Introduction

Fungi are incredibly diverse in their morphology, ecological niches, metabolic processes, and evolutionary relationships ¹. They play an important role in the emerging bio-economy, helping enhance resource efficiency, create renewable alternatives to fossil fuels, repurpose waste into valuable food and feed, combat lifestyle diseases and antibiotic resistance by bolstering gut health, fortify crops against climate change, and serve as hosts for the development of new biological properties and nutritional value, showing potential to be used as a dietary nutritional supplement ². A mushroom is a macrofungus with a distinctive fruiting body, which can be found either above ground (epigeous) or below ground (hypogeous) and large enough to be seen with the naked eye and to be picked by hand ³.

WEM are not only valued as culinary delicacies but are also appreciated for their rich nutritional content, having been consumed by various cultures around the world for centuries. ^4-6. They are a natural source of vitamins, minerals, and other beneficial compounds that contribute to overall health and well-being ^7-9. Additionally, they are an excellent source of carbohydrates and protein, while being remarkably low in fat and calories. ^10-12. With such a well-rounded nutritional profile, consuming edible mushrooms is linked to numerous health benefits, including improved immune function, prevention of chronic diseases, and cardiovascular health ^13,14. The high nutritional value of wild edible mushrooms makes them a valuable addition to a healthy diet.

Mizoram, a small state in the north-eastern region of India, is located within the Indo-Burma biodiversity hotspot, renowned for its diverse flora and fauna. The heavy precipitation (annual rainfall of 1551.6 mm in 2021) in the region provides a suitable environment for numerous wild mushroom species ^15-16, adding to its rich biodiversity. Previous studies on macrofungi have predominantly focused on their taxonomy, phylogeny, and diversity ¹⁷. There has been little research into the nutritional properties of wild edible mushrooms, with only a few studies conducted in this field ^9,10. Previous studies have shown that edible wild mushrooms found in Mizoram are nutritionally significant, and comparable to other commonly consumed vegetables. However, there are still many wild edible mushrooms in the region that remain unexplored in terms of their nutritional content. Limited consumption of wild edible mushrooms among the people of Mizoram is due to lack of extensive research on macrofungi in the region. The present study aims to address this research gap by investigating the nutritional value of various mushroom species found in Mizoram.

Materials and Methods

Collection, Storage, Identification and Samples Preparation

Basidiomata were collected from the Mizoram University campus (23.7338° N, 92.6680° E) in Aizawl during the 2021-2022 rainy seasons. Following collection, the samples were thoroughly cleaned to remove any debris and properly labelled. The collected specimens were identified using standard methods based on macroscopic and microscopic characteristics ^18-20. Vouchers number are given to the specimens and stored in Department of Environmental Science, Mizoram University. Three samples were selected and oven-dried at 45 – 50 °C for three days in a Hot Air Oven (HOA). After drying, without separating the cap and pileus, the samples were crushed into a fine powder and stored in a freezer at 4 °C before evaluating their nutritional properties.

Figure 1: Map of study sites showing Mizoram University campusClick here to view Figure

Analysis of Nutrients and Minerals

The nutritional compositions of the mushrooms were expressed on percentage dry weight basis. The samples were analysed for moisture, fat, protein, ash, and crude fiber contents using the standard methods provided by AOAC ²¹. A dry powdered mushroom sample weighing 1 g was placed in a porcelain crucible and then subjected to ashing at 450°C for 5-6 hours. Afterward, the resultant ash was dissolved in 2 mL of concentrated HNO₃ and subjected to heating for 1 minute followed by cooling. Subsequently, it was filtered through a Whatman No. 42 filter paper into a 50 mL volumetric flask and diluted to volume with triple deionized water. A blank was prepared using the same procedure ^21,22. Mineral concentrations, such as calcium (Ca), iron (Fe), magnesium (Mg), potassium (K), and zinc (Zn), were assessed using an atomic absorption spectrophotometer (AAS) ²¹.

Results and Discussion

The nutrient and mineral analysis was conducted on a dry weight basis, with each parameter being analysed three times to obtain the mean result. The Mizo people are familiar with these three common wild edible mushrooms: Schizophyllum commune (Local name: Pasi, Specimen Voucher No – TPZ/18/023), Phallus indusiatus (Local name: Phungsahmim, Specimen Voucher No – TPZ/18/006), and Termitomyces heimii (Local name: Pasawntlung, Specimen Voucher No – TPZ/18/012) which are widely consumed across various regions of Mizoram ⁹. These three wild edible mushrooms were chosen due to their abundance in the Aizawl District and their fruiting bodies and proximate compositions were shown in Table 1.

Figure 2: Fruiting bodies of collected wild edible mushrooms (a) Schizophyllum commune (b) Phallus indusiatus (c) Termitomyces heimii Click here to view Figure

Table 1: Proximate analysis of collected wild edible mushrooms from Aizawl, Mizoram

Each Value is expressed in mean ± SD, (n = 3)

The nutritional value of mushrooms is closely related to moisture and environmental conditions. A number of variables affect the nutritional value of different species of mushrooms, including growth conditions such as soil type, climate, and nutrient availability, as well as species differences resulting from distinct genetic makeup. Furthermore, as mushrooms mature and grow, their nutritional composition may change depending on their stage of development ⁹. Nutrient levels are also impacted by post-harvest treatment, which includes techniques for processing, preparation, and storage. Additionally, certain mushrooms develop symbiotic partnerships with particular plants, which affect the mushrooms’ nutrient absorption and overall nutritional composition ²³. Microwaving and grilling were also identified as the optimal methods for preserving the nutritional integrity of mushrooms ²⁴.  In this study, the highest moisture content in fresh weight was found in Phallus indusiatus (91.59%), while the lowest was found in Schizophyllum commune (71.58%). However, in dried weight, the highest moisture content was found in Schizophyllum commune (12.98 %), and the lowest was found in Termitomyces heimii (9.59 %). The moisture concentrations were in line with the study of others. Ash content of the sample was found to be highest in Termitomyces heimii (8.41 %) and lowest in Schizophyllum commune (6.05 %). It is known that mushrooms with high ash content contain more minerals ²⁵. Fat content was found to be highest in Phallus indusiatus (4.56 %) and lowest in Schizophyllum commune (2.16 %).

Fiber is a component of carbohydrates, and its presence in mushrooms is an important characteristic and contributes significantly to a healthy human diet ²⁶. It is also known that fungal proteins have superior digestive properties, can regulate blood lipid and cholesterol levels, improve immunity, and promote gut health ²⁷. In the present study, crude fiber and protein was highest in Termitomyces heimii (7.70 % and 30.36), followed by Schizophyllum commune (6.18 % and 19.26 %) and lowest in Phallus indusiatus (5.09 % and 15.93 %).  Carbohydrate was found to be the dominant component in the dried fruiting bodies, consistent with their prevalence as the dominant constituent in other studies as well¹². Phallus indusiatus (55.24 %) had the highest carbohydrate content, followed by Schizophyllum commune (53.37 %), and Termitomyces heimii (39.05 %) had the lowest content.

Compared to other studies, our findings for Termitomyces heimii were consistent with the protein content reported from Sri Lanka⁵. However, their study reported higher ash content (13.58%) and fat content (12.35%) than what we observed in our sample. For Schizophyllum commune, their study found a protein content of 14.41%, while our study reported a higher protein content of 19.26%. This indicates that our sample had more protein compared to their findings. With an average protein content ranging from approximately 14.0 to 33.6 g/100g dry weight, mushrooms are known to have more naturally occurring bioactive proteins and peptides than most vegetables⁹. Moreover, a study from another district in Mizoram reported an even higher protein content of 30.33% for Schizophyllum commune¹⁰, which is significantly higher than our observations. This variation highlights how nutritional content can differ even within the same species, reflecting the impact of local environmental and growing conditions.

The mineral content of the collected three WEM were presented in Table 2. Potassium (K) is the most abundant mineral compared to other elements. Mushrooms contain significant amounts of potassium and calcium, which makes them known as key minerals ²⁸.

Table 2: Mineral content of the collected wild edible mushrooms

Minerals are crucial for numerous bodily functions, including the formation of strong bones, the transmission of nerve impulses, and the regulation of muscle function. They also support metabolic processes and help maintain fluid balance. By fulfilling these essential roles, minerals contribute significantly to overall health, helping to prevent deficiencies and ensuring a long, healthy life²⁹. In the current study, it was found that Termitomyces heimii had the highest mineral concentrations, followed by Schizophyllum commune, while Phallus indusiatus had the lowest. Particularly, Phallus indusiatus had a higher potassium concentration than Schizophyllum commune. Although Phallus indusiatus had a higher ash level, Schizophyllum commune contained more minerals. This discrepancy could be the absence of numerous additional mineral components from the examination, including sodium, manganese, phosphorus, and selenium etc.

Macrofungi have the capability to accumulate high levels of mineral elements³⁰ even in soil with low concentrations of metals. The concentration of minerals correlates directly with factors such as species, geographical region of growth, fruiting body maturation period, substrates, and proximity to pollution sources^31,32. As a result, numerous mushrooms exhibit elevated levels of heavy metals, which can adversely affect human health upon consumption and potentially lead to severe health issues or even death. These heavy metals can cause a range of problems, including organ damage, neurological issues, and other serious health conditions, depending on the type and concentration of the metals involved³³.

In general, all three samples are nutritional-rich, with Termitomyces heimii having the highest nutritional content. The high nutritional content observed in Termitomyces heimii could be attributed to several interrelated factors. Optimal soil conditions and environmental factors, such as soil pH, levels of moisture, and nutrient availability, may contribute to its enhanced nutritional profile. Additionally, the symbiotic relationships Termitomyces heimii forms with certain organisms likely facilitate improved nutrient uptake and absorption. All species of Termitomyces are definitely edible and possess unique food value owing to their texture, flavor, nutrient content, and beneficial medicinal properties³⁴. The developmental stage at harvest further influences its nutritional composition, with optimal harvesting times potentially improving nutrient levels⁹. Lastly, adaptations to environmental stressors could drive the species to accumulate higher nutrient levels as a survival strategy. 

Conclusion

The Mizo people hold a high regard for these three types of wild edible mushrooms, particularly Termitomyces heimii and Schizophyllum commune. Schizophyllum commune is found abundantly during the summer season, and many locals sun-dry or air-dry them for sale in local markets throughout the year when mushrooms are less available. These wild edible mushrooms are essential for the Mizo people, and it is clear that all the three species are rich in both macro and micronutrients, providing significant nutritional value to the community. However, further research is necessary to expand our understanding of other wild edible mushrooms as well as more nutritional parameters.

Acknowledgement

The authors acknowledge the Department of Environmental Science, the Department of Biotechnology, and the Department of Chemistry, Mizoram University for their invaluable help and assistance.

Funding Sources

The authors express gratitude to the Ministry of Tribal Affairs, Government of India, for the support extended through the National Fellowship for Scheduled Tribe (NFST), awarded to Laltanpuia Renthlei (201920-NFST-MIZ-00821).

Conflict of Interest

The author declare no conflict of interest.

Data Availability Statement

This statement does not apply to this article.

Ethics Approval Statement

This research did not involve human participants, animal subjects, or any material that requires ethical approval.

Authors’ contributions

Laltanpuia Renthlei, Zohmangaiha Chawngthu, and VL Thachunglura collected and identified the samples, with Joshua Khumlianlal joining to assist in analysing the nutrients and minerals content. Laltanpuia Renthlei, Joshua Khumlianlal, and Madhurima draft the manuscript, which was later reviewed and rewritten by John Zothanzama and BP Mishra.

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