Abstract:The formation of polyphenol-protein complex is one of the important reasons for precipitation of cloudy apple juice. High performance liquid chromatography was used to analyze the contents of phenols in six varieties of cloudy apple juice in western Liaoning province, and the interaction rules of characteristic phenolic compounds with gliadin were studied using fluorescence spectroscopy. The effects of processing temperature on the interaction between polyphenols and protein were also investigated. The results showed that, chlorogenic acid, gallic acid and epicatechin were the three characteristic phenolic compounds in cloudy apple juice. With the increase of characteristic phenolic compounds concentration, the fluorescence quenching for gliadin was stronger, and the quenching mode were all static quenching. Kinetic analysis showed that, the binding ability of characteristic phenolic compounds with gliadin was in the order of epicatechin-gliadin > chlorogenic acid-gliadin > gallic acid-gliadin. The binding stability of characteristic phenolic compounds with gliadin was as follows: chlorogenic acid-gliadin > gallic acid-gliadin > epicatechin-gliadin. Thermodynamic analysis showed that, hydrogen bonds and hydrophobic interaction were mainly formed between epicatechin and gliadin, chlorogenic acid and gliadin, gallic acid and gliadin. With the increase of temperature, the binding stability of characteristic phenolic compounds with gliadin in cloudy apple juice tend to decrease. This study could provide reference for improving the stability of cloudy apple juice during processing.