Polysaccharides (PPs-H, PPs-F, and PPs-I) were extracted from the pumpkin flesh dried by hot air, freezing, and far-infrared drying, respectively. It was found that there were some differences in the color, appearance, and microstructure of the three pumpkin powders. The three PPs had similar infrared spectra and monosaccharide composition, but their microscopic morphology, molar ratio of monosaccharide, molecular weight, M_w/M_n ratio, and configuration of anomeric carbon were different. The scavenging capacities of the three PPs to DPPH·, ABTS⁺, and ·OH were different, but all of them were concentration-dependent. The three PPs shifted the survival curve of Caenorhabditis elegans to the right under oxidative stress compared with the negative control and significantly reduced the malondialdehyde content by more than 38% (p < 0.05). PPs-F had a leading effect on the mean lifespan, extending it by 28.43%, followed by PPs-H with 23.45%; both significantly upregulated the mRNA expressions on lifespan and oxidative stress-related genes, such as skn-1, sir-2.1, sod-1, sod-2, and sod-3 (>1.21-fold, p < 0.05). In summary, drying methods are chosen according to their effects on structural characteristics and the antioxidant ability of PPs.

中文翻译：

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干燥方法对南瓜多糖结构特性及抗氧化应激潜力的影响

分别从热风干燥、冷冻干燥和远红外干燥的南瓜果肉中提取多糖（PPs-H、PPs-F 和 PPs-I）。结果发现，三种南瓜粉的颜色、外观、微观结构存在一定差异。三种PP具有相似的红外光谱和单糖组成，但_其微观形貌、单糖摩尔比、分子量、M _w / Mn比和异头碳构型不同。三种PP对DPPH ·、ABTS ⁺、· OH的清除能力不同，但均呈浓度依赖性。与阴性对照相比，三种PP使线虫在氧化应激下的存活曲线右移，丙二醛含量显着降低38%以上（p < 0.05）。 PPs-F 对平均寿命具有主导作用，延长了 28.43%，其次是 PPs-H，延长了 23.45%；两者均显着上调寿命和氧化应激相关基因的 mRNA 表达，例如skn-1、Sir-2.1、sod-1、sod-2和sod-3（> 1.21 倍，p < 0.05）。综上所述，干燥方法的选择取决于其对PP结构特性和抗氧化能力的影响。