How To Freeze Dry Mushrooms

Dehydrated vegetables as a new type of food more and more people's attention. In  the same country, the United States, Hong Kong and other countries and  regions, dehydrated vegetables has become a popular lifestyle fast-paced  modern food. In  our country, it is not only used extensively in the field of instant  food, but also an effective method to solve the trouble of eating  vegetables in the departments of tourism, army and geology. Dehydrated  vegetables with raw materials to maintain the color, smell, taste and  nutritional content, food is not perishable, rehydration, light weight,  can be stored at room temperature and so on. In  this experiment, the mushrooms were stored and kept fresh first, then  the dehydrated mushrooms were produced by the vacuum freeze-drying  technology, the optimal experimental conditions were optimized and  compared with the traditional hot-air drying method. The results showed  that the freeze- , The retention of aroma components and rehydration, etc. than the hot air drying has obvious advantages.

1.Mushroom preservation technology and the characteristics of aroma in the preservation of the law of change.

3.jpg(1)  The selection of browning inhibitors, the sensory score and the  characteristic aroma of mushroom as indicators of browning inhibitors,  the results showed that adding browning inhibitors cysteine 1.0g / L,  ascorbic acid 0.8g / L,  citric acid 20g / L, soaking time 20min, get the sensory score and the  characteristic aroma component 1-octen-3-ol content of high storage  mushrooms, mushrooms obtained at this time the degree of browning is  small, high sensory score The  preparation for the drying of the subsequent mushrooms, the purpose of  its preservation is to ensure the quality of raw materials before  processing, to prevent browning, decay and the measures taken.

(2)  By analyzing the main characteristic aroma of mushroom during storage,  the results showed that with the extension of storage time, the content  of 1-octen-3-ol gradually decreased, the relative content of the total  volatile aroma components More  than 80%, other ingredients such as benzaldehyde, 3-octanol, 3-octanone  content did not change much during storage, the choice of good quality  raw materials for the dehydration of mushrooms.

2. Mushroom vacuum freeze-drying process. The  quadratic universal rotary combination design was used to establish the  regression equation of pre-thawing rate and sublimation temperature,  and to analyze the temperature on the recovery ratio of mushrooms after  drying. The results showed that at the pre-freezing rate of 2.5 ℃ / min,  ℃  for 5h and maintained at 13 ℃ for 6h, the rehydration ratio obtained  was 5.62. The rehydration ratio after drying was 5.49 and the relative  error was 2.37%, which provided some theoretical data for the future  production of fruits and vegetables by freeze-drying. 3. Drying methods on the quality of mushrooms.

freeze dried mushroom.jpg

(1)  The effects of hot air drying and freeze drying on the quality of dried  mushrooms were compared. The nutrients such as ash, polysaccharides,  proteins and amino acids were compared. The  results showed that the content of ash and crude fiber had little  difference, while the content of polysaccharides, protein, free amino  acids and water-soluble vitamins of mushroom after freeze-drying was  higher than that of hot-air drying. As  the freeze-dried slices of mushroom slices covered with uniform size, a  large number of micropores, showing sponge-like porous structure, and  hot air dried mushroom slices after a large number of micropores, the  number of small and uneven, the appearance of shrinkage, the formation  of dense The hard shell, resulting in freeze-dried mushrooms than the hot air drying has good rehydration performance. The  characteristic aroma components after lyophilization are the same as  those of fresh mushrooms and contain benzaldehyde, 1-octen-3-ol,  3-octanol and 3-octanone, while the dried mushrooms have only  benzaldehyde , So hot-air dried mushrooms do not have the smell of fresh mushrooms.

(2)  A high performance capillary electrophoresis method was established for  the determination of water-soluble vitamins in mushrooms. The pressure  was injected for 5sec, the column temperature was 25 ℃, the separation  voltage was 20KV, vitamin V, B1, V, B6, , B2> and Vc detection wavelength 190nm. ,  The electrophoresis buffer is 20mM borax ~ boric acid buffer pH8.72,  running time 10min, you can achieve a good separation of vitamins in  mushrooms, and compared by freeze drying and hot air drying two kinds of  mushrooms dried, the results show that freezing Drying of mushrooms on vitamin retention was significantly higher than the hot air drying method.

(3)  The common fruits and vegetables were dried by microwave vacuum drying  and freeze-drying respectively. Onion, apple slices, banana slices,  garlic slices, mushrooms and onions were dried by microwave vacuum. Slices  of carrots, ginger, chives and red peppers are also dried. It has been  found that lyophilized fruits and vegetables have the advantages of less  deformation and less degree of browning than microwave vacuum drying.