Effect of rhubarb juice on phenolics and colour of unclarified apple juice

Rhubarb juice was used to protect apple juice against browning and its phenolic compounds against oxidation. Pressed apple pulp of three varieties with 2-3% w/w rhubarb juice contained 5-18 times higher level of flavanols and procyanidins compared to rhubarb-free pulp. High correlation between rhubarb juice percentage, colour and apple juice phenolics was found (r2 = 88 - 98%). Rhubarb juice at 2 % w/w in Anton6wka var. pulp or 3% w/w in Kronselska var. pulp bad the same antioxidative effect as 0.5% w/w ascorbic acid.