Methods of preservation of mushroom-
Introduction
🍄 Mushroom play a very important role in huaman nutrition, it has several health boosting properties.
🍄 Mushrooms are best consumed as fresh. But mushrooms are very delicate and perishable due to very high rate of respiration.
🍄 It remains fresh only for 12-18 hr at room temperature.
In unprotected condition mushroom begins to loose turgidity, become yellowish brown and starts decaying.
🍄 Since technology must be applied to preserve it or added with values ( value addition)
Methods of preservation of mushroom-
1. Refrigeration/ Instant packing:-
Freshly harvested mushrooms are packed in 25 gauge polythene bags without making any holes. Immediately after packing they are stored at 5°C in a refrigerator. This process extends the storage life for 3-5 days. This process helps in reducing the respiratory rate and minimizing the water loss.
2.FREZE DRYING-
The mushrooms are sliced and immersed in 0.05 per cent sodium meta bisulphite and 2 per cent common salt solution for 30 minutes. They then blanched in boiling water for 2 minutes, followed by cooling. This then frozen for one minute at -12°C and store at –20°C. This process extends the storage life for 3-4 months.
Also read : Competitor Moulds of mushroom
3. DRYING/DEHYDRATION:-
It involves 3 steps Pre treatment, Drying , Storage
Pre-treatment –
-Clean the mushroom and blanch it in boiling water for 2 minutes and immerse it in cold water for 2 minutes.
-Dip the mushroom in water containing 0.2% potassium meta bisulphite(KMS) and 1% citric acid and use for drying.
Drying-
-Sun drying: The pre treated mushroom is dried in open sunlight till it reaches 1/10th weight of the fresh product. After drying, it can be stored for 3 months.
-Drying in flow drier: Dry the pre treated mushroom at 60°C with heated air for 6-8 hr. This process lead to bring the final moisture level to 3-5%.
-Vacuum drying: Dry the pre treated mushroom at 40°C under vacuum condition instantly. This process yield a very good quality mushrooms but cost of processing is heavy.
And the dried mushroom can be powdered and mixed with flour to use in making biscuit , bread, cake etc.
Sun Drying increases Vit D content in mushroom.
4.CANNING—
Canning is adopted on a very large scale, especially for preservation of button mushrooms. For canning purpose, the mushrooms should be harvested at an early stage. The mushrooms of uniform size are selected and stalks are cut before processing.
Steps-
👉 Wash the mushroom in clean water to remove dirt and other foreign materials.
👉 Dip the mushroom in boiling water for 2 minutes, take it out and dip in cold water for 2 minutes.
👉Fill the mushrooms in the specially made cans upto ¾ capacities.
👉Add salt solution consisting of 2 per cent common salt, 2 per cent sugar and 0.3
per cent citric acid just to fill up to the brim. (Before adding, the salt solution should be boiled and filtered through muslin cloth) (Approximately 125 ml. Solution is needed for 450gm can).
👉Place the lid on the can and keep the cans in boiling water or steam till the temperature in the centre of the cans reaches 80-85° C.
👉Seal the can on a seamer to get an air tight seam.
👉Sterilize the cans in an autoclave at 10 lb. Pressure for 20-25 minutes.
👉Keep the cans immediately after sterilization in clean cool water for cooling.
👉Wipe the cans with a dry cloth and store in a cool dry place. This process extends the storage life up to 12 months.
Flow chart for Canning
5.Steep Method-
This method is simple and economical and the mushrooms can be preserved for short period by steeping them in solution of salt or acids. Solution consisting of 2% sodium chloride, 2% citric acid, 2% sodium bicarbonate and 0.15% KMS is used for steeping preservation of blanched mushrooms for 8-10 days at 21-28°C.