In order to investigate the processing suitability of Agaricus bisporus, coarse (passing through a 60-mesh sieve) and superfine (passing through a 300-mesh sieve) powders were prepared from the mushroom after dried by hot air drying (HAD), heat pump drying (HPD) or vacuum freeze drying (VFD) and were used to evaluate the effect of different drying methods and grinding degrees on the physicochemical, nutritional and functional properties of A. bisporus. The results showed that among the three drying methods, VFD dried sample had the smallest color difference, lowest browning degree, highest rehydration and hydration capacity, highest tap density and largest dissolution of polysaccharides, soluble protein, and total triterpenoids, indicating the best overall quality. The overall quality of HAD dried sample was the worst. The dissolution of ergosterol from HPD dried sample was the highest, and its overall sensory quality was between that of VFD and HAD dried samples. Compared to coarse powder, superfine powder showed a smaller particle size, a larger tap density, better water solubility, higher dissolution of nutritional and functional components, stronger antioxidant activity, and lower water retention capacity and swelling degree. In general, VFD is the most effective in maintaining the eating quality of A. bisporus, which is more suitable for the production of high value-added products. The eating quality of HPD dried mushroom is much superior to that of HAD dried mushroom, and HPD requires low energy consumption and is a better choice for the industrial dehydration of A. bisporus. Additionally, superfine grinding can significantly decrease the particle size of A. bisporus powder and improve its water solubility, antioxidant activity and nutrient dissolubility, which can be used as a pre-treatment method for the development of functional foods based on A. bisporus.

To investigate the effects of three circulation methods including normal temperature, cold chain, and broken cold chain on the flavor substances of fresh Lentinula edodes before and after storage and transportation, the changing trends of volatile flavor compounds and taste components of L. edodes during simulated transportation under the three temperature conditions were analyzed using an electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS), an electronic tongue, high performance liquid chromatography (HPLC), and an automatic amino acid analyzer. The results showed that electronic nose was able to quickly distinguish between the aroma characteristics of L. edodes under different simulated temperature conditions. In total, 55 volatile compounds were detected by GC-IMS, including 16 alcohols, 10 aldehydes, 8 terpenes, 6 ketones, 4 esters, and 11 other compounds. The electronic tongue revealed differences in the sourness, bitterness, astringency, umami, richness, and saltiness among early storage and transportation (control), simulated normal temperature logistics (NTL), simulated cold chain logistics (CCL), and simulated broken chain logistics (BCL), with the CCL group being characterized by moderate sourness and prominent umami. In the NTL, CCL, and BCL groups, the total amounts of free umami amino acids were 90.82, 81.83, and 84.31 mg/g, respectively, and the 5’-nucleotide contents were 122.99, 107.42, and 118.27 μg/g, respectively. Among them, the volatile flavor compounds and taste components in the CCL group were most similar to those in the control group, indicating that consistent low-temperature conditions are helpful for preserving the flavor quality of L. edodes during storage and transportation. In contrast, the BCL group, which experienced temperature fluctuations during both storage and transportation, exhibited slightly lower flavor quality than did the CCL group due to the negative impact on the flavor compounds before entering the shelf life. In conclusion, in the post-harvest circulation process of L. edodes, cold-chain transportation is needed to minimize quality deterioration caused by temperature fluctuations during storage and transportation. The results provide valuable insights for improving the cold chain distribution system for L. edodes.

In order to investigate the effects of different doses of ⁶⁰Co-γ-ray irradiation on rice, this experiment employed a texture analyzer, a rapid viscosity analyzer, a differential scanning calorimeter, a rheometer, an X-ray diffractometer, and a Fourier transform infrared spectrometer to characterize the eating quality of rice and the physicochemical properties and structure of rice starch. The results indicated that as irradiation dose increased, the water absorption and volumetric expansion of rice during cooking, and the pH, dissolved solid content and iodine blue value of rice broth fell significantly (P < 0.05). High doses of irradiation resulted in a noticeable increase in the total color difference (ΔE) of rice compared with that before irradiation, and a ΔE of 12.53 was obtained at 10 kGy, indicating a significant color change. Also, the irradiation notably affected the hardness of cooked rice. The peak viscosity, setback value, and gelatinization enthalpy of rice starch decreased significantly (P < 0.05) with the increase in irradiation dose; the irradiation also reduced the rigidity, elasticity, relative crystallinity and orderliness of rice starch, with the crystallinity being decreased from 23.68% to 15.69%. The measurement results of cooking indicators, rice soup properties, ΔE, and texture characteristics indicate that higher irradiation doses reduced the edible quality of rice. Moreover, the contents of slowly digestible starch and resistant starch in irradiated rice starch increased, with the latter being increased to 20.22% after irradiation treatment at 4 kGy. Compared with the unirradiated control, the irradiation reduced the hydrolysis rate of starch. Overall, γ-ray irradiation altered the crystalline structure of starch, thereby enhancing its pasting and rheological properties and inhibiting its digestibility, but rice is not suitable for high doses of irradiation treatment. This study provides theoretical guidance for the production of irradiated rice and its products, as well as for the modification of starch.