Physicochemical analysis of grape juice from Israel blue (Vitis vinifera L.) grape cultivar under different processing conditions and a comparison with Red Globe and Michele Palieri grape varieties

Abstract

Physicochemical properties of Israel blue grapes (Vitis vinifera L.) has been hardly addressed in literature despite its wide cultivation in Jaffna, Sri Lanka. This work evaluates the physicochemical properties of Israel blue grape juice compared with two imported grape varieties in Sri Lanka (Red Globe and Michele Palieri). Total Soluble Solids (TSS), Titratable Acidity (TA), pH, color and clarity of each grape cultivar subjected to four different processing conditions namely raw juice, pasteurized juice, 1.5 % pectinase enzyme treated juice with 40 0C incubation temperature, 2 hours’ incubation time and 2 % pectinase enzyme treated juice with 40 0C incubation temperature, 2 hours’ incubation time, were studied. Israel blue grape juice with 2 % pectinase enzyme treatment, 40 0C incubation temperature, 2 hours’ incubation time resulted in 18.75±0.27 TSS, 0.72±0.01% TA, 3.61±0.012% pH, 0.039±0.003 absorbance in terms of clarity and 21.79±0.860 hue angle indicating red color.