Journal of Food Processing & Technology

Chances in antioxidant activity and phenolic content of pomegranate juice concentrate during storage

19^th International Conference on Food Processing & Technology

October 23-25, 2017 | Paris, France

Alev Bingol, Elif Apaydin, Mehmet Ozkan and Meltem Turkyilmaz

Ankara University, Turkey

Posters & Accepted Abstracts: J Food Process Technol

Abstract:

Effects of clarification and pasteurization on the antioxidant activity and total phenolic content of pomegranate juice were studied at 5, 12, and 20°C for a period of 8 months. Pomegranates were processed into juice with a rack and cloth press. The resulting cloudy juice was divided into two parts. Halves were clarified with gelatin at 5°C (cold clarification) and the remaining juices were not clarified. Clarified and non-clarified juices were again divided into two parts. Half were pasteurized and the remaining juices were not pasteurized. Pomegranate juice concentrates (PJC) were obtained from both clarified and nonclarified juices. Antioxidant activity was determined by ABTS (2, 2-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) methods and the results were expressed as �??Trolox equivalents (TEAC)�?�. Total phenolic content was determined spectrophotometrically by Folin Ciocalteu method and the results were expressed as �??gallic acid equivalents.�?� Clarification led to significant reductions in total phenolic content and antioxidant activity of PJC, while pasteurization did not cause any losses in antioxidant activity and total phenolic content of PJC. The non-clarified PJC had 39% more total phenolic content and 25% higher antioxidant activity than clarified PJC. Similar to effect of pasteurization, there was not significant loss in the total phenolic content of PJC during storage. On the contrary, a decrease in antioxidant activity was determined in both non-clarified (10�??11%) and clarified (13�??17%) PJC during storage. Storage temperature had no effect on total phenolic content and antioxidant activity in both non-clarified and clarified PJC. In conclusion, PJC should be produced from pasteurized non-clarified juice to protect antioxidant activity of PJC. The reconstituted juice should be cold-clarified right before marketing.

Biography :

Alev Bingol completed her undergraduate studies in the Department of Food Engineering at Ankara University in 2015. She is pursuing Master of Science degree in the same department since 2016.