Effect of different drying methods on chemical composition and bioactivity of finger citron polysaccharides

Traditionally, people like to take dried finger citron fruits (FC) as adjuvant herbal medicines to treat a diversity of chronic diseases like asthma, hypertension and respiratory tract infections. Many healing properties are attributed to FC polysaccharides (FCPs), one of the main active ingredients of FC. Three drying methods, freeze drying (FDM), hot air drying (HDM) and vacuum drying methods (VDM) were comparatively studied on the physicochemical and antioxidant properties of FCPs. The results showed these FCPs were similar in UV and FT-IR spectrum. However, they showed significant differences (p<0.05) in yields of crude polysaccharides and contents of protein and ash. Compared with VDM and HDM, FDM resulted in the properties of FCPs with lower molecular weight distribution, higher reducing power and scavenging abilities on DPPH, OH, and O2(-). Available data obtained in vitro models suggested that FDM was an appropriate and effective treatment for obtaining crude polysaccharides from FC fruits. Hence, drying methods used for preparation of FCPs can affect physicochemical and associated functional properties.