Microencapsulation of Functional Polysaccharide-Rich Extract from Lentinula edodes Using Spray and Freeze-Drying

This study investigates and compares the efficacy of spray drying and freeze drying in preserving the bioactivity of polysaccharide-rich extracts from Lentinula edodes (shiitake mushroom), using maltodextrin as a wall material. Shiitake extracts were obtained through ultrasonic-assisted hot water extraction and purified by ethanol precipitation before being encapsulated at a 1:2 (core:wall) ratio. The resulting microcapsules were characterized for their physicochemical, functional, and antioxidant properties. Polysaccharide retention was higher in freeze-dried samples (64.39%) than in spray-dried samples (50.39%), whereas polyphenol and flavonoid retention remained low across both methods, likely due to thermal sensitivity and degradation during processing. Antioxidant activity, assessed via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assays, decreased following encapsulation, with both methods retaining approximately 37-40% of initial activity. Fourier-transform infrared spectroscopy (FTIR) confirmed structural integrity of the encapsulated polysaccharides, with no significant chemical interactions between core and wall materials. While both encapsulation methods proved effective in producing stable, functional mushroom-derived microcapsules, freeze-drying showed a slight advantage in preserving polysaccharide content and antioxidant activity, making it more suitable for sensitive bioactives in functional food and nutraceutical applications.