Studies on stability of blue grape anthocyanins

Abstract

SummaryThe stability of grape anthocyanins in grape squash and juice is influenced by the nature of packaging materials and preservatives. In grape squash losses were 65–70% in glass bottles, 64–67% in paper‐aluminium foil‐polyethylene (PFP) laminate pouches, 77–81% in polypropylene (PP) pouches and 68–73% in metallized polyester‐polyethylene (MPP) laminate pouches during 60 days storage at 15–35°C. After 60 days, loss of anthocyanins was lower in samples preserved with sorbate than with benzoate, but not after 120 or 180 days storage. Sugar increased losses of anthocyanins, which were more stable in isolated model systems of sugar and benzoate than in grape squash and juice. Anthocyanins were most stable in anhydrous systems, and their rate of degradation progressively increased with water activity.