Studies On Processing Products For Pleurotus Cornucopiae&Volariella Volvacea And Their Quality Control

Edible fungus is not only delicious, but also has medicinal value, with the functional factors. With characteristics of both food and drug, the mushroom market has expanded widely. However,the mushroom market is still in its infancy, as well as mainly concentrated in the demand for fresh products of edible fungus,which requires the deep further study on the deep and finishing-processing products of the edible fungus. In addition, edible fungus is weaker at the capacity of enrichment nitrite than other vegetables, which provides a theoretical basis for the solution to the problem of pickle with high nitrite contents. In this paper, as to these two issues, we are trying to develop a safer edible mushroom flavor food and an edible mushroom product with deep processing; results are as follows:1. In the study, we used Pleurotus cornucopiae as raw materials to develop an edible flavor food with low nitrite content in the natural fermentation conditions. Orthogonal experiment of three factors and three levels of L9(34) were designed; three factors(salt content, sugar content and fermentation time) affected the sensory quality, and primary factor was sugar content, the secondary one was the amount of salt and the last was fermentation time; in addition, comprehensive consideration of sensory quality, the optimum fermentation conditions of Pleurotus cornucopiae flavor food were salt concentration of3%, sugar concentration of4%and the fermentation time of10days; and it was to determine the time of fitting for human consumption by measuring the change of pH and nitrite contents in the Pleurotus cornucopiae flavor food under optimum fermentation conditions, and results showed that after eight fermentation days, Pleurotus cornucopiae flavor food was suitable for eating with high safety; taken together, the optimize fermentation condition of Pleurotus cornucopiae flavor food were:salt concentration of3%, sugar concentration of4%, the fermentation time of10days; the physical、chemical and health indicators of the Pleurotus cornucopiae instant flavor food were in line with the national standard limit of pickle food, and at the same time, the nitrite content was much less than the national (20mg/kg). Pleurotus cornucopiae instant flavor food was with higher security. 2. We mensurated nitrite content by HPLC in several commercial pickles with some common raw materials and several homemade ones with some edible mushrooms, finding that the nitrite content of flavor food with edible mushrooms as raw materials, like Flammulina velutiper、Auricularia polytricha and Pleurotus cornucopiae, were lower than that with other vegetables.This provides a stronger basis that if edible fungus was suitable for study on fermentation processing and solving the problem of high nitrite.3. By color protection control technology, texture protection technology combined with edible coating, we used Volvariella volvacea as raw material in vacuum-fried processing after hot air pre-dried trying to develop a kind of Volvariella volvacea crisp with low-oil. In protecting color control technology, the results of single factor experiments as well as the L9(34) orthogonal test to polyphenol oxidase (PPO) activity as an index were that the Volvariella volvacea PPO activity can effectively be inhibited in the condition that was0.03%L-Cysteine,0.12%ascorbic acid and0.35%citric acid, which can weaken its degree of browning to maintain the effect of itself primary color; the texture protection technology is the use of ultrasound-assisted malt dextrin impregnated to examine three single factors (ultrasound-assisted time, the concentration of the impregnating solution and the ratio of the solid to liquid malt dextrin) to optimize the optimum technology which is that the ratio of mushroom pieces to the impregnating solution was1:10with ultrasound-assisted impregnation30min at a concentration of20%(m/v) malt dextrin; it was examined that Volvariella volvacea was coated under some different concentration gradients by two types of edible films—sodium alginate and soybean protein isolate, and then was fried in vacuum condition to the oil and moisture content as indicators, moreover the results suggested that0.75%of sodium alginate coating can significantly reduce oil content and ensure more brittle of chips.4. Three single-factor (pre-dried time, fried time, fried temperature) tests and the L9(34) orthogonal test were designed to optimize the best processing parameters of the vacuum-fried Volvariella volvacea considered the sensory scores combined moisture and oil content; the research on the de-oiling process rotation at the best process condition for the single factor to the time of de-oiling was trying to further reduce the oil content, which was determined the final optimum process conditions of Volvariella volvacea crisps.The final optimum process condition of Volvariella volvacea crisps was that:degree of vacuum at about0.090MPa, hot-air dried temperature of80℃for35min,90℃fried temperature, fried time of8min, de-oiling time of5min. At the optimum condition, the oil rate of the Volvariella volvacea crisps was up to25.14%, which was significantly lower than that at the atmospheric frying conditions.