Effect of flour processing on the proximate composition, polyphenolic content, and antioxidant activity of 19 Philippine sweet potato cultivars

摘要

Nineteen sweet potato cultivars (white-, yellow-, and purple-fleshed) were investigated for the effects of flour processing on their proximate and mineral composition, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities in terms of oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Significant (p ＜ .05) variations for all parameters were observed among the cultivars. Flour processing also significantly affected these properties but varied depending on the cultivar. Contributions of phenolics and flavonoids to the antioxidant activities of sweet potato were indicated by the strong positive correlations among TPC, TFC, ORAC, and DPPH assays. Flour produced from the purple- fleshed cultivar (SG-08-09-11) consistently exhibited the highest value in terms of TPC (128.03 mg GAE/100 g), TFC (95.04 mg CE/100 g), ORAC (4099.37 μmol Trolox/100 g), and DPPH (10302.74 μmol TE/100 g). It also exhibited the highest dry matter assuring high flour yields, hence, it can be recommended as an alternative flour source with health benefits.