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In order to develop and utilize Lentinus edodes protein, the effect of glutamine transaminase (TGase) cross-linking on the physicochemical and processing characteristics of L. edodes protein was studied. The results showed that the addition of 0%–20% TGase gradually reduced the contents of total thiol, free thiol and β-sheet of L. edodes protein, while the fluorescence intensity, particle size, β-turn content and surface hydrophobicity showed a trend of initially increasing and then decreasing. As the shear rate increased, the shear stress of the protein increased and the apparent viscosity decreased, indicating that TGase cross-linking promoted the generation of macromolecular polymers. In addition, the cross-linked protein exhibited a dense texture similar to that of the original protein, indicating the formation of a stable three-dimensional network structure. As the addition level of TGase increased from 4% to 12%, the protein network structure became increasingly dense. Moreover, an appropriate amount of TGase significantly improved the solubility, emulsifying properties, thermal stability, and oil-holding capacity of L. edodes protein. These results indicate that TGase cross-linking improves the physicochemical and processing properties of L. edodes protein to varying degrees.

A high protein food that is easy to swallow for people with dysphagia was prepared by blending milk with Hericium erinaceus (HE) powder, soy protein isolate (SPI) or whey protein (WP) (which was added to obtain a final protein content more than 10% of the total mass), and one of three thickeners including xanthan gum (XG), kappa carrageenan (KC) and carboxymethylcellulose (CMC), and its rheology, viscoelastic properties and in vitro digestion characteristics were determined. The results showed that all samples exhibited a weak gel behavior. According to the steady-state rheological test, the values of high resistance to deformation (high G* value) and good elasticity (low tan δ value) were ranked as follows: HE-SPI-CMC > HE-SPI-XG > HE-WP-XG > HE-WP-KC, and higher G* values were more favorable for people with dysphagia and the elderly. In the in vitro simulated digestion test, the viscosity (η) and consistency coefficient (K) values were in the following order: HE-WP-KC > HE-WP-XG > HE-SPI-XG. The soluble protein contents were ranked as follows: HE-WP-CMC > HE-WP-KC > HE-SPI-KC. The contents of free amino acids after digestion were in the following order: HE-WP-CMC > HE-WP-KC > HE-SPI-KC > HE-WP-XG. Therefore, HE-WP-KC was more suitable for consumption by the elderly. This study has explained how protein-hydrocolloid interactions and food matrix determine the rheological properties and digestibility properties of the samples, which may provide theoretical support for meeting the dietary needs of people with dysphagia.

Polysaccharides from the fruiting body of Clitocybe squamulosaruiting (CSFP) were extracted by ultrasonic-assisted hot water extaction and were degraded by three different methods, i.e., H2O2 degradation, ultrasonic degradation and ultrasonic-assisted H2O2 degradation. The resulting products were named as H-CSFP, U-CSFP, and UH-CSFP, respectively. CSFP consisted of three fractions (I, II and III) with different molecular masses. The molecular masses of fractions I and III in H-CSFP, U-CSFP and UH-CSFP were lower than those in CSFP, and their proportions were higher in these degraded polysaccharides than in CSFP; however, the opposite was true for the molecular mass and proportion of fraction III. The monosaccharide composition of CSFP was not affected by each of the degradation methods. Scanning electron microscopy (SEM) showed that the density or diameter of pores on the surface of CSFP increased after degradation, indicating looser structure. The zero shear viscosity and average particle size of CSFP decreased significantly after degradation. Fourier transform infrared spectroscopy (FTIR) showed the major functional groups of CSFP were not damaged after degradation, while the apparent viscosity and gel properties were weakened. Compared with CSFP, all degraded polysaccharides except UH-CSFP showed no significant difference in total sugar content but an increase in the contents of sulfate and uronic acid. The decreasing order of the antioxidant activity in vitro was UH-CSFP > U-CSFP > H-CSFP > CSFP. Pearson correlation analysis showed that the content of sulfate group was largely significantly correlated with the hydrolxyl radical scavenging capacity and total reducing power (P 0.05). The results of this study provide a theoretical reference for the application of Clitocybe squamulosa polysaccharides in the fields of food, medicine and health products.

Morels (Morchella spp.) are valuable and rare edible mushrooms with unique flavors and high nutritional value. White mold disease occurring during cultivation has seriously affected the quality and yield of morels in China. In this study, the fungus causing white mold disease in morels was isolated, purified, and identified as Pseudodiploöspora longispora by morphology and molecular biology. In addition, research has shown that P. longispora infection causes wrinkled and rupturing asci, loosened cell walls, and obvious membrane breakage accompanied by severe cytoplasmic leakage in M. sextelata. Interestingly, research has shown that infection with P. longispora can induce the production of an unknown substance in the cells of M. sextelata, which accumulates on the cell membrane, leading to membrane breakage. Furthermore, integrated transcriptomics–proteomics analysis revealed the response mechanism of M. sextelata to P. longispora infection. The results indicate that DEGs and DEPs can be significantly enriched in pathways involved in oxidoreductase activity; peroxisomes, lipid transport, and metabolism; cell wall assembly; and integral components of membranes. Further electron microscopy analysis clarified the important role of changes in the cell membrane and cell wall in the response of mycelia to biological stress. This study clarified the response mechanism of M. sextelata to P. longispora, laying a foundation for further clarifying the infection mechanism of P. longispora. [ABSTRACT FROM AUTHOR]