Physico-Chemical Properties and Antioxidant Potential of Syrup Prepared from ‘Madhura’ Sweet Sorghum (Sorghum bicolor L. Moench) Cultivar Grown at Different Locations in Kenya

Abstract

The study was undertaken with the objective of producing sweet sorghum syrup, analyze its physical, chemical and antioxidant properties, and quantify the influence of environment on the properties of the syrup. The color coordinate values of Chroma and Hue angle were indicative of the dark brown coloration of the syrups and were most influenced by location compared to L* values. The density and the moisture content showed no significant difference while apparent viscosity and total acidity was significantly different between the syrup compared from two locations. The sweet sorghum syrups from the two locations had fructose levels of 12 and 2 %, sucrose at 66 and 88 % while and glucose levels were 17 and 6 %, respectively. Calcium was the macro-element with the highest concentration ranging between 108.0 and −272.33 mg/100 g of syrup and was significantly different (p ≤ 0.05) between the locations. For micro-elements, magnesium had highest (124 and 118 mg/100 g).The sweet sorghum syrups exhibited high level of total phenolic content and total flavonoid content at 261.31 mg Gallic acid equivalents and 197.50 mg quercitin acid equivalent per 100 g syrup respectively. Since the radical scavenging activity was greater than 50 % even at low syrup concentrations, indicates that the sweet sorghum syrups are potent free radical-scavengers. This study shows that the sweet sorghum syrup is comparable to sugarcane syrup. Because of its superior antioxidant properties the syrup may find application in the food industry.