Overview on the edible mushrooms in Egypt
Edible Mushrooms have been valued as a valuable food source due to its nutritional and medicinal characteristics. Edible mushrooms contain various bioactive components such as proteins, polyunsaturated fatty acids, polysaccharides, dietary fibers, amino acids, vitamins, and minerals. They have essential health effects, such as antioxidant, antimicrobial, immune-stimulatory, and anticancer, cholesterol-lowering properties. Because of their nutritional and medicinal benefits, mushrooms have become increasingly popular in recent years all over the world. Mushrooms were considered immortality plants in Ancient Egypt and were given to mankind by the god Osiris. Mushrooms were declared a delicacy reserved only for Egyptian nobility due to their distinct flavor. The current study focuses on the common species of edible mushrooms in Egypt and their different bioactive ingredients, nutritional values and the health benefits.
1. Introduction
Mushroom is a macro-fungi with generic name for the reproductive fruiting body, which belongs to Ascomycota and Basidiomycota. Mushrooms can be epigeous or hypogeous, and they can be harvested by hand if they are large enough to be seen with the naked eye. Mushroom has a high nutritional value due to their high protein, vitamin, mineral, fibre, and trace element content, as well as their low/no calorie and cholesterol content . For thousands of years, several of them have been utilised in folk medicine by producing potent nutriceuticals compounds.
Mushrooms are reported to be high in antiparasitic, antimicrobial, antioxidant, antiinflammatory, anticancer, antitumour, anticoagulant, cytotoxic, hypocholesterolemic, anti-HIV, antidiabetic, and hepatoprotective chemicals, among other bioactive components. Because of their nutritional and medicinal benefits, mushrooms have become increasingly popular in recent years all over the world. In 1961, the world's cultivated edible mushroom production totaled 495 127 metric tonnes, then production grew from 1961 to 2016, reaching 10 378 163 metric tonnes. Only about 2 000 of the approximately 14 000 known species are safe to eat, and about 650 of these have therapeutic characteristics. China produced over 73% of the world's mushroom crop, while Italy is the second-largest mushroom producer, followed by the United States.
Mushrooms have been valued as a valuable food source due to its nutritional and medicinal characteristics. Wild mushrooms have been devoured with delicacy by man since ancient times, most likely due to their taste and appealing flavour. People in ancient China thought that the mushroom established human body and health, prolonged youth, and was used as food and medicine. Mushrooms were thought to provide power to warriors in combat by the Greeks. Mushrooms were primarily used by the Mayans for religious rites by some regions. Also, Egyptians thought they were a gift from the god Osiris. The Romans considered edible mushrooms to be the Food of the Gods, and they even included mushrooms on a list of foods that were only served on special occasions.
The world's first artificially farmed mushroom was Auricularia auricularia, which first farmed mushrom, followed by Flammulina velutipes, and Lentinula edodes. Agaricus bisporus was farmed for the first time in France in the 1600s, while Pleurotus spp. was first cultivated in the United States in the 1900s. Only around 35 mushroom species have been professionally farmed to date, only about twenty are now being grown on an industrial basis. A. bisporus and Pleurotus ostreatus were the most common cultivated mushroom in Egypt, they contained 26.05% and 33.85% crude protein, 2.79% and 2.41% crude fats and 57.05%–42.56% carbohydrate in the dried P. ostreatus and A. bisspours .
2. History of mushroom
Mushroom consumption is likely as old as the history of food collection, which was one of primaeval society's mainstays. Fungi have been valued as a source of nourishment and medicine by many communities for millennia. According to radiocarbon analysis mushroom age found to be around 18 700 years old. The existence of mushrooms from the Boletales order and other nearly unidentified agaric mushrooms in the Red Lady's diet has been proved by food remains preserved in tooth calculus. We now know that the combination of agaric acid and toxic oils found in Fomitopsis betulina can be used to treat whipworm illness effectively. The fungus was also mentioned in Mayan culture, where hallucinogenic fungi (Psilocybe species and fly agaric) were referred to as Teonanácatl, which meant "body and food of gods". It's also thought that fly agaric could be one of the elements of a drink that allows individuals to perform heroic feats.
Mushrooms were considered immortality plants in Ancient Egypt, and were given to mankind by the god Osiris. Mushrooms were declared a delicacy reserved only for Egyptian nobility due to their distinct flavour. They were not only banned to consume, but they were also forbidden to touch. Mushrooms were likewise regarded with great reverence by the Romans. They were referred to as "God's food" by the ancient Romans. Mushrooms were also elevated to the status of a luxury item reserved for monarchs. Truffles, porcini mushrooms, Caesar's mushroom, mushrooms, and puffballs were enjoyed by the wealthy Romans [26]. The first mentions of mushroom toxic characteristics can be found among the existing records connected to mushroom consumption during ancient Roman times. The poisoners took advantage of the rulers' fondness for mushrooms, as mushrooms became the ideal tool for overthrowing emperors. Caesar Claudius, the ruler of the Roman Empire from AD 41 to 54, was a well-known mushroom enthusiast. Pliny the Elder's records show that on the day of his death, he requested a plate of boletes and Caesar's mushrooms.
3. Components of edible mushroom cultivated in Egypt
3.1. Bioactive component
Edible mushrooms contain various bioactive components such as proteins, polyunsaturated fatty acids, polysaccharides, dietary fibers, amino acids, vitamins, and minerals. They have essential health effects, such as antioxidant, antimicrobial, immune-stimulatory, and anticancer, cholesterol-lowering properties.
Several significant components and secondary metabolites control their biological activity. Lectins are carbohydrate-binding proteins that can be found in many types of edible mushrooms such as Agaricus campestris, Agaricus isporus, Grifola frondosam, Boletus satanus, F. velutipes, Tricholoma mongolicum, Ganoderma lucidum, and Volvariella volvacea. Lectins have been shown to increase insulin secretion, activate the immune system, and have anticancer effects. Lectins can also play essential roles in physiological processes such as dormancy, growth, morphogenesis, morphological changes and molecular recognition in the early stages of mycorrhization.
Glucans are one of the unique ingredients in mushrooms that have immune-stimulatory anticancer, anti-inflammatory, and antioxidant effects. They can be found in different types of edible mushrooms such as Jelly ears (Auricularia auricular), Reishi (G. lucidum), Shiitake (L. edodes), and Oyster (P. ostreatus). For example, beta-glucan isolated from Pleurotus pulmonarius, has potent anti-inflammatory and antinociceptive properties that inhibit pro-inflammatory cytokines. Glucans isolated from P. pulmonarius. Also suppressed colon carcinogenesis associated with colitis by regulating cell proliferation, inducing apoptosis, and suppressing inflammation. Beta-glucan is a high-molecular-weight polysaccharide of glucose bound by glycosidic bonds.
Phenolic compounds are considered secondary metabolites of edible mushrooms. Polyphenols have been extensively studied and shown to be effective against a variety of health complications. Phenolic acids such as p-hydroxybenzoic, cinnamic, gallic, salicylic, p-coumaric acids, syringic acids, caffeic, ferulic, chlorogenic, and flavonoid can be found in mushrooms. Gallic, caffeic, and p-coumaric acids are the main phenolic groups and play an essential role in the biological activity of mushrooms. Phenolic compounds have high antioxidant activity. Polyphenols from edible mushrooms such as Meripilus giganteus, Agaricus hydnum, and Rufescens silvaticus have high antioxidant capacity. Phenolic compounds have also shown anticancer activity against kidney cancer cell lines and human ovarian cancer cell lines.
Flavonoid compounds, including myricetin, rutin, naringenin, quercetin, morin, and hesperetin, are included in the polyphenol content, and they exhibit antiproliferative effect.
Other essential components in mushrooms called terpenoids such as monoterpenoids, sesquiterpenoids, diterpenoids, and triterpenoid. They have been shown to have antimicrobial, anticholinesterase, anticancer, anti-inflammatory, antimalarial, and antioxidant properties.
Currently, about 285 types of terpenoids have been discovered in mushrooms and have medicinal properties. For example, ganoderic acids are a lanastanoid type triterpenoid and have been isolated from Ganoderma amboinense, G. lucidum, etc. Ergosterol, the principal sterol in most edible mushrooms, is a valuable dietary precursor of vitamin D2 and a natural antioxidant. Phytosterols, such as ergosterols and ergosterol peroxide, have been shown to be more potent than the nonsteroidal anti-inflammatory drug indomethacin as shown by their 50% inhibitory effect. High levels of ergosterols can be found in A. bisporus, L. edodes, Grifola frondose, and P. ostreatus.
3.2. Nutritional values
Edible mushrooms are considered an important source of food for humans for thousands of years. The medicinal properties provided by the chemical composition and nutritional value of edible mushrooms have been investigated by several researchers. In recent decades the consumption of edible and medicinal mushrooms in Eastern and Western countries has gradually increased.
A. bisporus, L. edodes, and Pleurotus spp. are presently the most common cultivated edible mushrooms, with China as the largest producer of these mushrooms in the world. Edible mushrooms are known for their high contents of carbohydrates, protein, and crude fibers, as well as different bioactive compounds, which provide both nutritional and health benefits for humans. The relative content of these nutritional components differs by species and between countries as reported in Table 1.
Table 1. General nutritional values of some common edible mushrooms from different sources.
Mushroom speciesMoisture (%)Total protein (%)Total carbo-hydrate (%)Total phenols (%)Crude fiber (%)Ash (%)Refs.Only one speciesA. bisporus81.7929.2920.57-24.567.12[45]F. velutipes-18.4256.37-7.816.33[46]Lactarius deliciosus9217.1966.614.5–13.631.818.62[47]Pleurotus florida87.0534.5631.59-11.417.40[48]P. ostreatus85.5530.9231.40-12.107.05[48]Russula delica-26.2534.88-15.4217.92[49]Tremella fuciformis91.734.694.8-1.40.4[50]G. frondosa83.0621.158.8-10.17.0[51]Hericium erinaceus95.6923.357.0-7.89.4[51]Tricholoma giganteum-16.170.1-4.55.0[52]Many speciesA. bisporus, Agrocybe cylindracea, Boletus loyo, Cortinarius lebre, Cyttaria espinosae86–968.56–23.8862.97–83.650.75–4.727–155–13[43]A. bisporus, P. ostreatus, L. edodes88–921.70–2.113–91.1–1.520–370.80–1.15[53]A. bisporus, Boletus edulis, Calocybe indica, Calocybe gambosa, G. frondosa, F. velutipes-18.1–62.831.1–70.6-7.81–32.303.5–19.7[44]Pleurotus sajor-caju, C. indica87–891.74–3.403.33–3.37--1.2–1.3[54]
4. Medicinal and pharmacological uses of mushroom
The use of A. bisporus extracts and/or bioactive compounds as antioxidants, anti-cancer, and anti-inflammation agents in the treatment of many human diseases, including coronary heart disease, diabetes mellitus, bacterial and fungal infections, immune system disorders, and cancers, is increasing around the world. Because of their acetylcholinesterase and butyrylcholinesterase inhibitory action, A. bisporus extracts may be useful in the treatment of Alzheimer's disease . Hyperlipidemia, or high levels of triglycerides or cholesterol, is a major risk factor for cardiovascular disease and atherosclerosis, which is one of the most dangerous diseases in humans. Lovastatin is a statin medicine that reduces the risk of cardiovascular disease by reducing cholesterol (hypolipidemic agent) in those who have hypercholesterolemia. A. bisporus contained 565.4 mg/kg of lovastatin and white button mushroom A. bisporus may lower cholesterol levels in serum and/or liver.
Compared to L. edodes, P. ostreatus, Pleurotus eryngii, and G. frondosa, A. bisporus mushrooms, especially portabellas (brown A. bisporus), have increased antioxidant capacity. Gallic acid, protocatechuic acid, catechin, caffeic acid, ferulic acid, and myricetin were identified as the primary phenolic components in ethanolic extract of A. bisporus. The principal antioxidant components in mushrooms have been identified as phenolic compounds. A strong link was discovered between antioxidant activity and phenolic content, implying that phenolic chemicals may be the primary contributors to edible macrofungi's antioxidant activity.
A. bisporus extracts have been demonstrated to induce apoptosis in HL-60 leukaemia cells and inhibiting cell proliferation. Pre-menopausal women who eat mushrooms had a lower risk of breast cancer. On activated human peripheral blood mononuclear cells, mushrooms extracts have an immunostimulating effect. Arginine found in A. bisporus inhibits tumour growth and metastasis. A. bisporus inhibits aromatase, lowering the risk of breast cancer. Also extracts from mushrooms decrease aromatase activity and hence reduce oestrogen positive cancers. Its polysaccharide had high immunostimulatory and anticancer bioactivity in vivo and in vitro.
A. bisporus is abundant in dietary fibers and antioxidants, such as vitamin C, D, and B12, as well as folates and polyphenols, which may help prevent cardiovascular and diabetes disorders . A. bisporus has a number of chemicals that have potential anti-inflammatory and antioxidant health effects in persons who are prone to type 2 diabetes when consumed often over time. Consuming α-glucans from the A. bisporus mushroom reduced the production of lipopolysaccharide-induced tumor necrosis factor-alpha (TNF-α) by 69%. Eating A. bisporus could be a good way to avoid liver steatosis, which is a reversible stage of nonalcoholic fatty liver disease in postmenopausal women [66].
5. Common cultivated mushrooms in Egypt
A. bisporus (button mushroom) is the most frequently cultivated and consumed fungus on the planet, accounting for over 40% of global mushroom production. The white mushroom is the world's most popular and eaten edible mushroom species. It is popular not only for its flavour, but also for the nutrients it contains: fibers, amino acids, fatty acids such as linoleic and linolenic acids, easily digestible proteins, phenolic, sterols, and vitamins, particularly C, D2 and B1, B2, B6, B7. Its fruiting bodies contain antioxidant, anti-infectious, antibacterial, anticancer, and have immunomodulatory properties .
A. bisporus (Lange) Pilat morphologically description by Phillips as following; mushroom cap greyish in color, hemispherical with expanding convex (5−10 cm). Stem long white (38 mm × 6 mm), gills pinkish and darkened with age. Cheilocystidia is thin wall, elongated and clavate in shape ((4.0−7.5) µm × (4−14) µm). Spores are brown, sub-globose ((4.0−7.5) µm × 5.5 µm) and its basidia has two pores which charachterized it from other Agaricus species . A. bisporus thrives in cow dung-fertilized areas, compost piles, parks, and forests. Its occurrence in open areas is unusual. It can also be grown on specialised culturing substrates. In parks and forests, A. bisporus plays an important role in the breakdown of leaves and needles. Aside from its ecological importance, it is one of the most widely produced mushrooms on the planet. The first known report about A. bisporus cultivation comes from France in 1707, and the species is known as the Paris champion as a result.
