIENCE VOL. 37, NO, 10
acceptable, but modifications in pasteurization should be made to inhibit the oxidative catalyzing effect of added iron. This report summarizes effects of added iron on processing and storage behavior of whole milk dried by the vacuum foam process developed in our laboratory (13). Procedure
1. Preparation o~ dry milk. A supply of raw clarified whole milk, representative of a large pool supply, was purchased from a local dairy. The milk was divided into two lots with one lot having the equivalent of 10.6 mg of iron per liter from ferric ammonium citrate, and the other representative of a typical feed for the process. Ferric ammonium citrate has little effect on flavor and nutritive value of milk and very favorable biological adsorption as compared to other supplemental sources of iron (14, 15). The two lots of milk then were processed successively in the same day in accordance with the method established for vacuum foam-dried whole milk (13). One exception was in the pasteurization step to aecommodate recommendations when iron is added, i.e., pasteurize at 81 C instead of 78 C (5). Products of the process were packed in cans under nitrogen in the usual manner and stored at 3.3 C. 2. Taste panel evaluation. Samples were withdrawn from storage at intervals up to 40 wk and judged by triangle tests and by absolute scoring by a trained panel of judges. The objective of the triangle taste tests was to reveal differences in flavor due to iron only. Some samples were evaluated further in an absolute scoring method (2). Absolute scoring evaluations of typical products of the process