低温油炸与冷冻干燥生产草菇脆片的特性

为研究真空低温油炸草菇脆片和真空冷冻干燥草菇脆片的品质特征,采用化学方法和气相色谱-质谱联用技术对新鲜草菇和2种草菇脆片的感官品质、水分、脂肪、粗蛋白和粗多糖等营养成分以及挥发性风味成分进行检测分析。结果表明,真空冷冻干燥草菇脆片内部组织孔径大,其硬度和脆度分别为5.965 kg和1.881 mm,脆片的颜色和营养成分含量与新鲜草菇接近;真空低温油炸草菇脆片内部结构疏松,硬度和脆度分别为4.454 kg和3.336 mm,其呈现出油炸食品特有的色泽,与新鲜草菇相比,脆片中的主要营养成分含量显著降低。此外,2种草菇脆片中挥发性风味物质的种类和数量与新鲜草菇相比都存在很大差异。新鲜草菇、真空低温油炸草菇脆片和真空冷冻干燥草菇脆片中检测出的总挥发性风味物质种类分别为27、16种和29种。新鲜草菇中主要的挥发性化合物为醛类(54.0%)、酮类(40.27%)和醇类(4.1%),其主要呈现出清香、花香和蘑菇风味;真空低温油炸草菇脆片中主要的挥发性化合物为烷烃类(79.83%)、含氮、硫化合物类(12.12%)及酮类(6.6%),主要呈现出焦香和烤香风味;真空冷冻干燥草菇脆片中主要挥发性化合物为烷烃类(81.07%)、酯类(8.54%)和含氮、硫化合物类(7.9%),其呈现的主要是果香味辅以烤香风味,因真空冷冻干燥草菇脆片中含有较多的挥发性化合物使其整体风味更丰富多样。

Quality Characteristics of Straw Mushrooms (Volvariella volvacea) Chips Prepared by Low-Temperature Vacuum Frying and Vacuum Freeze Drying

This study aimed to evaluate the quality characteristics of fresh straw mushroom (Volvariella volvacea) and straw mushroom chips produced by either low-temperature vacuum frying or vacuum freeze drying. The sensory attributes were evaluated and the contents of moisture, fat, soluble protein, polysaccharide and volatile flavor components were analyzed by chemical method and solid-phase micro-extraction combined with gas chromatography-mass spectrometry (SPME-GC-MS). Results showed that the hardness and brittleness of vacuum freeze dried chips were 5.965 kg and 1.881 mm respectively; they revealed a porous structure with large pores and their color and nutritional content were nearly identical to those of fresh straw mushroom. The nutritional content of low-temperature vacuum fried chips was significantly lower than that of fresh straw mushroom (P < 0.05) and the hardness and brittleness were 4.454 kg and 3.336 mm, respectively. They showed a loose internal structure and exhibited the typical color of fried food. In addition, the types and amounts of volatile flavor components varied between fresh straw mushroom and mushroom chips. A total of 27, 16 and 29 volatile flavor components were detected in fresh straw mushroom, vacuum fried chips and vacuum freeze-dried chips, respectively. The main volatile compounds in fresh straw mushroom were aldehydes (54.0%), ketones (40.27%) and alcohols (4.1%), which contributed to the delicate floral aroma and mushroom flavor. The main volatile compounds of vacuum fried chips, having a toasted flavor, were alkanes (79.83%), nitrogen and sulfur compounds (12.12%) and ketones (6.6%). Alkanes (81.07%), esters (8.54%) and nitrogen and sulfur compounds (7.9%) were the major components in vacuum freeze-dried mushroom chips, which contributed to the fruity aroma accompanied by toasted flavor. In general, the overall flavor of vacuum freeze dried chips was more diverse compared to fresh straw mushroom and vacuum fried chips.