Study Of Freeze Drying Technology Of Mushroom

Dehydrated vegetables are a new-style food species that are favored by an increasing number of people.The food species have been become prevalent food which rapid rhythmic lifestyle needs in Japan,America or Hong Kong.Not only dehydrated vegetables are used in convenient food fields,but also in the department of tourism,frontier defense,and geological perambulation.It can preserve the color, aroma,taste and nutritional ingredients of raw materials,also have many advantages in indefectible quality,high re-absorption rate and portable weight and so on.The dehydrated mushroom pieces are made by freeze-drying technology in this experiment.The mushroom dehydrated by freeze-drying are more advantages in appearance,nutritional ingredients and volatile ingredients and re-solution rate than air-dryingTrails included1.Fresh-preserving technology and the change of characteristic aroma of mushroom(1)To confirm the effect of conventional browning inhibitors on the fresh-preserving, the orthogonal experiment is carried out.The sensory assess and the content of 1-octene -3-ol are exploited to assess guidelines.The results show that the addition dosage of Cys Vc and citric acid is respectively 1g,0.8g and 20g per liter water with the general consideration of the sensory evaluation and the content of 1-octene-3-ol for the preparation the dehydrated mushroom(2)The major aroma components of fresh mushrooms are benazldehyde,1-octene-3-ol, 3-octenone and 3-octenol,the content of 1-octene-3-ol is highest in these aroma components,the content of 1～octene～3～ol decreases with the time extension, accounting for 80%in total aroma components the content of 3-octenol are little, while the content of benazldehyde and 3-octenone change little during storage period.2.Freeze-drying technology of mushrooms pieces(1)Rotational designs are used to ensure the technology of freeze-drying.To establish the regressive equation about the three variable of the effect of pre-freeze rate, sublimation temperature and resolution temperature,the results showed that the pre-freeze rate are2.5℃/min,sublimation temperature and resolution temperature are 0℃,and 13℃in area coverage,the re-absorption rate of ultimate mushrooms are 5.62, the actual re-absorption rate 5.49,the relative deviation is 2.37%.3.Effect of drying styles on the quality of mushroom(1)The mushroom is dried by the freeze-drying and hot-air drying respectively and there are obvious differences in nutritional components between the products.The results indicated that the free amino acid and polysaccharides and protein in freeze-dried products are higher than the hot-air dried products.This paper also explained the reason that the re-hydrated performance by freeze-drying is better than air-drying product from microcosmic angles.The reason is that the symmetrical micro-hole in freeze-drying mushroom pieces is more than air-drying mushroom.The number of characteristic aroma components in freeze-dried products is same to fresh mushrooms,including 1-octene-3-ol,3-octenol,and 3-octene benazldehyde,while the products dried by hot-air drying merely have.benazldehyde(2)A rapid procedure using capillary electrophoresis to measure water-soluble vitamins in mushroom powder,The effective component of the samples was purified and enriched by means of a solid phase extraction step with a preconditions SPE column..Optimum separation of V_B1,,V_B2,V_B6,V_C and Nocitinamide were obtained by capillary electrophoresis using 20mM borate buffer solution(pH8.72),temperature and working voltage 25℃and 20kV in nearly 10 minutes(3)Common vegetables are dried by the vacuum micro-wave and freeze-drying.The dryness of onion,apple pieces,banana pieces,garlic pieces,shallot pieces in micro-wave Vacuum drying;garlic pieces,apple pieces,carrot,shallot pieces,chili pieces are dried by freeze-drying.Compared to the two drying style,It shows that the products dried by freeze-drying are less transformative than micro-wave vacuum drying...