Proximate composition, phytochemical properties, antioxidants activity and effect of refrigeration for long time storage of two different taste and maturity stage of Tamarindus indica pulp

The aim of this research was to assess the nutritional composition and the effect of refrigeration storage on phytochemicals and antioxidant activity among three different tamarind pulp. In this analysis, the nutritional composition, except for carbohydrate was examined according to the AOAC (2005) method. Phenolic content was measured as mg GAE per g, flavonoid content as mg QE per g of fresh weight and antioxidant activity, DPPH assay as percentage of activity and reducing power were applied to analyze the ethanoic extract of tamarind pulp. The results showed that fat, protein, fiber, and carbohydrate were highest in sweet ripened compared to other two types and sour immature tamarind contained higher moisture and ash content. After 90 days of refrigeration, a significant loss (p < 0.05) of phenolic compounds, flavonoids and antioxidant activity was observed. The highest reduction in phenolic content was found in sweet ripened tamarind pulp, decreasing from 40.57 to 14.45 mg GAE/g, whereas sour ripened pulp showed the greatest decline in both flavonoid content (6.45 to 1.33 mg QE/g of fresh pulp) and antioxidant activity (92.39 to 72.97%). Therefore, the fruit taste type, maturity, and storage time of tamarind significantly affect its chemical composition, phytochemical content, and antioxidant activity.