Mean nutrient content of raw mushrooms per 100 g edible portion.
Edible mushrooms are an excellent source of proteins, minerals, polysaccharides, unsaturated fatty acids, and secondary metabolites. Numerous studies have provided evidence for the protective effects of edible mushrooms against various chronic diseases. In this review, details on the compositions and nutritional values of edible mushrooms were discussed. Furthermore, bioactive compounds such as polyphenolic compounds and antioxidant capacity of edible mushrooms, as well as the application of these edible mushrooms as potential therapeutic agents, were covered. This chapter also endeavoured to review the recent progress on the potential utilisation of edible mushrooms in the development of functional food products and its effects on the nutritional, physical, and organoleptic properties of the developed food products. Based on the recent socioeconomic trends, the substitution of edible mushroom as an essential source of functional ingredients in food products could become a natural adjuvant for the prevention and alleviation of several lifestyle-related diseases. This information could be beneficial for the development of food products with health functionalities, which are of great interest to the medical nutrition industry, which is an industry that emerged from the convergence between the food and pharma industries.
- edible mushroom
- nutritional compositions
- functional properties
- nutraceutical properties
- therapeutic values
- food product quality
Mycophagy describes the practice of eating mushrooms. This practice can be dated back to ancient times, whereby wild edible mushrooms were collected and consumed. Mushrooms are an excellent source of vitamins, e.g. B vitamins and vitamin D , and minerals, e.g. phosphorus, magnesium, selenium, copper, and potassium , and are also rich in dietary fibre, chitin and β-glucans . Humans have, for centuries, consumed mushrooms not only for nutrition [4, 5] and taste  but also for their healing properties . Numerous studies have shown that mushrooms are a rich source of bioactive compounds, e.g. phenolic and flavonoid compounds, that exert antioxidant properties, and these could be beneficial to human health [8, 9, 10, 11, 12]. Mushrooms could help in reducing the risk of diseases, such as Parkinson’s, Alzheimer’s, hypertension, stroke, and cancer, as well as act as an antibacterial, immune system enhancer, and cholesterol-lowering agents .
Due to the numerous reports and findings on the health benefits of mushrooms to humans, studies on the use of mushrooms as a bioactive ingredient in functional food products have gained attention from the scientific community. Mushrooms are converted into powder before incorporated into food products, such as bread, muffins, pasta, patties, and snacks, to increase the nutritional quality of these products [14, 15, 16, 17, 18]. With the introduction of processed food products incorporated with mushrooms, this further expands the popularity of mushrooms among consumers. On average, consumers consumed about 5 kg of mushrooms per person per year, and this number is expected to continue to increase as consumers become more aware of the healthful benefits of incorporating mushrooms in their diet .
For the last 10 years, from 2008 to 2017, the global production of mushrooms and truffles grew from 6.90 to 10.24 million metric tons  ( Figure 1 ). Based on the latest statistic report from the Food and Agriculture Organization of the United Nations, in 2017, China (7.87 million metric tons, contributed almost 77% of world production), the United States (0.42 million metric tons), the Netherlands (0.30 million metric tons), Poland (0.30 million metric tons), and Spain (0.16 million metric tons) were reported as the top 5 mushroom and truffle producers in the world. As the demand for edible mushrooms increases and the amount of wild edible mushrooms shrinks, edible mushroom cultivation is becoming an important agriculture sector.
The most cultivated edible mushroom worldwide is
2. Nutritional compositions
Edible mushrooms possess high nutritional value, especially protein and carbohydrates. Besides, edible mushrooms have also been described as a rich source of minerals and vitamins [23, 24]. The mean nutrient values for these raw mushrooms  are presented in Table 1 . Han et al.  studied the quality properties of powder processed from oyster mushroom, a variety of
|Nutrient||Common mushroom||Shiitake mushroom||Oyster mushroom||Enoki mushroom|
|Moisture (g/100 g)||92.45||89.74||89.18||88.34|
|Energy (kcal/100 g)||22||34||33||37|
|Protein (g/100 g)||3.09||2.24||3.31||2.66|
|Fat (g/100 g)||0.34||0.49||0.41||0.29|
|Ash (g/100 g)||0.85||0.73||1.01||0.91|
|Carbohydrate (g/100 g)||3.26||6.79||6.09||7.81|
|Dietary fibre (g/100 g)||1.0||2.5||2.3||2.7|
|Ergosterol (mg/100 g)||56||85||64||36|
|Calcium (mg/100 g)||3||2||3||0|
|Copper (mg/100 g)||0.32||0.14||0.24||0.11|
|Iron (mg/100 g)||0.5||0.41||1.33||1.15|
|Magnesium (mg/100 g)||9||20||18||16|
|Manganese (mg/100 g)||0.05||0.23||0.11||0.08|
|Phosphorus (mg/100 g)||86||112||120||105|
|Potassium (mg/100 g)||318||304||420||359|
|Selenium (μg/100 g)||9.3||5.7||2.6||2.2|
|Sodium (mg/100 g)||5||9||18||3|
|Zinc (mg/100 g)||0.52||1.03||0.77||0.65|
|Thiamin (mg/100 g)||0.081||0.015||0.125||0.225|
|Riboflavin (mg/100 g)||0.40||0.22||0.35||0.20|
|Niacin (mg/100 g)||3.61||3.88||4.96||7.03|
|Pantothenic acid (mg/100 g)||1.50||1.50||1.29||1.35|
|Pyridoxine (mg/100 g)||0.10||0.29||0.11||0.10|
On the other hand, Han et al.  reported that PSC contained 22.4 g/100 g protein, 56.99 g/100 g dietary fibre (i.e. 56.99 g/100 g total dietary fibre, 48.79 g/100 g insoluble dietary fibre, and 8.20 g/100 g soluble dietary fibre), 7.79 g/100 g ash, and 3.32 g/100 g β-glucan but has low amount of sucrose (0.19 g/100 g) and crude fat (2.30 g/100 g). According to Elleuch et al. , polysaccharides especially dietary fibres are the most important active compounds among others. Hence, several medicinal and pharmacological properties of PSC are believed to be associated with dietary fibre which can provide functional properties.
It is interesting to note that different parts of mushroom, the cap, stalk, or cap with a stalk of oyster mushroom (
In another study by Kayode et al. , they found that the proximate compositions of exotic oyster mushroom grown on
According to Aremu et al. ,
Ishara et al.  fortified the maize flour with mushroom flour from
Further, Alexopolous et al.  reported that the fairy ring mushroom (
Another study was performed on the determination of β-carotene (vitamins A); α-tocopherol and γ-tocopherol for vitamin E, ascorbic acid (vitamin C), thiamine (vitamin B1), and riboflavin (vitamin B2); and several dominant and trace minerals on selected wild edible mushrooms, namely,
3. Functional properties
The functional properties of flours play an important role in determining the level of utilisation in ingredient formulation as well as in food product development. It is important to recognise the functional properties (i.e. water absorption capacity, oil absorption capacity, emulsifying, foaming, and gelification ability) of mushroom flours for their efficient use and acceptance by consumers . The analysis of functional properties, water absorption capacity, oil absorption capacity, oil emulsion capacity, foaming stability, foaming capacity, least gelation concentration, and bulk density on flour prepared from
Cruz-Solorio et al.  evaluated the functional properties of flours processed from fruit bodies of three
s showed a minimal gelation concentration (2%). For foam capacity formation, protein concentrates presented a higher value than that of flour at pH 8.0. However, for foam stability, both flours and protein concentrate s showed high value at pH 8.0 and pH 10.0 (alkaline conditions). The flours presented have 3.96–26.68 m2/g of emulsion activity index, whereas protein concentrates range from 1.55 to 10.28 m2/g. The authors concluded that flours and protein concentrates produced from
In addition, another report by Oluwafemi et al.  on various parts of
4. Nutraceutical properties
The importance of edible mushrooms as a nutraceutical source can be correlated to their composition and presence of phytochemicals. Reports have shown edible mushrooms to contain a wide array of bioactive compounds. These bioactive compounds present great potential to be applied as therapeutic agents. This is in agreement with the reports from Kozarski et al. , whereby the radical scavenging antioxidative activities of edible mushrooms come from an array of biomolecules from the carotenoid and polyphenol groups. Mushrooms are well-known to have rich various bioactive compounds that are widely used as raw material for the development of functional foods. It could emerge as the nutraceutical food for the next generation . According to Sánchez , phenolic compounds such as myricetin, quercetin, caffeic acid, catechin, and pyrogallol are present in all edible mushrooms. Besides, antioxidant components (i.e. phenolics, carotenoids, ascorbic acid, tocopherols, ergosterol, and polysaccharides) are mainly found constituted in both fruit bodies, mycelium, and culture of mushrooms .
Different edible mushroom cultivars and wild species are reported to possess varied concentrations of phytochemicals and antioxidant activities. Kayode et al.  reported that qualitative analysis of oyster mushroom grown on
Radzki et al.  studied the effect of hydrothermal treatment (i.e. citric acid solution blanching (5 min) and oiling in water (15 min)) on the antioxidant capacity (i.e. ferric-reducing antioxidant power assay (FRAP), and scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays) of three species of edible mushroom, namely,
Mujić et al.  evaluated the potential antioxidant activity content of antioxidant compounds, phenolics and flavonoids, and scavenging capacity on DPPH radicals of three edible mushroom species
Keleş et al.  evaluated total phenolic and antioxidant activity in the methanolic extracts of 24 types of dried wild edible mushrooms. The authors concluded that mushrooms contain 420–12775.56 mg/kg of phenolics and the FRAP and DPPH values range between 145.50–62771.43 μmol/g and 10.17–97.96% of dried matter, respectively; the total phenolics in methanolic extracts were the highest in
5. Therapeutic values
Apart from the nutritional values, edible mushrooms are also being used for a very long time to treat many types of diseases. Many of the common edible species have therapeutic properties and have been eaten for medical treatment purposes . Many therapeutic values of mushrooms traditionally used in folklores of many parts of countries are being scientifically corroborated and have been found to stem from numerous biologically active and health-promoting metabolites that the mushrooms produce [21, 49]. Mushrooms have been reported as useful in preventing diseases such as hypertension, hypercholesterolemia, and cancer  due to the presence of high antioxidative compounds in mushrooms. The consumption of food containing antioxidant compounds like mushrooms will protect against the damage of cells from free radical, delays ageing, as well as prevent various diseases . According to Zekovic et al. , mushrooms’ β-glucans have been reported to exhibit different effects (i.e. antitumour, immune-booster) when compared with β-glucans from oats and barley (i.e. lowering cholesterol and blood sugar). Often, the β-glucans produced by specific mushroom species have specific names such as ganoderan (
Valverde et al.  reported that several active compounds such as phenolics, ascorbic acid, carotenoids, and tocopherol isolated from the different species of mushrooms are responsible compounds to boost the immune system of the body and have anti-hypercholesterolaemic activity, antiviral activity, and anticancer, and ameliorate the toxic effect of chemo- and radiotherapy. The previous study conducted by Lau et al.  demonstrated that the protein extract from selected local edible mushrooms (i.e.
In Japan, lentinan, a complex carbohydrate, is isolated from a variety of mushrooms such as
6. Functional foods from edible mushrooms
Mushrooms are generally traded in food industries in three categories, which are fresh, dried, or canned and processed as mushroom-based products . Most of the fresh mushroom is used in soup, sauce, and as a filling in buns or pizzas. The fresh mushroom is usually sold in local markets due to its short shelf life. As reported by Akbarirad et al. , the shelf life of mushrooms is limited under normal refrigeration conditions. The short shelf life of fresh mushrooms is one of the constraints in the distribution and marketing of fresh products. Therefore, in order to maximise the use of mushrooms in the production of high-quality and nutritional food as well as to preserve and ensure that the mushroom can be used for a long period, various mushroom-based products are being developed.
Canned mushrooms have been widely marketed and used in the preparation of mushroom soup, stew, and pizza to replace the use of fresh mushrooms [69, 70, 71, 72, 73, 74, 75]. Dried mushrooms have been used in instant soup and sauce preparation . However, the dry form of the edible mushroom has limited uses in food production compared to powdered mushroom which has broad application in food developments. The mushroom powder has great potential as an ingredient in various food products due to its functional characteristics. Mushrooms are recognised as an alternative source of good quality protein and are capable of producing the highest quantity of protein per unit area and time from the worthless agrowastes . Based on a study by Salehi , mushrooms contain 22.41% of protein which is higher than the protein in wheat flour. This finding is in line with Wan Rosli et al.  and Mendil et al. , who reported that the protein content in mushroom is around 25%.
A few studies have been done on supplemented mushroom powdered into food products such as noodles, pasta, rice porridge, as well as bakery products [16, 81, 82, 83, 84]. The powder mushroom is mainly being used as a composite flour in bakery production. According to Coelho and Salas Mellado , nowadays, there is a lot of attention on the substitution of various flour types for wheat flour to satisfy demands for healthier food. Higher protein content in mushroom powder will develop a better gluten network and produce the right and better elasticity in bakery products as well as in pasta and noodles. The additional amount of mushroom in pasta enhances the antioxidant content .
Several studies have been done on the application of mushroom as food additives in food products. Süfer et al.  mentioned that the supplemented 5% of
7. The effects of edible mushrooms fortification on food quality
The increase in production and consumption of food products using edible mushrooms is due to their nutritional values as well as medicinal effects. Several studies reported that the addition of powdered mushrooms showed an increase in protein, crude fibre, and ash in various food products. Fortification of powdered mushroom at 6 and 10% showed better results for nutritional values as well as the quality for all food products. The protein content in both bread and muffin supplemented with 10% powdered mushroom showed an increase pattern compared to the control. The increase of protein content in both food products was attributed to the high level of protein in mushroom powder. However, the high level of protein content does not affect the specific volume . This suggests that the protein content in powdered mushrooms is unable to produce/develop the gluten network and improve the viscoelasticity of bread and muffin. According to Ortolan and Steel , gluten in protein can be categorised into two, which are vital and nonvital glutens. Nonvital gluten is only used for protein enrichment not for its viscoelastic properties.
The crude fibre content in bread is significantly higher than the control . The higher fibre content in food products is favourable due to its beneficial effect on human health such as protection from constipation, cardiovascular diseases, and obesity [90, 91]. The high fibre content in both bakery products is also one of the main reasons for the lower specific volume in bread and muffins. Increasing fibre content in composite flour generally increases the requirement of water absorption . Indirectly it gives heavier loaf and decreases the bread volume. The addition of high fibre content of flour also shows a negative effect on bread quality due to longer dough development, reduction of gas retention, and limitation of expanding the ability of the dough .
The supplemented powdered mushroom is high in protein in bakery products such as bread, cake, muffin, and biscuits [81, 82, 83, 90]. The addition of 10% of powdered desert truffles may increase the diameter and thickness of the biscuit. According to Gadallah and Ashoush , biscuits that have higher spread ratios are considered most desirable. The additional amount of dessert truffle powdered in biscuits is also proven to have higher antioxidant activities.
The enrichment of protein in pasta and noodles can be achieved by adding shiitake, porcini, and powdered oyster mushroom [16, 84]. The moisture content in noodles supplemented with 10% of mushroom powder shows lower enrichment than the control. According to Foschia et al. , the reduction of water is due to the competing of fibre in powdered mushrooms with starch during noodle formation, causing the reduction of starch swelling and water absorption. Besides, the fibre content in noodles with 10% additional powdered mushroom shows significant difference with the control which suggests lower moisture content in noodles.
Most of food products such as bread, cake, biscuits, paratha, rice porridge, and noodles show higher ash content compared to control. Higher ash content means a higher amount of mineral present in food products. The taste, texture, appearance, and stability of food products supplemented with powdered mushrooms also depend on the concentration of mineral [81, 82, 90]. The mushroom powder favoured in rice porridge is due to its meaty flavour. Moreover, they contain high protein, fibre, and minerals. The proximate composition and sensory characteristic of rice porridge were investigated by Aishah and Wan Rosli . Their result showed that consumer acceptability of rice porridge supplemented with 6% of oyster mushroom powder has a higher score than the control. A similar trend can be seen in paratha bread  except for fat content. Besides, the authors reported that there is a huge reduction of fat content in paratha bread supplemented with 6% of oyster mushroom .
Chun et al.  used shiitake mushroom in pork patty production. This powdered mushroom acts as phosphate in pork patties. Phosphate acts as food additives, which increase the water holding capacity, reduce cooking loss, and improve the texture of food products. Besides, it also protects the aroma and accelerates the formation of cured meat colour . However, in term of sensory characteristics, most of the food products supplemented with powdered mushrooms were less preferred by the panellists in terms of texture, aroma, taste, and overall acceptability. The colour of food products supplemented with mushroom powder shows darker colour, thus affecting the preference of most mushroom-based products .
Mushrooms are gaining popularity and are widely consumed across the globe by all age groups. Mushrooms are considered to be one of the superfoods due to its high nutrient content, especially protein, dietary fibre, vitamins, and minerals. In addition, mushrooms are also well-known to contain bioactive compounds, such as ergosterol, β-glucans, lentinan, and peroxidase, which possess health functionalities. This claim is backed by various studies showing that mushrooms possessed anti-hypercholesterolaemic, antiviral, anticancer, and antihypertensive activities. Studies have been conducted to investigate the potential of mushrooms in food applications. The findings from these studies showed promising results, whereby the incorporation of mushroom into food products enhances the nutritional values, as well as the physical properties of the food product. Hence, it is not a surprise to know that the food and pharmaceutical industries are using mushrooms or bioactive compounds from mushrooms to develop functional foods.
Conflict of interest
All authors declare there is no conflict of interest in this review.