OBJECTIVE To explore the effects of different types and amounts of excipients and different preparation methods on the fluidity and hygroscopicity of fermented Cordyceps powder.

METHODS Three kinds of excipients were selected from 10 kinds of excipients. The optimal mixing time and proportion of fermented Cordyceps powder were investigated by means of ultrafine composite particles and physical mixing. The improvement effect of fluidity and hygroscopicity was compared, and the fitting model of hygroscopicity equation was established.

RESULTS According to the comprehensive analysis of powder characteristics, rheological properties and moisture absorption characteristics, three excipients were selected as hydrophobic silicon dioxide(SiO₂), cross-linked polyvinylpyrrolidone and dextrin. The optimum process parameters obtained by the contact angle were as follows: The excipient-addition ratio-grinding time was SiO₂-3%-3 min, cross-linked polyvinylpyrrolidone-1%-1 min, dextrin-1%-1 min. After adding excipients for physical mixing, the moisture resistance and fluidity were good, and the SiO₂ effect was the best.

CONCLUSION Adding excipients is a common way to improve the fluidity of fermented Cordyceps powder. Hydrophobic SiO₂ has the best improvement effect in all aspects. Secondly, the physical mixing operation is simple, which makes the powder easier to flow. At the same time, the two hygroscopic kinetic models of double exponential model and Weibull model exhibited high goodness of fit for the fermented Cordyceps powder-excipients, which providing a solid theoretical basis for related research.