Study On The Effect Of Drying Method On Tremella Fuciformis Quality And The Process Technology Of Instant Tremella Fuciformis Food

Hot-air drying is the main drying method for dehydrating Tremella fuciformis, based on low cost and short drying time. However, hot-air drying could result in the nutrient contents’damage in Tremella fuciformis. Tremella fuciformis is one of popular edible fungi, but the categories of Tremella fuciformis instant food is not enough to meet the people’s demand in the modern society.The paper aims to study the effect of combined hot-air and vacuum drying on quality and microstructure of fresh Tremella fuciformis, and research a kind of instant Tremella fuciformis food, which is healthy, nutritional and convenient to eat. The main results were following:1. Combined hot-air and vacuum drying resulted in a dried product of superior quality, exhibiting higher shrinkage ratio, not below 60%, highest rehydration ratio of 12, better color appearance, above 22% polysaccharide content, and more excellent microstructure, compared to samples dried by single hot-air and vacuum drying. The cost of combined drying lowered by 19% and 51%, respectively, compared to those of single vacuum drying and freezing drying. The result showed combined hot-air and vacuum drying could be generalized as a high quality and low-energy drying method.2. As the stewing time got longer, the TPA indicators, including hardness, adhesiveness, springiness, cohesiveness and resilience, indicated interior structure of Tremella fuciformis damaged seriously, and rheological property showed increasing trend. Taking into account TPA result and rheological property,2h was best stewing time. Compared with freezing drying, hot-air drying and vacuum drying affected the color and nutrient contents more obviously, nevertheless, TPA result of rehydrated samples dried by hot-air drying and vacuum drying were superior to those of freezing dried sample. The viscosity in rheological property increased, as more crystal sugar was used.3. By single factor and orthogonal experiment, best rehydration conditions were obtained as:temperature was 50℃, time was 40min, volume of distilled water was 1600mL. Hot-air drying was determined to be the drying method of instant Tremella fuciformis food, according to drying ability comparison of three drying methods and the conclusion in chapter 3. The optimized hot-air condition was proved to be 60℃ (6h)-50℃. Through sensory evaluation, and taking into account the result in chapter 3, the rate of dosage of Tremella fuciformis to crystal sugar was 1:4.4. Compared with the similar product in the market, the instant Tremella fuciformis food researched in the paper showed its own characteristic and advantage. The product sensory description, physical and chemical indexes and microbiological indicators were listed in the end of paper.