Quality attributes of dried milk products packaged for long-term storage
M. A. LLOYD, Department of Food Science and Nutrition, Brigham Young University, S221 Eyring Science Center, Provo, UT 84602 and O. A. Pike.
There is a market for dehydrated foods, such as nonfat dry milk (NFDM), that are packaged for long-term storage in case of natural disasters or other emergencies. To maintain quality and optimize shelf-life, NFDM must be properly processed from good quality milk, well-packaged (minimizing moisture, light and oxygen), and stored appropriately. Research is needed to determine the variation in quality that exists in dried milk products intended for retail sale. The objective of this research was to evaluate and compare the quality of several types of dried milk products packaged for long-term storage. Ten brands of dried milk products (5 instant, 3 non-instant, and 2 whey beverages) packaged in No. 10 cans were obtained from retail distributors representing 7 manufacturers in 4 states. A 50-member consumer panel evaluated aroma, flavor, and overall acceptability using a 9-point hedonic scale. Other observations included headspace oxygen, method of oxygen reduction (nitrogen flush, oxygen absorbers), can seam evaluation, and water activity. Headspace oxygen ranged from 4.1 ppb to 20.8%. Extreme variation in can seam quality was observed. Water activity ranged from 0.137 to 0.270. Regular NFDM samples had a mean flavor score significantly higher than the instant NFDM, but there were no significant differences in overall acceptability. The whey beverages scored significantly lower than the other samples in flavor and overall acceptability. Hedonic scores for overall acceptability ranged from 4.20 to 6.03. The brand that was significantly preferred overall did not have a hermetic seal, suggesting that quality would not last over an extended storage time. There is wide variation in quality of dried milk products available at the retail level packaged for long-term storage. Manufacturers need to observe good manufacturing practices to optimize product quality. Consumers would be well advised to evaluate several brands of dried milk products prior to large quantity purchases.
Session 15A, Dairy Foods