Sweet potato color variety and flour production drying method determine bioactive compound content and functional properties of flour

Purple and yellow sweet potato flours (PSPF and YSPF, respectively) were prepared by oven drying (OD) and freeze drying, and were characterized in terms of chemical composition, bioactive compounds, antioxidant capacity, and functional properties. The protein content in YSPF was higher than in PSPF regardless of the drying process. YSPF also showed a higher raw fiber content (7.63–7.41 g/100 g db). Both the drying method and the sweet potato variety influenced the water absorption and water solubility values. The OD method decreased the concentration of the main polyphenol (coumaric acid) in both varieties, and caffeic acid was only detected in YSPF. The antioxidant capacity and the concentration of hydrolyzable polyphenols and condensed tannins were higher in PSPF than in YSPF. The pasting profile was also influenced by both the drying method and the variety. Colored sweet potato varieties are an alternative for producing starchy flour with specific antioxidant characteristics and functionality. Novelty impact statement: Colorful sweet potatoes are an alternative for the production of flours and to be used as functional ingredients due to their high content of fiber and bioactive compounds. Antioxidant compounds show great influence on viscosity properties.