Effect of modification methods on the physical properties and immunomodulatory activity of particulate -glucan

beta-Glucan is an immunoenhancing agent whose biological activities are linked to molecular structure. On that basis, the polysaccharide can be physiochemically modified to produce valuable functional materials. This study investigated the physical properties and immunostimulatory activity of modified beta-glucan. Alkali-treated beta-glucan had a distinct shape and smaller particle size than untreated beta-glucan. The reduced particle size was conducive to the stability of the suspension because the beta-glucan appeared to be completely dissolved by this treatment, forming an amorphous mass. Furthermore, alkali treatment improved the immunostimulating activity of beta-glucan, whereas exposure of macrophages to heat-treated beta-glucan decreased their immune activity. beta-Glucan with reduced particle size by wet-grinding also displayed immunomodulatory activities. These results suggested that the particle size of beta-glucan is a key factor in beta-glucan-induced immune responses of macrophages. Thus, the modification of the beta-glucan particle size provides new opportunities for developing immunoenhancing nutraceuticals or pharmacological therapies in the future.