3. Results and discussion
3.1. Preparation of lactose–zinc complex
A detailed study was carried out to optimize zinc (as zinc sulphate) concentration on the basis of maximum zinc binding ability of lactose. To remove free/unbound zinc completely from the complex; the complex preparation method involved two steps (centrifuge and washing) to get rid of free or unbound zinc. The results obtained from the present work discussed in two phases i.e. Phase I: zinc remaining in the supernatant after centrifugation. Phase II: zinc retained in the lactose–zinc complex after crystallization (Table 1).