Effect of whey protein concentrate as drying aid and drying parameters on physicochemical and functional properties of spray dried beetroot juice concentrate

Beetroots are good source of functional betalain pigment inherent with antioxidant activity and TPC. The feasibility of spray drying was devised along with the effects of whey protein concentrate (WPC) (5-15%), inlet air temperatures (160-180 degrees C) and feed flow rate (400-600 ml/h) to produce powder from beetroot juice concentrate (BJC). The total solids content of BJC was adjusted to 25% (w/w) with the addition of WPC. The obtained powders were analyzed for powder yield, moisture content, hygroscopicity, bulk density, a-value (color), antioxidant activity (AOA), TPC, and betalain content. The results revealed that increasing inlet temperature lowered the bulk density, AOA, TPC and betalain content in terms of 0.590 to 0.482 g/ml, 74.75 to 68.85%, 22.23 to 19.36 mg GAE/100 g and 268.54 to 267.45 mg/100 g. Depending on the analysis of the results, inlet air temperature, WPC concentration, and the interaction among them had a significant effect on the studied responses (p < 0.0001). Feed flow rate on contrary, showed nonsignificant effect. (c) 2016 Elsevier Ltd. All rights reserved.