Content of health-beneficial compounds and sensory properties of organic apple juice as affected by processing technology

Abstract

Quality of cloudy organic apple juice processed by rack-and-frame press (RFP), water press (WP) or belt press (BP) was evaluated in terms of sensory properties and instrumentally measured colour, content of ascorbic acid (AsA), total soluble solids (TSS), titratable acidity (TA), polyphenols and total antioxidant capacity (TAC).‘Cortland’, ‘Krista’, ‘Krameri tuviõun’ and ‘Talvenauding’ apples from Estonia were separately processed into juice by RFP, WP and BP. Juice was pasteurized at 85 °C. Pressing methods had a significant effect on juice quality.RFP-juices had the lowest TAC and content of health-beneficial polyphenols (chlorogenic acid, (−)epicatechin, (+)catechin, procyanidin B2). BP-juices had the highest content of these polyphenols, but had the poorest sensory quality characterized as less sweet, more sour, bitter and astringent compared to other juices. RFP- and WP-juices had no differences in sweetness, sourness, astringency and bitterness, but WP-juices had the highest intensity of fresh aroma and -flavour, yellowness and clearness. Compared to RFP-juices, WP-juices had higher TAC and content of several health beneficial polyphenols, especially quercetin derivatives. Thus, WP is a good alternative to RFP in order to produce apple juice which would have higher antioxidant capacity, better appearance and higher aroma intensity.