Thermal stability and characteristics of enoki mushroom dietary fiber by autoclaving pretreatment combined with enzymatic hydrolysis

This study is based on Flammulina velutipes (enoki mushroom) cultivation farm and considers the existing equipment conditions. As a large number of autoclaves are commonly used for pretreatment and sterilization of bulk bags in mushroom cultivation farms, this situation has been integrated into the research design. Actually, most of the enoki mushroom fiber is insoluble dietary fiber (IDF), which is not in favor of its development. Conversion of insoluble dietary fiber (IDF) to soluble dietary fiber (SDF) is a regular method for better use of dietary fiber in the food industry. Here, autoclaving treatment was conducted for 10 min, and then combined with the enzymatic hydrolysis and adjusting the solid-liquid ratio to 20% (w v(-1)), the extraction rate of enoki mushroom SDF increased from 7.55 to 11.48 mass%, which is the best conversion ratio; it was also found that its glucose content increased by 1.82 mg g(-1). Furthermore, through the analysis of liquid chromatography, microstructure, and specific functional groups, it was confirmed that autoclaving pretreatment combined with the use of enzymatic hydrolysis can convert the almost cellulose structure of enoki mushroom into natural additives of SDF and IDF; they can be extensively used in food processing. In addition, a scanning rate of 4 & DEG;C min(-1) was selected as the reference benchmark for comparing the thermal stability and characteristics. From the perspective of the onset temperature of the crystallization reaction, IDF is approximately 220 & DEG;C, while SDF begins to exhibit a crystallization exothermic reaction at around 230 & DEG;C. In terms of thermal decomposition reaction, SDF has a higher onset temperature of exothermic decomposition above 280 & DEG;C, while IDF is only around 270 & DEG;C. The enthalpy of exothermic decomposition is also different between the two, with SDF having a value approximately twice that of IDF (27 kJ kg(-1)) Overall, using autoclaving combined with enzymatic extraction, the issues with products with unsalable period and poor selling appearance can be solved, and the high-quality dietary fiber also can be used for food additives, realizing agricultural waste reduction and added value to circular economy for SDG12 by responsible consumption and production.