Lactose-Zinc complex preparation and evaluation of acceptability of complex in milk

Zinc deficiency is now recognized as one of the most severe problems of human malnutrition world-wide. Lactose being a reducing sugar is able to chelate zinc and reduce the reactivity of zinc with other food components. Therefore, a process for the preparation of lactose-zinc complex has been standardized in the present work. Level of zinc salt was optimized on the basis of maximum binding ability of lactose to chelate zinc. The microstructure of lactose-zinc complex revealed that the size of the lactose crystals decreased and formed noticeable aggregates upon complexation. Sensory scores of milk fortified with zinc salt were significantly lower (P < 0.05) than milk fortified with lactose-zinc complex during storage. The heat coagulation time (HCT) of milk fortified with lactose-zinc complex was comparable with control and exhibited Type A curve with HCT-pH maxima at acidic side of natural pH. Milk fortified with lactose-zinc complex showed non-significant differences in physicochemical properties (such as pH, acidity, viscosity, HMF and TBA) than control milk during storage upto 7 days. Milk fortified with lactose-zinc complex showed significantly (P < 0.05) higher in vitro bioavailability than unfortified (control) and zinc salt fortified milk.