前处理对真空冷冻干燥香菇脆品质的影响

目的 研究前处理对真空冷冻干燥香菇脆品质的影响。方法 对真空冷冻干燥香菇脆进行冻融处理、糖渍处理、酶解处理，对香菇脆的质构、感官性质、微结构进行测定。结果 冻融处理有利于香菇脆微观结构的破坏，香菇脆品质随冻融处理次数的增加而逐渐改善。以麦芽糖浆为糖渍液时，3次冻融处理的香菇脆硬度从35.97 N降至23.43 N，组织纤维网孔破坏，糖渍液固形物含量从40%降至15.45%，糖渍效率大幅提高。麦芽糖浆糖渍液中添加麦芽糊精导致了香菇脆品质的劣化，香菇脆硬度高达39.48 N，糖渍效率和产品口感均明显下降。漂烫前对香菇进行蛋白酶酶解可促进组织结构的破坏，香菇脆硬度降至17.59 N，且酶解过程释放的鲜味肽加强了产品的特征风味，感官评分为89.49分，远高于漂烫后酶解和纤维素酶酶解所得样品。结论 多次冻融处理、麦芽糖浆糖渍处理和漂烫前蛋白酶酶解处理有利于提高真空冷冻干燥香菇脆的品质。本研究可为香菇的精深加工提供理论基础。

Effects of Pretreatments on the Quality of Shiitake Mushroom Crisps Prepared by Vacuum Freeze Drying

Objective To investigate the pretreatments on the quality of shiitake mushroom crisps prepared by vacuum freeze drying. Methods Shiitake mushrooms were treated with freeze-thawing, sugaring and enzymolysis and the texture property, sensory quality and microstructure of mushroom crisps were detected. Results The destruction of the microstructure of mushrooms was intensified by freeze-thawing treatment and the quality of crisps was gradually improved as the number of freeze-thawing cycle increased. When malt syrup was used as sugaring solution, the hardness of crisps treated with three freeze-thawing cycles was decreased from 35.97 N to 23.43 N. The destruction of the fiber pores on the surface of mushroom tissue resulted in an enhancement on the crispness of the products. The solid content of sugaring solution was also decreased from 40% to 15.45%, implying an improvement on the sugaring efficiency. The quality of mushroom crisps was deteriorated by the addition of maltodextrin. The hardness of crisps was increased to 39.48 N, with a distinct decrease in the sugaring efficiency and product flavor. The hardness of crisps hydrolyzed by protease before blanching was reduced to 17.59 N, attributed to the destruction of the microstructure of mushrooms. The characteristic flavor of crisps was also enhanced by the release of umami peptides during enzymolysis. The sensory score of crisps hydrolyzed by protease before blanching was 89.49, which was distinctly higher than that of crisps hydrolyzed after blanching or by cellulose. Conclusion Freeze-thawing cycles, malt syrup and protease hydrolysis can improve the quality of shiitake mushroom crisps prepared by vacuum freeze drying.This research provides theoretical basis for the deep processing of shiitake mushrooms.