【摘要】 以岩藻多糖为原料，DPPH自由基的清除率为指标，通过调整H₂O₂-V_C浓度、降解时间、降解温度和料液比优化H₂O₂-V_C氧化法降解岩藻多糖的工艺.进一步利用离子色谱法、傅里叶红外光谱、扫描电镜、X射线衍射和体外抗氧化活性检测等方法评价降解工艺对岩藻多糖结构和生物活性的影响.结果表明：最佳氧化降解工艺为料液比1∶100（g/mL）、H₂O₂-V_C浓度25 mmol/L、50℃下降解1.5 h,此条件下岩藻多糖的分子量（Mw）由902.38 kDa下降至64.66 kDa,平均粒径由371.30 nm降至230.17 nm.多糖结构分析结果证实降解后岩藻多糖糖链主体结构未发生改变，单糖组分仍以半乳糖和岩藻糖为主，硫酸基团和糖醛酸等活性基团含量增加.DPPH和超氧阴离子自由基清除实验结果表明，降解前后的岩藻多糖具有较强的O^2-·清除能力，降解后对DPPH·的清除活性显著增强.研究结果为改善岩藻多糖生物利用度，促进其在食品、医疗等领域的开发和利用奠定了理论基础.更多还原

【Abstract】 In this work, H₂O₂-V_C concentration, degradation time, degradation temperature, and solid-liquid ratio were regulated to optimize the oxidative degradation of fucoidans via H₂O₂-V_C with the detected indicator of the scavenging rate towards DPPH free radicals. Further, ion chromatography, fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and antioxidant activity assay in vitro were employed to evaluate the effect of degradation on the structure and activity of fucoidan. The results showed that the optimized parameters of H₂O₂-V_Cmethod for fucoidan degradation were as follows: a solid-liquid ratio 1∶100（g/mL）, both H₂O₂ and V_C concentration 25 mmol/L, degradation temperature 50 ℃, and reaction time 1.5 h. After being degraded, the molecular weight and average particle size of fucoidan were decreased from 902.38 kDa and 371.30 nm to 64.66 kDa and 230.17 nm. The results of polysaccharide structure analysis confirmed that the backbones of fucoidan were unchanged and the dominant monosaccharides were still galactose and fucose, which reflected that the main structure was not changed. But the content of active groups including the sulfate group and uronic acid increased. Furthermore, the degraded fucoidan performed high scavenging effects on superoxide anion radicals and relatively better effects on DPPH radicals. The results lay a theoretical foundation for improving the bioavailability of fucoidan and promoting its further utilization in food and medical fields.更多还原