Superfine grinding improves the bioaccessibility and antioxidant properties of Dendrobium officinale powders

Abstract In herbal markets, an overwhelming majority the D. officinale are sold in spiral or spring form, and this kind of product would lead to the incomplete release of some nutrients. To increase the bioaccessibility of D. officinale , we report a method of pulverisation treatments including general and superfine grinding to reduce the particle size. In comparison with coarse D. officinale , the superfine ground D. officinale with particle sizes of <18 μm resulted in significant higher bulk density, better flowability and greater hydration properties. The protein and polysaccharide solubility of D. officinale increased significantly as its particle size decreased. The extract of D. officinale with a particle size of <18 μm showed that highest total phenolic and total flavonoid contents accompanied with the best antioxidant activity through all antioxidant assays compared with coarse ground D. officinale and D. officinale products.