International Journal of Science, Engineering and TechnologyAuthors: Sneha Shende
Abstract: Color is an important quality attribute of flavored milk and can indirectly indicate physicochemical changes during processing and storage. The present study investigated the color characteristics of pasteurized and sterilized flavored milk prepared from lactose-hydrolyzed milk using immobilized β-D-galactosidase and compared them with untreated control flavored milk. Lactose hydrolysis was achieved using β-D-galactosidase immobilized in calcium alginate beads, with fresh and reused beads used to prepare lactose-hydrolyzed milk. Color was evaluated instrumentally using Hunter color parameters, namely L* (lightness), a* (redness/greenness), and b* (yellowness/blueness), during refrigerated storage of pasteurized flavored milk for 7 days and storage of sterilized flavored milk at 37 °C for 90 days. Pasteurized lactose-hydrolyzed flavored milk showed significantly lower L* and b* values and higher a* values than the control during storage (p < 0.05), indicating a gradual loss of whiteness and a comparatively darker, slightly reddish-brown appearance. In contrast, the differences in L*, a*, and b* values between sterilized lactose-hydrolyzed and control flavored milk were generally nonsignificant (p > 0.05), although progressive darkening and changes in redness and yellowness were observed during extended storage. The greater color changes in lactose-hydrolyzed products are plausibly associated with increased availability of glucose and galactose from lactose hydrolysis, which provide more reactive reducing sugars for Maillard reactions.
DOI: https://doi.org/10.5281/zenodo.23210331
