Study on the Enhancement of Hypoglycemic and Antioxidant Activities of Compound Herbal Tea through Solid-State Fermentation

Objective: The aim of this study was to optimize the fermentation process of Radix Ranunculi ternate via microbial fermentation and analyze the changes in the contents of the main components, the antioxidant and hypoglycemic capacities of the extract before and after fermentation. Methods: The solid-state fermentation process was optimized using single-factor tests and the response surface method, with the yield of the alcohol extract of R. ternate as an evaluation index. Results: The best fermentation process was optimized using solid-state endophytic fungus fermentation technology as follows: strain addition ratio of Chaetomium globosum/Fusarium equiseti = 1:1, fermentation for 5 d, sieve size of 40 mesh, liquid/material ratio of 0.8:1 mL·g−1, fermentation temperature of 31 °C, and inoculation amount of 7.5%. Under the optimized conditions, the contents of the water-soluble extract and total polysaccharides decreased by 12.71% and 12.95%, respectively. In the fermentation, the contents of the ethanol-soluble extract, flavonoids, saponins, polyphenols, organic acids, and total amino acids of the fermented R. ternate increased by 19.77%, 57.14%, 79.67%, 14.29%, 17.63%, and 3.82%, respectively. The scavenging rate for DPPH, ABTS+, and ·OH free radicals and inhibitory rate for α-amylase of the fermented R. ternate also increased by 19.02%, 14.17%, 7.53%, and 34.54%, respectively, compared with the unfermented R. ternate. Conclusions: Solid-state fermentation opens new avenues for the development and application of R. ternate as a natural antioxidant and hypoglycemic food.

The objective of this experiment was to study the effect of Solid-State Fermentation (SSF) on jackfruit by-products using filamentous fungi. Rags from a ripen jackfruit were fermented for 5, 10 and 15 days by Aspergillus niger, Aspergillus oryzae and Rhizopus oryzae at 30 °C. Then the bioactive compounds were extracted using methanol. Total phenolic content, total flavonoid content, antioxidant activity and hypoglycemic activity of each liquid extract were estimated. The results showed significant increase and improvement in the samples in which SSF was applied. The highest total phenolic contents were found in fermented products with A. niger and R. oryzae with an average of 14.16 mg GAE/g D.S which was almost 3 times over the concentration found in unfermented products (4.83 mg GAE/g D.S). The same fermented products showed a significant increase in total flavonoid content which was 2 times higher than unfermented products with an average of 31.79 mg QuE/g D.S for fermented products and 15.08 for unfermented. The antioxidant activity was correlated to the total phenolic and flavonoid contents with the highest activity of around 76 % found in fermented products against 55 % for the unfermented ones. Finally, hypoglycemic activity was also found to be higher in fermented products than the unfermented with the best activity obtained in 5-days fermented product with A. oryzae (35.62 %) which was 8 times higher than non-fermented products (4.52 %). The present study showed that Solid-State Fermentation has a great potentiality to improve and enhance antioxidant and hypoglycemic activities of plant by-products. HIGHLIGHTS SSF improved the Antioxidant and hypoglycemic properties of jackfruit rags niger and R. oryzae had better capacity in improving the antioxidant activity Phenolic Content, Flavonoid Content and Antioxidant Activity were correlated Better hypoglycemic activity was seen in fermented products with oryzae oryzae could produce a new bioactive compound with high hypoglycemic activity GRAPHICAL ABSTRACT

In this study, a controlled atmosphere (CA) treatment was used in the submerged (SM) and solid-state (SS) fermentation of Inonotus obliquus to determine the optimal conditions. The goal was to accelerate the artificial fermentation to obtain I. obliquus as an ingredient for dietary supplements. The results indicated that when CA treatment was used, the SM and SS fermentation of I. obliquus yielded polysaccharide and betulinic acid contents 2–2.5 times higher than those obtained when such treatment was not used. The two fermentation methods yielded similar outcomes in terms of DPPH scavenging ability, bioactivity, and antioxidant activity. Although SS fermentation yielded highly bioactive fruiting bodies when the period of fermentation was extended to 60 days, the mycelia produced by SM reached a similar bioactivity quality with only 30 days of fermentation. It was indicated that SM fermentation is more economically feasible than SS fermentation in the production of I. obliquus.

Corn silk is a waste product when harvesting corn, but it contains many bioactive compounds. This research characterized and assessed the antioxidant bioactivity of compounds isolated from corn silk. Two different biological fermentation processes were compared: Solid-state fermentation (SSF) and submerged fermentation (SmF). Fresh corn silk (Zea mays L.) from both sweet corn and feed corn were fermented separately with various microorganisms (Bacillus subtilis, Lactobacillus sp. and Saccharomyces cerevisiae). Biological compounds were identified using LC-MS/MS. The extract was then tested for total phenolic content (TPC) and total flavonoid content (TFC). Next, the extract was tested for xanthine oxidase inhibition and antioxidant inhibition using the ABTS method. Potential contamination with the heavy metals As, Pb, and Hg was checked. The results show that fermented corn silk extract contains numerous bioactive compounds and amino acids. Among the different extract process variations, the highest TPC and TFC were 6.1 ± 0.7 µg GAE/g dry wt. and 68.3 ± 1.1 µg QE/g dry wt., respectively, and the highest xanthine oxidase inhibition was 76.5 ± 6.4 %. The above highest results were obtained using SmF of sweet corn for 60 days. In contrast, the highest antioxidant activity of 66.9 % was found using SSF of sweet corn for 20 days. Neither sweet corn nor feed corn were found to contain heavy metal ions. In summary, fermented corn silk extract samples contain numerous bioactive compounds, including both flavonoid and phenolic compounds, and the extract demonstrates antioxidant activity. Corn silk extracts from fermentation thus have potential for utilization in health products. HIGHLIGHTS Feed corn silk and sweet corn silk underwent solid-state fermentation (SSF) or submerged fermentation (SmF) for extraction using heterofermentative microbes of Bacillus subtilis, Lactobacillus and Saccharomyces cerevisiae to produce the high bioactive compounds, amino acids, and organic acids Metabolomic analysis of the fermentation extracts was carried out by LC-ESI-QTOF-MS/MS (Liquid Chromatography-Mass Spectrometry) using the heatmaps generated metabolites profiles The main amino acids found in the extractions were phenylalanine, leucine, and their derivatives SmF of sweet corn silk yielded the highest xanthine oxidase inhibitory activity (76 %) SSF of feed corn silk and sweet corn silk displayed the high antioxidant activity GRAPHICAL ABSTRACT

This research aims to study antioxidant compounds of two rice bran strains (Khao Bahn Nah and Thai jasmine) in different moisture contents (50 and 75% w/v) with solid state fermentation (SSF) by lactic acid bacteria (LAB) as Lactobacillus casei and Lactobacillus plantarum . After the incubation at 24, 48, and 72 h, the highest total polysaccharide (38.77 ± 1.21 mg/mL) found in Thai jasmine without SSF at 75% w/v moisture after 72 h. While the rice bran extract with SSF by both LAB presented higher amount of phenolic content and antioxidant activity than the rice bran extract without SSF, particularly Khao Bahn Nah extract with 50% w/v moisture by L. plantarum at 48 h showed the maximum phenolic compound (2.85 ± 0.05 mg/mL). As well as the best percentage of antioxidant activity found in both fermented rice bran extract strains with 50% moisture by L. casei with the same incubation time at 48 h (Thai jasmine = 78.79% and Khao Bahn Nah = 78.49%). HPLC chromatogram revealed the composition of phenolic compounds in both rice bran extract strains, mainly in Thai jasmine with SSF by L. casei at 50% w/v moisture for 48 h displayed the best quantity of tocopherol (4.51 ± 0.38 mg/L), gamma-oryzanol (3.61 ± 0.15 mg/L), coumaric acid (14.47 ± 1.20 mg/L) and ferulic acid (35.23 ± 0.82 mg/L). From the potential of antioxidant activity and total phenolic content of rice bran extract showed the possibility of adding value to the agricultural residue. Therefore, the rice bran extract by SSF may be applied to become a functional food product in the future.

BackgroundThe use of agricultural and food by-products is an economical solution to industrial biotechnology. The apricot press residues are abounding by-products from juice industry which can be used as substrates in solid state fermentation process (SSF), thus allowing a liberation and increase of content from various biomolecules with high added value.MethodsThe evolutions of phenolic levels (by colorimetric assays and high performance liquid chromatography, HPLC–MS) and antioxidant activities (by DPPH assay) during SSF of apricot pomaces with Aspergillus niger and Rhizopus oligosporus were investigated. The changes in fatty acid compositions of oils in apricot kernels during SSFs were also analyzed by gas chromatography (GC–MS).ResultsThe results showed that the levels of total phenolics increased by over 70% for SSF with R. oligosporus and by more than 30% for SSF with A. niger. A similar trend was observed in the amounts of total flavonoids (increases of 38, and 12% were recorded for SSF by R. oligosporus and A. niger, respectively). Free radical scavenging capacities of methanolic extracts were also significantly enhanced. The main phenolic compounds identified through HPLC–MS in fermented apricot press residues were chlorogenic acid, neochlorogenic acid, rutin, and quercetin 3-acetyl- glucoside. This work also demonstrated that the SSF with filamentous fungal strains not only helped in higher lipid recovery from apricot kernels, but also resulted in oils with better quality attributes (high linoleic acid content).ConclusionThe utilization of apricot by-products resulting from the juice industry as waste could provide an extra income and at the same time can help in solving solid waste management problemsGraphical abstractChanges in phenolic compositions, antioxidant activities and total lipid contents during solid state fermentation (SSF) of apricot pomaces from juice industry with Aspergillus niger and Rhizopus oligosporus

Solid state fermentation (SSF) is a sustainable process that uses low amounts of water and transforms plant-based agro-industrial residues into valuable products such as enzymes, biofuels, nanoparticles and other bioactive compounds. Many fungal species can be used in SSF because of their low requirements of water, O2 and light. During SSF, plant-based wastes rich in soluble and insoluble fiber are utilized by lignocellulolytic fungi that have enzymes such as lignases, celullases or hemicelullases that break fiber hard structure. During the hydrolysis of lignin, some phenolic compounds are released but fungi also synthetize bioactive compounds such as mycophenolic acid, dicerandrol C, phenylacetates, anthraquinones, benzofurans and alkenyl phenols that have health beneficial effects such as antitumoral, antimicrobial, antioxidant and antiviral activities. Another important group of compounds synthetized by fungi during SSF are polysaccharides that also have important health promoting properties. Polysaccharides have antioxidant, antiproliferative and immunomodulatory activities as well as prebiotic effects. Fungal SSF has also proved to be a process which can release high contents of phenolics and it also increases the bioactivity of these compounds.

UPLC–QQQ–MS/MS-based widely targeted metabolomic analysis, antioxidant and α-glucosidase inhibitory activities of mulberry leaves processed by solid-state fermentation

Known as carrageenan, Kappaphycus alvarezii is a popular species of red edible seaweed which is mainly cultivated for its hydrocolloids. K. alvarezii is a good source of phenolics which are considered to be natural antioxidants that promote myriads of health benefits. Extraction of phenolic compounds using conventional solvent extraction may result in hazards and toxicological effect and low yield of bound phenolics. Therefore, this study was conducted to increase the release of bound phenolics through solid substrate fermentation. In the present study, three different varieties of K. alvarezii were fermented with Aspergillus oryzae through solid substrate fermentation (SSF) at 30 ℃ for 2 to 6 days. The changes of total phenolic content and antioxidant activity due to the effects of SSF were investigated. Results obtained revealed that the highest total phenolic content for green (10.022 mg GAE/g) and purple (4.037 mg GAE/g) varieties of K.alvarezii were on the fourth day of fermentation while for yellow (4.479 mg GAE/g) variety was on the sixth day of fermentation. A remarkable enhancement of antioxidant activity was discovered through DPPH radical scavenging activity on the fourth day of fermentation for all varieties of K. alvarezii tested. Total phenolic content also showed a significant correlation with antioxidant activity of fermented seaweed. Cellulase, xylanase, and β-glucosidase enzymes produced by A.oryzae during SSF were also investigated to see the relationship with the release of phenolic compounds after fermentation. The highest cellulase activity was observed on the fourth day of fermentation. The similar observation was also found for xylanase enzyme in yellow and purple varieties of K. alvarezii , except for green variety where the highest xylanase activity was on the sixth day of fermentation. The maximum β-glucosidase activity in yellow and green varieties was observed on the fourth day of fermentation while purple variety exhibited the maximum β-glucosidase activity on the sixth day. There are positive correlation between the enzymes studied and the polyphenols content in all varieties of K. alvarezii . This study demonstrated that fermented K. alvarezii contained more phenolic content compared to non-fermented seaweed.

Changes in rice bran bioactives, their bioactivity, bioaccessibility and bioavailability with solid-state fermentation by Rhizopus oryzae

Metabolite profiling, antioxidant and α-glucosidase inhibitory activities of buckwheat processed by solid-state fermentation with Eurotium cristatum YL-1

In this study, black soybean was firstly processed by solid-state fermentation (SSF) with a probiotic fungus Eurotium cristatum YL-1. The effect of SSF on the nutritional components (including proximate, amino acids, minerals, and fatty acids), total phenolics, isoflavones, antioxidant activity, and volatile organic compounds of black soybeans were revealed. Results of this work demonstrated that black soybean processed by SSF with E. cristatum greatly increased the contents of protein, essential amino acids, and some minerals (e.g., calcium, phosphorus, and magnesium). GC results revealed that more than 80% of the total lipids from both fermented and non-fermented black soybeans were unsaturated fatty acids, and SSF influenced the fatty acids composition. Higher contents of total phenolics and aglycone isoflavones (i.e., genistein, daidzein, and glycitein) of fermented black soybeans were achieved by SSF. Furthermore, SSF with E. cristatum considerably augmented the ferric reducing antioxidant power, scavenging effects against ABTS·+ and DPPH radical, reducing power, and chelating ability of black soybeans, which evaluated with various polarity solvent extracts. HS-GC-IMS analysis detected a total of 66 volatile compounds in FBS and BS, and 56 volatile organic compounds were successfully identified. The intensities of main volatile compounds (i.e., 10 esters, 11 alcohols, and 19 aldehydes) differed remarkably by fermentation with E. cristatum. The intensities of seven alcohols and nine aldehydes considerably decreased, whereas higher levels of esters were achieved by SFF. Thus, our results confirmed that black soybeans processed by SSF with E. cristatum is a promising approach to substantially improve its nutritional value, flavor characteristics, and biological effect, and might have great potential in the development of new functional foods or be used as a new nutritional ingredient applied in food design.

Effect of solid-state fermentation of Brewer's spent grain on digestibility and digestive function of european seabass (Dicentrarchus labrax) juveniles

Solid-state fermentation may produce therapeutic compounds with higher biomass or better product characteristics than those generated by submerged fermentation. The objectives of this study were to analyze the antioxidant activities and biosafety of products obtained by white truffle (Tuber magnatum) solid-state fermentation in media with different ratios of soybean and red adlay. High levels of antioxidant components and high antioxidant activities such as DPPH radical scavenging, ferrous ion chelation, and reducing power were measured in 20 mg/mL water and ethanol extracts of the white truffle fermentation products. When the solid-state fermentation medium contained soybean and red adlay in a 1:3 ratio (S1A3), the fermentation product had more uniform antioxidant compositions and activities by principal component analysis (PCA). In addition, a 200 ppm water extract of the mycelial fermentation product was able to protect zebrafish embryos from oxidative stress induced by 5 mM hydrogen peroxide. Sprague–Dawley rats were fed the mycelial fermentation product for 90 consecutive days, revealing a no-observed-adverse-effect level (NOAEL) of 3000 mg/kg BW/day. Therefore, mycelial products obtained by white truffle solid-state fermentation can be used instead of expensive fruiting bodies as a good source of antioxidant ingredients.

Sorghum contains antioxidants such as tannins. However, these are considered antinutritional factors since they are responsible for the low digestibility of proteins and carbohydrates. Nevertheless, these can be extracted by solid-state fermentation (SSF). Therefore, this study aimed to evaluate the effects of SSF from Aspergillus oryzae and Aspergillus niger Aa210 on the tannin contents, phenolic profiles determined by HPLC-MS, and antioxidant activities (ABTS, DPPH, and FRAP) of two genotypes of sorghum. The results showed that with SSF by A. niger Aa210, a higher tannin content was obtained, with yields of 70–84% in hydrolyzable tannins (HT) and 33–49% in condensed tannins (CT), while with SSF by A. oryzae the content of HT decreased by 2–3% and that of CT decreased by 6–23%. The extracts fermented by A. niger at 72 and 84 h exhibited a higher antioxidant activity. In the extracts, 21 polyphenols were identified, such as procyanidins, (+)-catechin, (-)-epicatechin, scutellarein, arbutin, and eriodictyol, among others. Therefore, SSF by A. niger was an efficient process for the release of phenolic compounds that can be used as antioxidants in different food products. It is also possible to improve the bioavailability of nutrients in sorghum through SSF. However, more studies are required.