Abstract:In order to research the changes of phenolic compounds and antioxidant activites of litchi fruit during high temperature heat pump drying(HTHPD) processing,the content,composition and antioxidant activities of phenolic compounds of litchi pulp at different period were investigated.Results indicated that the contents of free and bound phenolic compounds and its ORAC antioxidant activities significantly decreased after HTHPD processing(P <0.01).Free phenolic compounds contributed greatly to total antioxidant activity.There was a direct relationship between free and bound phenolics contents and antioxidant activities in phytochemical extracts of litchi pulp.The higher phenolic contents in fruits resulted in higher antioxidant activity.The contents of free phenolic of gallic acid,vanillic acid,caffeic acid,(-)-Epicatechin and rutin significantly increased(P <0.05),(+)-Catechin and tetramethyl catechol significantly decreased(P <0.05).While the contents of bound phenolic of gallic acid,(+)-Catechin,caffeic acid and(-)-Epicatechin significantly increased(P<0.05),rutin significantly decreased(P<0.05).
