Effects of Variety, Maturity and Processing on Pear Juice Quality and Protein Stability

ABSTRACT ?Anjou, Comice, and Bartlett pears were processed into clarified juices from hard green and soft ripened fruits. Processing trials with and without SO 2 were conducted. Effects of variety, maturity and processing on browning, turbidity, proteins, and stability were investigated. Browning increased with heat treatment, and was reduced by processing with SO 2 . Total soluble protein content increased with fruit maturity and processing with SO 2 . Protein fractions from a clarifying enzyme preparation (mainly arabinase and amylase) with MW in the range of 64,000–92,000 and containing glycoproteins were not removed by fining/clarification. They contributed to protein instability in the clarified pear juices, but could be removed by heat treatment (pasteurization) prior to final filtration and bottling. Our results indicate some enzymes added for clarification during processing may contribute to post‐clarification haze and sediment formation.