Studying Physicochemical Properties of Sardasht Red Grape Skin Encapsulated Extract and Stability Evaluation of These Compounds in Yoghurt

Sardasht’s red grape (Vitis Viniferae cv. Rash) skin is one of the most abundant wastes found in juice factories annually and is a rich source of bioactive compounds. In this research after preparing the extract with ethanol- chloride-acid solution from the skin of Sardasht’s red grape, the bioactive compounds were determined using high performance liquid chromatography (HPLC). The results showed the highest amount of phenolic compounds were for gallic acid then catechin, salicylic acid and vanillic acid. The highest levels of anthocyanins were Petunidin 3-o glucopyranoside and Peonidin 3-o-glucoside chloride. Microencapsulation of the skin of Sardasht’s red grape extracted is done by maltodextrins and Arabic gum with ratios of 50-50, 75-25. The experiments were carried out, including moisture content, water activity, solubility, anthocyanin, phenolic compounds and antioxidant activity. According to the results, The powder obtained from the microencapsulation of the sample with maltodextrin and Arabic gum (50-50) with the highest phenolic compounds and antioxidant activity were selected and used in yoghurt (0.3-0.6) with tannic acid (1% by weight). Phenolic compounds, anthocyanins, antioxidant activity level of our samples during the 21 days of storage were investigated. The results showed that the most amounts of anthocyanin and phenolic compounds and antioxidant activity were observed in yoghurt with 0.6% powder with tannic acid. Significant increase in phenolic compounds, anthocyanins and antioxidant activity of yogurt containing encapsulated powder were observed compared to control yogurt. The results showed that red grape’s skin extract and powder can be used in functional food formulations