Processing & Technology
Balaswamy et al., J Food Process Technol 2011, 2:3
Preparation of Sour Grape (Vitis Vinifera) Beverages and Evaluation of their Storage Stability
Karakala Balaswamy, Pamidighantam Prabhakara Rao, Allani Nagender and Akula Satyanarayana* Central Food Technological Research Institute (Council of Scientific and Industrial Research), Resource Centre, Habshiguda, Uppal Road, Hyderabad-500 007, India
‘Thompson seedless’ grapes (Vitis vinifera) possessing < 13° brix and > 1.0% acidity were used in the preparation of beverages with and without carbonation. Sour grape juice was extracted, bottled and clarified by racking for three months. Palatable blended grape beverages were also prepared using sour grape juice with phalsa / purple grape juice. Process parameters such as quantity of juice, blending proportions and brix / acid ratio for different beverages were optimized. Squashes were prepared by maintaining brix at 45° and acidity 0.75%. Readyto-serve (RTS) beverages were standardized with brix 15° and acidity 0.14%. The appearance, color and flavor characteristics of sour grape beverages were improved by blending with purple grape juice and phalsa juice at 2:1 and 1:1 ratios respectively. A set of carbonated beverages in the above combinations were also prepared to check their compatibility and acceptability. A marginal rise in total sugars and decrease in acidity were observed in all beverages after 6 months of storage. Sensory evaluation indicated that carbonated beverages were highly acceptable than plain beverages throughout the storage period. Highest scores of 7.4 and 7.5 were recorded for blended grape beverages with purple grape and phalsa juice respectively even after a storage period of 6 months.
Keywords: Sour grapes; Phalsa; Purple grapes; Blended beverages; Carbonated beverages
Fruit beverages are well relished by all age groups of the society. Sour grapes (Vitis vinifera) ‘Thompson seedless’ are grown in some parts of Punjab, Haryana, and Tamil Nadu possess low total soluble solids (< 13° brix) with higher titratable acidity (>1%) which are not suitable for consumption as table variety. Recently, sour grapes were explored in our laboratory for the production of various shelf stable products such as raisins, jam, spread, sweet chutney and canned grapes . It was reported that consumption of grape products at moderate level helps in prevention of aging related diseases . Since higher acidity is a major obstacle in fruits for consumption, fruit juices were subjected to de-acidification by electro dialysis , and palatable raisins were produced from sour grapes by osmo-air dehydration . Literature review revealed various combinations of fruit juice, sugar and citric acid in preparation of ready - to - serve (RTS) beverages such as mango-papaya nectar, guava-lemon and papaya-passion fruit juice blends etc [5-7].
Blending of fruit juices is practiced to overcome the high cost of some exotic fruit juices, scarcity or seasonal availability, balancing of strong flavors, high acidity, astringency, or bitterness, improving total soluble solids, bland flavor, improving and stabilizing color. Nutritional or phytochemical properties can be improved by blending which offers to adjust sugar/acid ratios and compensate undesirable juice consistency .
Comminuted guava drinks were prepared maintaining the ratio
of fruit bases to water at 100:200 and sugar to acid ratio at 450:7.6 to obtain superior organoleptic properties . Guava beverages were prepared using 5, 10% peeled fruit pulp, with 12.5% total soluble solids and 0.25% acidity. The beverages were preserved using 70 ppm SO2, 120 ppm sodium benzoate, and pasteurization at 85°C for 15 min . The juices were also assessed for retention of vitamin C and flavor in presence of carbonated water. The effect of...