Carrageenan, a polysaccharide mostly extracted from Kappaphycus alvarezii (KA), is valuable for cosmetic and food uses due to large quantities of κ-carrageenan. High-pressure sequential extractions can recover high-purity carrageenan from KA, adequate for aerogel production. The biopolymer properties such as size, shape, and sulphate groups affect the gel form and aerogel characteristics. In this work, aerogels were obtained by supercritical CO2 drying, and cryogels by freeze-drying, using high-purity carrageenan, recovered by sequential high-pressure extractions (HP), and commercial carrageenan (CC). The results indicated that HP samples showed higher volumetric shrinkage (96 %), firmness (254 N), and envelope density (0.008 g.cm−3) compared to CC samples. Aerogels presented characteristics of pore volume, surface area, and density suggesting supercritical drying as feasible method to produce porous materials. Besides, the aerogels present valuable properties compared to cryogel, including high firmness, useful for applications in packages, scaffolds, or delivery systems, a tendency that must be increasingly explored.

中文翻译：

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来自 Kappaphycus alvarezii 藻类的高纯度 κ-角叉菜胶，用于通过超临界 CO2 干燥生产气凝胶


角叉菜胶是一种主要从 Kappaphycus alvarezii （KA） 中提取的多糖，由于含有大量的 κ-角叉菜胶，因此可用于化妆品和食品。高压顺序萃取可以从 KA 中回收高纯度角叉菜胶，适用于气凝胶生产。生物聚合物特性（如大小、形状和硫酸盐基团）会影响凝胶形式和气凝胶特性。在这项工作中，通过超临界 CO2 干燥获得气凝胶，通过冷冻干燥获得冷冻凝胶，使用高纯度角叉菜胶，通过连续高压萃取 （HP） 和商业角叉菜胶 （CC） 回收。结果表明，与 CC 样品相比，HP 样品显示出更高的体积收缩率 （96%）、硬度 （254 N） 和包络密度 （0.008 g.cm−3）。气凝胶具有孔体积、表面积和密度的特性，表明超临界干燥是生产多孔材料的可行方法。此外，与冷冻凝胶相比，气凝胶具有有价值的特性，包括高硬度，可用于包装、支架或输送系统中的应用，这是必须越来越多地探索的趋势。