Evaluation of quality attributes of different parts of Poria cocos during stress sweating process based on AHP-EWM and RSM

Sweating is a crucial pretreatment required in the post-harvest processing of Poria cocos. In this study, the effect of stress sweating (SS) treatment on the quality attributes including water soluble polysaccharide (WSP), total triterpenoids (TT), alcohol soluble extract (ASE), color, microstructure, and monosaccharides in Poriae Cutis (PC), Rubra Poria (RP), and White Poria (WP) was investigated. The response surface methodology (RSM) combined with analytic hierarchy process and entropy weight method (AHP-EWM) was employed to optimize the sweating parameters. Experimental results showed that the optimized sweating parameters were the stress temperature of 35.2 °C, stress time of 58.4 h, and relative humidity of 74.7%, which obtained the highest comprehensive score (CS). The SS treatment significantly changed the distributions of water soluble polysaccharide, triterpenoids, and alcohol soluble extract in PC, RP, and WP. Also, the microstructure, amorphous region and phase structure of different parts in Poria cocos were modified. The relative quantitative values of 11 monosaccharides and 7 triterpenoids in the samples were determined by UHPLC-QTOF-MS/MS. The alterations in colour parameters, TT, ASE, microstructure, and monosaccharides were intricately attributed to the accumulation and degradation of WSP in different parts of Poria cocos. The obtained findings can provide valuable information to clarify the regulation mechanism on physicochemical properties in different parts of Poria cocos subjected to SS treatment.