|Van Hekken, Diane|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2015
Publication Date: 3/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62611
Citation: Tunick, M.H., Thomas-Gahring, A.E., Van Hekken, D.L., Iandola, S.K., Singh, M., Qi, P.X., Ukuku, D.O., Mukhopadhyay, S., Onwulata, C.I., Tomasula, P.M. 2016. Physical and chemical changes in whey protein concentrate stored at elevated temperature and humidity. Journal of Dairy Science. 99:2372-2383. DOI: 10.3168/jds.2015-10256.
Interpretive Summary: American dairy processors are finding new export markets for whey protein concentrate, a byproduct of cheesemaking, but they need to know if the bags of this powder will withstand high temperature and humidity levels during unrefrigerated storage. Therefore, environmental chambers were built to study the qualities of the powder under adverse conditions. Samples stored at 35 degrees C (104 F) became yellow after a year, but those stored at lower temperatures still performed acceptably after 18 months. Producers of whey protein concentrate will be able to export it to tropical areas knowing that the shelf life can be measured in months instead of weeks.
Technical Abstract: The chemistry of whey protein concentrate (WPC) under adverse storage conditions was monitored to provide information on shelf life in hot, humid areas. WPC34 (34.9 g protein/100 g) and WPC80 (76.8 g protein/100 g) were stored for up to 18 mo under ambient conditions and at elevated temperature and relative humidity. The samples became yellower with storage; those stored at 35 deg C were removed from the study by 12 mo because of their unsatisfactory appearance. Decreases in lysine and increases in water activity, volatile compound formation, and powder caking values were observed in many specimens. Microbial levels were < 3.85 log CFU/g in all samples. Relative humidity was not a factor in the results. When stored in sealed bags, WPC35 and WPC80 have a shelf life of 9 mo at 35 deg C but at least 18 mo at lower temperatures, which should extend the market for these products.