Determination of citric acid pretreatment effect on nutrient content, bioactive components, and total antioxidant capacity of dried sweet potato flour.

Orange flashed sweet potatoes are rich and inexpensive source of diet and antioxidants. The purpose of this study was to evaluate the effects of CA pretreatments and convective hot air drying temperature on proximate composition, bioactive components, and total antioxidant capacity of flour of five orange flashed sweet potato varieties. Moisture, protein, ether extract, ash, carbohydrate, fiber, β-carotene, total phenolic compounds, and total antioxidant capacity in the dried flour samples were evaluated and reported in the range of 4.1-7.4%, 2.4-4.2%, 1.2-1.1.8%, 2.2-3.2%, 82.7-87.1%, 1.3-1.8%, 35.5-91.6 mg/100 g, 49.8-107.9 mg GAE/100 g, and 27.3-85.4%, respectively. The interaction effects of varieties, drying temperature, and CA concentration were significant ( ˂ 0.05) except for fiber. Kulto and SPK006/6/6 performed better for most of the parameters studied followed by SPK00/06. For almost all varieties, samples dried at 55°C and after treated in 3% CA solution had the highest percentage in terms of proximate composition, bioactive components, and total antioxidant capacities.