Processing of Horticultural Crops (1+2)

Mushroom and Mushroom Products

Mushroom
Mushroom, a form of fleshy edible fungi is a rich source of high quality protein, minerals, folic acid and vitamins. Because of pleasant flavour, taste and freshness, mushroom are considered as an important delicacy in human diet. They are praised for their characteristic meaty biting texture and flavour.
White button mushroom (Agaricus bisporus), oyster mushroom or dhingri (Pleurotus sajorcaju) and paddy straw mushroom (Volvariella volvacea) are commercially cultivated in India. White button mushroom contributes more than 90% of the total production. However owing to high moisture content and delicate nature, mushroom are highly perishable and cannot be stored for more than 24 hours at ambient temperature. The deterioration is mainly caused due to their high metabolic activity, respiration rate and susceptibility to enzymatic browning. Drying, canning and freezing are the accepted methods for preservation of mushrooms and by converting into different products like pickle, chutney, soup etc their availability can be increased.

I. Canning of mushroom
White button mushrooms (Agaricus bisporus) are preferred over other types of mushroom for canning. Commercially mushrooms are canned in brine. Different unit operations used in canning are given in Fig-12.1.

1. Sorting and grading: Diseased, damaged, bruised, shriveled and browned mushroom are discarded. Only the healthy white and tight buttons are selected and separated into two grades i.e. cap diameter up to 2.5cm with compact head as ‘A’ and cap diameter beyond 2.5 cm as ‘B’ grade.

2. Washing: Graded mushrooms are thoroughly washed 3-4 times in cold running water to remove dirt, soil etc without damaging or rubbing them excessively.

3. Blanching: To inhibit enzymes activity blanching in necessary. It also removes the air from the tissues of raw material to enable a satisfactory and uniform pack. Mushrooms are blanched in boiling water for 2-3 minutes followed by immediate cooling in water. The steam blanching is preferred because the blanching losses in boiling water have been estimated to be about 30 percent.

Figure 12.1: Flow sheet for mushroom canning

4. Filling of cans: For mushroom canning, lacquered cans (sulphur resistant) are recommended in order to avoid sulphur staining of canned mushroom. The blanched mushrooms are filled into cans to its declared drained weight i.e. 230 g in A 1 tall can and 430gm in A2½ can size.

5. Brining: After filling mushroom in cans, add hot brine solution having a ratio of 2% common salt, 1% sugar and 0.05 % citric acid. Fill upto the brim of the can. Brining adds flavour to the product, reduces processing time and helps in increasing the shelf-life of canned mushroom.

6. Exhausting: After brining, cans are exhausted to remove any entrapped air and other occluded gases from the product to ensure longer shelf-life. Cans filled with brine solution are fed to the exhaust box for a specified period of time depending upon the length of exhaust tunnel and size of can. Exhausting can also be performed by placing the filled cans in boiling water till temperature of the centre of can reaches 85-900C for 1-2 minutes.

7. Double Seaming /can closing: Immediately after exhausting cans are sealed with the help of double seamer to get the hermetic seam. Sealed cans are then placed in upside down position to sterilize the coded lids.

8. Processing/sterilization: Processing is also designated as sterilization is an indispensable unit operation in canning. This is accomplished by processing the hermetically sealed cans at a pressure of 15 lbs psi for a specified period of time depending upon the size of the can and altitude of processing place. However for A1 tall and A21/2 size cans, processing is required for 35 and 45 minute respectively.

9. Cooling: Cooling of cans is done immediately after sterilization in cold running water to room temperature in order to give an abrupt shock to the micro-organisms to get rid of their adverse activities.

10. Labeling and storage: The cooled cans are stored in a cool and dry place and smeared with grease to remove any adhering moisture from the can body to avoid rusting. Cans are kept at ambient temperature for 8-10 days to check any swell, leakage, puffing and other disorders before labeling. Before the cans are exposed for sale, proper labeling is done to meet statutory requirements of Indian Food Laws.

II. Mushroom pickle in oil

Recipe for pickle

Ingredient	Quantity
Mushroom	1kg
Salt	100 g
Red chillies Powder	10 g
Turmeric powder	10 g
Coriander powder	10 g
Aniseed and cumin powder	5 g (each)
Spices (fenugreek, black pepper, cinnamon powder)	2 g (each)
Garlic chopped/paste	20 g
Onion chopped	100 g
Vinegar	80-100 ml
Mustard oil	200 g

Method for mushroom pickling: Wash and cut mushroom into pieces. Blanch by holding the pieces in muslin cloth in boiling water containing salt for 3-4 minutes followed by immersing in cold water. Remove excessive moisture by spreading the pieces on a muslin cloth. Fry onion garlic and ginger in oil, mix other ingredients and mushrooms except vinegar and mix thoroughly. Add vinegar and pack in a clean jar.



III. Mushroom soup
Recipe for soup

Ingredient	Quantity
Mushroom	1kg
Salt	30 g
Red chillies powder, cardamom, fenugreek, black pepper, cinnamon powder	5 g (each)
Butter	100 g
Wheat flour ( maida)	12 g (each)
Vinegar	20-30 ml
Milk	200 ml

Preparation of mushroom soup: Take fresh mushroom and wash in water and mash in blender. Pass slurry through an aluminum or plastic sieve to remove the fibrous portion. Melt the butter in a pan and fry the slurry till it is just brown. Add wheat flour, spices and milk to the mixture. Boil the whole mass to a reasonable consistency. After this process, the soup is ready for use. Fill boiling hot soup into the cans and process in a similar way as explained under canning of mushroom.

IV. Mushroom sauce
Recipe

Ingredient	Quantity
Mushroom	1kg
Salt	20 g
Red chillies powder	10 g
Cardamom powder	5 g
Dry ginger powder	5 g
Garlic paste	2 g
Mace	4 g
Vinegar	100 ml

Preparation of mushroom sauce (Fig 12.2)

• 1. Wash the mushroom thoroughly. Keep them in porcelain or an enameled can for 12hr after sprinkling with salt, alternatively dip the mushroom in vinegar.
• 2. Blend the soaked or salted mushroom into fine slurry.
• 3. Add vinegar and spices.
• 4. Heat the mass till it thickens to the consistency of sauce.
• 5. Fill hot in sauce bottles and seal with crown corks.
• 6. Sterilize for 30 minutes at 82-85⁰C.
• 7. Store in cool and dry place.

Figure 12.2: Flow sheet for preparation of mushroom sauce

V. Mushroom chutney

Recipe

Ingredient	Quantity
Mushroom Sugar	1kg 250 g
Salt	100 g
Red chillies Powder	5 g
Ginger chopped	75 g
Aniseed and cumin powder	5 g (each)
Spices (fenugreek, black pepper, cinnamon powder)	2 g (each)
Garlic chopped/paste	25 g
Onion chopped	100 g
Vinegar	10-15 ml
Mustard oil	100 g

Preparation of mushroom chutney: The mushrooms are thoroughly washed in water and cut into small pieces and cooked with a small quantity (100-150ml/kg) of water in a pressure cooker for 15-20 minute. Chopped onion, garlic and ginger are fried in oil and mixed with mushrooms, cook until the whole mass thickness (30-45 minutes). Now add spices and cook for 2-3 minutes. Finally, add sodium benzoate (dissolved in small amount of water) and acetic acid. Final TSS should be in the range of 55-58^oBrix. Pack the material in clean glass container while still hot.

VI. Dehydration of mushroom (Fig. 12.3)
Material required

Ingredient	Quantity
Mushroom	10kg
Potassium meta-bi-sulphite	150gm
Citric acid	20gm

Figure 12.3: Flow sheet for mushroom dehydration

Method for mushroom dehydration

1. Select sound white button mushroom and wash the fresh produce thoroughly in running cold water and then in salt and 0.1% KMS.
2. Cut into two equal halves longitudinally and wash again quickly in running cold water. If desired these can also be kept as such without cutting into halves. Keep the mushroom in 2 % salt water to check browning.
3. Blanch in boiling water for 4-5 minutes.
4. Cool immediately in cold water.
5. Steep the blanched mushrooms in water containing 1.5% potassium meta-bi-sulphite + 0.2% citric acid for 30 to 45 minutes.
6. Drain the mushroom and wash with water thoroughly.
7. Dry the product by placing over trays.
8. Place the loaded trays in dehydrator maintaining 60^oC temperature for 6-8 hours.
9. Pack in polyethylene bag.

Note: Dhingri can also be dried by using this method.