A. NON-FERMENTED PRODUCTS
Bakery Products: In USA nearly 50 percent of the whey is used in the production of icings, fillings, breads rolls and cookies etc.
Crop Production: Whey contains nearly 93 percent of water. In USA and Europe, the whey is used for nurturing the corn. Application of whey at 4, 8, 16 and 32 inches (1”=28,000 gallons) over a period of 4 years have been found to improve the quality of corn production (Peterson et al., 1979). Application of whey over a long period of time has been found to increase the concentration of phosphorus and potassium in the surface soil.
Animal Feed: Whey is used as a feed for livestock particularly the young calves. It was observed that young calves could obtain 20-30 percent of their total dry matter requirement from whey (Paul Lynch and McDonough, 1979). It also provided enough proteins necessary for adequate growth. Liquid acid whey permeates (LAWP) along with 19 percent dry protein supplements could provide 26 percent of the dry matter intake and showed adequate growth. The whey protein concentrate (WPC) resulting from the ultra filtration of whey could be used as a milk replacer for the calves.
Whey Protein Concetrate (WPC): Whey proteins are easily digestible, and are considered to be highly nutritional and physiologically complete. In addition, they posses excellent functional characteristics. WPC has been prepared commercially by ultra filtration, reverse osmosis and electro dialysis. It is used in milk replacers, egg substitutes, ice-cream mixes, processed cheese foods, whipped toppings and the like.
Polyurethane Foam: Dried whey is used for the production of polyurethane foam. The lactose present in the dried whey has been found to be a suitable source of Polyhydroxyl compound, which is used for the production of plastic materials (Husttod et al., 1970).
Confectionery Products: Whey solids are used as an ingredient for the formulation of confectionery products. Confectionery coatings prepared by using whey in the formulations have enhanced the texture, flavour and colour characteristics of the finished products. It also preserves the freshness of the product in year round usage.
Infant Formulation: The organs like kidneys and intestines are in a state of functional underdevelopment in neo-natal babies. Thus, there is a need for the supplementation of certain special nutritients in the diet in the first three months of its life. Infants exclusively fed on cow milk may develop some physiological alteration in intestinal functions because of the difference in the composition of cow milk from that of the milk of the mother. The altered state of intestinal physiology is manifested by various degrees of microcytosis, ferropenia and minimal anaemia (Woodruff et al., 1972). In addition, other physiological disorders e.g. lower nitrogen retention, higher excretion of urinary nitrogen, higher serum osmolarity and lower growth rate have been reported in infants exclusively fed on cow’s milk (Morita et al., 1970; Omsted and Sleigh, 1975). Thus modified whey solids with a formulation of casein and whey protein at a ratio of 60:40 (as in human milk) are used for normal physiological functions. Feeding of humanized formulation exerts considerably lower osmolar loads on the kidneys resulting in an increase in nitrogen retention and utilization (Saita, 1972).
Lactose: Lactose constitutes nearly 70 percent of the total solids in whey. In addition to the nutritional properties, lactose possesses many important properties e.g. protein stabilization, flavour enhancement, dispersion, emulsification, detergency and a lot more. The limitations are: low sweetness, limited and lactose-intolerance in certain individuals. Lactose can be used in various food products (Nickerson, 1976), the details of which are given bellow:
Nearly 30 percent of the unutilized whey is processed for the production of pharmaceutical or edible grade lactose by conventional process. The delactosed whey is dried and sold as a by-product for animal feed. It has limited application as a feed ingredient because of high mineral content and less functional property (Gupta and Mathur, 1989).
Non-Fermented Whey Drink: The cheapest and most efficient method of preparing a whey-based beverage is to drain the whey from chhana vat, pasteurize, deodorize if desired, flavour appropriately and pack for later consumption. In 1913, Jolles described the preparation of a “Salutary” drink from whey. The whey was decolorized and deodorized with charcoal and sterilized by addition of acid. Salts, medicaments, and / or carbon-di-oxide could then be added to produce a finished beverage. The whey flavour, particularly that of acid whey, is most compatible with citrus flavours, particularly orange. Several experimental citrus flavoured beverages have been developed, for which high consumer acceptability was claimed from cheddar and chhana whey. Meyer (1947) described beverages and tinctures prepared by mixing whey with vegetables or fruit juices. However, he considered them more as effective medicinal agents rather than as products for normal consumption. Kosikowski (1968) had shown that incorporating up to 6 % acid whey powder in reconstituted frozen orange juice could make an acceptable beverage. After storing for a period of one month, the reconstituted beverage retained the quality of the freshly reconstituted blend. Sharma et al., (1995) prepared whey based carrot juice beverage with carrot juice and buffalo milk paneer whey in the ratio of 60: 40 along with 70% sucrose. Shelf life of the pasteurized product was claimed to be 20 days at 5-100C.
The most popular method of deproteinization is by heating whey, which is usually acidified at 900 C at deferent intervals. The coagulated whey proteins are then removed by filtration or centrifugation, and the clear supernatant is processed further to produce the desired effect. Tannic acid, herbal leaf extracts containing large amount of tannis are also efficient protein precipitants, particularly in conjunction with heat. The latter two means add desirable flavours to the whey base, and several beverages have been developed by similar producers. Mathur et al., (1986) have developed a process, where whey was first adjusted to the pH 4.0 using citric acid, then heated at 900 C for 10 minutes in presence of 0.3% Calcium chloride, to precipitate the protein as well as colloidal salts. Department of Dairy Chemistry, WBUAFS, Mohanpur has standardized a whey beverage using deproteinized Chhana whey, citric acid, sugar and lemon juice (Mondal et al., 1997). The beverage could be stored without preservative for 45 days at refrigerated temperature and 35 days at room temperature with 0.66% sorbic acid.
B. FERMENTED PRODUCTS
Whey can be used in the manufacture of fermented products e.g. acidic and alcoholic beverages, yeast, alcohol, lactic acid, vitamins and vinegar etc. Some of them have enormous commercial value, while others have remained as laboratory curiosity. Some of the important fermented products manufactured from whey are given below:
Non-Alcoholic Fermented Whey Beverages: Gandhi (1985) had developed a refreshing and palatable beverage from whey named as “Acid whey”. Fresh cheese whey is pasteurized at 720 C for 15 seconds followed by cooling to 420 C. Lactic acid cultures of Lactobacillus acidophilus and Lactobacillus bulgaricus in the ratio of 1:1 are added to the whey and is incubated at 320 C till the product attains an average lactic count of 40x104 c.f.u. /ml, sugar and flavours are added to make the product palatable. The product is reheated at a temperature of 750 C for five minutes and then cooled to 500 C and stored under refrigeration for marketing. The shelf life of the product is reported to be 2-3 days. Whey from cheese can also be used for the preparation of a lassi type cultured beverage having a shelf-life of 6 days at a temperature of 50 C Kar and Misra (1998 a) have standardized a method to prepare a “wheyghurt drink” on commercial scale by addition of 4% yoghurt culture to deproteinized whey adjusted to 6.4 pH and incubated at 420 C for 8 hours. The product has a shelf life of 5 days under refrigeration.
Alcoholic Fermented Whey Beverages: A beverage with the flavour of orange and pineapple was developed by Bambha et al., (1972). It can be prepared by adding the culture of Saccharomyces cerevisiae to mildly fermented deproteinized whey. It contains 0.5-1.0 percent alcohol.
Whey Beer: Roeder (1939) showed that up to 30 percent of malt could be substituted by deproteinized whey. The whey was partly deproteinized by cooking at a pH of 4.5-5.5 with hops. The filtrate was blended with malt wort, followed by fermentation with bottom fermenting beer yeasts.
Whey Wine: Engel (1952) had patented a process for producing a sauterne or sherry like alcoholic beverage from whey. In wine production, the entire whey is utilized and there is no need for removal of water, which is an expensive process. Further, the yeast biomass produced during fermentation can be concentrated and used as an “animal feed”. Fortification with sugar increases the cost of production, but it has higher monetary value (Friend and Sahani, 1979).
Alcohol: Kar and Misra (1998 b) have successfully utilized deproteinized chhana whey for production of alcohol by using Kluveromyces marxianus. In this process, whey permeate is concentrated to 12.7% lactose for 30 hours. It produces 6.6 percent (V/V) alcohol conforming to BIS specification. The resultant ethanol (75.8% by volume) is suitable for production of “Gin” or “Vodka” and for blending with neutral spirit. This simple procedure can easily be adopted by small-scale producer of chhana-based sweets for effective and economic utilization of chhana whey.
Single Cell Protein: Whey can be utilized for the production of yeast, which is used as a source of dietary protein. Kar and Misra (1998 c) have developed a process for production of yeast from chhana whey proteins denatured by heat at a temperature of 900 C and pH 4.5. The whey was fortified with nutrients, inoculated with Kluyveromyces marxianus, incubated at 300 C with aeration at 1 vvm and fermented for a period of 3 days. The biomass yield was 11.2 gm/litre. The yeast protein compound contained protein 50%, carbohydrate 30%, lipids 8.4 % and minerals – 7.2 %.
Lactase (B-D-Galactosidase): The production of the enzyme β-Glactosidase or lactase has been of late the subject of considerable interest. Whey seems to provide the best medium for the production of this enzyme. The enzyme is produced from selected strains of Kluyveromyces species following growth on diluted whey. It is induced by lactose and is found within the cells. Βeta galactosidase is used to hydrolyse lactose to overcome the problem of lactose intolerance, and to produce syrups, which are sweeter than lactose but do not readily form crystals.
Lactic Acid And Lactase: Whey has remained a traditional feedstock for lactate production by fermentation. It is typically conducted in batch mode using homo-fermentative strains of Lactobacillus bulgaricus. Corn steep liquor and / or other complex nutrients e.g. malt or yeast extracts may be supplemented with the product. The pH is controlled to 5.5-6.5 by addition of Calcium di-hydroxide (Ca OH2) or Calcium carbonate (CaCO3) and the temperature is maintained at about 430 C. The medium is usually sterilized, but contamination is not considered to be a serious problem because of high temperature, high acid concentration and an inoculum (5-10%) of the fermenter volume. For natural-strength whey, the fermentation will be complete in less than 24 hours with a yield of 90-95%.
Fermentation Of Whey To Methane (Bio-Gas): The microbial production of methane from whey offers major benefits of an efficient waste treatment process coupled with production of a convenient source of energy. The methane fermentation is an anaerobic digestion process, which requires limited input of energy of nutrients and produce very little sludge for ultimate disposal in comparison with the conventional aerobic treatment process. A number of bioreactors are available for the treatment of high strength effluents e.g. whey. These reactors retain the microorganisms mediating the fermentation in the digester, so that the hydraulic residence time of the waste stream can be considerably reduced than the solids. It is necessary, since the cells grow slowly; when large volumes of waste are processed daily.
Conclusion
It is evident that there is no simple answer to the problem of whey utilization. The disposal of whey may be more problematic in future because of the stringent anti-pollution regulations coupled with the growing consciousness of people against environmental pollution. The only option open to the majority of the manufacturers appears to be to use the technique of lactose hydrolysis. But it is capital intensive and therefore unsuitable for small producers of chhana whey. The only alternate available to them is the production of whey beverages by fermentation technique. It is suitable for the small producers of chhana. The production of single cell protein through fermentation is also a viable alternative. The geometric increase in human population in contrast to arithmetic progress in food production has created the problem of protein-calorie malnutrition in most of the developing countries in the world. Single cell protein production may relieve this problem to a great extent. Chhana whey can also be used for the production of alcohol. It will ease the economic liability of this dairy industry to some extent.
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