Dry Whey Products

A. History

Although spray and roller processes have been used to dry whey for many years, development of a whey processing industry in the United States did not fully materialize until organization of the Whey Products Institute in 1971 (Clark, 1991). At that time, development of product identity and quality standards was undertaken as a guide to production of uniformly high-quality whey products. In 1981, the FDA accepted industry-recommended common and usual names for a variety of whey products and affirmed the generally recognized as safe (GRAS) status of these products and their method of manufacture (U.S. Department of Health and Human Services, 1981). Technological changes associated with whey processing are dynamic. In no area of the modern dairy industry have changes of a technical nature been as innovative and rapid as in the whey products segment. Important applications to whey processing include the use of selective membrane techniques that allow various whey constituents to be separated into protein-, carbohydrate-, or mineral-rich streams, which then may be further processed and made available in concentrated functional forms. Significant further developments, reflecting continuing changes, are anticipated in this area.

B. Products and Processing

The primary whey products currently manufactured in the United States are concentrated and dry whey and the modified whey products, including reduced-lactose whey, reduced-minerals whey, and whey protein concentrate. Other modified whey products manufactured in smaller quantities include lactalbumin (minimum protein content 80%) and whey protein isolate (minimum protein content 90%). Lactose, the carbohydrate of milk, also is being produced in large quantities as a coproduct with the manufacture of modified wheys. Table 2 defines the commonly known whey products currently being manufactured.

A typical processing scheme for manufacture of dry whey is shown in Figure 4. Some whey-drying operations receive only condensed whey for processing; others receive condensed and fresh fluid whey. The solids concentration of transported condensed whey and the time-temperature conditions of its shipment determine how the product is processed before entering the drying system. Currently, the USDA requires all condensed whey containing less than 40% solids to be pasteurized or repasteurized in the processing plant where it is to be dried. The process of drying is similar to that used to manufacture dry milks, and some processing plants may dry both products interchangeably.

Processing operations to manufacture modified whey products include reverse osmosis, ultrafiltration, and electrodialysis procedures, some of which may be proprietary in nature. For more information on these processes, various published texts (Sienkiewicz and Riedel, 1990; Gillies, 1974) may be consulted.

The American Dairy Products Institute (1999b) publishes data annually that reflect production and utilization trends for whey products. In 1998, nearly 2.2 billion pounds of whey solids were processed in the United States as follows: 1.2 billion pounds of dry whey; 109 million pounds (solids) as condensed whey; 105 million pounds of reduced-lactose and reduced-minerals whey; 285 million pounds of whey protein concentrate; and 454 million pounds of lactose.

Table 2 Composition of Whey Products

Major parameters (%)a

Table 2 Composition of Whey Products

Major parameters (%)a

Name of product

Protein

Fat

Ash

Lactose

Moisture

Wheyb

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