Atributos de qualidade e estabilidade de compostos antioxidantes em polpa congelada de amora (Morus nigra L.)

Abstract

The objective of this study was to evaluate the stability of the frozen blackberry pulp by pH monitoring, titratable acidity (TTA), total soluble solids (TSS), color and phenolic compounds, anthocyanins, ascorbic acid and antioxidant capacity at 0, 30, 60 and 90 days of storage. The physico-chemical analyzes showed that the freezing and storage interfered significantly (p≤0.05) in those properties. In general, pH values and SST decreased during storage. The pH increased from 4.33 to 3.97 and the TSS of 10.5 to 10.0 ° Brix after 90 days under freezing. Already, the TTA increased over storage. The color parameters examined indicate that the hue angle (°Hue) increased significantly (p≤0.05) during storage, indicating a tendency for the color blue, and the lightness (L*) decreased. In relation to the antioxidants analysis it can be seen that the processing and storage interfered with its antioxidant power, being able to verify that the phenolic compounds showed a loss of 26.21%, total anthocyanins a loss of 38.46% and ascorbic acid a loss of 84.24%, and this compound was more deteriorated during storage. The antioxidant capacity did not change significantly (p>0.05) during the 90-day storage, and phenolic compounds and anthocyanins show a positive correlation between this variable. Therefore it is concluded that the processing and storage under freezing can interfere with the quality attributes and stability of antioxidant compounds of mulberry pulp.