Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange
Abstract
Cheese production and sales are a major part of the U.S. dairy industry. Total hard cheese sales have increased 60% in the past 10 yr. Per capita consumption of cheese for the same period has risen from 2.81 kilograms (kg) to 4.03 kg for a 43% increase. In response to greater consumer demand the amount of milk utilized in cheese production has increased markedly during the past quarter century rising from the low of 10% of annual milk production in 1950 to 24% in 1976. This recent increase in cheese production emphasizes the importance of achieving maximum yields of cheese from milk used. The economic burden resulting from increased labor and packing costs make it even more imperative that the greatest possible yields be obtained. Ironically, the current lower solids in milk (2) are resulting in less than 9 to 10% cheese yields from milk that was common 20 yr ago. Attendant to more cheese being manufactured to meet consumer demands, more whey is being produced as a by-product. Whey has often been discarded; its bulk and low solids content make transport any distance uneconomical and promote lack of usage. Because of the large Biochemical Oxygen Demand (BOD), disposal of whey by dumping into lakes, streams, rivers, or pits has been forbidden by the Environmental Protection Agency; and discharging through the municipal sewage system has resulted in .extraordinarily high sewage treatment costs for most cheese plants. This situation has led the dairy industry to seek and consider new ways of utilizing the nutritional and/or functional properties of whey and its components. The total solids contents of milk approaches 13%; that in whey is 6.3%. Liquid whey contains approximately 4.7% lactose, 0.9% protein, 0.5% ash, and 0.2% lactic acid (29, 71). The whey produced in 1975 alone contained 675 million kg of lactose, 135 million kg of protein, 108 million kg of ash, and 27 million kg of lactic acid To recover these solids, whey has been concentrated by reverse osmosis or boiling under vacuum; fractionated by ultrafiltration or electrodialysis; or dried. According to the United States Department of Agriculture (USDA), U. S. whey powder production almost doubled from 183 million kg in 1965 to 347 million kg in 1975. Per capita consumption of dried whey jumped, for a 315% increase, from 0.13 kg in 1960 to 0.54 kg in 1973 (72). The uses for whey· are numerous; but by far the two largest users are the dairy and bakery industries which used 32 and 25%, respectively, of all dry whey produced in 1976 (74). However, only one-half of all whey produced is used; hence, new ways of utilizing whey would be distinctly advantageous to the cheese industry. One objective of this research was to find a process to utilize dry whey powder to increase yields of cheddar cheese. Another objective was to determine whether this addition would affect the curing process and especially if the cheese would meet federal compositional standards and be of satisfactory flavor and body after curing