热处理对莲藕中酚类物质消化释放与抗氧化活性的影响

为探究热处理对莲藕营养特性的影响，针对不同品种及不同生长期的莲藕，研究常压和高压蒸汽加热对其酚类物质含量、消化释放规律和体外抗氧化能力的影响。结果表明:6种藕原料的酚类物质含量和抗氧化能力存在明显差异，经热处理后游离酚和游离黄酮含量均显著下降(P<0.05)，且伴随DPPH自由基清除能力和FRAP总抗氧化能力的降低，而高压蒸汽加热造成的降幅较大。热处理还明显改变莲藕模拟消化过程中的酚类物质释放规律:未热处理样品在唾液、胃液和肠液消化过程中的平均酚类物质释放量分别为15.18，11.23，3.18 mg/g dw，而常压加热样品分别为9.74，15.14，4.92 mg/g dw。莲藕消化液的DPPH自由基清除能力以胃液>唾液>肠液，而FRAP抗氧化能力以唾液>胃液>肠液。热处理可能通过影响酚类物质的消化释放而改变莲藕的营养特性，研究结果为莲藕热加工品质调控提供参考。

Effects of Heat Treatment on the Digestive Release and Antioxidant Activity of Phenolic Compounds in Lotus Root

The present study aimed to investigate the impact of heat treatment on the nutritional characteristics of fresh lotus root， considering its different varieties and growth stages. Specifically， the alterations in phenolic content， digestive features， and in vitro antioxidant capacity induced by steam heating were studied. The results showed that heat treatment led to a significant reduction in free phenols and free flavonoids in lotus roots(P<0.05)， accompanied by a decrease in DPPH free radical scavenging ability and FRAP total antioxidant capacity. Notably， high-pressure heating resulted in a greater reduction compared to atmospheric heating. Furthermore， heat treatment significantly influenced the release of phenolic compounds during simulated digestion processes of lotus root. In unheat treated samples， the average amounts of released phenolic compounds were 15.18 mg/g dw in saliva， 11.23 mg/g dw in gastric juice， and 3.18 mg/g dw in intestinal juice； whereas for atmospheric heated samples these values were respectively 9.74， 15.14 mg/g dw and 4.92 mg/g dw. The order of DPPH free radical scavenging ability was found to be gastric juice > saliva > intestinal juice； while for FRAP antioxidant ability it was saliva > gastric juice > intestinal juice. Overall， the results suggest that heat treatment can modify the nutrient properties of lotus root by influencing the digestion process and release of phenolic compounds. These findings provide valuable insights for quality control during thermal processing of lotus root.