Synergistic inhibition of lipid and protein oxidation in refrigerated pork by a chitosan-based composite film incorporated with ZnO and lysine-modified walnut melanin.

Protein and lipid oxidation and their inhibition by various washing media were monitored during the preparation of beef heart surimi-like material. Lipid oxidation was measured as increases in thiobarbituric acid (TBA)-reactive substances and conjugated dienes, and protein oxidation was determined as formation of protein carbonyls. Water-soluble antioxidant tripolyphosphate (0.2%) and lipid-soluble antioxidants propyl gallate (0.02%) and α-tocopherol (0.2%), added to the washing solution, were effective inhibitors of both lipid and protein oxidation. Ascorbate (0.2%) also inhibited lipid oxidation but caused an increase in protein carbonyls. Phosphate buffer (25 mM NaH2PO4/Na2HPO4), high final pH (7.0) of surimi pellet, and the presence of salt (0.1 M NaCl) all inhibited both protein and lipid oxidation during storage. Several processing options are thus available for the preparation of shelf-stable surimi-like material from beef hearts for possible utilization in formulated meat products. Keywords: Beef ...

Protein bar hardening negatively impacts shelf life, quality, and consumer acceptance. Although oxidation is known to negatively affect the flavor and texture of foods, the specific roles of lipid and protein oxidation in bar hardening have not been thoroughly investigated. Furthermore, most research has concentrated on dairy proteins, with a notable lack of studies addressing the hardening of plant-based protein bars. We investigated the role of protein and lipid oxidation, Maillard reactions, moisture loss, protein aggregation, and microstructural changes in the hardening of pea, whey, and rice protein bars over a storage period of 6weeks (hardness increased 7.2×, 5.4×, and 4.4×, respectively). Changes in tryptophan fluorescence, free sulfhydryl content (e.g., loss of 57% for pea and 44% for whey), and carbonyl content demonstrated that pea and whey bars underwent protein oxidation. Lipid oxidation also occurred, demonstrated by increased peroxide and thiobarbituric acid-reactive substance values. Rice bars, however, did not undergo oxidation. Mass spectrometry indicated greater Maillard-reaction-related protein glycations formed in pea and whey bars (6.9% and 7.7%, respectively) than in rice bars (2.1%). SDS-PAGE revealed that pea and whey, but not rice, proteins aggregated during storage. Overall, this study found that moisture loss, protein and lipid oxidation, Maillard reactions, and protein aggregation correlated with bar hardening. Chemical changes may cause protein aggregation, resulting in hardening. Likely because of rice proteins' innate insolubility and disulfide linkages, rice protein bars were less susceptible to chemical changes and aggregation and hardened more slowly than whey and pea protein bars. PRACTICAL APPLICATION: This study shows that lipid and protein oxidation are correlated with protein bar hardening in both pea and whey protein bars. Additionally, this work suggests that rice protein bars may harden more slowly than pea and whey bars. These findings suggest that potential strategies to prevent bar hardening and extend shelf life include (1) adding antioxidants to prevent oxidation and (2) using rice proteins to partially or fully substitute other protein isolates.

A biodegradable packaging film containing cellulose nanofibers from olive tree pruning, a by-product of olives production, was obtained using a solvent casting method. Nanocellulose was added to polyvinyl alcohol (PVA) to enhance the technological properties of the composite film as food packaging material. Nanocellulose was obtained from unbleached and bleached pulp through a mechanical and TEMPO pretreatment. Crystalline and chemical structure, surface microstructure, UV and gas barrier, optical, mechanical and antioxidant properties, as well as thermal stability were evaluated. Regarding optical properties, the UV barrier was increased from 6% for the pure PVA film to 50% and 24% for unbleached and bleached nanocellulose, respectively. The antioxidant capacity increased significantly in unbleached mechanical nanocellulose-films (5.3%) compared to pure PVA film (1.7%). In terms of mechanical properties, the tensile strength of the 5% unbleached mechanical nanocellulose films was significantly improved compared to the pure PVA film. Similarly, the 5% nanocellulose films had increased the thermal stability and improved barrier properties, reducing water vapor permeability by 38–59% and presenting an oxygen barrier comparable to aluminum layer and plastic films. Our results support the use of the developed films as a green alternative material for food packaging.

In order to solve the problems of traditional plastic packaging materials like poor degradability and insufficient active packaging function, this study successfully designs and synthesizes tannic acid (TA)‐titanium (Ti) dual network coated hydrotalcite‐like layered clay (LDHs@TA‐Ti) and catechol grafted chitosan (C‐CS) based on the principle of mussel bionics. And a novel idea is first put forward to fabricate LDHs@TA‐Ti/C‐CS/polyvinyl alcohol (PVA) nanocomposite films by solution casting method. The result of infrared and thermal analysis indicate that strong interfacial interaction is formed in the nanocomposites, which leads to the limitation of molecular chain movement and the increase of glass transition temperature. Although the addition of LDHs@TA‐Ti significantly increases the crystallization temperature, the crystallinity does not change significantly. The water resistance, UV barrier, tensile strength and antibacterial properties of the final nanocomposite films are improved significantly, and all the films show good transparency in the visible range. Especially when the addition amount of LDHs@TA‐Ti reaches 1 wt%, compared with C‐CS/PVA composite film, the UV (at 300 nm) barrier property and tensile strength are increased by 36.3% and 45.1% respectively. Therefore, LDHs@TA‐Ti/C‐CS/PVA nanocomposite films show great potential as environmentally friendly active packaging films or coatings in extending the shelf life of food products.

The antioxidant activity of berry phenolics (at concentrations of 1.4, 4.2, and 8.4 mug of purified extracts/mL of liposome sample) such as anthocyanins, ellagitannins, and proanthocyanidins from raspberry (Rubus idaeus), bilberry (Vaccinium myrtillus), lingonberry (Vaccinium vitis-idaea), and black currant (Ribes nigrum) was investigated in a lactalbumin-liposome system. The extent of protein oxidation was measured by determining the loss of tryptophan fluorescence and formation of protein carbonyl compounds and that of lipid oxidation by conjugated diene hydroperoxides and hexanal analyses. The antioxidant protection toward lipid oxidation was best provided by lingonberry and bilberry phenolics followed by black currant and raspberry phenolics. Bilberry and raspberry phenolics exhibited the best overall antioxidant activity toward protein oxidation. Proanthocyanidins, especially the dimeric and trimeric forms, in lingonberries were among the most active phenolic constituents toward both lipid and protein oxidation. In bilberries and black currants, anthocyanins contributed the most to the antioxidant effect by inhibiting the formation of both hexanal and protein carbonyls. In raspberries, ellagitannins were responsible for the antioxidant activity. While the antioxidant effect of berry proanthocyanidins and anthocyanins was dose-dependent, ellagitannins appeared to be equally active at all concentrations. In conclusion, berries are rich in monomeric and polymeric phenolic compounds providing protection toward both lipid and protein oxidation.

This study aimed at investigating protein and lipid oxidation during frozen storage of rainbow trout. Rainbow trout fillets were stored for 13 months at -20, -30, or -80 degrees C, and samples were analyzed at regular intervals for lipid and protein oxidation markers. Lipid oxidation was followed by measuring lipid hydroperoxides (PV), as well as secondary oxidation products (volatiles) using dynamic headspace GC-MS. Free fatty acids (FFA) were measured as an estimation of lipolysis. Protein oxidation was followed using the spectrophotometric determination of protein carbonyls and immunoblotting. Significant oxidation was observed in samples stored at -20 degrees C, and at this temperature lipid and protein oxidation seemed to develop simultaneously. FFA, PV, and carbonyls increased significantly for the fish stored at -20 degrees C, whereas the fish stored at -30 and -80 degrees C did not show any increase in oxidation during the entire storage period when these methods were used. In contrast, the more sensitive GC-MS method used for measurement of the volatiles showed that the fish stored at -30 degrees C oxidized more quickly than those stored at -80 degrees C. Detection of protein oxidation using immunoblotting revealed that high molecular weight proteins were oxidized already at t = 0 and that no new protein oxidized during storage irrespective of the storage time and temperature. The results emphasize the need for the development of more sensitive and reliable methods to study protein oxidation in order to gain more explicit knowledge about the significance of protein oxidation for food quality and, especially, to correlate protein oxidation with physical and functional properties of foods.

ObjectivesOxidation is a major contributor to degradation of color and flavor in ground beef. Mushrooms have been shown to inhibit lipid oxidation when added to meat products. One of the major components in mushrooms that acts as an antioxidant is Ergothioneine, a compound that works as a free radical scavenger. The objective of this study was to evaluate the impact of mushroom addition to ground beef patties on lipid and protein oxidation, cohesiveness, and color.Materials and MethodsIn addition to a control containing no mushrooms, 4 treatments were used; chopped, whole mushroom; dried mushroom powder; aqueous extract; and residue remaining after extraction. Half of the patties for each treatment were packaged in aerobic over-wrap packaging while the remaining patties were packaged using modified atmosphere packaging (MAP) containing 70% nitrogen, 30% CO2, and 0.4% carbon monoxide. Patties were stored in a cooler at approximately 36°F for 4 d, cooked, and tested by Thiobarbutiric acid (TBA) assay for lipid oxidation, Dinitrophenyl hydrazine (DNPH) assay for protein oxidation, and resistance to tear (RTT) for cohesiveness. Patty color was measured daily during storage by Hunter L*a*b* using a colorimeter (Minolta CR-300 series). All statistical analyses were performed using Statistical Analysis Software (SAS; SAS Inst. Inc., Cary, NC).ResultsLipid oxidation levels were significantly (p < 0.05) lower for the aerobic and MAP whole, powder, and extract samples compared to the aerobic control. Patties with mushroom residue in both packaging treatments had significantly higher levels of lipid oxidation than other mushroom treatments and the control. After 4 d, MAP patties exhibited significantly lower a*(redness) values than those packaged aerobically with the exception of the aerobically packaged mushroom powder treatment, which also had significantly lower redness compared to the aerobic treatments. Although the results were not significant, a trend can be seen among the data showing that patties treated with whole mushroom or residue tend to have lower redness values. Free carbonyls and cohesiveness did not differ among mushroom or packaging treatments. There were no observed differences (p = 0.4581) in protein oxidation among treatments, indicating mushrooms may preferentially inhibit pathways for lipid oxidation rather than protein oxidation. There were also no observed differences among treatments for patty cohesiveness (p = 0.875).ConclusionIn conclusion, adding whole, powdered or extracted mushroom inhibits lipid oxidation in ground beef patties, but does not significantly affect protein oxidation or cohesiveness. Although powdered mushroom effectively inhibits lipid oxidation, it triggers pigment oxidation causing patties to become an undesirable brown color rather. Among the treatments used, the most suitable for commercial production would be the mushroom extract because it significantly lowered lipid oxidation while allowing the patties to retain a bright cherry red color. In the future, sensory testing is needed to determine if consumer perception matches the laboratory results.

Spatiotemporal assessment of lipid and protein oxidation is key for understanding quality deterioration in emulsified food products containing polyunsaturated fatty acids. In this work, we first mechanistically validated the use of the lipid oxidation-sensitive fluorophore BODIPY 665/676 as a semi-quantitative marker for local peroxyl radical formation. Next, we assessed the impact of microfluidic and colloid mill emulsification (respectively producing mono- and polydisperse droplets) on local protein and lipid oxidation kinetics in whey protein isolate (WPI)-stabilized emulsions. We further used BODIPY 581/591 C11 and CAMPO-AFDye 647 as colocalisation markers for lipid and protein oxidation. The polydisperse emulsions showed an inverse relation between droplet size and lipid oxidation rate. Further, we observed less protein and lipid oxidation occurring in similar sized droplets in monodisperse emulsions. This observation was linked to more heterogeneous protein packing at the droplet surface during colloid mill emulsification, resulting in larger inter-droplet heterogeneity in both protein and lipid oxidation. Our findings indicate the critical roles of emulsification methods and droplet sizes in understanding and managing lipid oxidation.

Sea bass (Lateolabrax japonicus), a marine fish, is prone to spoilage due to its high nutritional value. Preservatives are commonly used for storage for the production of fish fillets. In this work, chitosan (CS) was grafted onto chlorogenic acid (CA) to obtain a new preservative, chitosan grafted chlorogenic acid (CS-g-CA), which could enhance the biochemical properties of chitosan and obtain better antibacterial and antibacterial properties. This study therefore investigated the inhibitory effects of CS-g-CA on antioxidant enzyme activity, and lipid and protein oxidation of sea bass fillets stored at 4 °C. Compared with the control group on day 9, the activity of 63% catalase (CAT), 78% superoxide diamidase (SOD), 73% glutathione peroxide enzyme (GSH-Px) and 60% DPPH scavenging activity was retained by CS-g-CA treatment. Changes in thiobarbituric acid (TBA) and conjugated diene (CD) values were delayed by CS-g-CA treatment. The use of CS-g-CA retards protein oxidation by inhibiting the formation of free amino acid and carbonyl groups, and maintaining a higher sulfhydryl content. Regarding myofibril degradation, CS-g-CA could maintain protein secondary structure by increasing the ratio of α-helices. Chitosan-grafted chlorogenic acid could protect the activity of antioxidant enzymes and inhibit lipid oxidation by slowing down the production of lipid oxidation products. It also delayed protein oxidation by inhibiting oxidation product generation and stabilizing protein structure. It could therefore be used as a promising preservative for seafood. © 2022 Society of Chemical Industry.

Oxidation of lipid and protein in horse mackerel ( Trachurus trachurus) mince and washed minces during processing and storage

Protein and lipid oxidation in meat: A review with emphasis on high-pressure treatments

Fresh beef is a typically perishable food because of its high water and protein content; thus, it requires proper packaging condition and storage temperature to ensure its quality. In this study, the beef steaks were stored at 4°C under HiO2 modified atmosphere packaging (MAP) (78.8% O2 + 18.8% CO2 + 2.4% N2) and HiCO2 MAP (60.0% CO2 + 40.0% N2). The traditional air packaging (AP) and vacuum packaging (VP) were used as the controls. The total viable count (TVC), colour, water holding capacity (WHC), myofibrillar protein (MP) oxidation and lipid oxidation of beef meat were investigated. The moisture distribution and migration were also analysed using the low‐field nuclear magnetic resonance (LF‐NMR). The association amongst all parameters was analysed by correlation analysis and principal component analysis (PCA). The results showed that the TVC values in the HiCO2 MAP (5.6 log CFU/g) steaks were lower than those of VP (5.9 log CFU/g), AP (7.0 log CFU/g) and HiO2 MAP (6.3 log CFU/g) steaks because of the sufficient CO2 after 15 days of chilled storage. The bright red colour and the higher WHC were maintained in the HiO2 MAP steaks than in the AP group during storage. However, higher levels of protein and lipid oxidation also occurred. The beef steaks stored under HiCO2 MAP had the lowest protein and lipid oxidation and highest value of immobile water content and WHC, however, similar to the VP group, the bright red colour was not shown. The moisture attributes (drip loss, cooking loss and P23), protein oxidation (protein solubility and carbonyl content) and lipid oxidation (TBARS value) have shown a close correlation by correlation analysis and PCA. Overall, two different packaging methods of MAP can prolong microbial‐shelf life and maintain higher WHC of beef steaks compared to AP and VP steaks, but higher oxidation level in HiO2 MAP and unattractive colour in HiCO2 MAP are concerns that need to be addressed.

With the demand for the reduction in sodium consumption, low-salt dry-cured fish as a traditional preserved food has gained growing popularity. However, the salt reduction affects adversely the shelf-life of dry-cured fish. This study aimed at evaluating the quality changes of low-salt dry-cured black carp packaged under vacuum during storage and constructing a predictive model for the shelf life based on quality indicators. Four-degree Celcius storage delayed the lipid and protein oxidation in comparison with that of 25°C, and the sensorial shelf life of the dry-cured black carp stored at 4 and 25°C were 20 and 30 days, respectively. The odor was found to be more sensitive in revealing the quality deterioration among all sensorial indicators. Pearson correlation analysis showed that the TBARS and TVC value had a higher correlation with the sensory score, and the shelf life predictive model based on TBARS and TVC value showed high accuracy, indicating the predictive model constructed is effective for predicting the shelf life of low-salt dry-cured black carp. Novelty impact statement Four-degree celcius (4°C) of storage can delay the process of protein and lipid oxidation, and the odor is sensitive in revealing the quality deterioration of low-salt dry-cured black carp. The TBARS and TVC values have a higher correlation with sensory quality, and the predictive models based on TBARS and TVC can be a reliable tool for shelf life prediction.

PurposeBlack cumin (Nigella sativaL.) is well known for its strong, hot, peppery taste and has many nutritional, pharmaceutical and traditional therapeutic uses. The aim of this study was to investigate the antioxidant effect of different solvent extracts of black cumin seed to retard lipid and protein oxidation in raw ground pork meat during refrigerated storage (4 ± 1°C) for nine days.Design/methodology/approachBlack cumin extracts (BCEs) were prepared using different solvents, namely, ethanol, water, ethanol:water (60:40) and methanol:hot water (60:40). Extracts were analysed for total phenolic content (TPC), 1,1 diphenyl-2-picrylhydrazil (DPPH) radical scavenging activity and reducing power. Based on the results, water extract (WE) and ethanol–water extract (EHWE) of black cumin were selected and incorporated at 1.5 per cent into freshly minced pork meat and compared with a synthetic antioxidant, butylated hydroxytoluene (BHT; 100 ppm), in retarding lipid and protein oxidation. Treated and control samples were aerobically packed in low-density polyethylene bags for analysis of various parameters (pH, colour and odour score, peroxide, lipid and protein oxidation) during nine-day refrigerated storage study.FindingsResults showed that BCEs had a good amount of TPC (4.4-7.4 mg gallic acid equivalents/g) and also DPPH scavenging activities (33.96-44.23 per cent), with WE and EHWE extracts showing highest reducing power and promising antioxidant capacity. Hence, BCEs (WE and EHWE) incorporated at 1.5 per cent into freshly minced pork meat was tested, compared to BHT (100 ppm) and control samples, in retarding lipid and protein oxidation during storage. In BCE-treated samples, thiobarbituric acid reacting substances, free fatty acids, peroxide, formation of protein carbonyls and off-odour or rancid odour development were lower than control and values were comparable with BHT. Incorporation of BCE did not negatively affect the colour of ground pork.Originality/valueBCEs (WE and EHWE) at 1.5 per cent inhibited protein and lipid oxidation and it could be exploited commercially as an effective alternative in retarding oxidative deterioration of meat products.

Insights into the characteristics and molecular transformation of lipids in Litopenaeus vannamei during drying from combined lipidomics