PROTEIN IN VARIETALLY DERIVED APPLE JUICES

摘要

The effect of oxidation during apple juice manufacture on the levels of flavan-3-ol and protein was determined. Increased oxidation reduced levels of protein to 84-184 mg/L in oxidized juice from 133-424 mg/L in less oxidized product. Flavan-3-ol levels were also markedly reduced. Oxidation caused SDS-PAGE patterns to be increasingly smeared or streaked with increasing amounts of material trapped at the origin. Throughout these oxidative effects on juice protein and flavan-3-ol, there was persistence of a protein of approximately 32 kDa in the juices of McIntosh, Golden Delicious, and Jonagold apples. The possible relationship of this ''32 kDa'' protein to haze formation in clarified apple juice is discussed.