Physical and Chemical Characteristics of Raspberry Pulp: Storage Effect on Composition and Color

Raspberry pulp at different soluble solids contents was made from thawed fruit by milling, vacuum concentration (10-37°Brix), pasteurization and canning. The influence of storage at 4, 20, and 37°C was investigated. The variations in anthocyanin and ascorbic acid content and additional color indices, including Hunter parameters, were determined. Minor changes occurred when the raspberry pulp concentrate was stored at 4°C. While percent residual anthocyanin and ascorbic acid content decreased following first order reaction kinetics, increases in percent polymeric color followed near zero order kinetics and the index of polymeric color remained practically constant throughout the storage. Hunter DELTA Evariation during storage was in accordance with the thermal degradation of anthocyanin as cyanidin-3-glucoside.