Effects of Different Storage Time and Temperature on Physicochemical Properties and Fatty Acid Profiles of Commercial Powder Goat Milk Products

摘要

Dehydration has a benefit of extending shelf life of foods, which can reduce or minimize nutritional and physicochemical changes in powdered goat milk products during storage. The objectives of this study were to evaluate physicochemical properties and fatty acid compositions of powdered goat milk (PGM) during storage. Three batches of commercial whole goat milk powders were purchased from a local retail outlet in Warner Robins, Georgia, and the PGM samples were stored at 4 and 22°C for 0, 2, and 4 months. Results showed that there were significant (P<0.05) differences in peroxide value (POV) between storage temperatures and periods of the samples. PGM samples stored at higher temperature and longer period revealed higher lipid oxidation than those of lower temperature and shorter storage period. Storage time also had significant (P<0.05) influence on pHs, but not on water activity of PGM products. Fatty acid profiles showed that both C18:1 and C8:0 had the highest concentrations among all fatty acids tested in the PGM. Among the three main factors, batch and storage time had significant (P<0.05, 0.01, 0.001) effects on majority of fatty acids, while storage temperature had a minimal effect. Two-way interactions of storage temperature x storage time and batch x storage temperature had no significant impacts on fatty acid contents. However, 2-way interaction of batch x storage time was significant for most fatty acids, including C8:0, C10:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, and C20:0. In addition, 3-way interaction of batch x temperature x period had significant effects on C10:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, 20:0. It was concluded that lipid oxidation of commercial PGM products were significantly (P<0.05) affected by storage temperature and period, while fatty acids contents were influenced by mainly batch, storage period and some interaction effects.