Chemical, physicochemical and antioxidant stability of freezing pasteurized and unpasteurized pulp

Abstract The aim of this work was to evaluate the physicochemical, chemical and antioxidant stability of unpasteurized and pasteurized Physalis peruviana L. pulp during 120 days of storage at -18 °C. Total titratable acidity (TTA), total soluble solids (TSS), TSS/TTA ratio, pH, moisture, ash, reducing sugars, color, vitamin C, total carotenoids, total phenolic compounds and antioxidant capacity were evaluated. The physicochemical and chemical analysis showed that storage under freezing did not cause significant loss of pulp quality for pH, TTA, TSS and reducing sugars. In the unpasteurized pulp, there was a significant increase in moisture content and a significant decrease in the ash content along the days of storage. The application of pasteurization promoted significant variations for the TSS and reducing sugars, at the end of the storage period, observing higher levels. The color was negatively affected by the heat treatment, observing lower values of a* and higher values of hue angle (°h). As regards the stability of antioxidant compounds, there was a reduction in vitamin C, carotenoids, total phenolic compounds and antioxidant capacity during storage at -18 °C in unpasteurized and pasteurized pulps. There were losses of 82.38% and 88.88% for vitamin C, 66.29% and 66.51% for carotenoids, and 22.26% and 31.31% for total phenolic compounds in unpasteurized and pasteurized pulps, respectively. It was concluded that the storage under freezing of pasteurized and unpasteurized Physalis peruviana L. pulp and pasteurization affected the physicochemical and chemical characteristics evaluated.