The usage of sour grape juice in beverage technology: Self life stability, kinetic variations and determination of bioactive compounds

In this study; the production, the concentration conditions and the usability of clear sour grape juice in beverage technology were investigated. Variations of beverages in 4, 20 and 24ºC were monitored during six months. In production of carbonated drink, iced tea and sherbet three different concentrate additive ratios and taste balance were studied for each group. Depending on the addition of concentrates; pH and transmittance values decreased, acidity, mineral, TFM, TF, RY, phenolic compounds, amounts of organic acid and antioxidative properties increased in beverages. The pH value of carbonated drinks were between 3,37-3,39; in iced teas 3,75 and in sherbets 3,17-3,31. Acidities were % 0,23-0,30; 0,22-0,23 and 0,30-0,48 respectively. K, Mg, Ca and Na were the most abundant minerals in beverages. In carbonated drinks TFM were between 33,36-41,16 mgGAE/L, in iced teas 396,44-418,93 mgGAE/L and in sherbets 27,30-35,00 mgGAE/L. TF amounts in iced teas were between 93,97-101,91 mgC/L and in sherbets 2,75-4,18 mgC/L. The DPPH inhibition were found between % 18,09-35,29 in carbonated drinks; between %82,61-83,82 in iced teas and between % 53,54-67,84 in sherbets. Among all investigated phenolic compounds epicatechin (EC), epicatchingallate (ECG), p-coumaric acid, ferulic acid, cinnamic acid myricetin ve quercetin were not determined in carbonated drinks and sherbets, while gallic acid (GA), epigallocatechin (EGC), catechin (C), epigallocatechingallate (EGCG); cafeic and vanilic acid were determined. In iced tea samples all investigated phenolics were found. In each of the three beverages groups tartaric, malic, citric and fumaric acid were found, but acetic acid was not found among all investigated organic acids. Malic acid was the dominant organic acid in the beverages. In the result of sensory analysis G2 in carbonated drinks, Ş3 in sherbets and Ç3 in iced teas were found as promising. During the storage period, storage temperature applications together with concentrate additive applications affected the many observed physical and chemical parameters of the samples besides. It was determined that the applied storage temperatures were effective on beverage quality. As a conclusion; sour juice can be used in carbonated and non-carbonated beverage production it was especially determined that sherbet and iced tea have high potential. Meanwhile, physicochemical and biochemical properties of sour grape juice concentrate and beverages were investigated in detail.