In vitro gastrointestinal digestion of Lentinus squarrosulus powder and impact on human fecal microbiota

Abstract

Humans have long-used mushrooms as food and medicine, but digestion and colonic fermentation of most mushrooms, including Lentinus squarrosulus is markedly unknown. Here, nutritional profile, digestion and colonic fermentation of L. squarrosulus powder (LP) were determined. The powder contained mainly carbohydrate and protein. SEM and F-TIR analysis of the resistant hydrolysate (RH) revealed that the structure and ratio of carbohydrate and protein components were altered, and released known immunomodulation agents; beta-glucans and mannose. Both LP and RH promoted selected probiotic bacteria, especially Bifidobacterium strains. Using fecal microbiota of five volunteers (V1, V2, V3, V4 and V5), RH stimulated the microbiota of all used volunteers, via decreasing the ratio of Firmicutes/Bacteroidetes ranging from 1.3 to 8.2 times. Also, RH increased the relative abundance of vital immunomodulators; Bacteroides, Bifidobacterium, Clostridium cluster XIVa and IV, and Sutterella. Additionally, RH fermentation enriched the content of branch-chain fatty acids (BCFA) and short-chain fatty acids (SCFA), indicating protein and carbohydrate usage. Notably, propionic and butyric acids were abundant in V1, V2 and V3, while in V4 and V5, acetic and butyric acids were most enriched. Suggesting L. squarrosulus as functional mushroom to improve health and prevent diseases by enhancing gut health.

Nutritional Quality and Biological Application of Mushroom Protein as a Novel Protein Alternative

“…Crude protein ranged from 6.60 to 30.69 g/100 g among mushrooms obtained from the Kilum-Ijim forest in Cameroon [ 7 ]. Lentinus squarrosulus powder presented an excellent protein value of 30.12 g/100 g [ 11 ]. Even though the whole fruiting body of a mushroom is commonly consumed, it is interesting to note that different parts of the mushroom present different protein values.…”

“…Concurrently, unhydrolyzed protein may improve health by stimulating the gut microbiota as revealed in previous studies. Ayimbila et al found that simulated gastro-intestinal digestion of L. squarrosulus powder resulted in 58.59% of its protein hydrolyzed in gastric condition and only reached 59.59% after hydrolysis in intestinal condition [ 11 ]. Protein profile and digestibility of G. lingzhi (GZ) and G. lucidum (GL)-Madrid mushroom proteins in simulated gastric fluid differ significantly.…”

“…GL and GZ contain some proteins that are totally or partially resistant to simulated gastric fluid [ 37 ]. Partially hydrolyzed protein components in the mushroom are fermentable by gut microbes to release branch-chain fatty acids to enhance host health [ 11 ]. Dietary fiber in the aforementioned mushrooms may have reduced protein digestibility by obstructing enzymatic diffusion and limiting protein hydrolysis.…”

“…Fortunately, protein digestibility can be improved by removing the above-mentioned food components through processing [ 9 ]. It is worth noting that mushroom fruiting bodies are commonly consumed as a source of protein, which may provide a substantial portion of amino acids for body functioning as well as fermentable substrates to stimulate the microbiota for host health benefits [ 11 ], indicating the ability of both processed and unprocessed mushroom proteins to positively influence human health. Current studies have discovered that mushroom protein concentrates, hydrolysates, and peptides have potent angiotensin-converting enzyme (ACE) inhibitory, antioxidant, antimicrobial, anticancer, antiviral, and gut microbiota modulation properties [ 8 ••, 11 ].…”

“…It is worth noting that mushroom fruiting bodies are commonly consumed as a source of protein, which may provide a substantial portion of amino acids for body functioning as well as fermentable substrates to stimulate the microbiota for host health benefits [ 11 ], indicating the ability of both processed and unprocessed mushroom proteins to positively influence human health. Current studies have discovered that mushroom protein concentrates, hydrolysates, and peptides have potent angiotensin-converting enzyme (ACE) inhibitory, antioxidant, antimicrobial, anticancer, antiviral, and gut microbiota modulation properties [ 8 ••, 11 ]. Moreover, there are other bioactive proteins found in mushrooms include lectins, fungal immunomodulatory proteins (FIP), ribosome-inactivating proteins (RIP), antimicrobial/antifungal proteins, ribonucleases, and laccases [ 12 ].…”