Abstract:The target of this manuscript was to investigate the effect of vacuum freeze drying,spray drying,vacuum drying and hot air drying on the quality of chitooligosaccharides.For this,Chitooligosaccharides powder was made by different drying methods.Physical properties,contents of reducing sugar,total sugar and free amino groups,antioxidative activity were determined.It was found that vacuum freeze-dried product possessed the highest contents of reducing sugar,total sugar and free amino groups,and exhibited the best hydroxyl free radical scavenging capacity,color,and solubility.The quality of spray-dried product was almost the same as that of vacuum freeze-dried product.The tested indices of vacuum dried product were better than that of hot air dried but less than vacuum freeze dried and spray dried product except its superoxide anion radical scavenging activity.Hot air drying produced the poorest chitooligosaccharides powder which possessed dark color,poor solubility,low content of free amino groups,reducing and total sugar.Among of them,spray drying is more suitable for the actual industrial production.
