Nutritional Significance

Abstract

An array of nutrients like carbohydrates, proteins, amino acids, fats, fatty acids, fibers, minerals, and vitamins are present in macrofungi. These nutrients make them an ideal candidate to be used in nutraceutical formulations. Macrofungi are low in calories and cholesterol and are rich in antioxidants adding more to their health-promoting qualities (Akata et al. 2013; Chauhan et al. 2014; Sinanoglou et al. 2014; Ghosh 2016; Reis et al. 2017; Üstün et al. 2018; Tietel and Masaphy 2018). The amount of proteins, carbohydrates, fats, fibers, moisture, and ashes lies approximately in the range of 31.40–49.05%, 41.25–65%, 0.25–1.08%, 6.41–17.97%, 54.75–76.97%, and 2.64–10.34%, respectively (Vishwakarma et al. 2016). This range of mycochemicals varies with the species under investigation. Polysaccharides in mushrooms are made up of many monosaccharides such as glucose, galactose, fructose, xylose, mannose, fucose, rhamnose, arabinose, trehalose, and mannitol (Valverde et al. 2015). Fungi are known for their high protein content consisting of various types of amino acids. Amino acid profiling of A. hemibapha, Boletinus pinetorus, Baorangia bicolor, B. speciosus, B. sinicus, B. craspedius, B. griseus, B. ornatipes, Suillus placidus, T. microcarpus, Tricholoma terreum, Tricholomopsis lividipileata, and Xerocomus has been performed through pre-column derivatization reversed-phase high-performance liquid chromatography (RP-HPLC). These species have been found containing all the 20 amino acids, aspartic acid, glutamic acid, serine, glycine, alanine, praline, cysteine, valine, methionine, phenylalanine, isoleucine, leucine, lysine, histidine, threonine, asparagine, glutamine, arginine, tyrosine, and tryptophan, but each species has presented its own amino acid profile. The total free amino acid content varies from 1462.6 to 13,106.2 mg/100 g. Alanine, cysteine, glutamine, and glutamic acid represent the most abundant amino acids present in these species (Sun et al. 2017). Fats occur in low amounts in macrofungi and are rich in both saturated and unsaturated fatty acids such as cis-11-eicosenoic acids, cis-10-pentadecenoic acid, linoelaidic acid, linoleic acid, myristic acid, oleic acid, palmitic acid, pentadecanoic acid, etc. as analyzed by gas chromatography coupled with flame ionization detector (GC-FID) and chromatography coupled with mass spectroscopy (GC-MS). Unsaturated fatty acids dominate fats in macrofungi and mainly consist of linoleic acid (10–51%) (Türkekul et al. 2017; Bengu 2020). Besides, carbohydrates, proteins, fats, various minerals, and vitamins have also been found in many macrofungal taxa (Thatoi and Singdevsachan 2014; Nakalembe et al. 2015). Mineral profiling performed through wavelength dispersive X-ray fluorescence (WDXRF) technique has detected the presence of several mineral nutrients in the dry ash made from basidiocarps of Phellinus mushrooms, namely, Ph. conchatus, Ph. rimosus, Ph. igniarius, Ph. gilvus, and Ph. nigrolimitatus (Chenghom et al. 2010). Several mineral nutrients such as Cu, Zn, Fe, Mn, Co, Cd, Ni, and Pb have been determined in 24 macrofungal species (Yilmaz et al. 2003). Vitamins such as A, B, C, D, and E have been detected in several fungal species (Wani et al. 2010; Phillips et al. 2011; Phillips and Rasor 2013; Gaitán-Hernández et al. 2019). The liquid chromatography-mass spectroscopy (LC-MS) reported the presence of several phenolics and flavonoids in the mature and immature summer truffle (T. aestivum) (Shah et al. 2020). Since macrofungi contain a variety of nutrients such as carbohydrates, proteins, minerals, vitamins, amino acids, fatty acids, etc. (Table 6.1), the consumption of these species has enhanced either as whole mushrooms or extracted supplements. The DSs of mushrooms boost the innate immunity and help the body to fight against various diseases. Edible mushroom supplements enriched with nutrients have also been screened for their pharmaceutical potential especially against cancer. A. bisporus (white button mushroom) nutritional supplements have been found to strengthen the innate immunity which proves helpful to fight against tumors and viruses by promoting natural killer (NK) cell potential probably mediated through enhanced production of interferon gamma (IFNγ) and tumor necrosis factor alpha (TNFα) (Wu et al. 2007). A dietary supplement, MycoPhyto® Complex (MC), is a mixture of mycelia from A. blazei, G. frondosa, G. lucidum, T. versicolor, O. sinensis, P. umbellatus, and β-1,3-glucan extracted from Saccharomyces cerevisiae. This mixture possesses antiproliferative properties and arrests the cell cycle at G2/M phase of human breast cancer cells MDA-MB-231 through the suppression of cell cycle regulatory genes (ANAPC2, ANAPC2, BIRC5, Cyclin B1, Cyclin H, CDC20, CDK2, CKS1B, Cullin 1, E2F1, KPNA2, PKMYT1, and TFDP1). The anti-invasive effect of MC is due to the inhibition of production of urokinase plasminogen activator (uPA) from MDA-MB-231 cells (Jiang and Sliva 2010). It has been reported that dietary supplementation of P. eryngii powder (1.5 and 2%) improves the humoral innate immune responses, antibacterial efficiency of skin mucus, and growth performance of Koi fish (Safari and Sarkheil 2018). The cultivated basidiocarps of G. lucidum have been found to accumulate elements from the substrate and can be utilized for the production of supplements rich in mineral nutrients (Rzymski et al. 2016). Taiwanofungus camphoratus mushroom is parasite on Cinnamomum kanehirae, and the cold water-soluble polysaccharide (galactomannan-repeated, molecular weight >70 kDa) isolated from this mushroom exhibits immuno-enhancing properties. The DSs of this polysaccharide show immunomodulation in mouse macrophages and human dendritic cells. It can be used as adjuvant in immunotherapy and vaccination (Perera et al. 2018). Mushroom polysaccharides have also been developed and exploited as functional foods such as the lentinan in L. edodes, schizophyllan in S. commune, pleuran in Pleurotus species, calocyban in Calocybe indica, and ganoderan in G. lucidum (Villares et al. 2012; Badalyan 2016). They function as dietary fibers and interact with microbiota residing in the gastrointestinal tract bringing changes in the gut microbiota abundance which in turn impacts the host health (Jayachandran et al. 2017). Basically, gut microbiota degrade the polysaccharides, and some specific gut bacteria use them as energy source which help in their propagation and release many beneficial compounds mainly short chain fatty acids such as acetate, propionate, butyrate, and valeric acid (Kong et al. 2016; Zhu et al. 2016; Ma et al. 2017). The impacts of fungal polysaccharides on gut microbiota can prove beneficial in the treatment of various health issues such as the autoimmune diseases, allergic disorders, inflammatory bowel disease, irritable bowel syndrome, ulcers, colorectal cancer, necrotizing enterocolitis, and obesity (Milani et al. 2016). Polysaccharides from 53 wild-growing mushrooms have been observed to stimulate Lactobacillus acidophilus and Lactobacillus rhamnosus growth. These polysaccharides can pass through the stomach unchanged, reach the colon, and enhance the growth of beneficial gut microbes stronger than commercially available prebiotics like inulin or fructo-oligosaccharides (Nowak et al. 2018). There are different authorities, namely, the World Health Organization (WHO), US Food and Agriculture Organization (FAO), US Food and Drug Administration (FDA), New Zealand Dietary Supplements Regulations (NZDSR), etc., active to regulate the quality, intake, safety, and effectiveness of food and medicinal products including mushroom-derived DSs and functional foods (Wasser and Akavia 2008). To ensure adequate intake of DSs and functional foods, several national medical research bodies such as the Indian Council of Medical Research (ICMR) in India are regularly releasing advisories and recommend the dietary intakes of mushrooms, e.g., G. lucidum species (Singh et al. 2020).