Optimization of extraction conditions and enhancement of phenolic content and antioxidant activity of pearl millet fermented with Aspergillus awamori MTCC-548

Effects of different processing methods on phenolic compounds in flaxseed meal

This study examined effects of different processing methods on phenolic compounds in flaxseed meal. The optimal SE treatment was 1.0 MPa for 3 min, and the contents of total flavonoids and phenolic acid were 2.26 times and 1.63 times of the control group, respectively. Notably, erucic acid increased 85.76 %. Optimal extrusion conditions (15 % moisture content, 140 °C, 29 hz) led to the presence of rutin and a 2.81 times increase in protocatechuic acid content over the control. Fermenting with 3 % Bacillus subtilis for 4 days yielded gallic acid in bound form and vanillic acid in free form, with protocatechuic acid increasing 40.65 % compared to the control. Among all the treatments, extrusion produced the highest levels of phenolic compounds in flaxseed meal. Each treatment significantly increased the open ring isomer ester phenol (SDG) compared to the control. Overall, various processing methods impacted the phenolic content and composition in flaxseed meal differently.

Antioxidant capacities and non-volatile metabolites changes after solid-state fermentation of soybean using oyster mushroom (Pleurotus ostreatus) mycelium

Given the abundance of beneficial properties and enzymes secreted by edible oyster mushrooms, their mycelium could serve as a starter for fermented foods to enhance their nutritional and bioactive quality. This study aimed to investigate the effects on the nutritional ingredients, antioxidant activity, and non-volatile metabolites during solid-state fermentation (SSF) of soybeans by Pleurotus ostreatus mycelium. The results indicated that the contents of dietary fiber and starch in fermented soybeans decreased, while the amounts of protein and lipid increased after SSF (P < 0.05). Analysis of the total phenolic content (TPC) and antioxidant activities of the fermented soybeans revealed that the methanolic extracts significantly increased TPC and antioxidant activities against intracellular reactive oxygen species (ROS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, as well as against DPPH and ABTS radicals in vitro. A total 154 differential metabolites were identified after SSF, and a Spearman correlation study revealed a direct relationship between antioxidant activities and certain metabolites including phenolic compounds, oligopeptides, and free fatty acids etc. Among these metabolites, phenolic compounds produced by the shikimic acid pathway were diverse in variety and had the greatest multiple differences. The study discovered that a potential mechanism involving SSF with P. ostreatus mycelium increased the antioxidant activity of soybeans.

Exploring the potential of lactic acid bacteria and its molecular mechanism of action in the development of biosurfactants: Current finding and future outlook

Biosurfactants generated from lactic acid bacteria (LAB) offer an advantage over standard microbial surfactants due to their antifungal, antibacterial and antiviral capabilities. Many LAB strains have been related to the manufacture of biosurfactant, an essential chemical with uses in the treatment of a number of illnesses. Furthermore, their effectiveness as anti-adhesive agents against a diverse variety of pathogens proves their utility as anti-adhesive coating agents for medical insertional materials, reducing hospital infections without the need of synthetic drugs and chemicals. LAB produces both low and high molecular weight biosurfactants. Biosurfactants from L. pentosus, L. gasseri and L. jensenii have been reported to produce glycolipopeptides that comprise carbohydrates, proteins and lipids in the ratio of 1:3:6 with palmitic, stearic acid, and linoelaidic acid as the major fatty acid component, whereas L. plantarum has been reported to make surlactin due to the presence of non-ribosomal peptide synthetase genes (NRPS) genes. Antimicrobial activity of sophorolipids and rhamnolipids generated from LAB against B. subtilis, P. aeruginosa, S. epidermidis, Propionibacterium acnes and E. coli has been demonstrated. The safety of biosurfactants is being evaluated in compliance with a number of regulatory standards that emphasize the importance of safety in the pharmaceutical industry. This review attempts, for the first time, to provide a comprehensive evaluation of several approaches for the synthesis of biosurfactant-mediated molecular modulation in terms of their biological value. Future biosurfactant directions, as well as regulatory considerations that are crucial for the synthesis of biosurfactants from novel LAB, have also been explored.

Aspergillus awamori: potential antioxidant, anti-inflammatory, and anti-apoptotic activities in acetic acid-induced ulcerative colitis in rats

Ulcerative colitis (UC) is a chronic colonic inflammation with a significant health hazard. Aspergillus awamori (A. awamori) is a microorganism with various bioactive compounds with natural antioxidant and anti-inflammatory properties. The present work aimed to elucidate the protective and therapeutic effects of varying concentrations of A. awamori against acetic acid (AA)-induced ulcerative colitis (UC) in rats. Nine groups of albino male rats were established: a control negative group (G1), a control positive group (G2,AA), and preventive protocol groups (including G3A, G4A, and G5A) that received 100 mg, 50 mg, and 25 mg/kg b.w, respectively, of A. awamori orally and daily from the 1st day of the experiment and for 7 consecutive days. Then, they were subjected to one dose of AA intrarectally on day 8th. G3B, G4B, and G5B were termed as curative protocol groups that received one dose of AA on day 8th and then administered 100 mg, 50 mg, and 25 mg/kg b.w. of A. awamori, respectively, on day 9th and continued receiving these doses daily until day 16th. Rats in the AA group exhibited marked histopathological alterations of the distal colon, with an exaggeration of the DAI. In addition, a remarkable increase in oxidative stress was represented by the elevation of MDA and NO levels with a decline in SOD and GPx activities. In addition, upregulation of TNF-α, IL-6, and IL-1β mRNA expressions and downregulation of Muc2 and Nrf2 levels were detected. Unambiguously, a remarkable anti-inflammatory effect was noticed either in A. awamori prevented or treated groups expounded by reducing and regulating TNF-α, IL-6, and IL-1β with improved pathological lesion scoring. The Muc2, Nrf2, and bcl-2 gene levels were upregulated and restored also. In summary, the findings in this work reveal that A. awamori supplementation successfully alleviated the UC induced by AA, which had a better effect when administered before colitis induction.

Formulation and characterisation of Azadirachta indica nanobiopesticides for ecofriendly control of wheat pest Tribolium castaneum and Rhyzopertha dominica

This study aimed to formulate the green, sustainable, and ecofriendly nanobiopesticides of Azadirachta indica with enhanced pest control efficacy. Nanoprecipitation method was used for the development of nanobiopesticides. Optimisation was done by response surface methodology. Nanoformulations were characterised by zetasizer, scanning electron microscopy, energy dispersive x-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy. Pesticidal potential of nanosuspensions was evaluated by insecticide impregnated filter paper method. Optimised nanobiopesticide showed an average particle size of 275.8 ± 0.95 nm, polydispersity index (PDI) 0.351 ± 0.002, and zeta potential of -33 ± 0.90 mV. Nanobiopesticides exhibited significantly higher mortality rates of 86.81 ± 3.04 and 84.97 ± 2.83% against Tribolium castaneum and Ryzopertha dominica, respectively, as compared to their crude extract. Minor change in particle size from 275.8 ± 0.95 to 298.8 ± 1.00 nm and PDI from 0.351 ± 0.002 to 0.445 ± 0.02 were observed after 3 months of storage at 4 °C. Pesticidal efficacy of A. indica was significantly enhanced by the formulation of its nanobiopesticides.

Process optimization for simultaneous production of phenolic acids and enzymes with high transfructosylation activity in cupuassu (Theobroma grandiflorum) residue by submerged fermentation with Aspergillus carbonarius

Cupuassu (Theobroma grandiflorum) generates a large amount of waste, which can be better used to obtain products with high added value through biotechnological processes. Thus, the present study aimed to obtain optimized conditions for the simultaneous production of phenolic acids, invertases and transferases enzymes in cupuassu residue with Aspergillus carbonarius. The main methodologies used to select the variables that influence the system were a Plackett-Burman design, followed by a Central Composite Rotational Design. The optimal conditions were use of 17.3% sucrose, 5.1% residue and 4.6% yeast extract to produce 2204.89 ± 5.75 mg GAE/100 g, 39.84 ± 2.08 U/mL of hydrolytic activity, 168.09 ± 3.81 U/mL of transfructosylation activity and 4.23 ± 0.19 of transfructosylation and hydrolytic activity ratio. Among the phenolic acids identified by the UFLC-DAD system, there was an increase of 148.17% in gallic acid and 205.51% in protocatechuic acid. The antioxidant activities also showed changes after fermentation, with an increase of 350% for the ABTS assay, 51.97% for FRAP, 22.65% for ORAC and 16.03% for DPPH. To the best of our knowledge, this is the first time that cupuassu residue is fermented with Aspergillus carbonarius to obtain invertases and transferases enzymes and phenolic acids.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05418-z.

Fermented soybean foods: A review of their functional components, mechanism of action and factors influencing their health benefits

After thousands of years of evolution and development, traditional fermented soybean foods, with their unique charm, have gained a stable place in the global market. With the explosive development of modern biological technologies, some traditional fermented soybean foods that possess health-promoting benefits are gradually appearing. Physiologically active substances in fermented soybean foods have received extensive attention in recent decades. This review addresses the potential health benefits of several representative fermented soybean foods, as well as the action mechanism and influencing factors of their functional components. Phenolic compounds, low-molecular-weight peptides, melanoidins, furanones and 3-hydroxyanthranilic acid are the antioxidative components predominantly found in fermented soybean foods. Angiotensin I-converting enzyme inhibitory peptides and γ-aminobutyric acid isolated from fermented soy foods provide potential selectivity for hypertension therapy. The potential anti-inflammatory bioactive components in fermented soybean foods include γ-linolenic acid, butyric acid, soy sauce polysaccharides, 2S albumin and isoflavone glycones. Deoxynojirimycin, genistein, and betaine possess high activity against α-glucosidase. Additionally, fermented soybean foods contain neuroprotective constituents, including indole alkaloids, nattokinase, arbutin, and isoflavone vitamin B12. The anticancer activities of fermented soybean foods are associated with surfactin, isolavone, furanones, trypsin inhibitors, and 3-hydroxyanthranilic acid. Nattokinase is highly correlated with antioxidant activity. And a high level of menaquinones-7 is linked to protection against neurodegenerative diseases. Sufficiently recognizing and exploiting the health benefits and functional components of traditional fermented soybean foods could provide a new strategy in the development of the food fermentation industry.

Formulation of a Culture Medium to Optimize the Production of Lipopeptide Biosurfactant by a New Isolate of Bacillus sp.: A Soil Heavy Metal Mitigation Approach

This research aimed to optimize a lipopeptide biosurfactant produced from Bacillus sp. SHA302 due to its high efficiency of heavy metal release in soil. The results demonstrated that the metal release capacity of the lipopeptide biosurfactant alone increased with increasing the biosurfactant concentration. Among treatments with different biosurfactant concentrations plus acid, the highest metal release rates of 53.8% ± 1.4 and 39.3% ± 1.7 for Zn and Pb, respectively, were observed in the critical micelle concentration (CMC) + HCl treatment. The results of a factorial experiment designed for optimizing biosurfactant production showed that among five inexpensive carbon sources and six mineral nitrogen sources, sugar beet molasses (1%) and ammonium chloride (0.1%) were the most efficient sources in lowering the surface tension (ST) of the culture media to 32.2 ± 0.76 mN/m. The second step of the experiment was a Plackett-Burman design with 11 factors and showed that the four factors of pH, ammonium chloride, magnesium sulfate, and molasses significantly affected (P < 0.05) the changes in ST and biosurfactant production. The third step of the experiment was done using the response surface methodology (RSM) with a central composite design. The results showed that a pH of 7.3, 1.5 g/l of ammonium chloride, 0.3 g/l of magnesium sulfate, and 10% of sugar beet molasses yielded values of 29.2 ± 0.71 mN/m and 5.74 ± 0.52 g/l for the two variables of ST and biosurfactant production, respectively, which reached their most optimal levels.

Effect of In Vitro Gastrointestinal Digestion on Amino Acids, Polyphenols and Antioxidant Capacity of Tamarillo Yoghurts

Laird’s Large tamarillo powder is high in protein (10%) essential amino acids (EAAs), gamma-aminobutyric acid (GABA) and polyphenols (0.6% phenolics plus anthocyanins) and fibre 25%. This study aimed to investigate, using a standardized static in vitro digestion model, the stability of amino acids and antioxidant capacity of polyphenols in yoghurt fortified with 5, 10 and 15% tamarillo powder either before (PRE) or after (POS) fermentation. Compared to plain yoghurt, the fruit polyphenols (rutinosides and glycosides) were retained and substantial increases in FEAAs (free essential amino acids), total phenolic content (TPC) and antioxidant activity were observed particularly at the end of intestinal phase of digestion. Together with SDS-PAGE results, peptides and proteins in tamarillo yoghurts were more easily digested and therefore may be better absorbed in the small intestine compared to the control. TPC and antioxidant activity of fortified yoghurts increased significantly after in vitro digestion. Relatively high bioaccessibilty of chlorogenic acid and kaempferol-3-rutinoside in digested PRE samples was observed. The results suggest that the yoghurt matrix might protect some compounds from degradation, increasing bioaccessibility and in the small intestine allow increased absorption and utilization possible. Fortification would deliver intact polyphenols and fibre to the large intestine and improve gut health. Further research of acceptability, shelf life, and then trials for health effects should be implemented.

Vibrational Spectroscopy-Based Chemometrics Analysis of Clinacanthus nutans Extracts after Postharvest Processing and Extract Effects on Cardiac C-Kit Cells

Chemical constituents in plants can be greatly affected by postharvest processing, and it is important to identify the factors that lead to significant changes in chemistry and bioactivity. In this study, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used to analyze extracts of Clinacanthus nutan (C. nutans) leaves generated using different parameters (solvent polarities, solid-liquid ratios, ultrasonic durations, and cycles of extraction). In addition, the effects of these extracts on the viability of cardiac c-kit cells (CCs) were tested. The IR spectra were processed using SIMCA-P software. PCA results of all tested parameter sets were within acceptable values. Solvent polarity was identified as the most influential factor to observe the differences in chemical profile and activities of C. nutans extracts. Ideal extraction conditions were identified, for two sample groups (G1 and G2), as they showed optimal total phenolic content (TPC) yield of 44.66 ± 0.83 mg GAE/g dw and 45.99 ± 0.29 mg GAE/g dw and CC viability of 171.81 ± 4.06% and 147.53 ± 6.80%, respectively. Validation tools such as CV-ANOVA (p < 0.05) and permutation (R² and Q² plots were well intercepted to each other) have further affirmed the significance and reliability of the partial least square (PLS) model of solvent polarity employed in extraction. Hence, these approaches help optimize postharvest processes that encourage positive TPC and CCs results in C. nutans extracts.

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.

Food Processing Technologies to Develop Functional Foods With Enriched Bioactive Phenolic Compounds in Cereals

Cereal grains and products provide calories globally. The health benefits of cereals attributed to their diverse phenolic constituents have not been systematically explored. Post-harvest processing, such as drying, storing, and milling cereals, can alter the phenolic concentration and influence the antioxidant activity. Furthermore, cooking has been shown to degrade thermo-labile compounds. This review covers several methods for retaining and enhancing the phenolic content of cereals to develop functional foods. These include using bioprocesses such as germination, enzymatic, and fermentation treatments designed to enhance the phenolics in cereals. In addition, physical processes like extrusion, nixtamalization, and parboiling are discussed to improve the bioavailability of phenolics. Recent technologies utilizing ultrasound, micro- or nano-capsule polymers, and infrared utilizing processes are also evaluated for their effectiveness in improving the phenolics content and bio-accessibility. We also present contemporary products made from pigmented cereals that contain phenolics.

Evaluation of Chemical Compositions, Antioxidant Capacity and Intracellular Antioxidant Action in Fish Bone Fermented with Monascus purpureus

Fish bones (FBs) are aquatic by-products that are sources of antioxidant-active peptides, calcium dietary supplements, and biomedical materials. Usually, fermentation of these by-products via microorganisms brings desirable changes, enhancing their value. This study investigates the value addition of FB when fermented with Monascus purpureus (MP) for different time intervals, such as 3 days (F3) and 6 days (F6). The results indicate that the soluble protein, peptide, amino acid and total phenol content, as well as the antioxidant capacity (DPPH, ABTS⁺ radical scavenging activity, and relative reducing power), of F3 and F6 were significantly increased after fermentation. Furthermore, the ROS contents of F3 and F6 were reduced to a greater extent than that of hydrogen peroxide (H₂O₂) in Clone-9 cells. The MMP integrity, as well as the SOD, CAT, and GPx activity, of F3 and F6 were also increased significantly compared to the H₂O₂ in Clone-9 cells. Notably, F3 and F6 displayed significant reductions in ROS content, as well as elevate, SOD activity and MMP integrity in Clone-9 cells, when compared with the native FB. These results indicate that the FBs fermented with MP for 3 days (F3), and 6 days (F6) have antioxidant capacity, with possible applications as natural food supplements.

Optimization of Natural Antioxidants Extraction from Pineapple Peel and Their Stabilization by Spray Drying

Pineapple peel still contains an important amount of phenolic compounds and vitamins with valuable antioxidant activity. In this way, the aim of this study was the recovery of the bioactive compounds from pineapple peel using environmentally friendly and low-cost techniques, envisaging their application in food products. From the solid-liquid extraction conditions tested, the one delivering an extract with higher total phenolic content and antioxidant capacity was a single extraction step with a solvent-pineapple peel ratio of 1:1 (w/w) for 25 min at ambient temperature, using ethanol-water (80-20%) as a solvent. The resulting extract revealed a total phenolic content value of 11.10 ± 0.01 mg gallic acid equivalent (GAE)/g dry extract, antioxidant activity of 91.79 ± 1.98 µmol Trolox/g dry extract by the DPPH method, and 174.50 ± 9.98 µmol Trolox/g dry extract by the FRAP method. The antioxidant rich extract was subjected to stabilization by the spray drying process at 150 °C of inlet air temperature using maltodextrin (5% w/w) as an encapsulating agent. The results showed that the antioxidant capacity of the encapsulated compounds was maintained after encapsulation. The loaded microparticles obtained, which consist of a bioactive powder, present a great potential to be incorporated in food products or to produce bioactive packaging systems.

Dietary Plant Polyphenols: Effects of Food Processing on Their Content and Bioavailability

Dietary plant polyphenols are natural bioactive compounds that are increasingly attracting the attention of food scientists and nutritionists because of their nutraceutical properties. In fact, many studies have shown that polyphenol-rich diets have protective effects against most chronic diseases. However, these health benefits are strongly related to both polyphenol content and bioavailability, which in turn depend on their origin, food matrix, processing, digestion, and cellular metabolism. Although most fruits and vegetables are valuable sources of polyphenols, they are not usually consumed raw. Instead, they go through some processing steps, either industrially or domestically (e.g., cooling, heating, drying, fermentation, etc.), that affect their content, bioaccessibility, and bioavailability. This review summarizes the status of knowledge on the possible (positive or negative) effects of commonly used food-processing techniques on phenolic compound content and bioavailability in fruits and vegetables. These effects depend on the plant type and applied processing parameters (type, duration, media, and intensity). This review attempts to shed light on the importance of more comprehensive dietary guidelines that consider the recommendations of processing parameters to take full advantage of phenolic compounds toward healthier foods.

Pretreatment of tamarind pericarp to increase antioxidant availability and its application in a functional food

Diverse researchers have considered by-products of food and agricultural processing industries as a source of antioxidants. Tamarind (Tamarindus indica) is a leguminous tree, native from tropical Africa bearing edible fruit. The fruit is composed of 30% pulp, 40% seed, and 30% pericarp. Currently, tamarind pericarp is a waste from tamarind processing (approximately 54,400 tons of pericarp in 2012 worldwide) and is contributing to environmental contamination. This research aimed to determine the effect of maceration, microwaves, and ultrasound on the increase in the antioxidant availability in tamarind pericarp and its incorporation as a functional ingredient in cookies (5 and 10% substitution). Antioxidant content, antioxidant activity, proximate, and sensorial analysis of the cookies were conducted. The microwave method was the best pretreatment compared with sonication and maceration since it showed 1.3-fold higher amounts of phenolic compounds and 1.2-fold higher antioxidant capacity. The 10% substitution of tamarind pericarp powder in cookies, significantly increased the fiber content (four-fold) and phenolic compounds content (2.6-fold) and the product presented good acceptance in a sensorial test. Thus, tamarind pericarp powder could be considered as an antioxidant and fiber source and could be used as a functional ingredient in food products.

Enzymes produced by solid state fermentation of agro-industrial by-products release ferulic acid in bioprocessed whole-wheat breads

Solid-state fermentation (SSF) presents low cost and the possibility of adding value to waste by generating products rich in enzymes. The production of enzymes by SSF and its application in bakery have been previously reported separately in the literature. However, very few studies combine both approaches to evaluate the feasibility of applying enzymes produced by SSF to bread processing. The objective of this study was to use cocoa bean shell (CBS), wheat bran (WB) and brewer's spent grain (BSG) for enzyme production by SSF, and to evaluate their addition in breads. Three breads were produced: control bread (CB), bioprocessed bread added with fermented wheat bran (WBB) and bioprocessed bread added with fermented BSG (BSGB). Feruloyl esterase highest activities were 1,730 mU/g for WB fermented for 24 h and 1,128 mU/g for BSG fermented for 72 h. Xylanase highest activities were 547.9 U/g for BSG fermented for 48 h and 868.1 U/g for WB fermented for 72 h. CBS showed the lowest enzymatic activities. Bioprocessing breads with fermented WB and BSG led to an increase in soluble ferulic acid of 159% and 198%, respectively. The combination of SSF enzyme production and bread enzymatic bioprocessing strategies proved to be an effective green option for the valorization of agro-industrial by-products and the production of breads with enhanced ferulic acid content.

Recent trends in extraction of plant bioactives using green technologies: A review

Phenolic compounds from plant sources have significant health-promoting properties and are known to be an integral part of folk and herbal medicines. Consumption of phenolics is known to alleviate the risk of various lifestyle diseases including cancer, cardiovascular, diabetes, and Alzheimer's. In this context, numerous plant crops have been explored and characterized based on phenolic compounds for their use as supplements, nutraceutical, and pharmaceuticals. The present review highlights some important source of bioactive phenolic compounds and novel technologies for their efficient extraction. These techniques include the use of microwave, ultrasound, and supercritical methods. Besides, the review will also highlight the use of response surface methodology (RSM) as a statistical tool for optimizing the recoveries of the phenolic bioactives from plant-based matrices.

Aspergillus oryzae Fermented Rice Bran: A Byproduct with Enhanced Bioactive Compounds and Antioxidant Potential

Rice bran (RB) is a byproduct of the rice industry (milling). For the fermentation process and to add value to it, RB was sprayed with fungal spores (Aspergillus oryzae MTCC 3107). The impact of fermentation duration on antioxidant properties was studied. Total phenolic content (TPC) determined using the Folin–Ciocalteu method, increased during fermentation until the 4th day. The antioxidant activity analyzed using the 2,2 Diphenyl–1′ picrylhydrazyl (DPPH) assay, total antioxidant activity (TAC), 2,2′-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS⁺) assay, reducing power assay (RPA) and hydroxyl free radical scavenging activity (HFRSA) for fermented rice bran (FRB) were determined and compared to unfermented rice bran (URB). TAC, DPPH, ABTS⁺ and RPA of FRB increased till 4th day of fermentation, and then decreased. The specific bioactive constituents in extracts (Ethanol 50%) from FRB and URB were identified using high performance liquid chromatography (HPLC). HPLC confirmed a significant (p < 0.05) increase in gallic acid and ascorbic acid. On the 4th day of fermentation, the concentrations of gallic acid and ascorbic acid were 23.3 and 12.7 µg/g, respectively. The outcome of present investigation confirms that antioxidant potential and TPC of rice bran may be augmented using SSF.

Impact of Fermentation on the Phenolic Compounds and Antioxidant Activity of Whole Cereal Grains: A Mini Review

Urbanization, emergence, and prominence of diseases and ailments have led to conscious and deliberate consumption of health beneficial foods. Whole grain (WG) cereals are one type of food with an array of nutritionally important and healthy constituents, including carotenoids, inulin, β-glucan, lignans, vitamin E-related compounds, tocols, phytosterols, and phenolic compounds, which are beneficial for human consumption. They not only provide nutrition, but also confer health promoting effects in food, such as anti-carcinogenic, anti-microbial, and antioxidant properties. Fermentation is a viable processing technique to transform whole grains in edible foods since it is an affordable, less complicated technique, which not only transforms whole grains but also increases nutrient bioavailability and positively alters the levels of health-promoting components (particularly antioxidants) in derived whole grain products. This review addresses the impact of fermentation on phenolic compounds and antioxidant activities with most available studies indicating an increase in these health beneficial constituents. Such increases are mostly due to breakdown of the cereal cell wall and subsequent activities of enzymes that lead to the liberation of bound phenolic compounds, which increase antioxidant activities. In addition to the improvement of these valuable constituents, increasing the consumption of fermented whole grain cereals would be vital for the world's ever-growing population. Concerted efforts and adequate strategic synergy between concerned stakeholders (researchers, food industry, and government/policy makers) are still required in this regard to encourage consumption and dispel negative presumptions about whole grain foods.

Optimization of Total Phenolic and Flavonoid Contents of Defatted Pitaya (Hylocereus polyrhizus) Seed Extract and Its Antioxidant Properties

The present study was conducted to optimize extraction process for defatted pitaya seed extract (DPSE) adopting response surface methodology (RSM). A five-level central composite design was used to optimize total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), and 2,2′-azino-bis (3-ethylbenzothizoline-6-sulfonic acid (ABTS) activities. The independent variables included extraction time (30–60 min), extraction temperature (40–80 °C) and ethanol concentration (60%–80%). Results showed that the quadratic polynomial equations for all models were significant at (p < 0.05), with non-significant lack of fit at p > 0.05 and R² of more than 0.90. The optimized extraction parameters were established as follows: extraction time of 45 min, extraction temperature of 70 °C and ethanol concentration of 80%. Under these conditions, the recovery of TPC, TFC, and antioxidant activity based on FRAP and ABTS were 128.58 ± 1.61 mg gallic acid equivalent (GAE)/g sample, 9.805 ± 0.69 mg quercetin equivalent (QE)/g sample, 1.23 ± 0.03 mM Fe2+/g sample, and 91.62% ± 0.15, respectively. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) analysis identified seven chemical compounds with flavonoids constituting major composition of the DPSE.

Fermented pearl millet (Pennisetum glaucum) with in vitro DNA damage protection activity, bioactive compounds and antioxidant potential

In the present study, pearl millet cultivar PUSA-415 was fermented by solid state fermentation (SSF) process using Aspergillus sojae (MTCC-8779) as starter culture. The fermentation was carried out for the period of ten days. The effect of SSF on phenolic content, condensed tannin content, antioxidant potential and DNA damage protection of pearl millet during different fermentation period was determined. Results showed that SSF and thermal processing significantly affect the bioactive profile and antioxidant potential of bio-transformed pearl millet. Extracts prepared from 6th days fermented pearl millet flour exhibited the highest TPC, antioxidant potential and DNA damage protection activity. Qualitative and quantitative analysis of bioactive compounds were done by HPLC. During SSF, production of enzymes (α-amylase, β-glucosidase and xylanase) as well as specific bioactive compounds (ascorbic acid, gallic acid and p-Coumaric acid) was significantly increased. Thus, bio-transformed Aspergillus sojae fermented pearl millet could be used in preparation of functional foods and novel nutraceuticals in health promotions. Chapatti was formulated from unfermented as well as fermented flour and the effect of thermal processing on bioactive compounds and antioxidant potential was studied. Thermal processing resulted in decrease in TPC of both, AFM and UFM by 4.75-16.27% and increase in CTC by 38.52-67.41%.