Evaluation of Functional and Antioxidant Properties in Alocasia macrorrhiza Corm Flour

Abstract

Alocasia macrorrhiza is an edible corm native to Sri Lanka. Despite its nutritional and medicinal benefits, it is not consumed in Sri Lanka due to its acridity and is regarded an underutilized corm. These corms can be processed into flour after applying thermal processing which can alter the properties of flour. The present study aimed to evaluate functional properties and antioxidant properties of flours after milling raw, boiled and roasted corm into flour. The water and oil absorption capacities (166.61±14.43 and 132.58±5.34% respectively) of raw corn flour was significantly similar to that of commercial wheat flour (116.67±15.28 and 160.00±5.00% respectively). Moreover, the flour showed better solubility characteristics than wheat flour. The swelling power of the flours ranged between 3.01±0.01 and 7.34±0.13 g/g and these values were lower than swelling power of commercial wheat flour. The gelatinization temperatures of flour samples were in the range of 72.67±2.08 to 89.67±0.58°C which was higher than commercial wheat flour. Higher bulk densities showed by all samples while the highest bulk density (0.71±0.02 g/cm3) and tapped density (0.89±0.00 g/cm3) were shown by roasted corm flour. The processed corm flour showed moderate flowability while raw corm flour showed poor flowability. Total phenolic contents of raw, roasted, and boiled corm flours were 50.01±1.36, 77.42±1.67, and 49.39±1.75 mg GAE/ 100 g, respectively. However, total flavonoid contents were not significantly different among flour samples. The roasted corm flour showed the highest radical scavenging activities with a minimum IC50 value (66.70±2.52 mg/ml) for DPPH assay and reducing power (155.7±20.6 mg TE/100 g) compared to raw and boiled corm flour. The boiled corm flour showed the highest radical scavenging activities with a minimum IC50 value (9.96±1.23 mg/ml) for ABTS assay. In concluding, thermally processed corm flours showed higher functional and antioxidant properties than raw corm flour.