Abstract: Purple sweet potato powder (PSP) and Lactobacillus plantarum fermented PSP were separately used to prepare bread in this study. The effect of lactic acid bacteria (LAB) fermentation for PSP on the quality of bread make from PSP, anthocyanins content, total phenolic content and DPPH radical-scavenging activity was explored. The results showed that the bread made from LAB-fermented PSP had lower pH and higher TTA, and its specific volume revealed a decrease compared to that made from non-fermented PSP. After LAB fermentation, the color of PSP was changed from light purple to pink, and the chroma (C*) of the bread with LAB-fermented PSP increased while the hue (H*) decreased. Sensory evaluation of both bread samples could be accepted by consumers. The bread made from LAB-fermented PSP revealed an increase in total phenolic content and DPPH radical-scavenging activity by 90.8% and 6.1%, respectively compared to that made from non-fermented PSP. Therefore, LAB fermentation can enhance the antioxidant activity of PSP bread.

Key words: Lactobacillus plantarum, purple sweet potato powder (PSP), bread fermentation, anthocyanins, antioxidant activity