3.2.2. Heat stability
The results revealed that HCT of control toned milk at 140 ± 1 °C at its original pH (6.76) was 26.87 min and that of milk fortified with lactose–zinc complex (pH 6.74) was 25.96 min i.e. slight difference was observed in the HCT of control milk and milk fortified with lactose–zinc complex at their original pH. The findings clearly showed that the HCT of control and milk fortified with lactose–zinc complex (at the rate of 30 mg/L) at their original pH remained comparable and found slight variation in maxima in HCT/pH curve (i.e. maxima at pH 6.5 for control and milk fortified with lactose–zinc complex was 29.80 and 28.54 min, respectively). The comparable heat stability of control and milk fortified with lactose–zinc complex could be due to negligible change in initial pH of milk after addition of fortificant. Therefore, it could be inferred that addition of zinc at the rate of 30 mg/L in the form of lactose–zinc complex did not affect the heat stability of milk adversely. (Fig 4).