Antioxidant activity, total phenolics and some chemical properties of Okuzgozu and Narince grape pomace and grape seed flours


GÜL H. , ACUN S., SEN H., NAYIR N., TURK S.

JOURNAL OF FOOD AGRICULTURE & ENVIRONMENT, cilt.11, sa.2, ss.28-34, 2013 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 11 Konu: 2
  • Basım Tarihi: 2013
  • Dergi Adı: JOURNAL OF FOOD AGRICULTURE & ENVIRONMENT
  • Sayfa Sayıları: ss.28-34

Özet

In the scope of this study, the grape pomace, which arises as a result of process of Okuzgozu (red) and Narince (white) grape types in wine industry and which is used generally as animal feed and fertilizer. After convectional drying, the pomace samples are divided into 3 groups as whole pomace, seedless pomace and only seeds. They were ground to obtain their flours. Besides chemical properties of those 6 different sample forms, their total phenolic material, antiradical activity, anthocyanins and total dietary fiber content were determined and compared with each other. According to obtained results; while there was no significant difference between final moisture values of pomaces, the ash content of grape seeds was higher than that of others. The first ranks among all samples belong to Okuzgozu seedless pomace flour in terms of protein (14.87%), Okuzgozu seed flour samples in terms of oil content (17.34%) and Narince seed samples follow it with value of 14.1% oil. The total sugar values of seedless pomace and whole pomace of Narince (21.5% and 19.33%, respectively) were evaluated as high when compared with all other pomace forms. It was determined that while seed samples of Narince and Okuzgozu species have rich composition in terms of total phenolic material (respectively 563.27 g/kg GAE and 552.10 g/kg GAE), they exhibit high antioxidant property in parallel with it (respectively 104.44 IC50= mu g/ml and 100.71 IC50= mu g/ml). The dietary fiber (72.45% and 72.78%, respectively), phosphorus and magnesium contents were higher than those of other samples. While whole pomace flour of Okuzgozu grape species had the highest anthocyanin (5754.0 mg malvidin-3-glucoside/kg) value, seedless pomace sample of Okuzgozu grape species follows it with value of 4853.29 mg malvidin-3-glucoside/kg. As a result, Okuzgozu and Narince seed flours can be functional food additive due to their rich composition of phenolic material, total dietary fiber, total oil, magnesium and phosphorus. Okuzgozu grape pomace seedless flour and whole flour may be used in production of natural anthocyanins and/or natural coloring material.