Chemical Components, Nutritional Value, Volatile Organic Compounds and Biological Activities In Vitro of Coconut (Cocos nucifera L.) Water with Different Maturities

The differences in chemical components, nutritional value, volatile organic compounds, antioxidant activity and alpha-glucosidase inhibiting capacity in vitro in coconut waters with different maturities (8, 10, and 12 months after pollination and germination height below 10 cm were named CW-8, CW-10, CW-2, and MCW, respectively) from the tall coconut variety were compared and analyzed. Results showed that as the maturity increased, the ash and reducing sugar in coconut water gradually decreased, while the protein content and fatty acids continued to increase. Potassium, phosphorus, and sodium in four coconut waters showed a trend of first increasing and then decreasing, and CW-12 had the highest content of 2133.85 mg/kg, 239.74 mg/kg, and 310.75 mg/kg, respectively. The volatile organic compounds (VOCs) present in higher amounts are alcohols and esters in coconut waters, among which 2-methylbutyl acetate, ethyl acetate monomer, and 2-methyl-1-propanol dimer were the characteristic volatile substances that distinguish MCW from the other three coconut waters. MCW has the best DPPH-scavenging and ferrous-ion-chelating ability (87.39% and 7.65%), while CW-8 had the highest hydroxyl and ABTS radicals scavenging rate (97.31% and 83.48%) and alpha-glucosidase inhibitory rate (81.36%). These results can provide support for the differential and high-value utilization of coconut water with different maturities.