Optimization of low alcoholic bitter gourd apple beverage by applying Response surface methodology (RSM)

Abstract

Bitter gourd (Momordica charantia) - a member of the cucurbitaceae family, and a popular vegetable among gourds is known as bitter melon, bitter gourd, balsam pear and karela. It has bitter taste and is known to possess many medicinal properties including those for the cure of diabetes caused by insulin deficiency or resistance. Attempts were made to prepare a low alcoholic beverage from bitter gourd and apple by standardizing the concentration of apple juice, DAHP and inoculum size by applying central composite design (CCD) of RSM. On the basis of physico-chemical and sensory characteristics, a run having 40% apple juice, 0.15 % DAHP and 2.5% inoculum level were rated as the best. It has the highest TSS, rate of fermentation, ethanol, reducing and, total sugars and total phenols. With the addition of 0.15% DAHP as a nitrogen sources, bitter gourd based wine had the highest total soluble solid (TSS), titratable acidity, ethanol, total and reducing sugar content and lowest volatile acidity and higher alcohols. Different concentrations of yest innoculum used did not significantly influenced most of the physic-chemical characteristics. Must inoculated with 2.5% Saccharomyces cerevisiae var ellipsoideus used for the preparation of bitter gourd based wine had the highest fermentability and ethanol content. However, the product being low alcoholic, need pasteurization at 62 degreesC for 20 min. keeping a head-space of 2.5 cm in a glass bottle. Bitter gourd beverage so prepared holds promise as a medicinal drink as bitter gourd is known to be antidiabetic.