Potential of Food Hydrolyzed Proteins and Peptides to Chelate Iron or Calcium and Enhance their Absorption

Edible Insects versus Meat-Nutritional Comparison: Knowledge of Their Composition Is the Key to Good Health

Recently, attention has been drawn to the fact that increasing the consumption of edible insects may positively impact the state of the natural environment and reduce the problem of malnutrition in large parts of society. Indeed, insects are seen as an alternative to traditional meat products, primarily meat. This article aimed to compare the nutritional value of edible insects and meat. Based on tables of composition and nutritional value and on the licensed computer program Diet 6D, data on the nutritional value of 10 commonly consumed meat types were compiled. Based on a literature review, data on the nutritional value of seven commercially available edible insect species were collected and collated. There was a comparison of 100 g of edible insects with 100 g of meat (fresh weight). In addition, the atherogenic index thrombogenic index, the hypocholesterolemic/hypercholesterolemic ratio, and the nutritional quality index were calculated. It was found that both meat and insects are rich in nutrients, including those considered essential for the proper development and functioning of the human body. At the same time, it has been shown that the content of individual nutrients in both insects and meat varies significantly.

A Rational Approach for the Production of Highly Soluble and Functional Sunflower Protein Hydrolysates

Exploitation of plant proteins as an alternative to animal proteins currently presents an important challenge for food industries. In this contribution, total sunflower protein isolate from cold press meal was used as a starting material for the generation of highly soluble and functional hydrolysates that could be used in various food formulations. To do this, a rational and complete approach of controlled hydrolysis was implemented using the individual Alcalase and Prolyve enzymes. The method of stopping the hydrolysis reaction was also evaluated. The influence of operating conditions on hydrolysis kinetics and enzymatic mechanism was studied to identify the appropriate hydrolysis conditions. The gain of the solubility was then analyzed and compared to that of the initial proteins. Finally, the emulsifying and foaming properties (capacities and stabilities) of the resulting hydrolysates were also assessed. As a result, controlled enzymatic proteolysis significantly improved the sunflower protein solubility at neutral pH (twofold increase) and generated highly soluble hydrolysates. The limited proteolysis also maintained the good foam capacities and allowed an improvement in the initial foam stabilities and emulsifying capacities and stabilities of sunflower proteins. This contribution can greatly increase the value of sunflower meal and help in the development of sunflower protein products in the future.

Inhibition of low-density lipoprotein oxidation, antioxidative and bile acid-binding capacities of hydrolyzed proteins from carbohydrase-treated oat bran

This study investigated the valorization of oat bran and the use of its proteins to generate polypeptides with antioxidant and bile acid-binding properties. Ten protein hydrolysates were prepared by treating cellulase (CPI) or Viscozyme (VPI) protein isolates with five proteases. VPI-pepsin was the best peroxyl radical scavenger (497 ± 6-μM Trolox equivalents [TE]/g) while VPI-Flavourzyme quenched hydroxyl radicals (28 ± 0.6) and VPI-pepsin superoxide anion radicals (45.3 ± 6.6%). Hydrolysates, except those produced with pepsin, dose-dependently chelated iron whereas VPI-Protamex had the best copper-chelating capacity (59.83 ± 1.40%). These antioxidative capacities were important in preventing by 50% in vitro copper-induced oxidation of human low-density lipoprotein. Furthermore, due to their aromatic amino acid contents and hydrophobicity, the hydrolysates bound up to 46.3% the bile acids taurodeoxycholate and taurocholate. PRACTICAL APPLICATIONS: The presence of oxidants in foods can damage food molecules and decrease their quality. They are also known to increase the risk of developing chronic conditions like cardiovascular disease. Finding new antioxidant molecules are therefore useful in the management of chronic diseases. Data from this work showed that hydrolyzed oat bran proteins can be useful in stabilizing commercial oil as they reduced the oxidation of peanut oil. Additionally, the protein hydrolysates not only prevented the oxidation of linoleic, a common component of both vegetable oils and biological cell membranes, they also inhibited the oxidation of human LDL cholesterol and chelated bile acids. These hydrolysates can then be further explored as multifunctional ingredients for the development of stable functional food products with potential beneficial effects on the cardiovascular system.

Identification of zinc-binding peptides in ADAM17-inhibiting whey protein hydrolysates using IMAC-Zn2+ coupled with shotgun peptidomics

Abstract

Food components possessing zinc ligands can be used to inhibit zinc-dependent enzymes. In this study, zinc-binding peptides were derived from whey protein hydrolysates, and their ultrafiltration (> 1 and < 1 kDa) fractions, produced with Esperase (WPH-Esp), Everlase and Savinase. Immobilized metal affinity chromatography (IMAC-Zn2+) increased the zinc-binding capacity of the peptide fraction (83%) when compared to WPH-Esp (23%) and its < 1 kDa fraction (40%). The increased zinc-binding capacity of the sample increased the inhibitory activity against the zinc-dependent “a disintegrin and metalloproteinase 17”. LC-MS/MS analysis using a shotgun peptidomics approach resulted in the identification of 24 peptides originating from bovine β-lactoglobulin, α-lactalbumin, serum albumin, β-casein, κ-casein, osteopontin-k, and folate receptor-α in the fraction. The identified peptides contained different combinations of the strong zinc-binding group of residues, His+Cys, Asp+Glu and Phe+Tyr, although Cys residues were absent in the sequences. In silico predictions showed that the IMAC-Zn2+ peptides were non-toxins. However, the peptides possessed poor drug-like and pharmacokinetic properties; this was possibly due to their long chain lengths (5–19 residues). Taken together, this work provided an array of food peptide-based zinc ligands for further investigation of structure-function relationships and development of nutraceuticals against inflammatory and other zinc-related diseases.

Graphical abstract

Calcium-fortified foods in public health programs: considerations for implementation

Low calcium intake is common worldwide and can result in nutritional rickets in children and osteomalacia in adults. Calcium-fortified foods could improve calcium intake. However, there is limited calcium fortification experience, with technical and practical issues that may hamper its adoption. The objective of this landscape review is to summarize these issues to help policymakers guide the planning and design of calcium fortification as a public health strategy. One challenge is the low bioavailability of calcium salts (∼20-40%); thus, large amounts need to be added to food to have a meaningful impact. Solubility is important when fortifying liquids and acidic foods. Calcium salts could change the flavor, color, and appearance of the food and may account for 70-90% of the total fortification cost. Safety is key to avoid exceeding the recommended intake; so the amount of added calcium should be based on the target calcium intake and the gap between inadequate and adequate levels. Monitoring includes the quality of the fortified food and population calcium intake using dietary assessment methods. Calcium fortification should follow regulations, implemented in an intersectorial way, and be informed by the right to health and equity. This information may help guide and plan this public health strategy.

Metabolomics approach based on LC-HRMS for the fast screening of iron(II)-chelating peptides in protein hydrolysates

Production of iron-chelating peptides from protein hydrolysates requires robust and adequate screening methods to optimize their purification and subsequently valorize their potential antioxidant properties. An original methodology was developed for direct and sensitive screening of iron(II)-chelating peptides based on ion-pair reverse phase liquid chromatography (IP-RPLC) coupled to high-resolution mass spectrometry (HRMS). Peptide mixture was first added to iron(II) solution to form iron(II)-peptide complexes. Then IP-RPLC-HRMS analysis was conducted on this iron-peptide mixture and on the iron-free peptide solution for comparative mass spectra analysis. This protocol, initially applied to a range of low molecular weight standard peptides, allowed detection of [(Peptide-H)+⁵⁶Fe^II]⁺ complex ion for iron(II)-chelating peptides (GGH, EAH, DAH, βAH, DMH, DTH, DSH). GGH was added in complex peptide mixtures and targeted analysis of [(GGH-H)+⁵⁶Fe^II]⁺ complex showed a limit of detection (LOD) below 0.77 mg L^-1 of GGH. This protocol was finally tested in combination with metabolomics software and additional digital processing for non-targeted search for iron(II)-chelating peptides. Applicability of this new screening methodology has been validated by detection of GGH as iron(II)-chelating peptide when added at 0.77 mg L^-1 in casein hydrolysate. Graphical abstract.

Electrochemical device based on nonspecific DNAzyme for the high-accuracy determination of Ca2+ with Pb2+ interference

Calcium is one of the most abundant and indispensable elements in biology, as it is a vital component of nerves, bones, and muscles and maintains the excitability of normal neuromuscular muscles. However, it may be harmful to the human body and even damage the organs if the calcium content exceeds the standard value by several times. To evaluate the level of calcium ions (Ca²⁺), an electrochemical biosensor (FET/SWNTs/Cazyme) was developed using a nonspecific DNAzyme with high stability, which combined the unique advantage of field-effect transistors and single-walled carbon nanotubes, while being easy-to-use and having excellent sensitivity. The incubation time and voltage after optimization were 15 min and +0.02 V. The nonspecific DNAzyme-based biosensor was sensitive to Ca²⁺, but it was also interfered with by Pb²⁺, which affected the detection accuracy. To solve this shortcoming, an electrochemical device was proposed, in which FET/SWNTs/Cazyme combined with other specific biosensors for Pb²⁺, and then established some data processing models were established through support vector machine regression (SVMR) and artificial neural network fitting (ANNF). For the optimal SVMR, the electrochemical device can determine the Ca²⁺ concentration in the range of 7.5-1000 μM with a detection limit of 5.48 μM. Finally, the prepared electrochemical device was employed to detect the Ca²⁺ in different milk and water samples.

Iron-caseinglycomacropeptide complexes: Characterization and application in beverages

Complexing iron with organic compounds has been considered an alternative strategy to mitigate the problems associated with the level of bioavailable iron and the acceptability of products supplemented with this mineral. CMP contains specific amino acids associated with iron binding. The present study aims to optimize the conditions of Fe/CMP complex formation and understand the molecular basis of interactions between CMP and iron ions. Results showed that CMP can bind ferrous iron in a 1:1.5 M ratio, forming a stable peptide-iron complex, where CMP assembles in a tetrameric form. FTIR spectra indicated that iron binding altered the secondary structures of CMP. The iron-binding sites of CMP corresponded primarily to acid residues of Glu, Asp and sialic acid. Moreover, Fe/CMP complex remained stable in a wide pH range (2.0-6.5), suggesting the adequacy to be efficiently added in food or beverages and to keeping complexed in the digestion environment. Finally, Fe/CMP complex was added to a commercial beverage (2 mg of Fe per serving of beverage) and no changes were observed in their colour during storage. A model to explain the binding between CMP and iron is proposed. These results suggest a potential application of this peptide for iron fortification.

Herring egg phosphopeptides as calcium carriers for improving calcium absorption and bone microarchitecture in vivo

Phosphorylation may enhance the functional properties of proteins/peptides. Herring egg phosphopeptides (HEPPs) have been found to be more effective than the non-phosphorylated variant in calcium-binding activities due to the introduced phosphate groups. However, whether HEPPs as calcium carriers will be superior to herring egg peptides (HEPs) in improving calcium bioavailability in vivo, for the equivalent calcium intake prerequisite, remains to be clarified. This study aimed to evaluate the effect of HEPPs-calcium complex and HEPs-calcium complex on calcium absorption and bioavailability in calcium-deficient mice. Results showed that the remarkably lower calcium absorption and bone calcium deposition induced by long-term calcium deficiency were accompanied by deterioration of the trabecular bone microarchitecture (P < 0.05). The HEPPs-Ca supplements significantly improved the apparent calcium absorption, increased the serum calcium level, decreased the alkaline phosphatase activity, strengthened the bone biomechanical property, and increased bone volume/tissue volume (BV/TV) and trabecular number (Tb·N) in calcium-deficient mice (P < 0.05), as determined by micro-computed tomography (micro-CT) assay. The effect of HEPPs-Ca on calcium absorption and bioavailability was comparable to that of CPPs-Ca, but better than that of HEPs-Ca and CaCO₃. This study brings new insights into the potential of HEPPs as an alternative to CPPs for use in calcium supplements.

Opportunities for plant-derived enhancers for iron, zinc, and calcium bioavailability: A review

Understanding of the mechanism of interactions between dietary elements, their salts, and complexing/binding ligands is vital to manage both deficiency and toxicity associated with essential element bioavailability. Numerous mineral ligands are found in both animal and plant foods and are known to exert bioactivity via element chelation resulting in modulation of antioxidant capacity or micobiome metabolism among other physiological outcomes. However, little is explored in the context of dietary mineral ligands and element bioavailability enhancement, particularly with respect to ligands from plant-derived food sources. This review highlights a novel perspective to consider various plant macro/micronutrients as prospective bioavailability enhancing ligands of three essential elements (Fe, Zn, and Ca). We also delineate the molecular mechanisms of the ligand-binding interactions underlying mineral bioaccessibility at the luminal level. We conclude that despite current understandings of some of the structure-activity relationships associated with strong mineral-ligand binding, the physiological links between ligands as element carriers and uptake at targeted sites throughout the gastrointestinal (GI) tract still require more research. The binding behavior of potential ligands in the human diet should be further elucidated and validated using pharmacokinetic approaches and GI models.

Revisiting phytate-element interactions: implications for iron, zinc and calcium bioavailability, with emphasis on legumes

Myo-Inositol hexakisphosphate or phytic acid concentration is a prominent factor known to impede divalent element bioavailability in vegetal foods including legumes. Both in vivo and in vitro studies have suggested that phytic acid and other plant-based constituents may synergistically form insoluble complexes affecting bioavailability of essential elements. This review provides an overview of existing investigations on the role of phytic acid in the binding, solubility and bioavailability of iron, zinc and calcium with a focus on legumes. Given the presence of various interference factors within legume matrices, current findings suggest that the commonly adapted approach of using phytic acid-element molar ratios as a bioavailability predictor may only be valid in limited circumstances. In particular, differences between protein properties and molar concentrations of other interacting ions are likely responsible for the observed poor correlations. The role of phytate degradation in element bioavailability has been previously examined, and in this review we re-emphasize its importance as a tool to enhance mineral bioavailability of mineral fortified legume crops. Food processing strategies to achieve phytate reduction were identified as promising tools to increase mineral bioavailability and included germination and fermentation, particularly when other bioavailability promoters (e.g. NaCl) are simultaneously added.

Food-derived antioxidants and COVID-19

SARS-CoV-2 (previously 2019-nCoV), the pathogenic agent of COVID-19 disease, started to expand from Wuhan, China, on December 2019 and in 2 months, it spread worldwide giving origin to a pandemic. COVID-19 has a stronger transmission capacity by inhalation of infectious aerosols and after an incubation time of 3-14 days, it may be responsible for diseases ranging from the asymptomatic to fatal consequences. COVID-19 has emerged as a multifaceted, multisystem, multi-organ disorder, which produces its pathogenic effects through a quite ubiquitous target at the level of multiple organs and in which oxidative stress and inflammatory process play relevant roles. Thus, besides the development of a pharmacological therapy, in the field of alternative and coadjutant therapeutic, the use of dietary supplements or nutraceuticals for the prevention or treatment of SARS-CoV-2 infection may be a useful strategy. Herein, we specifically comment on some literature evidences, which link the food-derived antioxidants and metal-chelating agents with treatment and prevention of oxidative stress and inflammation that play a key role in the progression of COVID-19. PRACTICAL APPLICATIONS: Oxidative stress and inflammation are key factors increasing COVID-19 severity especially in the presence of chronic diseases associated with the antioxidant system fragility. These evidences support the recommendation of antioxidants supplementation as useful strategies against COVID-19. In light with these observations, herein, a comment which describes the major antioxidants and metal-chelating agents from food sources that might be useful for the treatment and prevention of oxidative stress and inflammation during COVID-19.

Investigating the calcium binding characteristics of black bean protein hydrolysate

The black bean protein has been widely utilized to prepare hydrolysates with different bioactive properties. Herein, we hydrolyzed the black bean protein to prepare hydrolysate with calcium binding activity and characterized its behavior. Our results showed that ficin was superior in obtaining hydrolysate with calcium binding capacity in comparison with trypsin, alcalase and bromelain. In particular, the optimal capacity of ficin hydrolysate reached 77.54 ± 1.61 μg mg-1, where the optimal hydrolysis conditions of ficin were a temperature of 70 °C, a pH value of 6.2, an enzyme concentration of 1.61% and a time of 3 h. This might be due to high proportions of aspartic acid and glutamic acid (35.59%). Further spectral analysis evidenced the formation of hydrolysate-calcium complexes, demonstrating that the interaction between hydrolysate and calcium ions primarily occur on carboxyl oxygen atoms and amino nitrogen atoms. These findings provide a possible utilization of black bean hydrolysate to serve as a calcium supplement nutraceutical to enhance the absorption and bioavailability.

Dietary green tea powder supplementation enriched egg nutrients and physicochemical property in an indigenous chicken breed

Dietary supplementation of green tea changes the antioxidative capacity of chickens. However, the effect of green tea supplementation in the diet on egg quality and the consequent change in processing capacity is still not well known. The aim of this study was to determine whether green tea powder (GTP) supplementation could affect egg quality, egg antioxidant capacity, and sensory and egg processing characteristics. Huainan partridge chickens (1,080) at 20 wk old were divided into 2 groups, one group fed a basal diet (control) and one group fed a basal diet plus 10 g kgˆ-1 GTP for 12 wk. After the levels of yolk cholesterol had been determined, chickens from the control group were further divided into low- and high-cholesterol groups and were fed a basal diet or a diet with 10 g kgˆ-1 GTP by orthogonal design. After 4 wk, the egg processing characteristics were investigated. Egg specific gravity, shell strength, shell thickness, albumin height, Haugh unit (HU) and cholesterol content were significantly lower in the GTP group than in the control group (P < 0.05). Egg weight, albumin height, yolk color, and HU increased in a time-dependent manner in both the control and GTP groups (P < 0.01). The yolk C16:0, C20:0, C18:1, C18:2, and polyunsaturated fatty acid (PUFA) contents were higher in the GTP group than in the control group (P < 0.05). Egg whites from the GTP group showed increased radical scavenging activity (P < 0.05). Egg appearance and texture from the GTP group were more preferred than those of the control group (P < 0.05). Eggs from the GTP group had lower hardness, chewiness, and water retention capacity than those of eggs from the control group (P < 0.05). Eggs from the GTP group with high yolk cholesterol showed lower chewiness than those from the basal diet group (P < 0.05). The results suggested that GTP supplementation could enrich the PUFA content in egg yolks, improve the overall taste, and change processing characteristics.

Peptide-Mineral Complexes: Understanding Their Chemical Interactions, Bioavailability, and Potential Application in Mitigating Micronutrient Deficiency

Iron, zinc, and calcium are essential micronutrients that play vital biological roles to maintain human health. Thus, their deficiencies are a public health concern worldwide. Mitigation of these deficiencies involves micronutrient fortification of staple foods, a strategy that can alter the physical and sensory properties of foods. Peptide-mineral complexes have been identified as promising alternatives for mineral-fortified functional foods or mineral supplements. This review outlines some of the methods used in the determination of the mineral chelating activities of food protein-derived peptides and the approaches for the preparation, purification and identification of mineral-binding peptides. The structure-activity relationship of mineral-binding peptides and the potential use of peptide-mineral complexes as functional food ingredients to mitigate micronutrient deficiency are discussed in relation to their chemical interactions, solubility, gastrointestinal digestion, absorption, and bioavailability. Finally, insights on the current challenges and future research directions in this area are provided.

Bioactive peptides derived from plant origin by-products: Biological activities and techno-functional utilizations in food developments - A review

Agro-industrial by-products containing considerable amounts of protein (10-50%) such as soybean meal, rice bran and coconut pulp are promising bioactive peptide sources with annual disposal rate of 800 million tons in the world. More recently, plant by-products rich in protein content have been studied under various prisms that include recovery techniques, peptide production methods, determination of technological benefits and functional properties, and their applications in foods. The researches in bioactive peptides provide evidence over the techno-functional properties and the health benefits are highly dependent upon their amino acid sequences, molecular weights, conformations and surface properties. Research findings compared bioactive properties of the obtained peptides with respect to their amino acid sequences and also reported that hydrophobic/hydrophilic properties have direct effect on both functional and health effects. In addition, the resultant properties of the peptides could be affected by the conducted extraction method (alkaline, enzymatic, ultrasound assisted, microwave assisted, etc.), extraction solvent, precipitation and purification techniques and even by the final drying process (spray, freeze, vacuum, etc.) which may alter molecular weights, conformations and surface properties. Latest studies have investigated solubility, emulsifying, foaming, water/oil holding capacity and surface properties and also antioxidant, antimicrobial, anticarcinogenic, hypocholesterolemic, antihypertensive, immunomodulatory and opioid activities of bioactive peptides obtained from plant by-products. Moreover, the application of the bioactive peptides into different food formulations has been a recent trend of functional food development. These bioactive peptides' bitter taste and toxicity are possible challenges in some cases that need to be resolved before their wider utilization.

Assessment of Techno-Functional and Nutraceutical Potential of Tomato (Solanum lycopersicum) Seed Meal

Tomato (Solanum lycopersicum) is a widely consumed fruit all around the world. The industrial exploitation of tomato generates a lot of waste. Most of the utilization of tomato seeds waste is focused on animal feeding, as well as a food ingredient aimed to increase the protein content, and raw material for some organic bioactive component extraction. The aim of this work was to evaluate the techno-functional properties of tomato seed meal (TSM) and its nutraceutical properties after applying defatting processing (TSMD), and to evaluate the nutraceutical properties after a fermentation processing (TSMDF) by Lactobacillus sp. The results showed that, at alkaline conditions (pH 8-9), the techno-functional properties for TSM and TSMD improved. In comparison with TSM, TSMD showed higher water holding capacity (WHC ≈32%), higher oil holding capacity (OHC ≈13%), higher protein solubility (49-58%), more than 10 times foaming activity (FA), more than 50 times foam stability (Fst), as well as an improved emulsifying activity (EA) and emulsion stability (Est) wich were better at pH 9. Regarding the nutraceutical properties, after 48 h of fermentation (TSMDF), the antioxidant activity was doubled and a significant increase in the iron chelating activity was also observed. During the same fermentation time, the highest angiotensin-converting enzyme inhibition (ACEI) was achieved (IC50 73.6 μg/mL), more than 10 times higher than TSMD, which leads to suggest that this fermented medium may be a powerful antihypertensive. Therefore, the strategy proposed in this study could be an option for the exploitation of tomato wastes.

Peptide-metal complexes: obtention and role in increasing bioavailability and decreasing the pro-oxidant effect of minerals

Bioactive peptides derived from food protein sources have been widely studied in the last years, and scientific researchers have been proving their role in human health, beyond their nutritional value. Several bioactivities have been attributed to these peptides, such as immunomodulatory, antimicrobial, antioxidant, antihypertensive, and opioid. Among them, metal-binding capacity has gained prominence. Mineral chelating peptides have shown potential to be applied in food products so as to decrease mineral deficiencies since peptide-metal complexes could enhance their bioavailability. Furthermore, many studies have been investigating their potential to decrease the Fe pro-oxidant effect by forming a stable structure with the metal and avoiding its interaction with other food constituents. These complexes can be formed during gastrointestinal digestion or can be synthesized prior to intake, with the aim to protect the mineral through the gastrointestinal tract. This review addresses: (i) the amino acid residues for metal-binding peptides and their main protein sources, (ii) peptide-metal complexation prior to or during gastrointestinal digestion, (iii) the function of metal (especially Fe, Ca, and Zn)-binding peptides on the metal bioavailability and (iv) their reactivity and possible pro-oxidant and side effects.

Assessment of chemical, biological and immunological properties of "Damiana de California" Turnera diffusa Willd extracts in Longfin yellowtail (Seriola rivoliana) leukocytes

In Mexican herbal medicines or natural remedies, Turnera diffusa (Turneraceae) known as "Damiana de California", has ethnopharmacological relevance, including aphrodisiac, diuretic, and antimicrobial activities. To explore the immunological effect of infusion and methanolic extracts from Damiana de California, this study investigated its chemical, biological, antimicrobial and immunological properties in Longfin yellowtail Seriola rivoliana leukocytes. The analysis of chemical compounds revealed a considerable level of total phenolic and flavonoid contents in the infusion compared with methanolic extract. Furthermore, the antioxidant activity showed high hydroxyl radical scavenging activity in infusion extract compared with BHT positive control. Superoxide radical scavenging activity and ion chelation were higher in methanolic extract followed by infusion treatment. Interestingly, notable antimicrobial activity was observed in both extracts of T. diffusa against Vibrio parahaemolyticus. An in vitro study was performed using leukocytes of S. rivoliana treated with infusion or methanolic extracts at 12.5, 25 and 50 μg/mL for 24 h. Remarkably, infusion extract induced proliferation at any concentration but not the methanolic extract, which was diminished in a dose-dependent fashion. The immunostimulation study demonstrated that the phagocytosis activity increased in those leukocytes stimulated with methanolic extract but diminished the respiratory burst activity, in contrast to the activity observed in those leukocytes stimulated with infusion treatment. Finally, leukocytes incubated with the extracts and confronted with V.parahaemolyticus up-regulated the transcription of proinflammatory cytokine IL-1β gene in a dose response relationship. These findings suggest that the infusion treatment has potential therapeutic properties, promoting the antioxidant capacity and enhancing immune parameters in Longfin yellowtail S. rivoliana.

Chromium and arsenic speciation analysis in meats by HPLC-ICP-MS in the presence of hydrolyzed oat proteins with radical scavenging activities

Transition metals play an important role in a wide variety of biological processes, but their functions are dependent on the quantity and the type of species present. Specific forms of arsenic (As) and chromium (Cr) are associated with oxidative stress, cellular damage and inflammation. The aim of this research was to test in a food system whether, in the presence of hydrolyzed oat proteins, arsenic or chromium will exist predominantly in a specific oxidative state, and to evaluate the potential implication of promoting or decreasing oxidative stress. Eight hydrolyzed proteins with different degrees of radical scavenging activities were produced by combining two extraction methods and four proteases. The addition of hydrolysates to ground chicken meat decreased lipid hydroperoxides by up to 50% when stored at 4 °C but had no effect at -20 °C. The ratio of pentavalent arsenic (As(V)) to arsenobetaine (AsB) in meat was about 2:1 but in the presence of the hydrolysates, meanwhile, the amount of AsB detected was 3-fold higher depending on the storage condition. This was due to better extraction of AsB in the presence of hydrolysates rather than to the conversion of other species. Data on chromium showed that Cr(VI) contents decreased from 14.3 ± 0.1 to 6.3 ± 0.5 μg/g while concentrations of Cr(III) increased from 2.8 ± 0. 2 to 8.6 ± 0.7 μg/g. In summary, the addition of hydrolyzed oat proteins to chicken meat enhanced the extraction of AsB, and had little effect on arsenic speciation during storage meanwhile, there was a reduction of Cr(VI) to Cr(III) which was in part due to the relative content of thiol groups. Additionally, there was a reduction of lipid oxidation in meats that contained the oat protein hydrolysates.

Bioactive Peptides from Walnut Residue Protein

Walnut residue is a kind of high-quality plant protein resource. The bioactive peptide prepared from walnut residue has excellent health care functions such as antioxidation and antihypertensive activity, but at present, walnut residue is often regarded as waste or low value feed, fertilizer and other materials. The uneconomical use of walnut residue has hindered the development of the walnut industry to some extent. Effective utilization of walnut residue protein to develop bioactive peptides and other products is of great significance to realize the comprehensive utilization of walnut residue, improve the added value of by-products, and change the current low utilization rate of walnut residue. In this paper, the preparation, purification and structure identification of walnut protein bioactive peptides are reviewed, and different functional walnut active peptides (WBPs) are introduced. The potential effects of these bioactivities on human health and their different uses in food, medicine and other industries are discussed. The purpose is to provide reference information for the effective utilization of walnut residue resources and the development of walnut industry.

Prevention of Zinc Precipitation with Calcium Phosphate by Casein Hydrolysate Improves Zinc Absorption in Mouse Small Intestine ex Vivo via a Nanoparticle-Mediated Mechanism

Casein phosphopeptides are known to enhance zinc absorption, but the underlying mechanism remains unclear. Here, a gastrointestinal casein hydrolysate (CH) was found to keep zinc in solution despite heavy precipitation of calcium and phosphate, the omnipresent mineral nutrients that could co-precipitate zinc out of solution instantly and almost completely under physiologically relevant conditions. Dynamic light scattering, transmission electron microscopy, and energy-dispersive X-ray analysis displayed the CH-mediated formation of zinc/calcium phosphate (Zn/CaP) nanocomplexes aggregated from rather small nanoclusters. The ex vivo mouse ileal loop experiments revealed enhanced intestinal zinc absorption by CH's prevention of zinc co-precipitation with CaP, and the treatments with specific inhibitors unveiled the involvement of macropinocytic internalization, lysosomal degradation, and transcytosis in the intestinal uptake of zinc from Zn/CaP nanocomplexes. A low calcium-to-phosphorus ratio adversely affected CH's efficiency to enhance zinc solubility and absorption. Overall, our study provides a new paradigm for casein phosphopeptides to improve zinc bioavailability.

The development of lentil derived protein–iron complexes and their effects on iron deficiency anemia in vitro

Lentil derived proteins have the capacity to chelate iron minerals and hydrolysed protein–iron complexes have functional properties on iron deficiency anemia in in vitro by influencing mRNA levels of iron regulating genes.

A new nutraceutical resource from a rare native plant growing in Turkey and for its spectro-chemical and biological insights: Endemic Diplotaenia bingolensis (Apiaceae)

The present study designed to investigate the quantitative distributions in the secondary metabolites and biological activity of sub-fractions obtained successively from water and methanol: dichloromethane (rate 1:1; v:v) solvent decoction of Diplotenia bingolensis aerial parts. The crude extracts were obtained from the aerial parts of the endemic D. bingolensis species refluxing with water and organic solvents. Sub-fractions of water extract were obtained by successive fractionation of the water extract with hexane (WH), dichloromethane (WD), ethyl acetate (WE) and n-butanol (WB), respectively. Sub-fractions of organic solvent were obtained by fractionation of the organic crude extract with hexane (OH), dichloromethane (OD), ethyl acetate (OE), n-butanol (OB) and water (OW), respectively. The total amount of phenols and flavonoids contained in each sub-fraction was analyzed by UV-VIS spectrophotometer, analysis of lipophilic components by GC-MS spectrometer, and quantitative analysis of hydrophilic components by HPLC-TOF/MS spectrophotometer. Furthermore, the biological activity of each sub-fraction was compared with different antioxidant activities such as DPPH radical scavenging activity and ferric ion reduction capacity. Sub-fraction WD (137.1 ± 2.1 μg QE/mg DI) and OE (127.1 ± 5.2 μg QE/mg DI) in terms of flavonoid content, sub-fraction WD (665.8 ± 47.6 μg GAE/mg DI) and OE (724.6 ± 43.6 μg GAE/mg DI) were the richest isolates in terms of total phenol content. Sub-fractions OH and OD contained linoleic acid (17.0 and 11.0%, respectively) and linolenic acid (22.1 and 18.5%, respectively). It was revealed that sub-fractions were rich in terms of rutin (1.2-47.2 μg HC/mg DI) and chlorogenic acid (0.1-12.1 μg HC/mg DI). Sub-fractions WD and OE were showed the highest DPPH radical scavenging activity with 46.4 ± 1.4 and 47.6 ± 10.0 μg/mL EC₅₀ values, respectively. This study is the first to demonstrate biological insight of the potential antioxidant activity of D. bingolensis. These findings warrant the popular use of the endemic D. bingolensis and highlight the potential of its active constituents in the development of new antioxidative drugs.

Protective effect of a 3 kDa peptide obtained from beef myofibrillar protein using alkaline-AK on neuronal cells

The protective effect of two 3 kDa peptide fractions (AK3KF1 and AK3KF2), obtained from beef myofibrillar protein using an inexpensive enzyme (alkaline-AK) on human neuronal cells (SH-SY5Y) against H₂O₂-induced apoptosis was investigated. These peptides were isolated and further separated by fast protein liquid chromatography (FPLC), and their protective effect against H₂O₂-mediated cell death was measured by determining cell viability, nitric oxide (NO) production, mitochondrial membrane potential (MMP), apoptosis, morphological changes in cell nuclei, and in vitro antioxidant assays. The results indicated that treatment with peptide fractions increased cell viability and MMP, and decreased NO production, fragmentation of cell nuclei, and apoptosis in H₂O₂-treated SH-SY5Y cells. This is the first study to report neuroprotective effects of a peptide obtained from beef myofibrillar protein. The peptide sequence was identified as Thr-Gln-Lys-Lys-Val-Ile-Phe-Cys (TQKKVIFC). Thus, these findings suggest that TQKKVIFC can prevent neuronal cell death and could be useful in preventing neurodegenerative diseases.

Antioxidant and Anti-Apoptotic Properties of Oat Bran Protein Hydrolysates in Stressed Hepatic Cells

The objective of this work was to find out how the method to extract proteins and subsequent enzymatic hydrolysis affect the ability of hepatic cells to resist oxidative stress. Proteins were isolated from oat brans in the presence of Cellulase (CPI) or Viscozyme (VPI). Four protein hydrolysates were produced from CPI and four others from VPI when they treated with Alcalase, Flavourzyme, Papain, or Protamex. Apart from CPI-Papain that reduced the viability of cell by 20%, no other hydrolysate was cytotoxic in the hepatic HepG2 cells. In the cytoprotection test, VPI-Papain and VPI-Flavourzyme fully prevented the damage due to peroxyl radical while CPI-Papain and CPI-Alcalase enhanced the cellular damage. Cells treated with VPI-hydrolysates reduced intracellular reactive oxygen species (ROS) by 20-40% and, also increased the intracellular concentration of glutathione, compared to CPI-hydrolysates. In antioxidant enzyme assays, although all hydrolysates enhanced the activity of both superoxide dismutase and catalase by up to 2- and 3.4-fold, respectively relative the control cells, the largest increase was due to VPI-Papain and VPI-Flavourzyme hydrolysates. In caspase-3 assays, hydrolysates with reduced ROS or enhanced antioxidant enzyme activities were able to reduce the activity of the pro-apoptotic enzyme, caspase-3 indicating that they prevented oxidative stress-induced cell death.

Antioxidant properties and potential mechanisms of hydrolyzed proteins and peptides from cereals

Cereals like wheat, rice, corn, barley, rye, oat, and millet are staple foods in many regions around the world and contribute to more than half of human energy requirements. Scientific publications contain evidence showing that apart from energy, the regular consumption of whole grains is useful for the prevention of many chronic diseases associated with oxidative stress. Biological activities have mostly been attributed to the presence of glucans and polyphenols. In recent years however, food proteins have been investigated as sources of peptides that can exert biological functions, promote health and prevent oxidative stress. This review focuses on the role of hydrolyzed proteins and peptides with antioxidant properties in various models and their mechanisms which include hydrogen or electron transfer, metal chelating, and regulation of enzymes involved in the oxidation-reduction process.

Aptamers: an emerging class of bioaffinity ligands in bioactive peptide applications

The food and health applications of bioactive peptides have grown remarkably in the past few decades. Current elucidations have shown that bioactive peptides have unique structural arrangement of amino acids, conferring distinct functionalities, and molecular affinity characteristics. However, whereas interest in the biological potency of bioactive peptides has grown, cost-effective techniques for monitoring the structural changes in these peptides and how these changes affect the biological properties have not grown at the same rate. Due to the high binding affinity of aptamers for other biomolecules, they have a huge potential for use in tracking the structural, conformational, and compositional changes in bioactive peptides. This review provides an overview of bioactive peptides and their essential structure-activity relationship. The review further highlights on the types and methods of synthesis of aptamers before the discussion of the prospects, merits, and challenges in the use of aptamers for bioaffinity interactions with bioactive peptides.

Isolation and identification of iron-chelating peptides from casein hydrolysates

Iron deficiency is a common nutritional disorder worldwide.