Effect of drying procedures on the physicochemical properties and antioxidant activities of polysaccharides from Crassostrea gigas

Crassostrea gigas polysaccharides (CGP) were obtained by different drying methods: freeze-drying (FD), spray-drying (SD) or rotary evaporation-drying (RED). The physicochemical properties of CGP were evaluated on the basis of polysaccharide content, protein content, color characteristics, FT-IR spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Antioxidant activities were researched three different free radicals, including DPPH free radicals, ABTS free radicals and reducing power. The results demonstrated that FDCGP, SDCGP and REDCGP have different physicochemical properties and antioxidant activities. Contrasted with FDCGP and REDCGP, SDCGP exhibited stronger antioxidant abilities. Therefore, considering the polysaccharides appearances and antioxidant activities, the spray drying method is a decent selection for the preparation of such polysaccharides, and it should be selected for application in the food industry.

长牡蛎多糖（Crassostrea gigas polysaccharides, CGP）通过三种不同干燥方式制备得到：冷冻干燥（freeze-drying, FD）、喷雾干燥（spray-drying, SD）以及旋转蒸发干燥（rotary evaporation-drying, RED）。本研究以多糖含量、蛋白质含量、色泽特性、傅里叶变换红外光谱（Fourier Transform Infrared Spectroscopy, FT-IR）、差示扫描量热法（differential scanning calorimetry, DSC）与扫描电子显微镜（scanning electron microscopy, SEM）为评价指标，对CGP的理化性质进行了表征分析。以1,1-二苯基-2-三硝基苯肼自由基（DPPH free radicals）、2,2'-联氮-双(3-乙基苯并噻唑啉-6-磺酸)自由基（ABTS free radicals）及还原力为考察对象，研究了不同干燥方式制备CGP的抗氧化活性。实验结果表明，FDCGP、SDCGP与REDCGP具有不同的理化性质与抗氧化活性。相较于FDCGP与REDCGP，SDCGP展现出更强的抗氧化能力。综上，结合多糖的外观特性与抗氧化活性综合考量，喷雾干燥法是制备此类多糖的优良选择，适合应用于食品工业领域。