Sapna Devi,Prof. Geeta Sumbali
Mushrooms have been appreciated as ingredient of gourmet cuisine across the world; especially for their tasteful flavour and have been valued by humankind as a culinary wonder. From the time immemorial, they have been consumed by man for their delicious taste and pleasing flavour. Romans and the Greeks described mushrooms as “gift from God” and they served them only on some special occasions. Mushrooms are the cheapest source of protein particularly for the vegetarian. The proteins found in mushrooms are considered to be intermediate between that of the vegetables and animals. Besides being rich in proteins, mushrooms also contain carbohydrates, fats, crude fiber and some essential minerals, which are the key factors for the normal functioning of the body. They also contain certain important vitamins like thiamine, riboflavin, ascorbic acid, nicotinic acid, pantothenic acid and biotin. This low cost vegetable is not only packed with essential nutrients but also has properties to fight many deadly diseases. About 651 species of mushroom belonging to 185 genera are reported to contain immune stimulating or anti tumour polysaccharides that inhibit tumorigenesis.
Mushroom farming has gained lot of importance in recent years due to the increasing global demand for high quality protein, vitamins and minerals, which can be of great benefit to the human health and fitness. It is an environmental friendly activity, which converts lignocellulosic waste residues into valuable food, feed and fertilizer. Studies have shown that mushroom cultivation can be placed at third place after crops and animal husbandry, as far as monetary gains are concerned. Mushroom farming is very economical, requiring less area and can be grown all over the year from the low cost starting materials.
A major output of most of the agricultural fields, forests and gardens is the unusable lignocellulosic waste material, which is mainly composed of cellulose, hemicellulose and lignin. The inappropriate management of these wastes give rise to many problems such as rapid spread of various infectious diseases. The several million tonnes of agricultural wastes are being disposed off by means of incineration, which adversely affects the environment. So, there is always a high demand for a method of agricultural waste management, which is cost effective and contributes less in environmental pollution. Among the various proposals, mushroom cultivation represents the most viable process for the biotransformation of such waste plant residues into protein rich food.
According to an estimate data, approximately 1,40,000 species of mushrooms are known to exist in nature, of which only 10% species have been described. Around 25 species are safe for human consumption and only few are cultivated commercially. Though cultivation of edible mushrooms in Asian countries started 1000 years ago, mushroom production is relatively new phenomenon in India. Mushroom farming is being practiced in more than 100 countries with an annual turnover rate of 6-7%. China is the leading country in mushroom cultivation, growing more than 20 different types of mushroom commercially followed by U.S.A which contributes 16% of the world output.
Even as the production and consumption of mushrooms are on the peak in rest of the world, India has witnessed a lukewarm response in its growth and contributes only one percent in world mushroom production. The per capita consumption of mushrooms in India is very meagre and is even less than 100 g per year. The mushroom entrepreneurs in India have not made significant impact in mushroom production despite of the favourable agro climatic conditions, abundance of the agricultural residues and inexpensive labour. Mushroom industries in our country are focussed mainly on white button mushroom (Agaricus bisporus) which is a highly sophisticated, laborious and capital-intensive activity. In India, five mushroom species viz., white button mushroom (Agaricus bisporus), paddy straw (Volvariella volvacea), oyster (Pleurotus spp.), shiitake (Lentinula edodes) and milky mushrooms (Calocybe indica) are cultivated commercially. The total production of mushrooms in our country is about 1,13,315 tonnes with Punjab, Odisha, Haryana and Maharashtra as the leading states in decreasing order. The major share of production (80%) goes to white button mushroom and rest of the share (20%) goes to tropical mushrooms (summer mushrooms) such as paddy (Volvariella), oyster (Pleurotus) and milky mushrooms (Calocybe).
Macrocybe is another tropical mushroom (summer mushroom), which belongs to the Family Tricholomataceae of the Order agaricales. It is characterized by its fleshy, large, white to creamish coloured fruiting bodies, convex to depressed pileus (cap) and swollen base stipe (stalk). Macrocybe and Calocybe are two mushrooms which can be grown in summers. They resemble to each other very much as both have conspicuous, saprophytic sporophores well differentiated into pileus and stipe but differ in that the Macrocybe lacks siderophilous granulation in their basidia and does not show similarity at the DNA level. Macrocybe has seven well recognised species distributed in the tropical regions of the world. From India, five wild species of Macrocybe have been reported and so far, cultivation of only M. gigantea has been attempted.
Macrocybe gigantea is an edible summer mushroom, which was reported for the first time from West Bengal where it is locally named as “Boro dhoodh chattu” because it smells like milk when dried. Later, It was even reported from Kerala, Karnataka and West Bengal. It is a new addition to the basket of the cultivated mushrooms, which can be grown during summer months.
Macrocybe gigantea requires a temperature between 25-35ºC, relative humidity of 70-80% and light of 8-10 hours for its growth. It does not have any off smell and can be stored in the refrigerator upto 10 days and at room temperature for 3-4 days without significant loss of quality. It retains fresh look and does not turn brown or black like that of button or oyster mushroom. In addition to edibility, Macrocybe gigantea is appreciated for its nutritional (proteins, polysaccharides, amino acids, mineral elements) and medicinal properties (anti-bacterial, anti-oxidation and anti-tumour). It strengthens and regulates the immunity, which makes it a powerful defense against infections. When cooked, it does not become watery like other mushrooms and can be added to everyday dishes. It is a vigorous growing mushroom which can grow on wide range of lignocellulosic wastes like agricultural, forest and garden litter. Cultivation of Macrocybe gigantea is very economical because it can be grown on various uncomposted substrates and gives good biological efficiency of 60-70%. Infrastructure and expenditure required to produce this mushroom is also very affordable.
Jammu division of Jammu and Kashmir (UT) has tropical to subtropical climatic conditions, which favour cultivation of summer mushrooms that are lignocellulosic. Conversion of lignocellulosic residues into protein rich food is one of the most sustainable biotechnological process to address the world food demand, especially protein demand. Therefore, efforts should be made to involve innovative technologies and disposal methods for converting lignocellulosic residues into protein rich biomass by solid state fermentation. The farmers, entrepreneurs and mushroom lovers of Jammu division need to come forward and start cultivation of Macrocybe gigantea – a new addition to the lignocellulosic summer mushrooms.
(The authors are from Department of Botany, University of Jammu)
Sapna Devi,Prof. Geeta Sumbali