Comparison of physicochemical and antioxidant properties of edible fruits in the Sundarbans’ mangrove forest, Bangladesh

Ten edible fruits of the Sunderbans’ mangrove forest in Bangladesh were analyzed to compare their physicochemical, nutritional and antioxidant properties. Among the fruits, the lowest pH of 4.2 was observed in Sonneratia caseolaris whereas the rest remains within 6.1 to 7.1. The highest electrical conductivity (596.3 μS/cm), total dissolved solid (298.2 ppm) and ash content (0.26%) were recorded in the fruit of Phoenix paludosa. Carbohydrate, protein, lipid and vitamin C contents were the highest in Avicennia officinalis, Ceriops decandra, Heritiera fomes and Bruguiera gymnorrhiza fruits, respectively. In these fruits, the most abundant macro and micro-elements were K and Fe, respectively. C. decandra showed the highest content of polyphenols (58.5 mg GAE, gallic acid equivalent/g powder), flavonoids (86.4 mg CE, (+)-catechin equivalent/g powder) and anthocyanins (0.39 μmol/g powder). C. decandra also showed the strongest DPPH free radicals scavenging, reducing power, and total antioxidant capacity. Noticeably, total polyphenols showed their strong correlation to total flavonoids (r2 = 0.90), anthocyanins (r2 = 0.81), reducing power (r2 = 0.98) and total antioxidant capacity (r2 = 0.88) of the fruits. Fruits of C. decandra, therefore, should be considered as a potential source of antioxidants followed by H. fomes and P. paludosa.