Changes in physicochemical properties of retort-sterilized dairy beverages during storage.

The effects of composition, storage time, and storage temperature on the physicochemical properties of a retort-sterilized dairy beverage were investigated. Drinks with eight formulations were stored at 4, 25, and 37 degrees C for 6 mo and were analyzed monthly for pH, net color difference, apparent viscosity, sedimentation index, homogenization index, particle size index, and soluble calcium. The changes in the physicochemical properties of the beverages increased as storage time and temperature increased. The degree of change was affected by the composition of the product. Sodium tripolyphosphate was implicated in promoting age gelation of samples with 11% nonfat milk solids, but sedimentation was observed in the absence of sodium tripolyphosphate and carrageenan. The apparent viscosity of samples affected the rate of age gelation and sedimentation, both of which increased as viscosity decreased. Interactions between milk fat, carrageenan, and nonfat milk solids were important in determining the apparent viscosity of the beverages and the rate of change observed during storage.