Effects of sweetpotato (Ipomoea batatas) puree on bread shelf-life

Abstract

Bioactive compounds in sweet potatoes of different flesh colors possessed potential antioxidant and antimicrobial properties important for human health and food quality. The objective of this study was to determine the levels of bioactive compounds and their inhibitory effects on mold fungi in bread. Composite bread was made by replacing 10, 20, 30 and 40% wheat flour with puree from the sweet potato of different flesh colors. The loaves of bread were incubated over 8-days and analyzed for the fungi load. Physiochemical characteristics: Proximate composition, specific sugars, composites of carotenoids, flavonoids, phenols, and antioxidant activity, as well as ascorbic acid, were analyzed. Orange Fleshed Sweetpotato (OFSP) puree bread, at all levels of wheat flour substitution and Purple Fleshed Sweetpotato (PFSP) puree bread at 10 and 20% wheat flour substitution showed increased shelf-life up to six days, compared to 100% wheat bread that staled at day 3. Microbial inhibition properties exhibited by OFSP and PFSP are attributed to their respective phytochemicals and antioxidant activity of 303.38 and 32.29 mgTE/100 g. Yellow Fleshed Sweetpotato (YFSP) puree bread stayed up to day 4 with antioxidant activity of 64.456 mgTE/100 g whereas White Fleshed Sweetpotato (WFSP) and Cream Fleshed Sweetpotato (CFSP) puree breads had significantly lower (p<0.05) levels of phytochemical contents limiting their inhibition.