Mushrooms are fungi belonging to the class basydiomycetes or Agricus sp, Auricularia sp. Tremella sp, and ascomycetes. Majority of edible mushrooms are of the species of basydiomycetes. There are around 4000 species of basydiomyces of which 200 are only edible and a dozen of them are cultivated on large scale currently.
The cultivation of edible mushrooms is one of the rare examples of a microbial culture where in the cultivated microscopic organism itself it directly used as human food. Mushroom growing is one of the fastest developing biotechnical industries worlds over. Further growth of mushroom industry is expected for the production of enzymes and pharmaceutical compounds including anti tumor agents and antibiotics.
Nutritive Value of Edible Mushrooms
Some people regard edible mushrooms as vegetable meat. Mushrooms contain 80 to 90% water depending on the growth conditions like temperature, humidity. Edible mushrooms are rich sources of protein having protein content being 35 to 405 of dry weight.
However all these proteins are not easily digestible by humans. Mushrooms also contains fats, and free fatty acids like 7 to 10%, carbohydrates 5 to 15% and minerals in good composition. Certain undesirable substances may also be present in edible mushrooms such as cadmium, chromium.
Many delicious edible mushrooms can be prepared. These actually depend on the dietary habits of the people. Some of the common recipes containing mushrooms are mushroom omelets, mushroom soup, mushroom salad etc.
Advantages of Edible Mushroom in biotechnology
1. Mushrooms can be produced by utilizing cheap and often waste substrates like industrial and wood waste.
2. They are of high nutritive value being rich in proteins, vitamins and minerals.
3. Being delicious mushroom has proven to be a main ingredient in many mouth watering recipes.
4. Due to low level in carbohydrate content consumption of mushrooms is advocated to diabetic patients.
Production of Edible Mushrooms
Mushroom production is basically a fermentation process. This is mostly carried out by solid substrates fermentation. A wide range of substrates like straw saw dust, compost, and wooden logs depending on the organism can be used.
Mushroom production is say good example of low technology utilization in an otherwise sophisticated modern biotechnology work.
The most common edible mushrooms cultivated world over that may constitute about 20% world mushroom production is the white butter mushroom. Agricus bisporus, Lentinula sp. Is the second most cultivated mushroom in the world. The substrates straw, compost or horse manure can be used. The substrate selection depends on the local factors.
The compost with desired formulation is prepared and sterilized. It is spread into the trays which are then transferred to production room and inoculated with spawns. Spawn is a term used for the mushroom inoculums containing spores and or small pieces of footing body. After inoculation or spawning the culture is maintitained at optimal growth conditions. The trays are regularly watered to maintain 70 to 80% humidity. The ideal or optimum temperature is about 15'C centigrade and pH about 7.0 or neutral. It takes about 7 to 10 days for each crop of mushroom production. It is possible to have three to four crops before terminating the production processes. The mushrooms can be harvested and sold to markets.
Mushrooms have a very short life like 8 to 12 hours. Unless stored at low temperature at refrigerator 2 to 5'C. Therefore they should be immediately stored, consumed as early as possible.
Variations in Culture in Mushrooms
The production in culturing mushrooms is highly variable. It mostly depends on the organism and the substrate used beside several other local factors. There are distinct differences in the mushroom cultivation methods between different countries for example garden and field cultivation methods are used in Europe while in Unites States cave and house cultivation techniques are employed.
Some mushrooms such as Volirariella sp. are suitable for cultivation in summer and rainy seasons. While others grow well in winter like Agricus bisporous, Pleuropus sp. it is however possible to grow this mushrooms any time in a year with appropriate temperature and humidity control arrangements.
There are certain poisonous mushrooms also. They usually possess unpleasant taste and odor. These mushrooms produce some poisonous substances like thallin and muscarium. The examples of poisonous mushrooms are Amanita thalloides, Amanita muscaria etc.
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