Effects of Supplementation of Microalgae (Aurantiochytrium sp.) to Laying Hen Diets on Fatty Acid Content, Health Lipid Indices, Oxidative Stability, and Quality Attributes of Meat.

The present study is conducted to investigate the effects of dietary docosahexaenoic acid (DHA)-rich microalgae (MA, Aurantiochytrium sp.) on health lipid indices, stability, and quality properties of meat from laying hens. A total of 450 healthy 50-wk-old Hy-Line Brown layers were randomly allotted to 5 groups (6 replicates of 15 birds each), which received diets supplemented with 0, 0.5, 1.0, 1.5, and 2.0% MA for 15 weeks. Fatty acid contents and quality properties of breast and thigh muscles from two randomly selected birds per replicate (n = 12) were measured. The oxidative stability of fresh, refrigerated, frozen, and cooked meat was also determined. Results indicated that supplemental MA produced dose-dependent enrichments of long-chain n-3 polyunsaturated fatty acids (n-3 LC-PUFA), predominantly DHA, in breast and thigh muscles, with more health-promoting n-6/n-3 ratios (1.87-5.27) and favorable lipid health indices (p < 0.05). MA supplementation did not affect tenderness (shear force) and color (L*, a*, and b* values) of hen meat nor muscle endogenous antioxidant enzymes and fresh meat oxidation (p > 0.05). However, the n-3 LC-PUFA deposition slightly increased lipid oxidation in cooked and stored (4 °C) meat (p < 0.05). In conclusion, MA supplementation improves the nutritional quality of hen meat in terms of lipid profile without compromising meat quality attributes. Appropriate antioxidants are required to mitigate oxidation when such DHA-enriched meat is subjected to cooking and storage.

Upregulation of antioxidant enzymes by organic mineral co-factors to improve oxidative stability and quality attributes of muscle from laying hens.

This study investigated the impact of organic trace minerals (OTM: Fe, Cu, Mn, and Zn proteinates premix) and Se-yeast (0.25 mg/kg) as a feed supplement versus inorganic forms of the same minerals (sulfated) on the enzymatic (GPX, CAT, SOD), oxidative, and physicochemical properties of fresh breast muscle from 68-week old hens during storage (4 °C) for 0, 2, 4 and 6 days. OTM with Se-yeast was more effective than sulfated minerals or selenite for enriching meat with Zn, Se and vitamin E (P < .05). At only one-third of the full inorganic mineral supplementation level, OTM with Se-yeast still induced higher GPX activity and greater inhibition of lipid (58% less TBARS) and protein (24% less sulfhydryl loss) oxidation. The organic mineral treatments significantly decreased drip loss and improved color stability of meat when compared with inorganic mineral supplements. Enhanced muscle cellular antioxidant enzymatic activity by the mineral co-factors was plausibly implicated in the protection.

Textural and sensorial quality protection in frozen dumplings through the inhibition of lipid and protein oxidation with clove and rosemary extracts.

BACKGROUND: Oxidation is a major reason for nutritional and quality loss of dumplings during frozen storage. The addition of spice extracts in frozen dumplings may limit and inhibit oxidative impairments. In this study, the antioxidant effects of clove extract (CE) and rosemary extract (RE) and their influence on sensory and quality attributes of the meat-based filler in frozen pork dumplings stored at -18 °C were investigated. RESULTS: CE and RE significantly suppressed lipid and protein oxidation in terms of thiobarbituric acid-reactive substances and protein carbonyls (P < 0.05) formation. During frozen storage up to 180 days, the dumpling samples with antioxidants had a significantly higher breaking strength and lower cooking loss (P < 0.05) compared with the control, and the effect of RE was stronger than that of CE. Sodium dodecylsulfate polyacrylamide gel electrophoresis showed that samples with antioxidants had reduced protein crosslinking, hence less aggregation. Differential scanning calorimetry analysis proved that the dumplings with antioxidants during storage had a higher thermal stability than those of the control. Based on dynamic rheological testing, the addition of RE to dumpling fillers was more effective in enhancing the gelling capacity of myofibrillar protein compared to the control. Sensory panel results confirmed significant positive effects of both spice extracts on oxidative stability (reduced rancidity) and palatability (texture and juiciness) of dumplings. CONCLUSION: The addition of phenolic-rich CE and RE in dumpling processing is an excellent approach for the inhibition of sensory and quality deterioration associated with oxidation during frozen storage. © 2019 Society of Chemical Industry.

Effect of Xanthan Gum/Soybean Fiber Ratio in the Batter on Oil Absorption and Quality Attributes of Fried Breaded Fish Nuggets.

Xanthan gum (XG) and soybean fiber (SF) at varying ratios were incorporated into the batter to inhibit oil absorption in fried battered and breaded fish nuggets (BBFNs). BBFNs were prepared with 1.2% XG and SF blends (at ratios 1:3, 1:2, 1:1, 2:1, and 3:1 w/w), fried at 170 °C (40 s) followed by 190 °C (30 s), then evaluated for pickup, oil absorption, textural characteristics, and other quality attributes. Compared with the control (without the addition of XG and SF), fried BBFNs prepared with XD and SF had a significantly reduced fat content (P < 0.05). Among all the treatments, fried BBFNs with a 1:2 w/w ratio of XG and SF had the lowest fat content in the crust and the core (16.2% and 0.6%, respectively) and the highest moisture content. When compared with other treatments, the 1:2 w/w treatment group displayed a more intense golden yellow color, higher crispness, lower hardness, and a more compact structure in the crust, a greater elasticity and chewiness of the core, and the least oil penetration. The results proved that the combined addition of XG and SF in the batter can effectively inhibit oil absorption, which may be used to guide the production of low-fat fried BBFNs. PRACTICAL APPLICATION: This study clearly showed that the combined addition of XG and SF at different ratios in the batter significantly affected fat content and quality attributes of fried BBFNs. The inhibition of oil absorption and improvement of color and textural characteristics in fried BBFNs depended on the XG/SF ratio added to the batter, and a 1:2 w/w ratio was found to produce the maximum enhancement.

High pressure homogenization combined with pH shift treatment: A process to produce physically and oxidatively stable hemp milk.

Hemp milk, an emerging beverage with high nutritional value and low allergenicity, is an attractive alternative to dairy, soy, and nut milks. To obtain a non-thermally processed, physically and oxidatively stable hemp milk, high pressure homogenization (HPH) combined with pH shift treatment was investigated. For hemp milk (4% protein, 5% fat) without pH shift, increasing the homogenization pressure (up to 60 MPa) resulted in a more uniform distribution of emulsion droplets (2.2-2.7 µm). When pH shift was applied prior to HPH, large clusters and aggregates of oil droplets (3.5-8.2 µm) were formed. Interestingly, hemp milk with such interactive structures was remarkably stable, showing negligible phase separation within 3-day storage at 4 °C. Moreover, hemp milk made by combined pH shift and HPH exhibited delayed hydroperoxides (expressed as peroxide value, PV) and malondialdehyde (expressed as thiobarbituric acid-reactive substances, TBARS) production, suggesting the resistance of such emulsion cluster structures to radicals. On the other hand, a significant reduction of microbial population was observed in hemp milk prepared by pH shift combined with HPH. The results indicate that the pH shift + HPH combination treatment may potentially be employed for the production of non-thermally processed hemp milk.

Effects of (-)-epigallocatechin-3-gallate incorporation on the physicochemical and oxidative stability of myofibrillar protein-soybean oil emulsions.

The dose-dependent effects of (-)-epigallocatechin-3-gallate (EGCG; at 0, 50, 100, 200, 500, and 1000 mg/L) on the physical, chemical, and oxidative stability of porcine myofibrillar protein (MP)-soybean oil emulsion systems were investigated. The results showed EGCG at all levels effectively suppressed lipid oxidation in MP emulsion composite gels during the entire chill storage (at 4 °C for 0, 3, or 7 days). The incorporation of EGCG at higher concentrations (>100 mg/L) promoted the loss of sulfhydryls, reduction of surface hydrophobicity, and aggregation and cross-linking of MP. As a result, high concentrations of EGCG (500 and 1000 mg/L) hampered emulsification and gel formation of MP. However, EGCG at lower concentrations (50-200 mg/L) improved the oxidative stability of meat emulsions without jeopardizing the textural stability.

Inhibition of hazardous compound formation in muscle foods by antioxidative phytophenols.

Individual and mixed herbal extracts, as well as plant spices, are widely used in the preparation of muscle foods to enhance the organoleptic attributes. Abundantly rich in phenolic compounds, many of the phytochemical extracts have been shown to possess strong radical-scavenging and metal ion-binding properties and hence exert antioxidant activity in meat products. Because of their antiradical nature, phenolic acids and flavonoids, such as tea catechins, caffeic acid, chlorogenic acid, and mixed polyphenols derived from rosemary, licorice, and other herbal materials, are capable of inhibiting the formation of harmful secondary products from oxidized lipids and proteins. The inactivation of carcinogenic compounds produced in some nitrite-cured and high temperature-processed meats (e.g., nitrosamines and aromatic amines) by phytophenols has also been demonstrated in recent studies. Here, I describe the application of phytochemical-rich food ingredients in prepared meat and discuss the mechanisms by which plant-derived phenolic antioxidants mitigate toxicant and mutagen production in muscle foods.

Dietary linseed oil supplemented with organic selenium improved the fatty acid nutritional profile, muscular selenium deposition, water retention, and tenderness of fresh pork.

Cross-bred pigs were fed a control diet (with 0.3ppm sodium selenite and 1.5% soybean oil) or organic selenium diets (0.3ppm Se-Yeast with 1.5% soybean or linseed oil) to investigate nutrient supplement effects on meat quality and oxidative stability. The organic selenium diets increased muscular selenium content up to 54%, and linseed oil increased n-3 fatty acids two-fold while lowering the n-6/n-3 fatty acid ratio from 13.9 to 5.9 over the selenite control diet (P<0.05). Organic selenium yeast treatments with linseed oil reduced pork drip loss by 58-74% when compared with diets with soybean oil. Lightness of fresh pork was slightly less for organic selenium groups than inorganic (P<0.05), but redness was mostly similar. Lipid oxidation (TBARS) and protein oxidation (sulfhydryl) during meat storage (4°C up to 6days) showed no appreciable difference (P>0.05) between diets, in agreement with the lack of notable difference in endogenous antioxidant enzyme activity between these meat groups.

Natural antioxidants as food and feed additives to promote health benefits and quality of meat products: A review.

Fresh and processed meats offer numerous nutritional and health benefits and provide unique eating satisfaction in the lifestyle of the modern society. However, consumption of red meat including processed products is subjected to increasing scrutiny due to the health risks associated with cytotoxins that potentially could be generated during meat preparation. Evidence from recent studies suggests free radical pathways as a plausible mechanism for toxin formation, and antioxidants have shown promise to mitigate process-generated chemical hazards. The present review discusses the involvements of lipid and protein oxidation in meat quality, nutrition, safety, and organoleptic properties; animal production and meat processing strategies which incorporate natural antioxidants to enhance the nutritional and health benefits of meat; and the application of mixed or purified natural antioxidants to eliminate or minimize the formation of carcinogens for chemical safety of cooked and processed meats.

Role of interfacial protein membrane in oxidative stability of vegetable oil substitution emulsions applicable to nutritionally modified sausage.

The potential health risk associated with excessive dietary intake of fat and cholesterol has led to a renewed interest in replacing animal fat with nutritionally-balanced unsaturated oil in processed meats. However, as oils are more fluid and unsaturated than fats, one must overcome the challenge of maintaining both physical and chemical (oxidative) stabilities of prepared emulsions. Apart from physical entrapments, an emulsion droplet to be incorporated into a meat protein gel matrix (batter) should be equipped with an interactive protein membrane rather than a small surfactant, and the classical DLVO stabilization theory becomes less applicable. This review paper describes the steric effects along with chemical roles (radical scavenging and metal ion chelation) of proteins and their structurally modified derivatives as potential interface-building materials for oxidatively stable meat emulsions.

Light backscatter fiber optic sensor: a new tool for predicting the stability of pork emulsions containing antioxidative potato protein hydrolysate.

The objective of this study was to determine whether light backscatter response from fresh pork meat emulsions is correlated to final product stability indices. A specially designed fiber optic measurement system was used in combination with a miniature fiber optic spectrometer to determine the intensity of light backscatter within the wavelength range 300-1100 nm (UV/VIS/NIR) at different radial distances (2, 2.5 and 3mm) with respect to the light source in pork meat emulsions with two fat levels (15%, 30%) and two levels (0, 2.5%) of the natural antioxidant hydrolyzed potato protein (HPP). Textural parameters (hardness, deformability, cohesiveness and breaking force), cooking loss, TBARS (1, 2, 3, and 7 days of storage at 4 °C) and CIELAB color coordinates of cooked emulsions were measured. The light backscatter was directly correlated with cooking losses, color, breaking force and TBARS. The optical configuration proposed would compensate for the emulsion heterogeneity, maximizing the existing correlation between the optical signal and the emulsion quality metrics.

Interfacial adsorption of peptides in oil-in-water emulsions costabilized by Tween 20 and antioxidative potato peptides.

Previous studies have shown that soybean oil-in-water (O/W) emulsions prepared with potato protein hydrolysate (PPH) are remarkably stable against oxidative changes. It was hypothesized that partitioning of peptides at the emulsion interface plays an important role in this phenomenon. The present study was conducted to examine the structural characteristics of the interfacial membrane. As revealed by atomic force microscopy, oil droplets costabilized with PPH and Tween 20 were more uniform than those stabilized with Tween 20 only (control). Confocal laser scanning microscopy images indicated the existence of peptides directly anchored into the interfacial membrane. The adsorbed peptides were mostly short oligopeptides composed of two to seven amino acids, of which Ser-Phe-Asp-Leu(Ile)-Lys matched the sequence of patatin. The adsorption of these peptides appeared to both improve the integrity of the interface and contribute to the oxidative stability of the emulsions. Furthermore, cryogenic transmission electron microscopy illustrated the morphology of the interfacial membrane as a noncontinuous short fibril structure. Partitioning of antioxidative peptides in the interfacial membrane provided steric hindrances and electrostatic effects to inhibit oxidation.

Synergy of licorice extract and pea protein hydrolysate for oxidative stability of soybean oil-in-water emulsions.

Previously developed radical-scavenging pea protein hydrolysates (PPHs) prepared with Flavourzyme (Fla-PPH) and Protamex (Pro-PPH) were used as cosurfactants with Tween 20 to produce soybean oil-in-water (O/W) emulsions, and the suppression of lipid oxidation was investigated. Both PPHs significantly retarded oxidation (P < 0.05) of the emulsions when stored at 37 °C for 14 days. Electron microscopy revealed an interfacial peptidyl membrane around oil droplets, which afforded steric restrictions to oxidation initiators. When licorice extract (LE) was also used in emulsion preparation, a remarkable synergistic oxidation inhibition was observed with both PPHs. LE adsorbed onto oil droplets either directly or through associating with PPH to produce a thick and compact interfacial membrane enabling the defense against oxygen species. Liquiritin apioside, neolicuroside, glabrene, and 18ß-glycyrrhetic acid were the predominant phenolic derivatives partitioning at the interface and most likely the major contributors to the notable synergistic antioxidant activity when coupled with PPHs.

Dietary antioxidant supplementation enhances lipid and protein oxidative stability of chicken broiler meat through promotion of antioxidant enzyme activity.

Recent nutrigenomic studies have shown that animal nutrition can have a major influence on tissue gene expression. Dietary antioxidant supplements can enhance the quality of meat through modification of tissue metabolic processes. This study investigated the influence of dietary antioxidants and quality of oil on the oxidative and enzymatic properties of chicken broiler breast meat stored in an oxygen-enriched package (HiOx: 80% O2/20% CO2) in comparison with air-permeable polyvinylchloride (PVC) or skin packaging systems during retail display at 2 to 4°C for up to 21 d. Broilers were fed either a diet with a low-oxidized (peroxide value 23 mEq of O2/kg) or high-oxidized (peroxide value 121 mEq of O2/kg) oil, supplemented with or without an algae-based Se yeast and organic mineral antioxidant pack for 42 d. Lipid and protein oxidation and tissue enzymatic activity were analyzed. In all packaging systems, lipid oxidation (TBA reactive substances) was inhibited by up to 32.5% (P < 0.05) with an antioxidant-supplemented diet when compared with diets without antioxidants, particularly in the HiOx and PVC systems. Protein sulfhydryls were significantly protected by antioxidant diets (e.g., by 14.6 and 17.8% for low-and high-oxidized dietary groups, respectively, in PVC d 7 samples). Glutathione peroxidase, catalase, and superoxide dismutase activities were significantly higher (P < 0.05) in antioxidant-supplemented diets compared with the basal diet, regardless of oil quality. Also, serum carbonyls were lower in broilers fed a low-oxidized antioxidant-supplemented treatment. The results demonstrate that dietary antioxidants can minimize the oxidative instability of proteins and lipids, and the protection may be linked to improved cellular antioxidant enzymatic activity.

Inhibition of lipid oxidation and rancidity in precooked pork patties by radical-scavenging licorice (Glycyrrhiza glabra) extract.

This study investigated the efficacy of licorice extract (LE) to curtail lipid oxidation and protect sensory attributes of ground pork during refrigerated and frozen storage. Pork patties (20% fat) were formulated with 0%, 0.02%, 0.05%, and 0.1% (meat basis) LE or rosemary extract (RE) as comparison or 0.01% (fat basis) BHA with 0 or 1.5% NaCl. Raw and precooked (75 °C) patties were packaged in polyvinylchloride overwrapped trays and stored at 2 °C up to 7 and 14 d, respectively, or at -20 °C up to 6 mo. Lipid oxidation (thiobarbituric acid-reactive substances [TBARS]) and sensory attributes of stored patty samples were evaluated, radical scavenging activity of the LE was measured, and the active phenolic compounds were identified. Cooking yield (<85%) was similar among antioxidant treatments, and lipid oxidation was minimal in refrigerated or frozen raw samples. However, TBARS values in refrigerated precooked control patties (0.22 mg/kg) rose to 9.3 to 9.4 mg/kg after 14 d, compared to 3.4 to 4.4 and 4.4 to 6.9 mg/kg in patties treated with 0.1% LE and RE, respectively. In frozen precooked samples, TBARS (0.22 mg/kg) increased to 1.3 mg/kg (P < 0.05) in control patties after 6 mo and had no significant change in patties treated with 0.1% LE or 0.01% butylated hydroxyanisol. Sensory panel evaluation confirmed strong inhibition of rancidity production by LE, corroborating its remarkable antiradical activity due to the presence of multiple phenolics. The results indicate that licorice has great potential as a natural antioxidative additive to extend the shelf-life of precooked pork.

Synergistic inhibition of lipid oxidation by pea protein hydrolysate coupled with licorice extract in a liposomal model system.

Fourteen pea protein hydrolysates (PPHs) were prepared using different proteases and tested for antioxidant activity in a liposomal model system under oxidative stress (100 µM FeCl3/2 mM ascorbate). Almost all PPHs inhibited lipid oxidation, and those prepared from heated protein with Flavourzyme (Fla-PPH) or Protamex (Pro-PPH) were the most effective. Remarkable synergistic effects were observed on both Fla-PPH and Pro-PPH with licorice extract (LE). Electron microscopy revealed a self-assembled network that appeared to provide crucial protection of liposome against oxidation. The presence of LE enhanced the antioxidant potential by producing a more compact network apparently via PPH-LE complexation. Zeta-potential measurements suggested electrostatic interactions are important driving forces for the accumulation of active peptides at the liposome interface. Peptides rich in leucine, lysine, glutamic acid, glutamine, valine, or proline with a hydrophobic N-terminus, as identified by mass spectrometry, were implicated in the antioxidative protection.

Extreme pH treatments enhance the structure-reinforcement role of soy protein isolate and its emulsions in pork myofibrillar protein gels in the presence of microbial transglutaminase.

Alkali (pH(12)) and acid (pH(1.5)) pH-treated soy protein isolates (SPI) were incorporated (0.25-0.75% protein) into sols of myofibrillar protein (MP, 3%, in 0.6 M NaCl at pH 6.25) with or without 0.1% microbial transglutaminase (TG) to investigate the potential as meat processing ingredients. Static and dynamic rheological measurements showed significant enhancements of MP gelling ability by the inclusion of pH(1.5)-treated as well as preheated SPI (90 °C, 3 min). A 7-h incubation with TG accentuated the gel-strengthening effect by these SPI samples. The B subunit in 11S of SPI was the main component manifesting structure reinforcement in the mixed gels. The MP gelling properties were also greatly improved (P<0.05) by the addition of 10% canola oil emulsions stabilized by pH-treated SPI. The principal force in the MP gels incorporated with pH-treated SPI was hydrophobic patches; in the presence of TG, cross-linking of previously dissociated A and B subunits of 11S was also intimately involved.

Textural attributes and oxidative stability of pork longissimus muscle injected with marbling-like emulsified lipids.

The objective of the study was to create marbling-like fat in lean pork with acceptable oxidative stability through the injection of canola/olive oil-substituted emulsions. Pork loins were injected with 5% water as control (CW) or 5% emulsion containing no tocopherols (E) or 0.07% tocopherols (ET) and stored at 2 °C in an oxygen-enriched package for up to 3 weeks. Lipid oxidation was totally inhibited in ET pork but increased 3-fold to 0.20mg malonaldehyde/kg in CW and E pork after 3 weeks. ET treatment also had a positive effect on meat red color. Emulsion-containing pork, showing less protein oxidation (carbonyl and disulfide formation), had reduced drip loss and shear force than CW samples (P<0.05). The results indicated that incorporation of antioxidant-containing emulsions could create marbling-like texture in lean pork without compromising oxidative stability.

Role of disulphide linkages between protein-coated lipid droplets and the protein matrix in the rheological properties of porcine myofibrillar protein-peanut oil emulsion composite gels.

The objective of the study was to establish disulphide interaction between protein-coated oil droplets and the surrounding protein matrix in myofibrillar protein (MP)-emulsion composite gels. An MP-stabilized peanut oil emulsion was treated with 0, 1, 3, 5 and 10 mM N-ethylmaleimide (NEM, a sulphydryl-blocking agent) and subsequently incorporated into a bulk MP sol to produce 5%-lipid, 2%-protein composites at pH 6.2. About 69% of sulphydryls in the emulsion (1% protein) were blocked by 1 mM NEM, and almost all were bound at ≥3 mM NEM. The loss of free sulphydryls resulted in a significant drop in the storage modulus (G') and rupture force of the composite gels. Microstructural examination revealed pores and oil leakage from emulsion droplets by NEM treatments, corresponding to declining rheological properties of the MP-emulsion composites. The results supported the hypothesis that disulphide cross-linking between MP-coated oil droplets and protein matrix contributed to the stabilization and reinforcement of protein-emulsion composite gels formed in comminuted muscle foods.

Chromatographic separation and tandem MS identification of active peptides in potato protein hydrolysate that inhibit autoxidation of soybean oil-in-water emulsions.

A previously developed antioxidative potato protein hydrolysate was fractionated using gel filtration. The efficacy of different fractions for inhibiting lipid oxidation in soybean oil-in-water emulsions, neutralizing 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+*)) radicals, and chelating prooxidative metal ions was investigated. Low-molecular-weight fraction Peak 3 (709 Da) exhibited the strongest antioxidant activity and radical scavenging activity. Active peptides based on the ABTS(+*) scavenging assay were isolated by RP-HPLC and purified by UPLC. The amino acid sequence determination by MS/MS identified eight prominent peptides in the antioxidative Peak 3 fraction, of which Thr-Tyr, Tyr-Phe-Glu, Tyr-Ser-Thr-Ala, and Asn-Tyr-Lys-Gln-Met matched the sequence of papatin.