Effect of ball milling time on physicochemical properties of Cordyceps militaris ultrafine particles

Cordyceps militaris powder with different particle sizes, a fungus rich in cordycepin and carotenoids, has different physicochemical properties. To explore the influence of different ball milling time on the properties, a batch ball-mill was used before high energy nano-impact mill to produce ultrafine particles from Cordyceps militaris. The particle formation kinetics was covering 2 to 16 hr of grinding was measured and explained. The surface charge (zeta potential), surface activity (surface tension), polarity and cordycepin, and carotenoids contents of particles during dissolution in water were measured and explained. The yield of ultrafine particles ~200 nm did not increase too much during 6–10 hr of grinding but they aggregated significantly at 16 hr of milling. The zeta potential, air-water surface tension reducing ability, and particle polarity of these ultrafine particles were particle size dependent. The dissolution of cordycepin and carotenoids in water was faster in these ultrafine particles but their dissolution patterns were different. The ultrafine particles of C. militaris can be preferably used in nutraceuticals and as emulsifiers. Practical applications: Consumers have recently become more favorite for the ultrafine particles of Cordyceps militaris with respect to its good active ingredient and nutrition. Hence, a comprehensive understanding of the effect of micronization on the particle size and also particle characteristics of Cordyceps would be useful for improving their functionality and to broaden their application. The research found that, ultrafine particles of Cordyceps militaris produced by ball milling have higher physicochemical characteristics.