Solid-state fermentation with Aspergillus niger for the bio-enrichment of bioactive compounds in Moringa oleifera (moringa) leaves

Evaluation of biotechnological processing through solid-state fermentation of oilseed cakes on extracts bioactive potential

Oilseed cakes (OC) are natural sources of lignocellulosic biomass, produced every year in large amounts. In addition to their main applications as animal feed, plant or soil fertilizer, and compost, they present enormous potential for being used in biotechnological processes for the obtainment and extraction of valuable bioactive compounds. This work evaluated the effect of solid-state fermentation on the bioactive properties of extracts obtained from the bioprocessing of OC and evaluated the effect of solvents on the recovery of compounds with higher bioactive potential. A general decrease of EC50 values was observed for fermented extracts obtained using a mixture of water/methanol (1:1) as extraction solvent. A decrease in the minimum inhibitory concentration was observed for fermented water extracts compared to non-fermented. Additionally, growth inhibition of Listeria monocytogenes was observed when using aqueous methanolic fermented extracts. These extracts also exhibited a higher percentage of growth reduction against phytopathogenic fungi, and some extracts exhibited increased protection against genotoxic agents such as camptothecin and bisphenol A. It was demonstrated that bioprocessing of OC through SSF is an effective approach to obtaining valuable compounds with bioactive properties for use in the food, pharmaceutical or cosmetic industries.

A Comprehensive Review of Moringa oleifera Bioactive Compounds-Cytotoxicity Evaluation and Their Encapsulation

Moringa oleifera Lam. has gained a lot of attention due to its potential use as a functional food not only for human health but also for animal health. Its bioactive molecules include carbohydrates, phenolic compounds, carotenoids, fatty acids, essential amino acids, and functional peptides. Despite significant efforts to isolate and characterize bioactive metabolites with health functions, few effective metabolites are accessible. The current review aims to describe the main processes for extracting and encapsulating bioactive compounds from Moringa oleifera for potential impact on food science and public health. Researchers have shown that different extraction techniques significantly impact the Moringa polysaccharides' molecular structure and biological activity. Encapsulation has been proposed to reduce oxidative stability and entrap active agents within a carrier material to deliver bioactive molecules into foods. Currently, polysaccharides and proteins, followed by lipids, are used for material encapsulation. Recent techniques include spray drying, cross-linking gelation, freeze-drying, nanoencapsulation, electrospinning, and electrospraying. Moreover, these encapsulations can overlap concerns regarding the Moringa oleifera compounds' cytotoxicity. Future studies should prioritize the effect of new encapsulation materials on Moringa extract and develop new techniques that consider both encapsulation cost and efficiency.

Phenolic Profile, Antioxidant Activity and Amino Acid Composition of Moringa Leaves Fermented with Edible Fungal Strains

Solid-state fermentation (SSF) is widely recognised as a technique to increase the bioactive potential and nutritional value of plant materials. However, the effect of this biotreatment differs for individual substrates. This study aimed to evaluate the impact of SSF with filamentous fungi (Rhizopus, Aspergillus, and Neurospora) on a moringa leaf phenolic profile, antioxidant activity, and amino acid composition. A total of 43 phenolic compounds were determined in the dried leaves analysed by HPLC-ESI-TOF-MS. The leaves contained 11.79 mg/g of free phenolics: flavonols (80.6%, mainly quercetin and kaempferol glycosides), hydroxycinnamic acid derivatives (12.3%), vitexin and vicenin (6.9%), and a small amount of lignan (isolariciresinol isomers). The result of the 1-day fermentation was a slight enhancement in the concentration of individual free phenolics (flavones) and the antioxidant activity of the leaves. However, extending the incubation period caused a significant decrease in those parameters and cannot be recommended for obtaining a food fortificant from moringa leaves. In contrast, the 3-day fermentation with N. intermedia led to a 26% average accumulation of individual amino acids. Therefore, the SSF with Neurospora can be a promising method for improving the nutritional composition of moringa leaves and needs further investigation.

Bioprocessing of pineapple waste biomass for sustainable production of bioactive compounds with high antioxidant activity

The effect of temperature, moisture content and pH during solid-state fermentation (SSF) of MD2 pineapple peel with Rhizopus oryzae (MUCL 28168) was evaluated on the release of bioactive compounds with antioxidant capacity. Applying a central composite design, it was found that temperature had a significant effect (p < 0.05) on the total phenolic content and DPPH antioxidant activity while for the ABTS radical elimination activity, the factor that presented a significant effect was the pH (p < 0.05); as this factor increases, the antioxidant activity enhances. The optimal conditions for fermentation process were 80% of moisture content, pH 5.5, temperature 37.3 °C and 24 h of process to maximize phenolic content and antioxidant activity. Gallic acid, chlorogenic acid, caffeic acid and cinnamic acid were identified in the extracts by HPLC analysis. These results permit to conclude that SSF of pineapple peel is an effective bioprocess for the release of phenolic compounds with antioxidant activity.

Graphical abstract

Impact of solid-state fermentation on factors and mechanisms influencing the bioactive compounds of grains and processing by-products

Cereal and legume grains and their processing by-products are rich sources of bioactives such as phenolics with considerable health potential, but these bioactives suffer from low bioaccessibility and bioavailability, resulting in limited use. Several studies have demonstrated that solid-state fermentation (SSF) with food-grade microorganisms is effective in releasing bound phenolic compounds in cereal and legume products. In this review, we discuss the effect of SSF on cereal and legume grains and their by-products by examining the role of specific microorganisms, their hydrolytic enzymes, fermentability of agri-food substrates, and the potential health benefits of SSF-enhanced bioactive compounds. SSF with fungi (Aspergillus spp. and Rhizopus spp.), bacteria (Bacillus subtilis and lactic acid bacteria (LAB) spp.) and yeast (Saccharomyces cerevisiae) significantly increased the bioactive phenolics and antioxidant capacities in cereal and legume grains and by-products, mainly through carbohydrate-cleaving enzymes. Increased bioactive phenolic and peptide contents of SSF-bioprocessed cereal and legume grains have been implicated for improved antioxidant, anti-inflammatory, anti-carcinogenic, anti-diabetic, and angiotensin-converting-enzyme (ACE) inhibitory effects in fermented agri-food products, but these remain as preliminary results. Future research should focus on the microbial mechanisms, suitability of substrates, and the physiological health benefits of SSF-treated grains and by-products.

Lactobacillus plantarum FNCC 0137 fermented red Moringa oleifera exhibits protective effects in mice challenged with Salmonella typhi via TLR3/TLR4 inhibition and down-regulation of proinflammatory cytokines

Background

Salmonella typhi is a foodborne pathogenic bacterium that threatens health. S. typhi infection exacerbated the antibiotic resistance problem that needs alternative strategies. Moringa oleifera possesses anti-inflammatory and antimicrobial effects. However, there is a lack of information about the pharmacological value of red M. oleifera. The fermentation of red M. oleifera leaves extract (RMOL) is expected to add to its nutritional value.

Objective

The present study aimed to evaluate non-fermented RMOL (NRMOL) and fermented RMOL (FRMOL) effects on S. typhi infection in mice.

Materials and methods

Female Balb/C mice were randomly divided into eight groups. The treatment groups were orally administered with NRMOL or FRMOL at doses 14, 42, and 84 mg/kg BW during the 28 days experimental period. Then S. typhi was introduced to mice through intraperitoneal injection except in the healthy groups. The NRMOL or FRMOL administration was continued for the next seven days. Cells that expressed CD11b⁺ TLR3⁺, CD11b⁺TLR4⁺, CD11b⁺IL-6⁺, CD11b⁺IL-17⁺, CD11b⁺TNF-a⁺, and CD4⁺CD25⁺CD62L⁺ were assessed by flow cytometry.

Results

Our result suggested that NRMOL and FRMOL extracts significantly reduced (p < 0.05) the expression of CD11b⁺TLR3⁺, CD11b⁺TLR4⁺, CD11b⁺IL-6⁺, CD11b⁺IL-17⁺, and CD11b⁺TNF-α⁺ subsets. In contrast, NRMOL and FRMOL extracts significantly increased (p < 0.05) the expression of CD4⁺CD25⁺CD62L⁺ subsets. NRMOL at dose 14 and 42 mg/kg BW was more effective compared to FRMOL in reducing the expression of CD11b⁺TLR3⁺, CD11b⁺TLR4⁺, and CD11b⁺TNF-α⁺ subsets.

Conclusion

Our findings demonstrated that NRMOL and FRMOL extracts could be promising agents for protection against S. typhi infection via modulation of TLR3/TLR4, regulatory T cells, and proinflammatory cytokines.

Bioactive Compounds from Agricultural Residues, Their Obtaining Techniques, and the Antimicrobial Effect as Postharvest Additives

Agricultural vegetable products always seek to meet the growing demands of the population; however, today, there are great losses in supply chains and in the sales stage. Looking for a longer shelf life of fruits and vegetables, postharvest technologies have been developed that allow an adequate transfer from the field to the point of sale and a longer shelf life. One of the most attractive methods to improve quality and nutritional content and extend shelf life of fruits and vegetables is the incorporation of bioactive compounds with postharvest technologies. These compounds are substances that can prevent food spoilage and the proliferation of harmful microorganisms and, in some cases, act as a dietary supplement or provide health benefits. This review presents an updated overview of the knowledge about bioactive compounds derived from plant residues, the techniques most used for obtaining them, their incorporation in edible films and coatings, and the methods of microbial inhibition.

Co-Fermentation by Lactobacillus brevis B7 Improves the Antioxidant and Immunomodulatory Activities of Hydroponic Ginseng-Fortified Yogurt

The development of convenient and accessible health-functional foods has become an area of increased interest in recent years. Probiotics, ginseng, and yogurts have been recognized as representative nutraceutical products. To improve the functionality of yogurts, co-fermentation was performed during yogurt preparation. Four kinds of yogurt were prepared using a combination of probiotic Lactobacillus brevis B7 and hydroponic ginseng based on plain yogurt. The fundamental characteristics of yogurts, including pH, titratable acidity, microbial counts, color, and physicochemical properties, were determined. To assess functionality, four different antioxidant assays and real-time PCR analysis using RAW 264.7 cells were performed. Finally, sensory evaluation was conducted to evaluate customer preference. Hydroponic ginseng supplementation influenced pH, solid content, lightness, and yellowness. However, probiotic supplementation did not affect most factors except pH. In functionality analysis, the yogurt co-fermented with probiotics and ginseng showed the highest antioxidant activity and gene expression levels of the immune-related factors TNF-α and iNOS in RAW 264.7 cells. Although ginseng supplementation received poor acceptance because of its color and flavor, these attempts were considered beneficial despite the risk. Overall, co-fermentation within a short yogurt preparation time presented the potential for improvement of functionality. These findings suggest a range of feasibility for the development of attractive nutraceutical products.

A Comprehensive Review on Valorization of Agro-Food Industrial Residues by Solid-State Fermentation

Agro-food industrial residues (AFIRs) are generated in large quantities all over the world. The vast majority of these wastes are lignocellulosic wastes that are a source of value-added products. Technologies such as solid-state fermentation (SSF) for bioconversion of lignocellulosic waste, based on the production of a wide range of bioproducts, offer both economic and environmental benefits. The versatility of application and interest in applying the principles of the circular bioeconomy make SSF one of the valorization strategies for AFIRs that can have a significant impact on the environment of the wider community. Important criteria for SSF are the selection of the appropriate and compatible substrate and microorganism, as well as the selection of the optimal process parameters for the growth of the microorganism and the production of the desired metabolites. This review provides an overview of the management of AFIRs by SSF: the current application, classification, and chemical composition of AFIRs; the catalytic function and potential application of enzymes produced by various microorganisms during SSF cultivation on AFIRs; the production of phenolic compounds by SSF; and a brief insight into the role of SSF treatment of AFIRs for feed improvement and biofuel production.