CHANGES OF PHENOL COMPOUNDS CONTENT, COLOR PARAMETERS AND ANTIOXIDANT ACTIVITY DURING STORAGE OF JUICES FROM SELECTED APPLE VARIETIES

The juice from mixture of apples comprised of 80% 'Szampion' variety (high phenol compounds content and high antioxidant activity) and 20% 'Lobo' variety (high polyphenol oxidase activity) was characterized during storage by a higher physical and biochemical stability in comparison with homogeneous juices obtained from the same, single apple varieties. It is suggested that the decrease of content of chlorogenic acid and epicatechine induced by polyphenol oxidase activity at the stage of mixed juice preparation, was the main cause for these differences. During one year storage of mixed juice, in contrast to the homogeneous juices stored during 5 months, their antioxidant activity was preserved at the same level whereas the decrease of phenol compounds content characteristic for apples was distinctly lower and refers mainly to chlorogenic acid.