Exploration of in vitro digestive, antioxidative, and anti-inflammatory benefits of yam (Dioscorea rhizoma) powder-enriched noodles

The effects of yam powder (YP) on the functional properties of wheat flour noodles were investigated to improve the nutritional value of noodles and provide a scientific basis for YP application in flour products. Using wheat flour as the main ingredient, the effects of different YP substitution ratios (0, 5 %, 10 %, 15 %, 20 %, and 25 %) on polyphenolic content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging rate, and starch digestibility of the prepared noodles were analyzed in vitro . Additionally, the effects of YP water-soluble extracts, wheat flour noodles, and YP-enriched noodles (hereinafter, YP noodles) on inflammatory factors in vascular smooth muscle cells (VSMCs) treated by H 2 O 2 (100 μM) were investigated. The results showed that YP had a substantial effect on polyphenolic content and DPPH free radical scavenging rate of wheat flour noodles, significantly increasing both values compared with those of the control group ( P < 0.05). The polyphenolic content reached a maximum of 2.17 mg/g in noodles with 20 % YP substitution, whereas DPPH free radical scavenging rate reached a maximum of 42.10 % in noodles with 25 % YP substitution. With an increase in YP amount, both starch hydrolysis rate and rapidly digestible starch content of the noodles decreased gradually, whereas resistant starch content increased significantly. Moreover, 50, 100, and 200 μg/mL of water-soluble YP and YP noodle extracts had no significant effect on the viability of VSMCs, and high concentrations of YP and YP noodle extracts resulted in cell death. Both YP and noodle extracts also reduced the secretion levels of inflammatory factors IL-6 and TNF- α in H 2 O 2 -treated VSMCs. Overall, YP addition reduced starch digestibility, increased antioxidative activity, and effectively improved functional quality of noodles. This study provides reference data that support the research and development of health-benefiting anti-inflammatory foods.