Antioxidant status, lipid and color stability of aged beef from grazing steers supplemented with corn grain and increasing levels of flaxseed

Isolation and antioxidant activity of peptides from Chinese hairy tofu

Hairy tofu is a famous Chinese snack that is made from soybeans and rich in various nutrients. In order to further explore the antioxidant peptides of hairy tofu hydrolysates, seven proteases were used to hydrolyze hairy tofu. The results of in vitro radical scavenging activity showed that hairy tofu hydrolysates obtained by pancreatin exhibited the highest antioxidant activity. After Sephadex G-25 gel filtration and reversed-phase high-performance liquid chromatography (RP-HPLC), 97 peptides were identified in the most antioxidant fraction using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Among them, nine peptides were synthesized and their antioxidant activities were assessed using a H2O2-induced oxidative 293T cell model. Finally, four peptides (QCESHK, LAWNEGR, NLQGENEWDQK, and FTEMWR) at concentrations of < 50 μg/ml significantly decreased the malondialdehyde content compared with the model group, displaying in vivo antioxidant activity and low cytotoxicity. Overall, this research provided the choice of using hairy tofu peptides as antioxidant products in the pharmaceutical and food industries.

Bioactive peptides in dry-cured ham: A comprehensive review of preparation methods, metabolic stability, safety, health benefits, and regulatory frameworks

Dry-cured hams contain abundant bioactive peptides with significant potential for the development of functional foods. However, the limited bioavailability of food-derived bioactive peptides has hindered their utilization in health food development. Moreover, there is insufficient regulatory information regarding bioactive peptides and related products globally. This review summarizes diverse bioactive peptides derived from dry-cured ham and by-products originating from various countries and regions. The bioactivity, preparation techniques, bioavailability, and metabolic stability of these bioactive peptides are described, as well as the legal and regulatory frameworks in various countries. The primary objectives of this review are to dig deeper into the functionality of dry-cured ham and provide theoretical support for the commercialization of bioactive peptides from food sources, especially the dry-cured ham.

Antioxidant peptides, the guardian of life from oxidative stress

Reactive oxygen species (ROS) are produced during oxidative metabolism in aerobic organisms. Under normal conditions, ROS production and elimination are in a relatively balanced state. However, under internal or external environmental stress, such as high glucose levels or UV radiation, ROS production can increase significantly, leading to oxidative stress. Excess ROS production not only damages biomolecules but is also closely associated with the pathogenesis of many diseases, such as skin photoaging, diabetes, and cancer. Antioxidant peptides (AOPs) are naturally occurring or artificially designed peptides that can reduce the levels of ROS and other pro-oxidants, thus showing great potential in the treatment of oxidative stress-related diseases. In this review, we discussed ROS production and its role in inducing oxidative stress-related diseases in humans. Additionally, we discussed the sources, mechanism of action, and evaluation methods of AOPs and provided directions for future studies on AOPs.

Preparation, Characterization, and Antioxidant Properties of Selenium-Enriched Tea Peptides

The research on the activity of selenium (Se)-enriched agricultural products is receiving increasing attention since Se was recognized for its antioxidant activities and for its enhancement of immunity in trace elements. In this study, antioxidant Se-containing peptides, namely, Se-TAPepI-1 and Se-TAPepI-2, were optimally separated and prepared from Se-enriched tea protein hydrolysates by ultrafiltration and Sephadex G-25 purification, and subsequently, their physicochemical properties, oligopeptide sequence, and potential antioxidant mechanism were analyzed. Through the optimization of enzymatic hydrolysis conditions, the Se-enriched tea protein hydrolyzed by papain exhibited a better free radical scavenging activity. After separation and purification of hydrolysates, the two peptide fractions obtained showed significant differences in selenium content, amino acid composition, apparent morphology, peptide sequence, and free radical scavenging activity. Therein, two peptides from Se-TAPepI-1 included LPMFG (563.27 Da) and YPQSFIR (909.47 Da), and three peptides from Se-TAPepI-2 included GVNVPYK (775.42 Da), KGGPGG (552.24 Da), and GDEPPIVK (853.45 Da). Se-TAPepI-1 and Se-TAPepI-2 could ameliorate the cell peroxidation damage and inflammation by regulating NRF2/ARE pathway expression. Comparably, Se-TAPepI-1 showed a better regulatory effect than Se-TAPepI-2 due to their higher Se content, typical amino acid composition and sequence, higher surface roughness, and a looser arrangement in their apparent morphology. These results expanded the functional activities of tea peptide and provided the theoretical basis for the development of Se-containing peptides from Se-enriched tea as a potential natural source of antioxidant dietary supplements.

Aging mechanism for improving the tenderness and taste characteristics of meat

Tenderness and taste characteristics of meat are the key determinants of the meat choices of consumers. This review summarizes the contemporary research on the molecular mechanisms by which postmortem aging of meat improves the tenderness and taste characteristics. The fundamental mechanism by which postmortem aging improves the tenderness of meat involves the operation of the calpain system due to apoptosis, resulting in proteolytic enzyme-induced degradation of cytoskeletal myofibrillar proteins. The improvement of taste characteristics by postmortem aging is mainly explained by the increase in the content of taste-related peptides, free amino acids, and nucleotides produced by increased hydrolysis activity. This review improves our understanding of the published research on tenderness and taste characteristics of meat and provides insights to improve these attributes of meat through postmortem aging.

Animal performance and meat quality characteristics from feedlot-finished steers fed increasing levels of wet distillers grain

One hundred forty-four steers were group-housed in 24 pens that were randomly assigned to one of four dietary treatments defined by the proportion of wet distiller grain plus solubles (WDGS; 0, 15, 30, or 45%) and fed for 84 d pre-slaughter. Animal performance was evaluated using the pen as the experimental unit. Whereas for carcass and meat quality characteristics, meat oxidative stability, and the consumer sensory quality of longissimus thoracis muscle one animal from each pen was randomly selected and used as the experimental unit. No differences (P > 0.05) were observed for subcutaneous fat thickness, rib eye area, marbling score or pH, color parameters, proximate composition, sarcomere length, Warner Bratzler shear force, and cooking loss. Feeding WDGS linearly increased total PUFA (P = 0.05), C18:2 n-6 (P = 0.004) proportions, and n-6/n-3 ratio (P < 0.01) but reduced C16:1 to C18:0 ratio (P < 0.01). Lipid oxidation was greater in beef from steers fed 30% and 45% WDGS (P = 0.05). Dietary WDGS linearly improved (P < 0.05) flavor and overall linking score in the consumer sensory panel.

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.

Transepithelial transport and cytoprotection of novel antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham

As a traditional fermented meat product, dry-cured Xuanwei ham could be a rich source of bioactive peptides. This study intended to investigate the transepithelial transport and cytoprotection of antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham. Through ultrafiltration and gel filtration chromatography after simulated digestion, five new antioxidative cell-penetrating peptides (CPPs) with 16-27 amino acid residues were identified, and protective effects of the pretreatment with GHYTEGAELVDSVLDVVRK (GK-19) and TDEFQLHTNVNDGTEFGGSIYQK (TK-23) on H₂O₂-induced damaged HepG2 cells were investigated. The results showed that the peptide TK-23 at 0.5 mg mL^-1 showed a good antioxidant activity through upregulating the activity of antioxidant enzymes (CAT, SOD and GR) and decreasing the MDA level in H₂O₂-induced damaged HepG2 cells with a better protective effect compared to GSH. Our observations of novel antioxidant CPPs with 16-27 amino acid residues could enrich the antioxidative CPP database, and these findings could provide data support for further study of CPPs.

A Review on Edible Fungi-Derived Bioactive Peptides: Preparation, Purification and Bioactivities

Edible fungi bioactive peptides (BAPs) are extracted from fruiting bodies and the mycelium of edible fungus. They have various physiological functions such as antioxidant activity, antihypertensive activity, and antibacterial activity. In this paper, the preparation and purification methods of edible fungus BAPs were reviewed, their common biological activities and structure-activity relationships were analyzed, and their application prospects were discussed.

Dietary linseed supplementation improves meat quality and flavor of sheep by altering muscle fiber characteristics and antioxidant capacity

Linseed as a common oil crop that has been implicated in regulating the meat quality of animals. The aim of this investigation was to establish the effects of dietary linseed supplementation on carcass traits, meat quality, muscle fiber characteristics, volatile compounds and antioxidant capacity of sheep. Twenty-four Sunit sheep were distributed into 2 groups with different diet: control (CO) fed a standard diet and linseed (LS, 8% of extruded linseed). The results showed that linseed not only increased M. longissimus thoracis (LT) increased the loin-eye area but also decreased pH24h, L* and shear force. Meanwhile, linseed increased mRNA expression of MyHCI and MyHCIIx and decreased in cross-sectional area (CSA) and muscle fiber diameter. In addition, linseed altered the composition of meat volatile flavor compounds, such as Z-10-Pentadecen-1-ol, pentanal, 2-Octenal, (E)-, decanal, butane, and 2-heptanone. Moreover, linseed increased total antioxidative capacity (T-AOC) activity, the mRNA expression of glutathione peroxidase (GSH-Px) and catalase (CAT), decreased malondialdehyde (MDA) content. Overall, the results suggest that linseed is an effective feed additive in improving meat quality and flavor. The underlying mechanisms for its effectiveness may be partly due to a change in muscle fiber characteristics and antioxidant capacity.

Quality of milk fat obtained from cows and buffaloes fed a diet supplemented with flaxseed or soybean oils

The experiment was carried out to evaluate the quality of anhydrous milk fat (AMF) of cows and buffaloes supplemented with flaxseed oil (FO), soybean oil (SO), or their mixture (FSO). Lactating crossbred cows and buffaloes were fed with control diet or with one of three supplements: 2% FO, 2% SO, and 2% FSO according to a double 4 x 4 Latin Square Design. The diets with FO, SO, or FSO reduced saturated FA, mainly C4:0, C14:0 and C16:0, while increased the unsaturated FA C18:1 and C18:2 in milk from cows and buffaloes. Cholesterol content decreased in cow's AMF while increased in buffalo's AMF when a diet supplemented with FO, SO, or FSO. The diet with SO or FSO increased the content of vitamin E in AMF obtained from cows (25.06 and 17.89 mg 100 g-1) and buffaloes (28.48 and 30.32 mg 100 g-1) compared with the control diet (11.02 and 15.68 mg 100 g-1), respectively, which correlated positively with scavenging activity for DPPH• (r2 = 0.66) and ABTS• (r2 = 0.67) radicals. Solid fat content (SFC) was high for cow’s AMF, with 58.12-60.37% at 5°C compared to that of buffalo's AMF, with 52.37-56.98%, but was low for cow's AMF at >15°C. Finally, supplementing a diet with vegetable oils, particularly SO, improves the quality of AMF; increases USFA/SFA ratio, vitamin E content, and antioxidant activities

Attention to the Details: How Variations in U.S. Grass-Fed Cattle-Feed Supplementation and Finishing Date Influence Human Health

As the global population increases, so does meat consumption. This trend is accompanied by concerns regarding the meat industry, and consumers are demanding transparency on the environmental and health effects of the products they are purchasing. Many leading health organizations recommend reducing red meat consumption. Nevertheless, no differentiation is made among red meats and beef. The beef production system is generally ignored despite nutritional differences between grain- and grass-fed beef. Compared to grain-fed beef, grass-fed beef contains a healthier fatty acid profile, including more omega-3 polyunsaturated fatty acids and conjugated linoleic acid, and increased concentrations of phytochemicals desired by health-conscious customers. However, there is a lack of consistency among grass-fed beef in the United States regarding clear product labeling and cattle dietary components. Grass-fed beef labeling confusion has emerged, including misunderstandings between grass-fed and grass-finished beef. Along with this, previous studies observed significant nutritional variation among grass-finished beef from different producers across the country. Cattle diet has the strongest influence on the nutritional composition of beef. Therefore, understanding differences in feeding practices is key to understanding differing nutritional quality of grass-fed beef. Feeding cattle diverse pastures composed of multiple plant species including grasses and legumes managed in a rotational grazing fashion results in higher omega-3 polyunsaturated fatty acids and phytochemical levels in beef compared to feedlots and monocultures. Seasonal differences including changes in temperature, rainfall, grazing practices, and plant growth cycles affect the nutritional composition of feeds and ultimately meat. Additional feeds utilized in grass-fed beef production systems such as conserved forages may reduce or increase health-promoting nutrients in grass-fed beef, while supplements such as grape byproducts and flaxseed may improve its nutritional profile. Further research should measure the effects of individual feedstuff and the finishing period on the nutritional profile on grass-fed beef. A better understanding of these details will be a step toward the standardization of pasture-raised ruminant products, strengthening the relationship between grass-fed beef consumption and human health.

Effect of Aging and Retail Display Conditions on the Color and Oxidant/Antioxidant Status of Beef from Steers Finished with DG-Supplemented Diets

The aim of this work was to study the effect of finishing diets including distiller grains (DG) on color and oxidative stability of beef after being exposed to aerobic retail display conditions, with or without previous aging. For this purpose, beef samples from animals fed with finishing diets including 0%, 15%, 30%, and 45% DG (on a dry matter basis), which had been exposed to aerobic retail display conditions, with or without previous aging under vacuum packaging, were evaluated. The content of γ-tocopherol, β-carotene, and lutein in diet samples increased with the level of DG. Beef evaluated at 72 h post-mortem showed greater content of γ-tocopherol and retinol as the DG level increased. Meat color was not affected by DG inclusion, but color parameters decreased with retail conditions. Meat from animals fed with DG showed the lowest values of thiobarbituric acid reactive substances (TBARS), independently of the retail display conditions. However, all samples were below the threshold associated with rancid aromas and above the a* value related to meat color acceptance. Thus, feeding diets including up to 45% of DG improved the antioxidant status of meat, preserving the color, and delaying lipid oxidation in meat samples under the display conditions evaluated.

Byproducts (Flour, Meals, and Groats) from the Vegetable Oil Industry as a Potential Source of Antioxidants

The present study presents the use of photochemiluminescence assay (PCL) and 2,2 diphenyl-1-picryl-hydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), the ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) methods for the measurement of lipid-soluble antioxidant capacity (ACL) of 14 different byproducts obtained from the vegetable oil industry (flour, meals, and groats). The research showed that the analyzed samples contain significant amounts of phenolic compounds between 1.54 and 74.85 mg gallic acid per gram of byproduct. Grape seed flour extract had the highest content of total phenolic compounds, 74.85 mg GAE/g, while the lowest level was obtained for the sunflower groats, 1.54 mg GAE/g. DPPH values varied between 7.58 and 7182.53 mg Trolox/g of byproduct, and the highest antioxidant capacity corresponded to the grape seed flour (7182.53 mg Trolox/g), followed by walnut flour (1257.49 mg Trolox/g) and rapeseed meals (647.29 mg Trolox/g). Values of ABTS assay of analyzed samples were between 0 and 3500.52 mg Trolox/g of byproduct. Grape seed flour had the highest value of ABTS (3500.52 mg Trolox/g), followed by walnut flower (1423.98) and sea buckthorn flour (419.46). The highest values for FRAP method were represented by grape seed flour (4716.75 mg Trolox/g), followed by sunflower meals (1350.86 mg Trolox/g) and rapeseed flour (1034.92 mg Trolox/g). For CUPRAC assay, grape seed flour (5936.76 mg Trolox/g) and walnut flour (1202.75 mg Trolox/g) showed the highest antioxidant activity. To assess which method of determining antioxidant activity is most appropriate for the byproducts analyzed, relative antioxidant capacity index (RACI) was calculated. Depending on the RACI value of the analyzed byproducts, the rank of antioxidant capacity ranged from −209.46 (walnut flour) to 184.20 (grape seed flour). The most sensitive methods in developing RACI were FRAP (r = 0.5795) and DPPH (r = 0.5766), followed by CUPRAC (r = 0.5578) and ABTS (r = 0.4449), respectively. Strong positive correlations between the antioxidant capacity of lipid-soluble compounds measured by PCL and other methods used for determining antioxidant activity were found (r > 0.9). Analyses have shown that the different types of byproducts obtained from the vegetable oil industry have a high antioxidant activity rich in phenolic compounds, and thus their use in bakery products can improve their nutritional quality.

Effect of Fresh Citrus Pulp Supplementation on Animal Performance and Meat Quality of Feedlot Steers

The use of fruit by-products such as citrus pulp represents a feeding ingredient that deserves to be evaluated as an energy source in animal rations. Thirty-six British breed steers were allotted to one of the three feeding treatments (12 steers/treatment): 0%, 15% and 30% of fresh citrus pulp inclusion in the ration in a randomized complete block design to evaluate animal performance and carcass and meat quality traits. In the present study, the inclusion of fresh citrus pulp up to 30% of the diet did not affect the animal average daily gain (p > 0.05) but steers that were fed the pulp consumed less feed (p < 0.05) and presented a lower feed conversion ratio (p < 0.05) than their counterparts without citrus pulp in their diet. No effect of fresh citrus pulp was observed on carcass and meat quality (p > 0.05). A greater lipophilic antioxidant capacity (p < 0.05) in meat was observed when fresh citrus pulp was offered at 15% of the diet. Fresh citrus pulp used up to 30% as a feed ingredient in feedlot rations does not negatively affect animal performance or meat quality but, rather, has a positive effect on dry matter intake and a better feed conversion ratio.

Effects of Age and Rice Straw Inclusion Levels in the Diet of Yiling Cull Cows on Growth Performance, Meat Quality, and Antioxidant Status of Tissues

Simple Summary

Several negative attributes are associated with carcass and meat from cull cows, including lower carcass weights, inferior tenderness, etc. These undesirable characteristics are normally more distinct with increasing age. In addition, there are no recommended standards for forage levels in the diet of Chinese local cattle to produce high marbled beef. In the current study, we evaluated the effects of age and forage levels on the finishing performance of Yiling cull cows under high-energy ration conditions, and also investigated their antioxidant status related to age and diet. We found that younger age and adequate forage had better growth performance and carcass traits. Our findings highlight the importance of selecting according to age and providing adequate forage feed for Yiling cull cows. Moreover, our study also demonstrated the excellent capability of producing high marbled beef for Yiling cattle.

Abstract

The objectives of this study were to investigate the effects of age and dietary straw levels on growth performance, carcass and meat traits, as well as tissue antioxidant status of Yiling cull cows. Twenty-four Yiling cull cows were arranged in a 2 × 2 factorial design: two age classes consisting of younger cull cows (YCC; appearing with three or four pairs of permanent teeth) and older cull cows (OCC; worn out teeth); two dietary treatments consisting of lower and higher rice straw levels (LRS and HRS; providing 0.7 kg/d and 1.2 kg/d rice straw per head based on air-dry basis, respectively). Cows were fed twice a day. Straw was offered at half of the predetermined weight each meal; concentrate was separately supplied ad libitum. After 300 d of feeding, final body weight (BW), total BW gain, average daily gain and gain:feed intake were higher (p < 0.01) in the YCC group than in the OCC group. Total dry matter intake was higher (p = 0.03) in the HRS group than in the LRS group, but neutral detergent fiber apparent digestibility was negatively affected (p = 0.01) by increased straw levels. Decreased C15:0, C17:0, C20:5n3c, and saturated fatty acids (SFAs) proportion as well as increased C18:1n9c and monounsaturated fatty acids (MUFAs) proportion in meat from YCC with HRS diet were observed as compared to that in meat from YCC with LRS diet (p < 0.05). Meat from HRS group had higher (p = 0.04) C18:3n3c proportion than meat from LRS group. No significant differences (p > 0.05) were found for meat quality attributes except for cooking loss, which was higher (p = 0.02) in the HRS group than in the LRS group. Both YCC group and HRS group had higher (p < 0.05) cold carcass weight compared to OCC group and LRS group. Moreover, catalase activity of liver tissue was higher (p = 0.045) in YCC than in OCC, while superoxide dismutase activity of muscle tissue was higher (p = 0.01) in LRS than in HRS. Based on results, we concluded that younger age and feeding high-level straw can improve the finishing performance of Yiling cull cows.

Effect of copaíba essential oil (Copaifera officinalis L.) as a natural preservative on the oxidation and shelf life of sheep burgers

We evaluated the effects of the inclusion of copaíba (Copaifera officinalis L.) essential oil at 0.05 and 0.1% as a possible replacement of synthetic additive butylated hydroxytoluene (BHT) in sheep burgers during 14 days of storage in a refrigerated display case (4°C). During the shelf life days, analyzes of antioxidant activity, lipid oxidation, pH, color, cooking loss, texture and consumer acceptability were carried out on refrigerated burgers. The addition of copaíba essential oil showed an antioxidant effect in sheep burgers (P > 0.05), reducing lipid oxidation. Copaiba essential oil added at 0.05% showed the highest antioxidant activity, decreased cooking losses and delaying discoloration (loss of redness) during storage; it further improved, the tenderness of sheep burgers (P < 0.05). The treatments had no effect (P > 0.05) on consumer acceptability. Copaiba essential oil is a promising natural antioxidant to increase the shelf life of meat products, as well as being a viable solution to replace synthetic antioxidant BHT, thereby promoting the fresh‐like quality appeal of sheep burgers.

Quality, nutrient and sensory characteristics of aged meat from lambs supplemented with selenomethionine

Selenium (Se) as a co-factor of antioxidant enzymes is metabolically essential for animals. Its presence in muscle can improve the oxidative stability of meat and is a desirable nutrient for consumers. A novel approach to Se supplementation for meat-producing livestock was demonstrated in a 95-day study of young lambs. DL-selenomethionine (SeMet) was administered by subcutaneous injection at day 0 (3-4 weeks of age) and again at day 54. A Control group (n = 9) received carrier only, whilst Medium and High groups (n = 10) received graded levels of Se. Physicochemical attributes of meat quality and sensory characteristics were measured at 1, 3, 14 and 42 days of ageing (vacuum packaged at -1.5 °C), followed by instrumental colour measurements after 7 days of simulated retail display. There were no significant interactions between SeMet treatment and ageing. Muscle pH, drip and cooking losses, initial display colour and sensory evaluations by trained and consumer panels were unaffected by treatment. Smaller changes in colour during display were observed for the Medium group compared to Control (P < 0.05). The shorter range of ageing times improved meat tenderness however extended ageing decreased colour stability. SeMet markedly increased Se concentrations in muscle, blood, kidney and liver (P < 0.05), resulting in Se enriched meat without appreciable changes in meat quality.

Identification of novel antioxidant peptides from snakehead (Channa argus) soup generated during gastrointestinal digestion and insights into the anti-oxidation mechanisms

Antioxidant peptides obtained from snakehead (Channa argus) soup (SHS) after simulated gastrointestinal (GI) digestion were separated, identified and characterized. Results showed that the fraction with MW < 3 kDa had the highest antioxidant capacity. Four novel antioxidant peptides were identified after RP-HPLC and UPLC-MS/MS. PGMLGGSPPGLLGGSPP and SDGSNIHFPN had the highest DPPH radical scavenging activity (IC₅₀ = 1.39 mM) and Fe²⁺ chelating ability (IC₅₀ = 4.60 mM), respectively. Structures in silico for IVLPDEGK, PGMLGGSPPGLLGGSPP and SDGSNIHFPN suggest at least one β-turn and/or α-helix, which are associated with antioxidant activity. Moreover, our results showed that these three peptides docked with a recombinant Kelch-like ECH-associated protein 1 (Keap1) with a binding score greater than TX6, a good ligand of Keap1. The cell viability assay also showed significant cytoprotective effects against H₂O₂-induced cellular oxidative damage. This information implies that antioxidant mechanisms of novel SHS peptides occurred via activation of cellular anti-oxidation Keap1-Nrf2 signaling pathway.

Advances on Food-Derived Peptidic Antioxidants-A Review

The oxidation process is considered to be the main reason behind human aging, human degenerative diseases and food quality degradation. Food-derived peptidic antioxidants (PAs) have wide sources and great activity, and have broad application prospects in removing excess reactive oxygen species in the body, anti-aging and preventing and treating diseases related to oxidative stress. On the other hand, PAs are expected to inhibit the lipid peroxidation of foods and increase the stability of the food system in the food industry. However, the production pathways and action mechanism of food-derived PAs are diverse, which makes it is difficult to evaluate the performance of PAs which is why the commercial application of PAs is still in its infancy. This article focuses on reviewing the preparation, purification, and characterization methods of food-derived PAs, and expounds the latest progress in performance evaluation and potential applications, in order to provide an effective reference for subsequent related research of PAs.

Profiling of amino acids and their interactions with proteinaceous compounds for sewage sludge dewatering by Fenton oxidation treatment

During advanced oxidation treatment for enhancing sludge dewaterability, the peptide chains of protein can be decomposed into amino acids. Protein exhibits a great impact on sewage sludge dewaterability. However, the role of amino acids in sludge dewatering remains unclear. In this study, among the 23 types of amino acids investigated, tryptophane (Trp) and lysine (Lys) were identified as the key amino acids affecting sludge dewaterability during Fenton oxidation treatment. The content of lysine showed positive correlations with capillary suction time (CST), specific resistance to filtration (SRF), and bound water content, and the concentrations of total protein, low molecular weight protein, amines and amides, and 3-turn helix of proteinaceous compounds in bound extracellular polymeric substances (EPS), while the content of tryptophane showed negative correlations with the above parameters. The amino acids may be sourced from damage of the membrane and ribosomal proteins by hydroxyl radicals, and the peptide bonds connected with tryptophane were more inclined to be decomposed than other amino acids. Particularly, more amino acids of tryptophane can result in more hydrophobic interaction, and less necessary energy barrier for aggregation of particles. As such, regulating protein degradation towards production of tryptophane may be related with enhanced sludge dewaterability by Fenton oxidation treatment.

Stability of fatty acid composition of intramuscular fat from pasture- and grain-fed young bulls during the first 7 d postmortem

In order to study the effect of different amounts of concentrate feed and the effectiveness of natural antioxidants on the fatty acid stability of intramuscular fat during the first days postmortem, 75 young bulls of the Retinta breed were divided in three groups: 30 were grazed, 30 were fed on medium concentrate diets, and 15 were fed on high-concentrate diets. Young bulls were slaughtered at commercial weight, around a 500 kg final body weight. Samples from Longissimus lumborum muscle were assigned to two ageing periods (0 and 7 d) and were vacuum packaged in vacuum bags (O2 permeability: 9.3 mL O2/m2 per 24 h at 0 ∘C) using an EGARVAC® sealer. Beef from grass-fed bulls showed a higher polyunsaturated fatty acid content than concentrate-fed bulls. During the first 7 d postmortem, no changes in the fatty acids profile were observed, because α-tocopherol content was optimal to prevent lipid oxidation. The higher level of natural antioxidants in grass than in grain resulted in the stability of the fatty acid profile. This study shows that the anti-oxidative potential of natural antioxidants in meat plays an important role during the first 7 d postmortem.

Structural and antioxidant analysis of Tartary buckwheat (Fagopyrum tartaricum Gaertn.) 13S globulin

BACKGROUND

The main component of buckwheat seed storage proteins is 13S globulin. In this study, Tartary buckwheat 13S globulin was separated and its structural features were investigated using Edman sequencing and matrix-assisted laser desorption / ionization time of flight mass spectrometry (MALDI-TOF-MS). The protective effect of its enzymatic hydrolysates against oxidative stress induced by H₂ O₂ was also evaluated to elucidate the antioxidant mechanism.

RESULTS

Results showed that the isolated Tartary buckwheat 13S globulin contained one acidic and one basic subunit, which were linked by a disulfide bond. Six Tartary buckwheat active peptides were obtained from the enzymatic hydrolysates of Tartary buckwheat 13S globulin acidic subunit with a molecular weight of 38 kDa, namely Pep-1, Pep-2, Pep-3, Pep-4, Pep-5, and Pep-6. Pre-treatment of cells with Tartary buckwheat active peptides maintained the redox state balance of HepG₂ cells and protected the activity of antioxidant enzymes in HepG₂ cells. The Tartary buckwheat active peptides improved oxidative stress in HepG₂ cells via the PPAR-α/HO-1 pathway.

CONCLUSION

These results provide an insight into the antioxidant mechanism of Tartary buckwheat 13S globulin and suggest that Tartary buckwheat active peptides can be used as a functional ingredient in the food industry. © 2019 Society of Chemical Industry.

Identification and characterization of novel antioxidant peptides from crucian carp (Carassius auratus) cooking juice released in simulated gastrointestinal digestion by UPLC-MS/MS and in silico analysis

The objective of this work was to separate, identify and assess antioxidant peptides from the simulated gastrointestinal (GI) digestion of crucian carp (Carassius auratus) cooking juice (CCCJ), which has been previously found with this activity. The CCCJ after simulated GI digestion treatment was separated gradually by ultrafiltration and RP-HPLC. Five novel antioxidant peptides with 10-13 amino acid residues were identified by UPLC-MS/MS. Their in silico assessments showed amphiphilic nature, good sensory quality and different target sites in the human body. Meanwhile, their three-dimensional structure predictions exhibited at least one β-turn, β-sheet and/or α-helix with partial hydrophobic and/or net-charged residues exposed to the external medium, which was good evidence for high antioxidant activity. Ultimately, four novel peptides with high antioxidant activity were found, among which IREADIDGDGQVN (1401 Da), PEILPDGDHD (1107 Da) and ASDEQDSVRL (1119 Da) exerted the highest DPPH radical scavenging activity with IC₅₀ of 1.78, 1.18 and 1.45 mM, respectively, while APLEEPSSPH (1063 Da) showed the highest Fe²⁺ chelating ability with IC₅₀ of 0.09 mM. This work could help understand the mechanism of CCCJ on human health promotion and improve the economic value of the crucian carp processing industry.

Protein degradation and peptide formation with antioxidant activity in pork protein extracts inoculated with Lactobacillus plantarum and Staphylococcus simulans

This study focused on sarcoplasmic and myofibrillar protein degradation and the formation of peptides with antioxidant activity by mixed starters (Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201). Gel electrophoresis indicated that the mixed starters can hydrolyze both sarcoplasmic and myofibrillar proteins, and the concentration of peptides increased (P < .05). Compared with the control group, using mixed starters led to a significant increase (P < .05) in the DPPH radical scavenging activity, Fe²⁺ chelating activity, and ABTS radical scavenging activity of sarcoplasmic proteins, but demonstrated no significant difference in myofibrillar proteins. Two hydrophobic fractions (C2, C5) separated by RP-HPLC in the inoculation groups with sarcoplasmic proteins showed high DPPH radical scavenging activity (66.60%, 60.50%). Eighteen peptides were identified by LC-MS/MS, which mainly arose from triosephosphate isomerase, creatine kinase M-type, and glyceraldehyde-3-phosphate dehydrogenase. Hydrophobic amino acids accounted for a large proportion. Our results indicate that mixed starters affect proteolytic characterization and contribute to the formation of peptides with antioxidant capacity in sarcoplasmic proteins.

Moisture content, fatty acid profile and oxidative traits of aged beef subjected to different temperature-time combinations

Temperature-time combinations (TTC) effects on beef fatty acid (FA) composition, moisture content and oxidative traits were investigated. TTC were designed so temperatures were constant over each time period, and there was at most one variation in temperature within a sample's combined (total) time period. Therefore, three temperatures (~ 3, 5 and 7 °C) and five time periods (6, 8, 10 and 12 d) resulted in 72 different TTC, which were compared to control samples held for 14 d at ~ 1 °C. It was found that moisture losses increased as TTC temperature and time periods increased. There were negligible effects of TTC on FA composition. Sample TBARS and vitamin E content did not respond to TTC. A positive relationship between beef vitamin E and long chain polyunsaturated FA contents was observed. We concluded that TTC could be applied to accelerate the rate of ageing for beef and achieve comparable yield, oxidative and FA characteristics compared to conventional ageing approaches.

Point of purchase fatty acid profile, oxidative status and quality of vacuum-packaged grass fed Australian beef held chilled for up to 12 weeks

We investigated the fatty acid (FA) composition, oxidative biomarkers and quality traits of chilled beef. Specifically, striploin portions were held in vacuo and chilled (~ 1.5 °C) for up to 12 weeks, and analysed dependent on their assigned chilled storage period (0, 2, 5, 8, 10 and 12 weeks). There were no practical effects observed on beef FA composition as a result of chilled storage - including several polyunsaturated FA (PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Intramuscular fat content was found to have a covariate effect, but only for saturated FA and monounsaturated FA. Vitamin E and thiobarbituric acid reactive substances were unchanged. Furthermore, improvements to shear force and particle size were evident at 2 weeks and thereafter, no further variation was evident. These findings suggest that beef produced to be healthier based on the EPA, DHA and PUFA content will remain so, for up to 12 weeks. Likewise, beef quality will be preserved across this same period.

Food-derived bioactive peptides and their role in ameliorating hypertension and associated cardiovascular diseases

Non-communicable diseases including cardiovascular diseases (CVDs) and associated metabolic disorders are responsible for nearly 40 million deaths globally per year. Hypertension or high blood pressure (BP) is one of the primary reasons for the development of CVDs. A healthy nutritional strategy complementing with physical activity can substantially reduce high BP and prevent the occurrence of CVD-associated morbidity and mortality. Bioactive peptides currently are the next wave of the promising bench to clinic options for potential targeting chronic and acute health issues including hypertension. Peptides demonstrating anti-inflammatory, anti-oxidant, and angiotensin-converting enzyme-I inhibitory activity are widely studied for the amelioration of hypertension and associated CVDs. Isolating these potent bioactive peptides from different food sources is a promising endeavor toward nutraceutical based dietary management and prevention of hypertension. Understanding the pathophysiology of hypertension and the action mechanisms of the bioactive peptides would complement in designing and characterizing more potent peptides and suitable comprehensive dietary plans for the prevention of hypertension and associated CVDs.

Effect of Linseed Supplementation on Total Longissimus Muscle Lipid Composition and Shelf-Life of Beef From Young Maremmana Bulls

Twenty young Maremmana bulls were randomly allotted to two dietary groups during a finishing period (~90 days): C diet (without lipid supplementation), and L diet (with linseed supplementation, 20% concentrate feed). The aim was to investigate the effects of dietary linseed supplementation on the intramuscular fat composition, and the shelf-life of minced beef. The L diet did not alter the dressing rate and daily weight gain, whereas the C18:3n-3 content in the intramuscular fat significantly increased (from 0.85 to 1.78 g/100 g of total fatty acid, +109%), leading to a reduction in a n-6/n-3 ratio below four and an increase in the overall proportion of long chain n-3 fatty acids in beef lipids. These effects were principally related to differences in the distribution of fatty acids between the neutral and polar lipids. The results demonstrated that linseed supplementation modified the lipid composition of beef, without negatively impacting overall productivity, in the period from weaning the bull until its slaughter. However, the total amount of n-3 fatty acids in the beef of young bulls on the L diet, was not sufficient for the aliquot of humans' n-3 fatty acid requirements. This was mainly related to the low levels of fat in the beef. Comparing beef samples from animals on the L diet, with samples from animals on the C diet, the higher levels of n-3 polyunsaturated fatty acids led to a significant reduction of shelf-life starting after 2 days of storage at 4°C, because of fatty acid and cholesterol oxidation. The L diet group samples showed a higher level of TBARS (+80%) and COPs (+73%), two important parameters to estimate the oxidation level of beef. This suggests that enriching beef with n-3 fatty acids should be coupled with packaging techniques that consider the higher susceptibility to lipid oxidation. In conclusion, dietary linseed supplementation led to a higher proportion of n-3 fatty acids in beef lipids, however, the natural content of antioxidant substances was not able to protect intramuscular fat from oxidation during storage at 4°C.

Physico-chemical composition and oxidative stability of South African beef, game, ostrich and pork droëwors

Droëwors are traditional South African salted and dried sausages, made without nitrites/nitrates and non- fermented. Different meat sources (beef, game and ostrich) are traditionally used in droëwors processing, while the use of pork is uncommon, as it is said to lead to rancidity. The first part of the study analysed the physico-chemical composition of commercially available beef, game and ostrich meat droëwors (n = 20). On average, they were composed of 26.3-29.2 g/100 g moisture, 41.3-44.0 g/100 g protein, 26.2-33.1 g/100 g fat and 5.9-6.5 g/100 g ash and 5.0-5.4 pH. Water activity (0.76-0.82) was sufficiently low to ensure shelf stability at ambient temperatures. In the second part beef and pork droëwors were formulated in accordance with these results and with similar fat content, dried for 2 days (30 °C, 40% relative humidity) and stored for 26 days (25 °C, 50% relative humidity); measuring moisture, water activity, pH and lipid oxidative stability (thiobarbituric acid reactive substances (TBARS)) weekly. At day 5, moisture and thus water activity of pork droëwors was slightly higher compared to beef ones and fat and ash content slightly lower (P ≤ 0.05) despite similar weight loss. Even with slightly less fat, TBARS in pork droëwors were significantly higher after drying and throughout storage (3.83 vs 0.99 mg MDA equivalents/kg dry matter at a maximum).

A comparison of the Nix Colour Sensor Pro™ and HunterLab MiniScan™ colorimetric instruments when assessing aged beef colour stability over 72 h display

We compared the capacity for the Nix Colour Sensor Pro™ (NIX) and HunterLab MiniScan™ (HUNTER) to detect colour variation using aged (0, 3 and 5 weeks) and then displayed (0, 1, 2 and 3 d) beef M. longissimus lumborum samples (n = 8). NIX L* and hue values were found to be respectively higher and lower than for the HUNTER. No significant interactions between instrument and display or ageing periods were identified for a* - unlike for b* and chroma where NIX measures were observed to be lower than those from the HUNTER. Both instruments identified ageing and display period effects on colorimetric traits. Based on these results, the NIX cannot be considered comparable to the HUNTER when measuring beef colour - albeit captured similar colorimetric trends over display and ageing periods which suggest its independent usefulness to beef colour assessment.

Okara residue as source of antioxidants against lipid oxidation in milk enriched with omega-3 and bioavailability of bioactive compounds after in vitro gastrointestinal digestion

The residue from soy processing (okara) was evaluated for phenolic compounds, flavonoids, radical scavenging activity and reducing power ability. The ability of okara to decelerate the oxidation of omega-3 fatty acids caused by light exposure in a milk matrix, as well as its bioavailability after in vitro digestion, were investigated. Okara contained phenolic compounds (106.7 mg gallic acid equivalents (GAE)/100 g) and flavonoids (32.7 mg quercetin equivalents/100 g) and showed antioxidant activity. The addition of okara to omega-3 fatty acids-enriched milk inhibited the production of conjugated dienes and malonaldehyde during 8 days of storage compared to the control (without okara), particularly at the higher (3 g/L) than lower inclusion concentrations studied (1 and 2 g/L). The bioavailability assay demonstrated that polyphenols (41 mg GAE/100 g) were still present after in vitro digestion and had antioxidant activity. Okara, which is considered a residue and is discarded, can potentially be used as an antioxidant ingredient for the enrichment of foods.

Multi-functional application of Moringa oleifera Lam. in nutrition and animal food products: A review

Research on the use of various parts of the Moringa oleifera Lam. plant (M. oleifera) as a nutritional and neutraceutical resource for human and animal diets has increased in recent years, emanating from the widespread use of the plant in traditional cuisines and medicinal remedies in several regions of the world. Analytical studies have identified M. oleifera as an important source of essential nutrients; rich in protein, essential amino acids, minerals, and vitamins, with a relatively low amount of antinutrients. It is also a rich source of other bio active compounds including flavonoids and phenolic compounds; with several studies detailing demonstrated in vitro and in vivo functional properties, most substantially, antioxidant activities. Moringa oleifera consumption has been reported to improve the health status, feed conversion efficiency, growth performance and product quality of several livestock species, at dietary inclusion rates generally not exceeding 5% of total dry matter intake. Fortification of processed foods with M. oleifera has been reported to increase nutritional value, some organoleptic properties, oxidative stability and product shelf life; with a notable need for further analytical and consumer studies in the development of these products. There is a paucity of literature detailing clinical studies, nutrient bioavailability, toxicity and the mode of action of the bioactive compounds to which the health claims associated with M. oleifera consumption are attributed. Many of these are not yet fully understood; therefore more research in these areas is required in order to fully utilize the potential benefits of this plant in human and livestock nutrition.

Metabolomics Profiling to Determine the Effect of Postmortem Aging on Color and Lipid Oxidative Stabilities of Different Bovine Muscles

The objective of this study was to identify metabolites that could be associated with oxidative stability of aged bovine muscles. Three muscles (longissimus lumbrum (LL), semimembranosus (SM), and psoas major (PM)) from seven beef carcasses at 1 day postmortem were divided into three sections and assigned to three aging periods (9, 16, and 23 days). Although an increase in discoloration was found in all muscles with aging, LL was the most color/lipid oxidative stable, followed by SM and PM (P < 0.05). Lower myoglobin and nonheme iron contents were observed in LL compared to those in SM and PM (P < 0.05). The HPLC-ESI-MS-based metabolomics analysis identified metabolites that were significantly responsive to aging and/or muscle type, such as acyl carnitines, free amino acids, nucleotides, nucleosides, and glucuronides. The results from the current study suggest that color and oxidative stability could be associated with aging but are also muscle-specific. Further studies determining the exact role of the identified metabolites in the color and oxidative stability of beef muscles are warranted.