Ph.D. Dissertation:

Extraction and encapsulation of sardasht red grape skin (Vitis Viniferae cv. Rash) bioactive compounds and stability evaluation of these compounds in yoghurt

Abstract The aim of this study was to compare the Optimization of Extraction Conditions of Bioactive Compounds from scum of Siahe Sardasht Grape through Response Surface Methods. Two methods were used for extraction of bioactive compounds. The method involves the Maceration and Ultrasonic- Assisted Extraction. A central Composite Design (CCD) was employed to investigate the effect of two independent variable, namely temperature and time on dependant variable (phenolic compounds, anthocyanins content and antioxidant activity). Independent Variable factors of Maceration Extraction included temperature (25-35° C) and time (12-24 hour) and Ultrasonic- Assisted Extraction included temperature (35-55 ° C) and time (15-30 minutes). The optimal conditions for extraction of phenolic compounds, anthocyanins content and antioxidant activity from Siahe Sardasht grape scum through ME and UAE methods were 35°C, 24 hours 55°C, 15 minutes, respectively. In optimal conditions through ME, the amount of phenolic compounds was 96.779 mg of gallic acid in 100 ml of extract, anthocyanins 118.345 mg/L and antioxidant activity was 55.4919% and through UAE, the amount of phenolic compounds was 114.115 mg gallic acid in 100 ml of extract, anthocyanins 121.645 g/L, and antioxidant activity was 64.89%. The results showed that the ultrasonic method is a better method than maceration to extract bioactive compounds in Siahe Sardasht grape extract. Under optimized conditions the empirical values well agreed with the values foretaste by the proposed models. Chromatographic identification of some phenolic compounds in the extract optimal ultrasonic method showed the highest amount of Catechin then gallic acid, salicylic acid and vanillic acid. Petunidin 3-o glucopyranoside and Peonidin 3-o-glucoside chloride are identified in optimized extract. The highest amount of anthocyanins is Peonidin 3-o-glucoside. After extraction of bioactive compounds, these compounds for use in food formulations to increase the stability of these compounds in food will be considered. Microencapsulation of major bioactive compounds extracted from grape skin of Siahe Sardasht is done by maltodextrins and gum Arabic with ratios of 50- 50, 75-25 and 25-75 according to optimal results and also in relation to core fixed to the wall Find the features optimal powder was used. The experiments were carried out, including moisture content, microencapsulation efficiency, water activity, solubility, colorimetry, morphology powder, anthocyanin, Phenolic compounds and antioxidant activity, respectively. According to the results of encapsulated powder characterization of samples 50-50 were selected for the final stage in our use was considered. Finally the powder 0.3 to 0.6 with respect to the optimal 50-50 in the parameters of our formulation was used to enhance the diversity and organoleptic characteristics, phenolic compounds, anthocyanins, antioxidant activity level of our samples during the 21 days of storage was investigated. The results showed that the most amounts of anthocyanin and phenolic compounds and antioxidant activity are observed in 0.6 powder with tannic acid. In addition to the significant reduction in anthocyanin compounds was considered through 21 days, the most amounts of anthocyanin related to 0.6 powder with tannic acid. Yogurt containing 0.3 powder was obtained the highest score compared to other samples by panelists. Keywords: Siahe Sardasht grape, Maceration method, Ultrasound-assisted extraction, RSM, HPLC, Microencapsulation, Maltodextrine, Gum Arabic.

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