Abstract

The chemical and functional properties of aqueous solutions of palm sugar and aqueous extracts of Tetrapleura tetraptera fruits, as well as their mixtures, were determined as a guide to their rational utilisation as bioactive sweetener and flavouring in food, beverage, and medicinal preparations. The sugar solutions exhibited highly acidic pH values of 3.42-2.70 at concentrations of 5-40g syrup/100 mL, while the water infusions of the T. tetraptera fruit had lower acidity of pH 4.8-6.96 at a concentration range of 0.1-3.0 g/100 mL. Infusions of the fruit at 0.1-3 g/100 mL in 20% syrup solution, exhibited pH of 3.35-4.15. The palm sugar solutions, and the T. tetraptera infusions exhibited high antioxidant capacity (determined as total phenolic content and DPPH radical scavenging activity) and α-amylase inhibitory activity. The wide acid pH range, high in vitro antioxidant capacity, and high antihyperglycemic (i.e., high α-amylase inhibition) activity characteristic of the palm sugar and the T. tetraptera infusions, indicate high potential for their use as functional sweeteners and flavouring in a variety of food, beverage, and medicinal formulations for the prevention and management of type 2 diabetes mellitus.

Key words: Tetrapleura tetraptera fruit infusions, Oil palm syrup, Antioxidant capacity, α-amylase inhibitory activity, Type 2 diabetes