In this study, the volatile flavor compounds in Stropharia rugoso-annulate were qualitatively and quantitatively analyzed by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The volatile odor profiles of S. rugoso-annulata roasted at different temperatures (0, 100, 120, 140, 160 and 180 ℃) were distinguished using an electronic nose. The aroma characteristics of roasted S. rugoso-annulate were determined by sensory evaluation. The results showed that a total of 87 volatile compounds were identified, including 13 aldehydes, 17 esters, 18 alcohols, 4 alkanes, 9 ketones, 8 acids, 4 pyrazines and 14 other compounds. A total of 25 volatile compounds like isovaleraldehyde and gamma-valerolactone were shared by the six samples. After roasting, the total contents of aldehydes, alkanes and pyrazines were increased, and the fruity, rose-like and cocoa-like aromas were enhanced, while the total content of alcohols was decreased significantly. From the perspective of overall odor perception, the electronic nose could effectively distinguish the volatile flavor profiles of S. rugoso-annulata roasted at different temperatures. Totally 34 key flavor compounds were identified according to their relative odor activity (ROV) values. Among them, isovaleraldehyde contributed the most to the flavor, being responsible for the malty and fruity aromas. The largest number (63) of flavor substances was found in S. rugoso-annulata roasted at 140 ℃. Roasting at 140 ℃ improved the richness of flavor, increased the malty, rose-like, nut-like and cocoa-like aromas, and improved the overall flavor of S. rugoso-annulata. The sensory evaluation showed that roasting enhanced the volatile flavor of S. rugoso-annulata, which was consistent with the above results.

In this study, the Auricularia auriculata polysaccharides extracted using high pressure-shearing extraction method were phosphorylated at different temperatures using sodium trimetaphosphite as a crosslinking agent, and the structure and in vitro hypoglycemic activity of the modified polysaccharides were characterized. The results showed that the phosphorylated polysaccharides were heteropolysaccharides mainly composed of xylose, fructose, mannose and glucose. With the increase of temperature, the molecular mass of the phosphorylated polysaccharides decreased significantly and a triple-stranded helical structure was observed. Infrared (IR) spectra showed that the characteristic absorption peaks of P=O and P–O–C appeared at 1205 and 898 cm^-1. Nuclear magnetic resonance (NMR) spectra showed that the phosphorylation mainly occurred on the C6 hydroxyl groups, and the signal peak of P in the phosphate group appeared in the range of δ 0–1.5. Scanning electron microscopic (SEM) results showed that the surface morphology of the modified polysaccharides changed significantly, and it was finer and more broken compared to the original polysaccharides. In addition, 5.0 mg/mL of the phosphorylated polysaccharide PAAP-4 had strong inhibitory effect on α-glucosidase and α-amylase. The inhibitory rate of α-glucosidase was 56.89%, and the in vitro hypoglycemic activity was enhanced compared to that of the original polysaccharides.

In this study, headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the composition and relative content of volatile compounds in Cyperus esculentus oils obtained by different methods (supercritical CO₂ extraction, pressing, leaching, and aqueous enzymatic extraction), and these oils were classified by using principal component analysis (PCA) and electronic nose. The key flavor compounds were determined by their relative odor activity values (ROAV). The results showed that the composition and relative content of volatile compounds were significantly different among the C. esculentus oils. A total of 101 volatile compounds were identified across all samples, 22 of which were common to them, the predominant ones being aldehydes, ketones, esters and alkanes. The relative content of aldehydes was higher in the samples obtained by supercritical CO₂ extraction (36.71%) and pressing (25.64%) than the other methods, and the relative contents of alkanes and esters were the highest in the samples obtained by leaching (31.07%) and aqueous enzymatic extraction (45.66%), respectively. Electronic nose combined with PCA effectively distinguished the four oil methods. Nonanal, cedrol and D-limonene were identified as key flavor compounds and were found in each sample.

To investigate the dose-effect relationship of Tremella fuciformis polysaccharides against water migration and adhesion in fresh wet noodles, we evaluated the farinograph and texture properties of fresh wet noodles made with different amounts of T. fuciformis polysaccharides, and we also characterized them by Fourier transform infrared (FTIR) spectroscopy, low field nuclear magnetic resonance (LF-NMR) spectroscopy, dynamic rheological analysis and laser confocal microscopy. The results showed that the fresh wet noodles with T. fuciformis polysaccharides had lower apparent viscosity compared with the control group without the polysaccharides, and the polysaccharides could inhibit the migration of free water, resulting in changes in water distribution. Compared with the control group, the relative α-helix content of fresh wet noodles with T. fuciformis polysaccharides increased by 9.96% and the relative β-turn content decreased by 7.11%. Addition of T. fuciformis polysaccharides in noodles enhanced the structural orderliness of gluten proteins and the microstructural compactness, reduced the exposure of starch granules, and improved the water-holding capacity, which in turn made noodles more stable during storage. The thermal properties and dynamic rheological properties showed that T. fuciformis polysaccharides could promote the formation of a uniform, orderly and stable gluten network structure in fresh wet noodles. Among all concentrations tested, addition of 0.5% T. fuciformis polysaccharides was the most effective in inhibiting water migration and improving adhesion during storage of fresh wet noodles.