Study on Quality of Verjuice Affected by Grape Types, Treatments and Storage at Ambient Conditions

Abstract

To improve the quality of grape berries and bunches, berry thinning is adopted. In this practice, a sizeable quantity of thinned berries is destroyed despite having valuable contents. Thinned berries are utilized to produce verjuice in different countries. To assess the effect of grape varieties and ingredients on verjuice quality, the present study was conducted at ICAR-National Research Centre for Grapes, Pune during the fruiting season of 2022-2023. Thinned grape berries (6-8 mm diameter) from four varieties namely Manjari Naveen, Crimson Seedless, Thompson Seedless and Manjari Kishmish were utilized with three treatments as the addition of 0.49 g NaCl salt/100 mL, 3 mL olive oil/100 mL and combination of 0.49 g NaCl salt and 3 mL olive oil/100 mL. Physico-chemical parameters of prepared verjuice types were observed initially as well as 15, 30 and 45 days of storage at ambient conditions. At the initial stage, among the varieties, treatments and their interactions showed non-significant differences for TSS, acidity and pH. Among the different verjuice types, except Crimson Seedless with salt and olive oil, were recorded with maximum TSS. The pH values Were ranged from 2.35 to 2.57 while the maximum recorded titratable acidity was 3.07% whereas the lowest acidity was 2.43%. Verjuice storage at ambient conditions resulted in reduced TSS, acidity and pH. Verjuice prepared from Manjari Kishmish showed superiority in all sensory parameters while verjuice from Thompson Seedless was scored minimum. Results recorded in the present study revealed that the quality of verjuice was acceptable and need to study the combinations of different type grapes to improve verjuice quality and pesticide degradation in the process.