The production and consumption of mushrooms is increasing very fast throughout the world, mainly due to
greater and greater awareness of their nutritive and medicinal attributes, besides, of course, unique flavour and
texture; consumption of such fancied items is also a natural corollary to the general economic development of a
country and, needless to say, the world economies are booming.
World production of mushrooms is estimated about 12 million tonnes, and the annual growth rate is still above 8 %; India too, though late starter, is fast catching up and the current production has crossed lakh tonne mark with annual growth rate of above 15 %; the venture is no more confined northern region, it has spread far and wide in the country. Besides the seasonal farmers, many big environmentally-controlled units.
The country is proud to have the biggest mushroom unit of the world producing 200 tonnes button mushroom per day and its export accounts for about 25 % of the US imports. Currently, about twenty species of mushrooms are commercially cultivated world over, but significant production is the button mushroom (Agaricus diasporas), Shiitake (Lentinula modes), Oyster mushroom (Pleurotus spp.), Black ear mushroom (Auricularia polytricha) and paddy straw mushroom (Volvariella volvacea).
In India, button mushroom still contributes more than 85 % of the total mushroom production, though its share is below 40 % in the global trade. Besides the button mushroom, oyster mushroom and paddy straw mushroom are the other types grown in limited but significant quantities mostly in the tropical pockets of the country.
Milky mushroom (Calocybe indicia), which may be the only commercial mushroom with a fruiting temperature between 35-400C, is the new introduction from India to the world and its production is catching up fast in different parts of the country during the summer months, and the mushroom has revolutionized the so-called off-season mushroom growing.
The fresh mushroom market is largely catered by the seasonal growers who do not have cool- chain storage and transport facilities and sell the produce in highly localized markets; needless to mention that such seasonal players at times face the consequences of the oversaturated market and understandably resort to distress sales at un-remunerative prices. Mushrooms are a good source of very good quality protein especially rich in lysine and thus supplement well the cereal based Indian diet.
FAO recognizes mushrooms as the right source of protein to fight protein malnutrition in the cereal–dependent developing countries like India. These are very low-calorie food suited to all those interested in cutting down the calorie intake, like obese persons. Being low in fat, but desirable fat devoid of cholesterol, these make an ideal diet for the heart patients. Mushrooms are a low-calorie: high protein diet, with no starch and sugars, and are called the diabetics delight.
These are also maintenance. Many mushrooms possess significant medicinal attributes like hypocholesterolemic, hypoglycemic and hypotensive properties. Mushrooms also exhibit strong antioxidant and hepatoprotective properties. Post harvest losses are very high in most of the horticultural commodities, and it may be one of the highest in mushrooms. Mushrooms even after harvesting continue to grow, respire, mature and senesce resulting in weight loss, veil-opening, browning, wilting and finally in spoilage.
Almost all the mushrooms have very short shelf-life, but the paddy straw mushroom has the shortest (few hours at the ambient), and Milky has very good shelf-life (3-5 days) if microbial spoilage is taken care of. Most damaging post harvest changes in mushrooms vary with species—it is blackening in the button mushroom, cap-opening in the paddy straw mushroom and mucilage in the oyster mushroom, which affect their marketability significantly.
Weight loss is very serious a problem in all the mushrooms as these contain very high moisture (85-90 %) and are not protected by the conventional cuticle. Due to very high moisture and rich nutritive value, microbial spoilage in mushrooms is also a problem. In the case of the button mushroom all the four most deleterious changes namely, browning, veil-opening, weight loss and microbial spoilage ask for the utmost post-harvest care. Needless to say that these changes are also accompanied by changes in the nutritional and medicinal attributes of these mushrooms.
Utmost post harvest care of mushrooms is needed not only for the fresh market but also for the processing, as most of these changes are irreversible. Gluts and distress sales are not uncommon in mushroom marketing especially during the peak months when seasonal produce hits the market in a big way. Withholding of the fresh mushrooms at any point of the chain— grower, wholesaler or the retailer—, is neither feasible nor advisable as it may result in further deterioration in quality leading to the total loss.
Information about proper post harvest care and processing of such a perishable commodity is therefore of vital importance to keep the wheels of this industry moving at the right speed; with the adoption of proper packaging, storage, and processing technologies, problems in marketing, like seasonal gluts and distress sales, can also be ameliorated.
A sizeable production of the button mushroom and almost entire production of other mushrooms still comes from the small seasonal growers although many commercial units produce button mushroom throughout the year under the controlled conditions. The problem of gluts exacerbates during the so-called peak season (December-February). India is predominantly a market for the fresh mushrooms, with very little quantity sold as canned mainly for the institutional consumers. Almost entire export is in the canned form accompanied with mushroom pickles as a bye-product of the canneries.
However, future is going to witness greater contribution from the processing sector, both as stored and really
processed mushrooms. Improved post harvest practices for the storage and processing of mushrooms including value-addition, readymade or ready-tomake products will not only be demanded but will add to the returns to the growers as well as processors.
Two most common post harvest practices and aspects of mushrooms are proper packaging and storage for the fresh mushrooms, and processing for long-term storage as well as value addition. Market for the fresh commodities is likely to continue; reverse trend has already started in the countries where processed products were being consumed.
Therefore most important of all, it is the proper packaging and storage of the fresh mushrooms which should receive the attention of all the players in the field—researchers, growers and traders. Besides canning, drying, steeping and pickling currently resorted to for the long-term storage and trade, it is the production and consumption of the readymade or ready-to-make value-added mushroom products which have, of late, been receiving the attention of the mushroom research and industry.
Mushroom-based soup powder,noodles and biscuits are already on the shelves. Technologies for ready-to make mushroom pizza, mushroom curry in reportable pouches, nuggets, ketchup, preserve in sugar syrup (murabba) have been developed. The bulletin aims at giving the current status of the science, art, and technology for the post harvest storage, processing and value-addition of mushrooms with special emphasis on the button mushroom keeping in view its present production and consumption in the country. Adoption of proper post harvest practices of the storage and processing may partially ameliorate the problems of marketing of mushrooms during the peak periods.
Directorate of Mushroom Research