Survey of salty and sweet whey composition from various cheese plants in Wisconsin

Salty whey is currently underutilized in the dairy industry because of its high salt content and increased processing and disposal costs. Salty whey accounts for 2 to 5% of the total whey generated during Cheddar and other dry-salted cheese manufacture. Because relatively little information is available on salty whey, this study was conducted to determine the range of compositional components in salty whey from commercial cheese plants. Gross compositional differences in percent protein, salt, solids, and fat between sweet whey and salty whey from various dry-salted cheeses from 8 commercial plants were determined. Differences between individual whey protein compositions were determined using sodium dodecyl sulfate-PAGE. Average total solids, fat, and salt content were significantly greater in the salty whey compared with the corresponding sweet whey. True protein was reduced in salty whey although great variability existed among samples. Individual whey proteins identified included lactoferrin (Lf), BSA, immunoglobulin G, beta-lactoglobulin, and alpha-lactalbumin. Salty whey showed an increase in Lf content and a decrease in alpha-lactalbumin and beta-lactoglobulin content when compared with sweet whey. Salty whey may be a source of Lf, potentially increasing its value to whey processors. However, the compositional assessments showed that commercial salty whey is a highly variable waste stream.