Effects of thermal processing on antioxidant, phenolic and anthocyanin levels in blackcurrant juice

Health and Wellness continues to be a major driver for consumers within the current marketplace. Given this climate, superfruits such as blackcurrant (Ribes nigrum) are gaining interest among beverage manufacturers due to their high content of antioxidants and anthocyanins. Blackcurrant juice, while very popular in Europe, is just beginning to gain acceptance in the domestic marketplace.;Various thermal processes are required throughout the production of a shelf stable juice product at both the raw material and finished beverage stages. The goal of this research is to evaluate the effect of these thermal processes on the retention of heat sensitive compounds such as phenolics, anthocyanins and overall antioxidants in the final consumer beverage. To this end, bulk samples of 13 brix flash pasteurized and 65 brix concentrated blackcurrant juice were obtained and further processed at beverage scale. The beverage scale processing entailed the three key thermal processes utilized by retail manufacturers: aseptic, hotfill and tunnel pasteurization. The raw material juices and fully processed samples were then analyzed for anthocyanin content, total phenolic content and antioxidant capacity to understand retention of these nutrients in the post process beverage.;The findings of this study show marked losses at the raw material level of all measured components with a reduction in Phenolic Content of approximately 35%, a reduction of Antioxidant Capacity by 48% and, most significantly, a reduction of Anthocyanin Content of approximately 80% in the concentrated juice as compared to the flash pasteurized Not From Concentrate (NFC) juice. The anthocyanin content was seen to undergo additional degradation (40-50%) by further processing the juice at beverage level, while little or no further change in either antioxidant capacity or phenolic content was seen. There was little to no difference in the impact of aseptic, hotfill or tunnel pasteurization as compared to each other.;Understanding the relationship between process and retention will allow industry to leverage the proper processes required to deliver the desired health benefits to consumers.