Development Of Instant Food Using By-products Of Pleurotus Eryngii

After industrial cultivated Pleurotus eryngii was screened, in addition to commodity fresh mushroom, by-products including the mushroom head, mushroom feet and off-normal mushroom accounted for about 20%. For example, in 2011, output of China’s industrial cultivated Pleurotus eryngii reached above 130 thousand tons, and the by-products were nearly 26 thousand tons. Except their poor appearance, their taste and flavor were almost the same as goods. And they were not utilized fully at present. To take fully advantage of industrial cultivated Pleurotus eryngii and improve the added value of products, extending the product chain of the Pleurotus eryngii, the nutritional value of by-products was analyzed and evaluated, which was taken as the research object; different pretreatment technologies’ influences were researched based on method of fuzzy mathematical sensory evaluation method; drying characteristics of two dry ways (hot air drying and vacuum drying) were explored and drying parameters of the hot air-vacuum by stages were optimized by secondary general rotation design, establishing the drying kinetics model; pulsed light which is a cold sterilization technology were combined to developed a ready-to-eat, safe and nutritious, delicious Pleurotus eryngii snack; and at last HACCP system was used in ready-to-eat Pleurotus eryngii products. The results were as follows:(1) By-products of Pleurotus eryngii were nutritious and there were no significant difference between Pleurotus eryngii by-products and goods in nutrients including crude protein, crude fat, crude polysaccharides and mineral elements and so on. There were 17 kinds of amino acids in by-products, and the content of essential amino acids was close to the FAO/WHO standard mode, furthermore, the content of the flavor amino acids of by-products was 27% higher than the mushroom commodity.(2) Using fuzzy mathematics sensory evaluation and food texture analyzer and colorimeter to analysis, by-products were more suitable than the commodity fresh mushrooms as materials for ready-to-eat products; when the by-products were cutted into 3.0cm x 2.0cm (length and width),0.8-1.0cm (thickness), sensory quality of ready-to-eat products was better. Comparing influence of four different seasoning technolones on ready-to-eat products, the secondary flavoring technology at room temperture and atmospheric pressure was batter than the other three kinds of seasoning techniques (infiltration seasoning of atmospheric pressure at room temperature, penetration seasoning of atmospheric pressure cooking, vacuum infiltration seasoning), which had more even taste, lower energy consumption and would be helpful for industrial production.(3) Ready-to-eat Pleurotus eryngii product of 71.0-73.0% moisture content was chewy, which had close texture and best taste; through temperature’s single factor experiment, optimum temperature of hot air and vacuum drying were both 60℃; the process of hot air-vacuum drying by stages was optimized by secondary general rotation design, setting up a kinetics model: Y=0.58+0.027A-0.018B-0.036C-0.024BC-0.06A2-0.051B2-0.018C2, where Y was an integrated value, A and B were the temperature and time of hot air respectively, C was vacuum temperature. The optimal parameters were the following:after drying in hot air at 60℃ for 20min, vacuum-dried was started at -0.09MPa and 55℃ until the final moisture content was about 72%.(4) Surface stained E. coli, Bacillus subtilis and Staphylococcus aureus’ orders of magnitude can be reduced from five to three by radiating 20s front and back of packaged ready-to-eat Pleurotus eryngii product, and the killing rate was 98.34%, 91.42%,98.73% respectively; without significant changes in color, taste and odor. Radiating 20s front and back, then sterilizing 20min in boiling water and adding Nisin 50mg·kg-1, with acceleration experiments of the shelf life of products (37℃ incubation) for 60 days, the sensory quality and the total number of colonies were in line with quality requirements.(5) HACCP system was applied in the products of ready-to-eat Pleurotus eryngii, the critical control points were estimated which included raw materials checking, steamed bleaching salt, vacuum packing, hot air-vacuum combination drying and pulsed light sterilization process, and the critical limit and preventive measures were determined, in order to ensure product quality and safety.