Antioxidative and anti-diabetic potentials of tigernut (Cyperus esculentus) sedge beverages fortified with Vernonia amygdalina and Momordica charantia

The utilization of tigernut is growing by the day due mainly to the myriads of health benefits attributed to it. Value addition is anticipated to further enhance the economic value and utilization of this sedge family crop. This study examined the physicochemical, antioxidant, anti-diabetic, and sensory properties of tigernut beverages fortified with extracts of Vernonia amygdalina and Momordica charantia with date and honey as sweeteners. Folin–Ciocalteau method was used to measure the total phenolic content while the ferric reducing antioxidant potential (FRAP), 2,2-diphenyl-1-picryhydrazyl (DPPH) and 2,2-azinobis (3-ethylbenzothiazoline-6-Sulfonate) (ABTS) were used to determine the in-vitro antioxidant activities. The inhibitory action of the beverages on α-amylase and α-glucosidase was used to assess the anti-diabetic potential. The DPPH, FRAP and ABTS scavenging activities were significantly higher in all the beverages with vegetable extracts. The inhibitory activity on α-glucosidase and α-amlyase are 38.82–75.54% and 20.59–60.14%, respectively. The sweeteners were able to significantly mask the bitter taste from the vegetable extracts thus improving consumer acceptability. The inhibitory effect of the beverages on diabetic related enzymes and the antioxidant activities suggest the formulation could be used as functional beverages with antidiabetic potential.