Phytochemical compounds, antioxidant activity and non-enzymatic browning of sugars extracted from the water of immature coconut (Cocos nucifera L.)

Abstract

The aim of the study was to evaluate the phytochemical compounds and the antioxidant activity of sugars extracted from the coconut water. The energy value and the products of the non-enzymatic browning had also been studied. The phytochemical screening of white sugars, brown sugars and syrups, had showed the presence of polyphenol compounds (340 and 581.33 mg of galate eq./ 100 g), flavonoids (10–25.9 mg/100 g), alkaloids (2.5–8.6 g/100 g), phytates (20–26.9 mg/100 g) and tannins (35 and 50 mg/100 g). The white sugar had shown a high potential of iron reducing and of scavenging of free radicals from DPPH, compared to the brown sugar and to the syrup. In fact, the capacity of the white sugar to reduce the iron ranged from 35 to 55 mg of Trolox/100 g against from 5 to 14.79 mg of Trolox/100 g approximately for the brown sugar. Similarly, the inhibition of the DPPH radical ranged from 35.09 to 39.64% for the white sugar, against 23 to 26% for the brown sugar. The absorbance increases linearly and significantly with the time/temperature couple at 280 nm and 480 nm. Sugars obtained from the hybrids (PB121+, PB113+) and from the tall coconut (WAT) presented the highest browning degrees, in contrast with the MYD and EGD sugars which displayed the lowest optical densities. The carbon/nitrogen ratio was higher in sugars of EGD, MYD and PB121+, and particularly higher in white sugars than in brown sugars and syrups. The energy value is more important in the brown sugars and syrups than in the white sugars. These phytochemical compounds could confer to the sugars of coconut water curative and preventive effects as antioxidants.