Physicochemical and Antioxidant Properties of Copper-Amaranth Leaf Purees Using Viscozyme-L Enzymatic Liquefaction

This study evaluated the effect of cell wall-degrading enzyme (Viscozyme® L) on the physicochemical properties and antioxidant activity of copper-amaranth (Amaranthus Viridis Linn.) leaf purees. The purees were liquefied with varying concentrations of Viscozyme® L (0–3% v/w) over different incubation times (30 minutes to 24 hours). It was observed that treatment with 1% Viscozyme® L (v/w) at pH 5 for 3 hours, followed by incubation at 45 °C, resulted in a significant increase in total soluble solids (°Brix), acidity, and total chlorophyll content. The enzyme-treated purees exhibited higher DPPH (13.52 mM (TE)/g fresh weight), and FRAP (6.04 mM (TE)/g fresh weight) values, as well as in reducing sugar (118.43 mg/mL), soluble dietary fibre (4.32%) content and greener colour (-0.35) values, as compared to non-enzyme treated purees (0.13 mg/g, 9.47 mM (TE)/g and 3.72 mM (TE)/g fresh weight, and 12.75 mg/mL, 0.60%, and -0.28, respectively). These findings demonstrate that treatment with Viscozyme® L enzymes can effectively improve the nutritional and functional quality of vegetable-based purees, with potential applications in the processing of green vegetable juices.