As a technology with the essence of unsteady heat transfer ability, the stir-fry process could improve the flavor of food significantly. Basically, the effects of different cooking time and temperature on the flavor characterization of Agaricus bisporus in novel ready-to-eat dishes (RTE dishes) were investigated in the present study, aiming to provide data basis for the development and production of edible mushroom RTE dishes.

The volatile flavors of A. bisporus under different conditions were evaluated by electronic nose firstly, followed by gas chromatography-ion mobility spectrometry (GC-IMS) and free fatty acid content determination. Then, the non-volatile flavor analyzation through electronic tongue, soluble sugar (alcohol), free amino acids, flavor nucleotides and organic acids detection, as well as the evaluation of equivalent freshness concentration (EUC) were carried out. At last, the sensory quality analysis was utilized to estimate the differences in shape, color, flavor, organization and taste of A. bisporus in novel RTE dishes under different conditions, from which the quality of different products was evaluated based on consumers' subjective perception.

The whole stir-fry process could be divided into three stages, mainly including 2 min, 4-8 min and 10 min based on the cooking time or 160-170℃, 180-190℃ and 200℃ based on the cooking temperature. The contents of 1-octene-3-ol and 3-octanol were considered the characteristic odor components of A. bisporus, which increased with the extension of cooking time. On the other side, the contents of 1-octene-3-ol and 3-octanol reached the maximum value at 180℃ with the increasing of cooking temperature. From the perspective of umami, the time of 4 min was the optimal time for the formation of non-volatile flavor of A. bisporus in RTE dishes. As for the cooking temperature, umami and sweet taste reached the highest peak at 180℃ with the increase of the cooking temperature. Moreover, the contents of soluble sugar (alcohol) and organic acids in the RTE dishes were decreased and increased, respectively, along with the cooking time extension. However, with the increasing of cooking temperature, the contents of soluble sugar (alcohol) increased first and then decreased, while the contents of organic acids displayed an increasing trend. In addition, it was found that different cooking conditions exhibited little effects on nucleotide, but longer cooking time or higher cooking temperature would reduce the contents of free amino acids in the RTE dishes. Finally, in accordance with the analysis of EUC and sensory evaluation, the umami and sensory evaluation of A. bisporus under the cooking time of 4 min and cooking temperature of 180℃ presented the highest score, indicating that the products prepared under this stir-fry conditions were mostly accepted by consumers.

In order to maintain the maximum freshness and sweetness, as well as the most suitable flavor of A. bisporus in the RTE dishes, the final stir-fry process conditions was intended to be stir-frying at 180℃ for 4 min.

In the present study, the investigation on the basic physicochemical properties of Pleurotus eryngii polysaccharide (PEP) and its related effects on diffusion and adsorption of glucose were conducted. PEP mimetic digestion products (D-PEP) were prepared using an in vitro stimulated digestion model to explore the effects of PEP and D-PEP on the digestive enzymes activities associated with glucose metabolism, as well as the interaction between PEP/D-PEP and α-glucosidase.

Firstly, the basic physicochemical properties of PEP were detected based on the methods in previous studies. Then the inhibitory effects of PEP/D-PEP on α-amylase and α-glucosidase activities were evaluated by DNS method and 4-Nitrophenyl α-D-glucopyranoside (PNPG) method, respectively. Finally, the relationship between PEP/D-PEP and α-glucosidase was studied with the utilization of the fluorescence spectroscopy technique.

PEP displayed great potential on the solubility, swelling property, water and oil holding capacities, and favorable inhibition on glucose diffusion and adsorption. Moreover, PEP had obvious inhibitory effects on maltase and α-glucosidase, while it did not suppress the activity of α-amylase. Specifically, PEP with its concentration of 4 mg∙mL^-1 exhibited (77.20±2.71)% inhibition ratio on maltase activity, while (78.91±0.51)% inhibition ratio on α-glucosidase activity. However, the digestion product D-PEP showed significant inhibition on the activities of all these three enzymes, with 4 mg∙mL^-1 of D-PEP inhibiting α-amylase, maltase, and α-glucosidase by (84.08±1.79)%, (20.58±1.20)%, and (95.58±0.12)%, respectively. The outcomes of fluorescence spectroscopy showed that the endogenous fluorescence of α-glucosidase was gradually decreased along with the increasing of the PEP/D-PEP concentration, and the quenching of the endogenous fluorescence of α-glucosidase by PEP/D-PEP was mainly static quenching, with the number of binding sites greater than or equal to 1.

In summary, D-PEP not only inhibited maltase and α-glucosidase activities but also showed great potential inhibition effects on α-amylase activity compared with PEP. Herein, D-PEP displayed stronger inhibitory effect on amylase and could be considered affect glucose metabolism to a certain degree.