An overview on antioxidant peptides from rice bran proteins: extraction, identification, and applications

Caffeic Acid Phenethyl Ester Encapsulated in Self-Assemble Rice Peptides Nanoparticles: Storage Stability, In Vitro Release, and Their Interaction Mechanisms

Caffeic acid phenethyl ester (CAPE) is an important active component of propolis with many bioactivities. However, its efficiency and practical application are restricted due to its poor aqueous solubility and storage stability. In this study, a nanocarrier was fabricated to encapsulate CAPE using self-assembled rice peptides obtained by controllable enzymolysis. The physicochemical properties, encapsulation efficiency, and loading capacity of rice peptides nanoparticles (RPNs) were characterized. The storage stability, in vitro release, and interaction mechanisms between CAPE and RPNs were investigated. The results showed that RPNs, mainly assembled by disulfide bonds and hydrogen bonds, possessed an effective diameter of around 210 nm and a high encapsulation efficiency (77.77%) and loading capacity (3.89%). Importantly, the water solubility of CAPE was increased by 45 times after RPNs encapsulation. Moreover, RPNs encapsulation also significantly increased CAPE stability, about 1.4-fold higher than that of unencapsulated CAPE after 18-day storage. An in vitro release study demonstrated that RPNs could delay the release of CAPE, implying a better CAPE protection against extreme environments during digestion. Hydrogen bond and van der Waals force are the predominant interaction forces between RPNs and CAPE. Therefore, the newly developed nanoparticle is a potential delivery system that could effectively improve the aqueous solubility and stability of CAPE.

Rice Bran Oil Improves Emphysema in Cigarette Smoke Extract-Induced Mice through Anti-Inflammatory and Antioxidative Effects

Lung inflammation and alveolar enlargement are the major pathological conditions of chronic obstructive pulmonary disease (COPD) patients. Rice bran oil (RBO), a natural anti-inflammatory and antioxidative agent, has been used for therapeutic purposes in several inflammatory diseases. This study aimed to investigate the anti-inflammatory and antioxidative effect of RBO on a cigarette smoke extract (CSE)-induced emphysema model in mice. The results indicated that CSE significantly induced airspace enlargement in mouse lung. Increased inflammatory cells, macrophage, and TNF-alpha levels in bronchoalveolar lavage fluid (BALF) were noticed in CSE-treated mice. RBO (low and high dose)-supplemented mice showed decreased total BALF inflammatory cell, macrophage, and neutrophil numbers and TNF-alpha levels (p < 0.05). Additionally, the administration of RBO decreased the mean linear alveolar intercept (MLI) in the CSE-treated group. Additionally, RBO treatment significantly increased the total antioxidant capacity in both mouse BALF and serum. However, RBO did not have an effect on the malondialdehyde (MDA) level. These findings suggested that RBO treatment ameliorates lung inflammation in a CSE-induced emphysema mice model through anti-inflammatory and antioxidant pathways. Therefore, the supplementation of RBO could be a new potential therapeutic to relieve the severity of COPD.

Novel Antioxidant Peptides Derived from Feather Keratin Alleviate H2O2-Induced Oxidative Damage in HepG2 Cells via Keap1/Nrf2 Pathway

Reactive oxygen species (ROS) are crucial for signal transduction and the maintenance of cellular homeostasis. However, superfluous ROS may engender chronic pathologies. Feather keratin is a promising new source of antioxidant peptides that can eliminate excess ROS and potentially treat oxidative stress-related diseases, but the underlying mechanisms have remained elusive. This study investigated the antioxidant effects and mechanisms against H2O2-induced oxidative damage in HepG2 cells of the two latest discovered antioxidant peptides, CRPCGPTP (CP-8) and ANSCNEPCVR (AR-10), first decrypted from feather keratin. The results revealed that CP-8 and AR-10 did not exhibit cytotoxicity to HepG2 cells while reducing intracellular ROS accumulation. Simultaneously, they enhanced the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), thus alleviating H2O2-induced cell apoptosis. Molecular docking analysis demonstrated that CP-8, AR-10 interacted well with the key amino acids in the Kelch domain of Keap1, thereby directly disrupting the Keap1-Nrf2 interaction. The peptides' biosafety and antioxidant activity via Keap1/Nrf2 signaling lay the groundwork for further animal studies and applications as functional food additives.

Phytosterols in rice bran and their health benefits

With the continuous technological innovation in the high-value utilization of rice bran byproducts, rice bran oil retains a higher concentration of beneficial components such as a well-balanced composition of fatty acids and abundant phytosterols. This makes it a highly nutritious and healthy vegetable oil. This review provides an overview of the advancements made in separating, purifying, and processing phytosterols in rice bran oil. The review also introduces techniques for assessing the stability of rice bran oil. Moreover, the review emphasizes the nutritional value of phytosterols found in rice bran oil, highlighting their various health benefits, including their anticancer, anti-inflammatory, anti-allergic, antibacterial, cholesterol-lowering, skin-protective, anti-obesity, anti-diabetic, neuroprotective, gastroprotective, and immune-enhancing effects. Attaining a comprehensive understanding of the research progress made in phytosterols derived from rice bran oil can offer valuable guidance for the efficient utilization of rice bran.

Shifting archetype to nature's hidden gems: from sources, purification to uncover the nutritional potential of bioactive peptides

Contemporary scientific findings revealed that our daily food stuffs are enriched by encrypted bioactive peptides (BPs), evolved by peptide linkage of amino acids or encrypted from the native protein structures. Remarkable to these BPs lies in their potential health benefiting biological activities to serve as nutraceuticals or a lead addition to the development of functional foods. The biological activities of BPs vary depending on the sequence as well as amino acid composition. Existing database records approximately 3000 peptide sequences which possess potential biological activities such as antioxidants, antihypertensive, antithrombotic, anti-adipogenics, anti-microbials, anti-inflammatory, and anti-cancerous. The growing evidences suggest that BPs have very low toxicity, higher accuracy, less tissue accretion, and are easily degraded in the disposed environment. BPs are nowadays evolved as biologically active molecules with potential scope to reduce microbial contamination as well as ward off oxidation of foods, amend diverse range of human diseases to enhance the overall quality of human life. Against the clinical and health perspectives of BPs, this review aimed to elaborate current evolution of nutritional potential of BPs, studies pertaining to overcome limitations with respect to special focus on emerging extraction, protection and delivery tools of BPs. In addition, the nano-delivery mechanism of BP and its clinical significance is detailed. The aim of current review is to augment the research in the field of BPs production, identification, characterisation and to speed up the investigation of the incredible potentials of BPs as potential nutritional and functional food ingredient.

Cereal bran proteins: recent advances in extraction, properties, and applications

The projected global population is expected to reach around 9.7 billion by 2050, indicating a greater demand for proteins in the human diet. Cereal bran proteins (CBPs) have been identified as high-quality proteins, with potential applications in both the food and pharmaceutical industries. In 2020, global cereal grain production was 2.1 billion metric tonnes, including wheat, rice, corn, millet, barley, and oats. Cereal bran, obtained through milling, made up 10-20% of total cereal grain production, varying by grain type and milling degree. In this article, the molecular composition and nutritional value of CBPs are summarized, and recent advances in their extraction and purification are discussed. The functional properties of CBPs are then reviewed, including their solubility, binding, emulsifying, foaming, gelling, and thermal properties. Finally, current challenges to the application of CBPs in foods are highlighted, such as the presence of antinutritional factors, low digestibility, and allergenicity, as well as potential strategies to improve the nutritional and functional properties by overcoming these challenges. CBPs exhibit nutritional and functional attributes that are similar to those of other widely used plant-based protein sources. Thus, CBPs have considerable potential for use as ingredients in food, pharmaceutical, and other products.

Preparation, Purification, and Identification of Novel Feather Keratin-Derived Peptides with Antioxidative and Xanthine Oxidase Inhibitory Activities

Feather keratin is an underappreciated protein resource of high quality, with limited bioavailability, and it urgently requires eco-friendly methods to enhance its value. Here, we report on the preparation, purification, and identification of novel peptides with antioxidant and xanthine oxidase (XOD) inhibitory activities from fermented feather broth, using Bacillus licheniformis 8-4. Two peptides, namely, DLCRPCGPTPLA (DA-12) and ANSCNEPCVR (AR-10), displayed remarkable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging abilities with half-maximal inhibitory concentrations (IC₅₀) values of 0.048, 0.034, and 0.95, 0.84 mg/mL, respectively. These values exceed those of the previously reported feather keratin-derived antioxidant peptides. Another peptide, GNQQVHLQSQDM (GM-12), demonstrated XOD activity inhibition, with an IC₅₀ value of 12.15 mg/mL, and it quenched the fluorescence of XOD. Furthermore, after simulating gastrointestinal digestion, DA-12, AR-10, and GM-12 retained their biological activities. Meanwhile, DA-12 and GM-12 showed an unexpected synergistic inhibition on XOD activity accompanied by fluorescence quenching. This study provides new insights into the potential applications of feather keratin, including functionalized feed with antioxidative and antigout (anti-hyperuricemia) activities.

Antioxidant capacity and antitumor activity of the bioactive protein prepared from orange peel residues as a by-product using fungal protease

Agricultural and industrial residues (AIR) are renewable biomass sources present in large quantities causing pollution. Converting AIR to eco-friendly products (bioactive materials) reduces their quantity and impact on the environment, in addition to reducing production costs. Therefore, orange peel (OP) protein degradation, antioxidant capacity, and antitumor activity were investigated using Aspergillus niger WA 2017 protease. The highest value of the protein hydrolysate with the highest antioxidant using the DPPH method was obtained after 24 h. The single-factor method boosted the protein hydrolysate and the DPPH antioxidant activity by 3.7 and 1.7-fold, respectively. Statistical optimized conditions (Central Composite Method) increased the hydrolysate value and the DPPH antioxidant activity by 1.6 and 1.1-fold, respectively. The central trial samples exhibited the highest DPPH antioxidant activity (62.37 %), while the control sample recorded 20 %. All antioxidant tests in vitro (DPPH, reducing power, ABTS, and FRAP) confirmed the superiority of the potent hydrolysate as a good antioxidant. In vitro antitumor activity, the potent hydrolysate exhibited the highest effect on the Ehrlich Ascites Carcinoma Cells viability as it recorded 60.62 % dead cells. In vivo antitumor activity, the volume of the untreated tumor mice was found to be 1.4-fold bigger than the volume obtained from the potent hydrolysate. The increase in life span (ILS %) for oral treatment and intraperitoneal injection treatment with the potent hydrolysate increased by 13.91 and 19.42 %, respectively, compared to the untreated tumor.

Food Peptides for the Nutricosmetic Industry

In recent years, numerous reports have described bioactive peptides (biopeptides)/hydrolysates produced from various food sources. Biopeptides are considered interesting for industrial application since they show numerous functional properties (e.g., anti-aging, antioxidant, anti-inflammatory, and antimicrobial properties) and technological properties (e.g., solubility, emulsifying, and foaming). Moreover, they have fewer side effects than synthetic drugs. Nevertheless, some challenges must be overcome before their administration via the oral route. The gastric, pancreatic, and small intestinal enzymes and acidic stomach conditions can affect their bioavailability and the levels that can reach the site of action. Some delivery systems have been studied to avoid these problems (e.g., microemulsions, liposomes, solid lipid particles). This paper summarizes the results of studies conducted on biopeptides isolated from plants, marine organisms, animals, and biowaste by-products, discusses their potential application in the nutricosmetic industry, and considers potential delivery systems that could maintain their bioactivity. Our results show that food peptides are environmentally sustainable products that can be used as antioxidant, antimicrobial, anti-aging, and anti-inflammatory agents in nutricosmetic formulations. Biopeptide production from biowaste requires expertise in analytical procedures and good manufacturing practice. It is hoped that new analytical procedures can be developed to simplify large-scale production and that the authorities adopt and regulate use of appropriate testing standards to guarantee the population's safety.

Biological functions of active ingredients in quinoa bran: Advance and prospective

Quinoa is known to be a rich source of nutrients and bioactive components. Quinoa bran, used mainly as animal feed in processing by-products, is also a potential source of bioactive ingredients being conducive to human health. The importance of nutrition and function of quinoa seed has been discussed in many studies, but the bioactive properties of quinoa bran often are overlooked. This review systemically summarized the progress in bioactive components, extraction, and functional investigations of quinoa bran. It suggests that chemically assisted electronic fractionation could be used to extract albumin from quinoa bran. Ultrasound-assisted extraction method is a very useful method for extracting phenolic acids, triterpene saponins, and flavonoids from quinoa bran. Based on in vitro and in vivo studies for biological activities, quinoa bran extract exhibits a wide range of beneficial properties, including anti-oxidant, anti-diabetes, anti-inflammation, anti-bacterial and anti-cancer functions. However, human experiments and action mechanisms need to investigate. Further exploring quinoa bran will promote its applications in functional foods, pharmaceuticals, and poultry feed in the future.

Virtual Screening for SARS-CoV-2 Main Protease Inhibitory Peptides from the Putative Hydrolyzed Peptidome of Rice Bran

The Coronavirus Disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the loss of life and has affected the life quality, economy, and lifestyle. The SARS-CoV-2 main protease (Mpro), which hydrolyzes the polyprotein, is an interesting antiviral target to inhibit the spreading mechanism of COVID-19. Through predictive digestion, the peptidomes of the four major proteins in rice bran, albumin, glutelin, globulin, and prolamin, with three protease enzymes (pepsin, trypsin, and chymotrypsin), the putative hydrolyzed peptidome was established and used as the input dataset. Then, the prediction of the antiviral peptides (AVPs) was performed by online bioinformatics tools, i.e., AVPpred, Meta-iAVP, AMPfun, and ENNAVIA programs. The amino acid composition and cytotoxicity of candidate AVPs were analyzed by COPid and ToxinPred, respectively. The ten top-ranked antiviral peptides were selected and docked to the SARS-CoV-2 main protease using GalaxyPepDock. Only the top docking scored candidate (AVP4) was further analyzed by molecular dynamics simulation for one nanosecond. According to the bioinformatic analysis results, the candidate SARS-CoV-2 main protease inhibitory peptides were 7–33 amino acid residues and formed hydrogen bonds at Thr22–24, Glu154, and Thr178 in domain 2 with short bonding distances. In addition, these top-ten candidate bioactive peptides contain hydrophilic amino acid residues and have a positive net charge. We hope that this study will provide a potential starting point for peptide-based therapeutic agents against COVID-19.

Mechanism of peptides from rice hydrolyzed proteins hindering starch digestion subjected to hydrothermal treatment

Clarifying the interactions between food components is critical in designing carbohydrate-based foods with low digestibility. To date, the hindering effect of starch-protein interactions on starch digestion has attracted extensive attention. In this study, rice proteins were further hydrolyzed, and rice peptides (RP) with different molecular weights were obtained by ultrafiltration. The effects and possible mechanisms of RP with different molecular weights on the structure, thermal properties, and in vitro digestibility of cooked rice starch were investigated. All peptides slowed the digestion of rice starch in a concentration-dependent manner. A concentration of 10% RP_>10 decreased the rapidly digestible starch content from 68.02 to 45.90 g/100 g, and increased the resistant starch content from 17.54 to 36.54 g/100 g. The addition of RP improved the thermal stability of the starch and reduced the amount of leached amylose. Infrared analysis shows that strong hydrogen bonds formed between RP (especially RP_>10) and starch during co-gelatinization. In addition, RP improved the compactness of aggregated structure and played an important role in hindering the enzymatic hydrolysis of starch. These results enrich the theory of starch-protein interactions and have important implications for the development of carbohydrate-based foods with low digestibility and protein functional foods.

An Update Regarding the Bioactive Compound of Cereal By-Products: Health Benefits and Potential Applications

Cereal processing generates around 12.9% of all food waste globally. Wheat bran, wheat germ, rice bran, rice germ, corn germ, corn bran, barley bran, and brewery spent grain are just a few examples of wastes that may be exploited to recover bioactive compounds. As a result, a long-term strategy for developing novel food products and ingredients is encouraged. High-value compounds like proteins, essential amino acids, essential fatty acids, ferulic acid, and other phenols, tocopherols, or β-glucans are found in cereal by-products. This review aims to provide a critical and comprehensive overview of current knowledge regarding the bioactive compounds recovered from cereal by-products, emphasizing their functional values and potential human health benefits.

Bioactive Peptides: An Understanding from Current Screening Methodology

Bioactive peptides with high potency against numerous human disorders have been regarded as a promising therapy in disease control. These peptides could be released from various dietary protein sources through hydrolysis processing using physical conditions, chemical agents, microbial fermentation, or enzymatic digestions. Considering the diversity of the original proteins and the complexity of the multiple structural peptides that existed in the hydrolysis mixture, the screening of bioactive peptides will be a challenge task. Well-organized and well-designed methods are necessarily required to enhance the efficiency of studying the potential peptides. This article, hence, provides an overview of bioactive peptides with an emphasis on the current strategy used for screening and characterization methods. Moreover, the understanding of the biological activities of peptides, mechanism inhibitions, and the interaction of the complex of peptide–enzyme is commonly evaluated using specific in vitro assays and molecular docking analysis.

Bioactivities, Applications, Safety, and Health Benefits of Bioactive Peptides From Food and By-Products: A Review

Bioactive peptides generated from food proteins have great potential as functional foods and nutraceuticals. Bioactive peptides possess several significant functions, such as antioxidative, anti-inflammatory, anticancer, antimicrobial, immunomodulatory, and antihypertensive effects in the living body. In recent years, numerous reports have been published describing bioactive peptides/hydrolysates produced from various food sources. Herein, we reviewed the bioactive peptides or protein hydrolysates found in the plant, animal, marine, and dairy products, as well as their by-products. This review also emphasizes the health benefits, bioactivities, and utilization of active peptides obtained from the mentioned sources. Their possible application in functional product development, feed, wound healing, pharmaceutical and cosmetic industries, and their use as food additives have all been investigated alongside considerations on their safety.

Evaluation of anti-cancer and anti-covid-19 properties of cationic pentapeptide Glu-Gln-Arg-Pro-Arg, from rice bran protein and its d-isomer analogs through molecular docking simulations

Bioactive peptides derived from food proteins are becoming increasingly popular due to the growing awareness of their health-promoting properties. The structure and mechanism of anti-cancer action of pentapeptide Glu-Gln-Arg-Pro-Arg (EQRPR) derived from a rice bran protein are not known. Theoretical and experimental methods were employed to fill this gap. The conformation analysis of the EQRPR pentapeptide was performed first and the obtained lowest energy conformer was optimized. The experimental structural data obtained by FTIR and CD spectroscopies agree well with the theoretical results. d-isomer introduced one-by-one to each position and all D-isomers of the peptide were also examined for its possible anti-proteolytic and activity enhancement properties. The molecular docking revealed avid binding of the pentapeptide to the integrins α5β1 and αIIbβ3, with Kd values of 90 nM and 180 nM, respectively. Moreover, the EQRPR and its D-isomers showed strong binding affinities to apo- and holo-forms of Mpro, spike glycoprotein, ACE2, and dACE2. The predicted results indicate that the pentapeptide may significantly inhibit SARS-CoV-2 infection. Thus, the peptide has the potential to be the leading molecule in the drug discovery process as having multifunctional with diverse biological activities.

Role of bioactive peptides derived from food proteins in programmed cell death to treat inflammatory diseases and cancer

Bioactive peptides are specific peptide which usually contains 2-20 amino acid residues and actively exerts various functions and biological activities and ultimately affect health. Programmed cell deaths are some styles of cell death discovered in recent years, which is the key to tissue development and balance, eliminating excess, damaged or aging cells. More importantly, programmed cell death is a potential way to treat inflammatory diseases and cancer. In this review, through screening references from 2015 to present, we introduce the effect of bioactive peptides derived from food proteins on inflammatory diseases or cancer through regulating programmed cell deaths, including apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis. And this review also introduces the targets of these bioactive peptides to regulate programmed cell death. The purpose of this review is to help to expand the prospective applications of bioactive peptides in the field of inflammatory disease and cancer to provide some guidance.

A Review on Extraction, Characterization, and Applications of Bioactive Peptides From Pressed Black Cumin Seed Cake

Plenty of black cumin cake was generated as a natural waste material after pressing the oil. Nigella sativa (black cumin) seeds and cakes are of precious nutritional value as they contain proteins, phenolics, essential amino acids, and bioactive compounds. Owing to their antioxidant properties, scientists and food manufacturers have extensively developed them. Notably, global awareness among consumers about the benefits of innovative food ingredients has been increased. Meanwhile, it has to be noted that vast amounts of cake by-products are not effectively utilized, which might cause economic loss and environmental consequences. This review aimed to highlight the antioxidant abilities, extraction, characterization, functional characteristics, and utilization of active peptides acquired from black seed oil cake. This overview would critically evaluate black seed cake proteins, plentiful in bioactive peptides that might be utilized as valuable additives in feed, food, pharmaceutical, and cosmetic industries. The addition of bioactive peptides to restrain the oxidation of fat-based products and preserve food safety is also addressed.

Rice Bran By-Product: From Valorization Strategies to Nutritional Perspectives

The aim of this study is to review the innovative techniques based on bioprocessing, thermal or physical treatments which have been proposed during the last few decades to convert rice bran into a valuable food ingredient. Rice bran (Oryza sativa) is the main by-product of rice grain processing. It is produced in large quantities worldwide and it contains a high amount of valuable nutrients and bioactive compounds with significant health-related properties. Despite that, its application in food industry is still scarce because of its sensitivity to oxidation processes, instability and poor technological suitability. Furthermore, the health-related effects of pretreated rice bran are also presented in this review, considering the up-to-date literature focused on both in vivo and in vitro studies. Moreover, in relation to this aspect, a brief description of rice bran arabinoxylans is provided. Finally, the application of rice bran in the food industry and the main technology aspects are concisely summarized.