Sea lettuce, or Ulva spp., dominates global algal biomass and significantly contributes to “green tides.”, representing a sustainable source for biomaterials. This study explores an innovative ultrasound-enzyme assisted extraction method with the novel Cellic® CTEC3 enzyme cocktail, applied for the first time in Ulva spp. succesfully enhancing ulvan release and extraction efficiency. Various processing methods, including ultrafiltration and dialysis, were employed to achieve higher ulvan purity. Dialyzation of ulvan resulted in a more purified product with a carbohydrate content up to 55.34 %, a sulfate content up to 21 %, and no glucose contamination. Liquid extracts were fractionated through ultrafiltration, with a 3 kDa MWCO yielding 93.51 % ulvan precipitate, representing 50.28 % of the total extractable ulvan. Sequential ultrafiltration concentrated ulvans but only partially modified their molecular weight distribution. Depolymerization using microwave and H2O2 shifted ulvans towards lower molecular weights, reducing high molecular weight residue. HPSEC confirmed pH-dependent aggregation behavior, with all isolated ulvans having molecular weights above 786 kDa. Hydrolysis methods were compared, with 2-hour 1 M TFA hydrolysis at 121 °C providing the best monosaccharide profile of ulvan. FTIR and NMR analyses showed preservation of sulfation. Rheology indicated biopolymeric behavior and stable gel formation. Ulvans demonstrated nutraceutical potential, being suitable for a low Na+ and high K+ diet, with a Na+:K+ ratio as low as 0.14, and were rich in Mg2+.

中文翻译：

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通过新型超声-酶辅助方法提取的石莼的表征、超滤、解聚和凝胶制剂


海莴苣或石莼属在全球藻类生物量中占主导地位，并为“绿潮”做出了重大贡献，代表了生物材料的可持续来源。本研究探索了一种创新的超声-酶辅助提取方法，该方法使用新型 Cellic® CTEC3 酶混合物，首次应用于石莼属，成功提高了石莼的释放和提取效率。采用各种加工方法，包括超滤和透析，以实现更高的石莼纯度。石莼的透析得到的产物纯度更高，碳水化合物含量高达 55.34%，硫酸盐含量高达 21%，并且没有葡萄糖污染。通过超滤对液体提取物进行分馏，使用 3 kDa MWCO 产生 93.51% 的石莼沉淀，占可提取物总石莼沉淀的 50.28%。顺序超滤浓缩了 ulvans，但仅部分改变了它们的分子量分布。使用微波和 H2O2 解聚使 ulvans 向较低分子量移动，从而减少高分子量残留物。HPSEC 证实了 pH 依赖性聚集行为，所有分离的 ulvans 的分子量均高于 786 kDa。比较了水解方法，在 121 °C 下 2 小时 1 M TFA 水解提供了石莼的最佳单糖谱。FTIR 和 NMR 分析显示硫酸盐化保留。流变学表明生物聚合物行为和稳定的凝胶形成。石莼表现出营养潜力，适合低 Na+ 和高 K+ 饮食，Na+：K+ 比例低至 0.14，并且富含 Mg2+。