PREPARATION AND STORAGE STABILITY OF YACON (Smallanthus sonchifolius) JUICE

Abstract

The main aim of this study was to prepare yacon juice and study its storage stability. Yacon brought from Uttarpani, Dhankuta which was used for the preparation of yacon juice. The fruit was sorted, washed, disinfected by sodium hypochloride solution and peeled for juice extraction. Yacon juice was analyzed for TSS, pH, titrable acidity and juce yield. Yacon juice was prepared maintaining optimum TSS (15°Bx) with addition of table sugar and optimal acidity was maintained with the help of citric acid. Pasteurization was carried out by holding at 93°C for 5 min. Then the juice was aseptically filled to sterilized plastic bottles followed by sealing with aluminum foil seal. Prepared juice was then stored for 45 days at room temperature (22±3°C) and chemical changes occurring during storage of yacon juice were analyzed. Effect of storage time on sensory attributes of the juice was evaluated using five point Hedonic scale rating test to identify the best product. The data were analyzed by two-way ANOVA using Genstat at 5% significance level. The pH, acidity(as citric acid), TSS (°Bx), vitamin C, reducing sugar (as dextrose), total sugar(as dextrose), glucose, fructose and TPC of juice on 0 day were found to be 3.82, 0.33% m/v, 15°Bx, 21.06 mg/100 ml, 4.03 % m/v, 7.98 % m/v, 160.33 mg/100 ml, 241.33 mg/100 ml and 0 respectively. Sensory analysis showed that there was significant difference among all the products with respect to smell, taste, flavor, color, consistency and overall acceptance. Increasing storage period affected the physiochemical properties of yacon juice. From sensory evaluation the juice stored for 15 days was found to be superior and had 15.33°Bx TSS, 0.34% acidity ( as % citric acid), 3.59 pH, 16.61 mg/100 ml ascorbic acid and TPC of 5×103 cfu/ml.