Optimization of spray-drying conditions for the preparation of whey protein concentrate-iron complex using response surface methodology

In this study, spray-drying process was optimized to produce whey protein concentrate-iron (WPC-Fe) complex with the aim of making iron compatible with food products. WPC-80 and FeSO4 complex formation was achieved using centrifugation (to remove insoluble iron), ultrafiltration (to remove unbound iron), and spray-drying. Spray-drying of WPC-Fe complex solution was carried out at inlet temperature, flow rate, and total solids (TS) ranging from 126.3 degrees C to 193.6 degrees C, 0.63 to 9.87 ml min(-1), and 1.59% to 18.40%, respectively, as generated by central composite rotatable design. The optimum operating condition for WPC-Fe complex production was 180 degrees C inlet drying temperature, 2.66 ml min(-1) flow rate, and 15% TS content. At this optimized condition, moisture content, yield, and solubility were observed to be 4.19%, 8.21 g 100 ml(-1), and 87.53% which were comparable with the predicted values, viz. 4.11%, 8.29 g 100 ml(-1), and 60.64 degrees C, respectively, derived from the equation validating the generated mathematical model. The spray-dried WPC-Fe complex generated could be used in foods as an organic fortifier to reduce the menace of iron deficiency.