PHENOLIC PROFILE, ANTIOXIDANT PROPERTIES AND THERMAL STUDIES OF MALTED SORGHUM FLOUR AND BISCUITS SUPPLEMENTED WITH GINGER POWDER

Abstract

The incorporation of spice as natural additives to food is on the increase, due to its acclaimed therapeutic approach in treating age – related diseases. The aim of this research was to produce biscuits that are rich in antioxidant properties using malted sorghum and ginger powder. The ginger powder was incorporated into the malted sorghum flour at 3, 4.5 and 6% and biscuits were produced from the flour blends. Malted sorghum biscuit without ginger powder was used as control. The biscuits and flour blends were analyzed for proximate, mineral, glycemic index and invitro starch digestibility, phenolic profile, antioxidant properties, thermal studies and micro-structural properties. The sensory and overall acceptability properties of the biscuits were also evaluated. The moisture content of the malted sorghum ginger biscuit ranged between 3.45 and 4.83 %, the crude fat content ranged between 2.58 and 2.69 %, the ash content ranged from 1.41 to 3.46 %, the crude fibre content ranged between 1.21 and 1.38 %, the crude protein content ranged from 5.31 to 7.31 %, carbohydrate content ranged between 82.10 and 84.55 %. The mineral content of the biscuits are: potassium(K) content ranged from 88.00 to 184.00 mg/100g, calcium (Ca) content ranged between 75.00 and 122.00 mg/100mg, sodium (Na) content ranged from 67.40 to 101.20 mg/100mg, magnesium (Mg) content ranged between 5.93 and 8.16 mg/100g, while iron (Fe) content ranged from 0.12 to 0.89 mg/100g. The glycemic index ranged between 55.58 and 58.34 % while the invitro starch digestibility ranged from 54.48 to 59.33 %. Phenolic compounds in biscuits were identified and quantified using HPLC – DAD. Eight bioactive compounds were identified and quantified in the malted sorghum ginger biscuits, the prominent bioactive compound was – caffeic acid in 3% and 4.5% malted sorghum ginger biscuits, Ellagic acid was the most pronounced in 6% malted sorghum ginger biscuits. Six bioactive compounds were identified and quantified in the malted sorghum without ginger