• Corpus ID: 17169635

Phenolic Compounds and Antioxidant Activity of White , Red , Black Grape Skin and White Grape Seeds

@inproceedings{Samah2012PhenolicCA,
  title={Phenolic Compounds and Antioxidant Activity of White , Red , Black Grape Skin and White Grape Seeds},
  author={Samah and Mutanda Ishmael and Sahar S. A. Soltan and Khaled and A. H. Selim and M. H. M. Ahmed},
  year={2012}
}

• Samah, M. Ishmael, +3 authors M. Ahmed
• Published 2012

Grape skin and seeds are sources for phenolic compounds that contribute to the sensory characteristics and beneficial bioactive of many processed foods. Hence, the study was aimed to evaluate and characterize the phenolic composition and evaluate the antioxidant activities of three grape varieties skin (white, red and black) and white grape seeds. The results indicated that among the grape skin of the three varieties, black grape skin (BGS) contained the highest amount of total phenolic compounds (2070.02mg GAE/100g dry weight). While white grape skin (WGS) found to have the lowest phenolic contents (296.27mg GAE/100g). On the other hand, white grape seeds (WG Seeds) contained the highest content of phenolic compounds compared to the skin samples (2536.5mgGAE/100g dry weight).The phenolic composition of the grape skin and grape seeds samples were determined by HPLC. The main phenolic compound in the three grape skins was Di-OH-cinamic acid. In the contrast, the main phenolic compounds in the grape seeds were Catechin and Brocyanidin B1. Besides, all the extracts showed remarkable DPPH radical scavenging activities with EC50 values ranged from 0.2626.91μg extract/μg DPPH. The results showed that scavenging capacity of black grape skin and grape seeds extracts increased with increasing concentration of the skin extract in the range 0 – 21.08 μg extract/μg DPPH and grape seeds extract up to 1.92 μg extract/μg DPPH. Effect of addition different concentrations of grape skin and seeds extracts on oxidative stability of sunflower oil at 100 °C by Rancimat was studied. The results indicated that at low concentration 200ppm all extracts improved the oxidative stability of sunflower oil comparing to the control. The addition of 2% WGS, RGS, BGS and WG Seeds to rats diet showed significant decrease P<0.05 of TC, LDL-C and TG. On the other hand, 4% (RGS, WG Seeds), 8% BGS and 2% WG Seeds showed the same effects as BHT. Feeding rats on diet containing 200ppm BHT and 4% (WGS, RGS, and BGS) showed that no significant change of HDL-C compared to the control group. Serum Glucose was increase by increasing the levels of grape skin and seeds, in the diet. Feeding rats on diet containing 8% (WGS, RGS, and BGS) and WG Seeds at different levels caused a significant increase in catalase enzyme activity compared to synthetic antioxidant. Meanwhile, Feeding rats on diets containing 4% and 8% grape skin and seeds decreased liver function more than 2% compared to the control group and synthetic antioxidant. In Conclusion grape skin and seeds had higher antioxidant activity a specifically at low concentrations. Moreover, higher concentrations lead to higher decrease of liver function more than low concentration. The high phenolic content and the considerable antioxidant activity of the grape skin and seeds could be potentially considered as sources for natural antioxidants [Samah, M. Ishmael; Sahar, S. A. Soltan; Khaled, A. Selim and Hoda, M. H. Ahmed. Phenolic Compounds and Antioxidant Activity of White, Red, Black Grape Skin and White Grape Seeds. Life Sci J 2012;9(4):34643474]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 514