| Edible fungi in china have rich resource and large production. As bulk spawn, the pleurotus eryngii has large output, but they usually sale in fresh with low value-added value. According to incomplete statistics, in 2013, the nationwide pleurotus eryngii yield reached 316.9 million tons. In view of the present situation, taking fresh pleurotus eryngii as a material, a pleurotus eryngii chip product was studied. The effect of slicing process, blanching process, impregnation process and vacuum frying process on chip food quality was investigated in detail. The main results were as follows:1. The best slicing process was longitudinal, which shrinkage rate was only 31.11%, but the difference with other two methods was not significant. Slice thickness had significant effect on crispness, color, oil content. Between 2 mm and 10 mm, the greater the thickness, the greater the crispness, the lower the color value(L value), and the higher the oil content were obtained. Therefore, the optimal slice thickness was 2 mm, and the crispness was 348.03 g/s, the value of L was 78.73, the oil content was 19.99%.2. Blanching time and temperature had a significant effect on peroxidase activity of chips. The higher the temperature, the longer the blanching time, the faster the rate of inactivation of peroxidase, and the less the texture were obtained. The optimum blanching process was at 95°C for 1.5 min.3. The immersion test of maltodextrin, L-cysteine, D-ascorbic acid, citric acid, Na Cl, sucrose showed that except Na Cl and sucrose, the other 4 impregnating solution with different concentrations had significant influence on chips. When the concentration of maltodextrin was 0-30%, the more the maltodextrin added, and the lower oil content, the bigger value of L, the higher solid content were obtained. The optimum maltodextrin dipping alone was 30%. When the concentration of L-cysteine was 0-0.15%, the value of L increased with the concentration of L-cysteine increasing. The optimum concentration of L-cysteine was 0.15%. When the concentration of D-ascorbic acid was in the range of 0-0.1%, the D-ascorbic acid was more, and the value of L was bigger. When the concentration was greater than 0.1%, the value of L had no significant change. Thus, the optimum concentration of D-ascorbic acid was 0.1%. The value of L increased with the concentration of citric acid increasing at the concentration between 0.1-0.6%. For the purpose of sensory and color protection, the optimum concentration of citric acid was 0.6%. The impregnation process optimized by response surface method was 30.67% for maltodextrin, 0.18% for L-cysteine, 0.11% for Dascorbic acid, 0.59% for citric acid. It was found that Na Cl and sucrose had little effect on product color, and the color value of the product will remain at L value = 81 ± 3 and 71 ± 2, Na Cl and sucrose have significant effect on flavor, which can improve the flavor of chips, Best concentration of Na Cl was 0.9%, and the sucrose concentration was 3.0%.4. Frying temperature, time and vacuum degree had significant influence on chips quality. The higher the temperature was, the lower the water content obtained. The chip had no brittle when the temperature was 60 and 70°C. The brittle of chip was bigger than 433.76 g/s when the temperature was higher than 80°C. The value of L, and the oil content was increased with the temperature increasing. While the longer the frying time was, the bigger the oil content and the lower the value of L obtained. The drying rate increased with the degree of vacuum increasing. Response surface methodology for the optimization of vacuum frying technology was as follows: frying temperature was 87.71°C, frying time was 12.79 min and vacuum degree was 0.92 MPa. At this condition, the oil content of chip was only 9.15%, and the value of L was 85.17.5. The test of color, crispness, greasy degree, flavor characteristics, shape and overall acceptance indexes of pleurotus eryngii chip that produced at optimum process showed that each indicator was above 7.82, and the score sum was 48.8, which indicated that the acceptance of pleurotus eryngii chip was relatively high. |
