In this study, Tremella fuciformis polysaccharides (TFPs) were extracted by ultrasound-assisted enzymatic extraction (UAE) at different extraction parameters in order to explore the potential of ultrasound in intensifying the extraction yield. The effects of experimental conditions on the extraction yields were optimized using response surface methodology, with the optimal ultrasonic power of 700 W, temperature of 45 °C and time of 50 min. The kinetic analysis revealed that UAE significantly promoted the dissolution, diffusion and migration with the maximum yield of 26.39%, which was enhanced by 40.45% and 156.96% compared with individual ultrasonic extraction (UE) and enzymatic extraction (EE). According to the modified Fick’s second law of diffusion, the extraction process of TFPs illustrated a good linear correlation (R² ≥ 0.9), and the rate constant gradually elevated as the temperature increased from 25 to 45 °C, while the presence of ultrasound exerted a vital role in extracting TFPs. Regarding to the thermodynamic results, the positive values of ΔH and ΔG demonstrated that UAE, UE and EE were endothermic and unspontaneous processes. This study provides a theoretical basis for polysaccharide extraction processing.

Our research focused on the integration of Flammulina velutipes soluble dietary fiber (Fv-SDF) into wheat flour during the production of dried noodles, delving into the impact of different addition ratios of Fv-SDF on both dough processing characteristics and the quality of the micro-fermented dried noodles. The viscometric and thermodynamic analyses revealed that Fv-SDF notably improved the thermal stability of the mix powder, reduced viscosity, and delayed starch aging. Additionally, Fv-SDF elevated the gelatinization temperature and enthalpy value of the blend. Farinograph Properties and dynamic rheology properties further indicated that Fv-SDF improved dough formation time, stability time, powder quality index, and viscoelasticity. Notably, at a 10% Fv-SDF addition, the noodles achieved the highest sensory score (92) and water absorption rate (148%), while maintaining a lower dry matter loss rate (5.2%) and optimal cooking time (142 s). Gas chromatography-ion mobility spectrometry (GC-IMS) analysis showed that 67 volatile substances were detected, and the contents of furfural, 1-hydroxy-2-acetone, propionic acid, and 3-methylbutyraldehyde were higher in the Fv-SDF 10% group. These 10% Fv-SDF micro-fermented noodles were not only nutritionally enhanced, but also had a unique flavor. This study provides a valuable theoretical basis for the industrial application of F. velutipes and the development of high-quality dried noodles rich in Fv-SDF.

Auricularia polytricha (A. polytricha), regarded as an edible and medical mushroom, has attracted toward the research interests because of the high nutrition and bioactivity. The nutritional and medical properties of A. polytricha have been well-studied; however, research about the difference of the nutritional properties and transcriptome profiling between the two different harvesting periods of A. polytricha was limited. In this study, the nutritional properties and transcriptome profiling were compared between the two different harvesting periods of A. polytricha: AP_S1 (the stage for the first harvesting period) and AP_S2 (the stage for the third harvesting period). This study showed that AP_S1 had the more growth advantages than AP_S2 including biomass, auricle area and thickness, protein and calcium contents, and most species of the amino acid contents, which contributed to the higher sensory evaluation and acceptability of AP_S1. Transcriptome profiling showed that a total of 30,298 unigenes were successfully annotated in the two different harvesting periods of A. polytricha. At a threshold of two-fold change, 1,415 and 3,213 unigenes were up- and downregulated, respectively. All the differentially expressed genes (DEGs) analysis showed that the some synthesis and metabolic processes were strengthened in AP_S1, especially the synthesis and metabolism of the amino acids and protein. The enhanced energy metabolism pathways could provide more energy for AP_S1 to synthesize the nutritional substance. Moreover, the expressions of 10 selected DEGs involved in the amino acid and protein synthesis pathways and energy metabolism pathways were higher in AP_S1 compared to AP_S2, consistent with Illumina analysis. To the best of our knowledge, this is the first study that compares the nutritional properties and transcriptome profiling between the two different harvesting periods of A. polytricha and the results can present insights into the growth and genetic characteristics of A. polytricha.