Primary Oxidation Research Articles

Comparison of efficacy of various natural and synthetic antioxidants in stabilizing the fish oil

Use of antioxidants (natural and synthetic) can retard oxidative degradation of fish oil having n-3 PUFA. The performance of each antioxidant is found to be affected by the composition of the oil, presence of impurities and storage condition. Hence an attempt was made to find the efficacy of catechin, resveratrol, β-carotene, caffeic acid, sinapic acid, ellagic acid, ferulic acid, vanillic acid, quercetin, rutin, TBHQ, BHA, and BHT at a concentration of 0.9 mM in the bulk fish oil, stored for 50 days exposed to air at 25°C under darkness. The extent of primary and secondary oxidation of the stored oil was determined every 5 days and were compared. The efficacy of TBHQ followed by BHA and BHT was found to be highest among all the antioxidants studied. Among the natural antioxidants, resveratrol and catechin were found to exhibit superior efficacy, whereas β-carotene was found to exhibit proxidant behavior. Novelty impact statement This is the first comprehensive study carried out to find the most effective antioxidant involving ten natural and three synthetic antioxidants in n-3 PUFA containing fish oil. TBHQ exhibited superior efficacy among all the antioxidants tested and at a concentration of 0.9 mM, the change in TOTOX value by the end of 40 days of storage was about 80%. None of the other antioxidants studied here, exhibited such superior stability. Among the natural antioxidants, resveratrol and catechin were found to be superior.

Fabrication, characterization, and oxidative stability of perilla seed oil emulsions and microcapsules stabilized by protein and polysaccharides

Perilla oil (PO) has a high unsaturated fatty acids content that is easily oxidized, causing nutritional and functional losses. This study investigated the fabrication of PO in emulsion and microcapsules using whey protein isolate (WPI), gum acacia (GA), maltodextrin (MD), and OSA-starch as wall materials, aiming to improve the oxidative stability and functionality of the PO. The results showed that both OSA-starch stabilized emulsion and microcapsules exhibited slower increases in peroxide and p-anisidine values and a slower decrease in antioxidant capacity than those produced with WPI/GA, WPI/MD, and WPI/GA via complex coacervation. The microcapsules fabricated with OSA-starch gave a better polydispersity index, encapsulation efficiency, and oxidative stability than the other samples, suggesting effective protection against primary and secondary oxidation during storage. Moreover, the oxidation stability of the emulsions and microcapsules could be improved via complex coacervation, although this technique could result in a larger droplet size. Overall, this study contributed to the knowledge of PO emulsions and microcapsules fabrication using protein and polysaccharides and provided insights for improving PO's oxidative stability and functionality. Novelty impact statement Perilla oil can be successfully encapsulated by OSA-starch-based carriers. The study contributed to the knowledge of perilla oil emulsions and microcapsules fabrication and provided insights for improving perilla oil's oxidative stability and functionality.

Possibilities of using the continuous type of UV light on the surface of lor (whey) cheese: impacts on mould growth, oxidative stability, sensory and colour attributes during storage.

This research paper addresses the hypothesis that the optimum doses of a continuous type of ultraviolet (UV) light applied to the surface of lor (whey) cheese needs to be identified to maximize mould inactivation and shelf life while minimizing quality deterioration. Therefore, the mould inactivation, protein and lipid oxidation products, sensory and colour attributes of lor cheese subjected to different doses of UV light (1.617, 4.018, and 36.832 kJ/m2) in a continuous type of UV system were evaluated. UV treated samples presented mould counts lower than those of untreated ones. UV treatment at more than 4.018 kJ/m2 allowed around 0.7-2.7 log reductions on mould growth during storage. The increase in UV light dose caused significant increases in primary and secondary lipid oxidation products. In particular, the highest doses applied to the surface of cheese samples had the highest values of protein carbonyls, as well as lipid oxidation products. Strong positive correlations were recorded between lipid and protein oxidation markers. Exposure to the highest doses of UV light increased foreign flavour perception, probably due to the oxidative reactions. The results indicated that the application of UV light to the lor cheese surface allowed delaying mould growth during storage but extreme doses could induce lipid and protein oxidation reactions, leading to quality deterioration.

Characterization of cinnamon essential oil and its application in Malva sylvestris seed mucilage edible coating to the enhancement of the microbiological, physicochemical and sensory properties of lamb meat during storage.

Firstly, Cinnamomum zeylani essential oil (CZEO) was isolated and characterized. Secondly, CZEO was used in Malva sylvestris mucilage (MSM) coating and its antioxidant and antimicrobial effects on lamb meat slices were evaluated in 10 days at 4°C. The main chemical compounds and functional groups of the CZEO were identified and quantified by a gas chromatograph coupled to a mass spectrometer and by an Fourier transform infrared spectrometer respectively. The total phenol and flavonoid contents of CZEO were determined by the Folin-Ciocalteu reagent-based and aluminium chloride methods respectively. Various microbiological, physicochemical analyses and sensory evaluations were also utilized regarding the coated lamb meat slices. CZEO contains benzyl benzoate (40.93%), caryophyllene oxide (26.07%) and (E)-cinnamaldehyde (13.01%), with strong radical scavenging activity and antibacterial effect against investigated pathogenic microorganisms. The CZEO-loaded MSM edible coating greatly postponed the growth of microorganisms and extended the product life (>10 days). The pH value, moisture content and hardness of the samples were also preserved more efficiently when high concentrations of the essential oil were incorporated into the edible coating (p < 0.05). The CZEO-rich MSM coating was also able to possess considerable activity against lipid oxidation in lamb meat samples, and significantly decreased the production of primary and secondary oxidation products (p < 0.05). Moreover, sensory parameters of the samples were preserved more efficiently during cold storage when the CZEO-enriched edible coating, particularly MSM + 2% CZEO was used. The use of edible coating based on MSM and CZEO is therefore effective in reducing microbial growth and chemical reactions in lamb meat during the storage period. The importance of the results of this study is in order to increase the use of natural preservatives, maintain food safety and of course the health of the people in the community.

Sulfide Variation in the Coeur Rochester Silver Deposit: Use of Geologic Block Modeling in the Prediction and Management of Mine Waste

Abstract A critical issue in mine waste management is the management and mitigation of acid rock drainage and metal leaching particularly from waste rock. This requires good understanding and characterization of materials most likely to generate acid pH waters and generate leachable metals and metalloids, as well as the presence of minerals most likely to neutralize acidic pH such as carbonates and certain silicates. For low-sulfidation epithermal deposits in silica-rich volcanic rocks, neutralization minerals are rare. Consequently, determination of acid generation is almost entirely a function of sulfide content of the rocks. By understanding the distribution of sulfide minerals within such a deposit, an initial mine waste management plan can be developed. The Rochester mine currently exploits a low-sulfidation epithermal gold-silver deposit and is located on the southern flank of the Humboldt Range in west-central Nevada. The Rochester mine is a conventional open-pit mining operation with cyanide heap leaching and Merrill Crowe processing. Silver and lesser gold mineralization occur associated with sulfide minerals hosted in Permian-Triassic Koipato Group rhyolitic units with extensive quartz-sericite-pyrite alteration. Gangue mineralogy of the deposit is dominated by slow or unreactive silicate minerals with little or no carbonate. Silver-bearing mineralization was controlled by primary hypogene sulfides and secondary supergene oxidation processes, and most of the mineralized material mined to date has been fully or partially oxidized. Oxidation mobilizes and depletes all forms of sulfur from primary sulfide minerals. Due to the low sulfate content and low content of neutralizing gangue phases, the waste rock classification can be based on total sulfur content. Based on the analysis of pulp samples collected from within the mine area, a sulfur block model was developed and compared to the results of standard acid-base accounting and net acid generation tests. This comparison demonstrates the benefit of the block model in identifying zones of potentially acid-generating material in the mined waste. Application of this information to mine planning has allowed more efficient management of acid-generating mine waste by allowing the operator to develop areas of the waste rock facility to receive the waste in a timely fashion. Such an approach is based on good mine geologic and mineralogical characterization and the use of a representative and comprehensive geologic block model.

Multi-omics revealed the formation mechanism of flavor in salted egg yolk induced by the stages of lipid oxidation during salting

To explore the contribution of different lipid oxidation stages to flavor formation in salted egg yolk, potential pathways of flavor formation were characterized by multi-omics strategy and partial least squares structural equation model (PLS-SEM). 72 lipids, 135 metabolites and 5 volatiles related to lipid oxidation were screened out. The degradation of aldehydes and ketones, and the generation of tryptamine and elaidic acid, etc. were promoted by triglycerides (TG) (10:0 16:0 18:1), triglycerides (TG) (18:0 20:1 22:0), etc. at primary and secondary oxidation stage, respectively. The generation of acetophenone, thianaphthene, etc. through the pathway of 2-phenylacetamide, hexanoylcarnitine, etc. was facilitated by these triglycerides (TG) at primary oxidation stage. Furthermore, amino acid metabolisms, pentose phosphate pathway and linoleic acid metabolism occurred at secondary oxidation stage were key pathways to form distinctive flavor. In conclusion, secondary oxidation stage may be more important for the formation of unique flavor (taste) in salted egg yolk.

Designing covalent sodium caseinate-quercetin complexes to improve emulsifying properties and oxidative stability

The complexation of proteins with phenolic compounds has been considered a promising route to improve the oxidative stability of oil-in-water (O/W) emulsions. In this context, physicochemical and techno-functional properties of sodium caseinate (SC) chemically modified by the interaction with quercetin (Q) under alkaline conditions were evaluated using different molar ratios of the components (SC:Q). The formation of covalent complexes was analysed by the changes in SC structure and properties.. The results showed that the surface hydrophobicity of SC gradually decreased with increasing Q concentration. Whereas an increase in phenolic content and antioxidant activity by DPPH and FRAP was observed. The techno-functionality of the complexes was evaluated by their capacity of stabilizing oil-in-water emulsions. The emulsion stabilized by complexes and non-modified SC showed an average droplet size (D4.3) between 1,632 ± 0,068 and 1,945 ± 0,431 µm. After 21d of storage, no coalescence was observed, evidencing the formation of stable emulsions. Furthermore, the highest oxidative stability of the emulsion was observed at the highest concentration of Q, while the formation of hydroperoxides and aldehydes was greater in the emulsions stabilized with non-modified SC. The formation of primary lipid oxidation compounds was approximately 3x higher in emulsions stabilized only with SC compared to those stabilized with the SC:Q complex in a 1:1 ratio. These results suggest that modification of SC with Q is a potential approach tuning both chemical and techno-functional properties of SC.

Changes in physicochemical characteristics of rice bran oil during mechanical‐stirring and ultrasonic‐assisted enzymatic degumming

AbstractThe current study investigated the comparison of enzymatic (phospholipase A1) degumming of crude rice bran oil on the mechanical‐stirring and ultrasonic‐assisted systems. The effect of process parameters like, water (1.5%, 2%, 2.5%, 3%, and 3.5%) and enzyme dosage (1.2, 1.8, 2.4, 3, and 3.6 ml/kg) and temperature (35, 40, 45, 50, and 55°C) was studied for mechanical‐stirring enzymatic degumming process. The maximum removal of phospholipids by mechanical‐stirring enzymatic degumming was observed with 3% water and 3.6 ml/kg of the enzyme at 40°C. Using the optimized levels of water, enzyme, and temperature, enzymatic degumming was carried out under ultrasonication with different power levels (20%, 30%, 40%, and 50%). The ultrasonic power level of 325 W (50% amplitude) showed maximum phospholipid removal with lesser time. Compared to mechanical‐stirring enzymatic degumming, ultrasonic‐assisted enzymatic degumming had a higher cavitational yield, leading to enhanced enzyme activity and maximum phospholipids removal. The studies on the physicochemical properties showed that ultrasonic‐assisted enzymatic degumming induced hydrolytic rancidity and primary oil oxidation due to the cavitation effect. As a result, more emphasis should be paid to the oxidative stability of the oil in future applications.Practical ApplicationsDegumming is the preliminary and important step in the refining of oil. Chemical degumming approaches don't remove maximum phospholipids and also cause higher neutralized oil loss. Enzymatic degumming results in maximum removal of phospholipids from the oil but also takes a long time to reduce the phosphorus content below the desired level. The application of ultrasound on enzymatic degumming effectively increases the reaction rate in lesser time. The ultrasonic‐assisted enzymatic degumming also results in better oil quality and physio‐chemical parameters. So, ultrasound can be effectively applied to enzymatic degumming of rice bran oil.

Relationship between protein native conformation and ultrasound efficiency: For improving the physicochemical stability of water–in–oil emulsions

To reveal the relationship between the native conformation of proteins and ultrasound efficiency, the effects of ultrasound power (0–500 W) on the structures and properties of different types of proteins (sodium caseinate, CAS; whey protein isolate, WPI; chickpea protein isolation, CPI; and pea protein isolation, PPI) were investigated. The results showed that the extent of structural changes of proteins depended on their native conformation rather than their origin. Irregular coil proteins (CAS) were more sensitive to ultrasound treatment and showed intense changes in secondary structure (e.g., 26.1% decrease in α–helix and 39.4% increase in random coil). In globular proteins, the smallest particle size (108 nm) of CPI limited the efficiency of ultrasound. The improvement in functional properties of proteins depended on the extent of structural modifications. The enhancement of functional properties improved the physicochemical stability of water–in–oil (W/O) emulsions (e.g., the turbiscan stability index of CAS–added emulsion was reduced by 2.33; the primary and secondary oxidation products of lipid oxidation were reduced by 16.96% and 17.31%). However, the effects of ultrasound–treated CPI on the physicochemical stability of W/O emulsions was not significant. For proteins with small particle size, future research could consider the application of chemical/enzymatic means in combination with ultrasound to enhance their performance.

A unifying approach to lipid oxidation in emulsions: Modelling and experimental validation

Lipid oxidation is a longstanding topic within the field of food technology, and is strongly related to loss of product quality and consumer acceptance. Both for bulk oils and emulsions, the chemical phenomena involved in lipid oxidation have been extensively researched, and various reaction pathways have been identified. They are different in bulk oil compared to oil-in-water (O/W) emulsions in which the oil–water interface plays a prominent role. Most probably because of the complexity of the reaction scheme in combination with mass transfer effects, there is no model that describes lipid oxidation in emulsions in a unified fashion, and that is the aim that we have set ourselves to achieve.We use lipid oxidation data previously obtained in O/W emulsions made with 5 different emulsifiers (2 surfactants, and 3 proteins), in well-mixed systems where the oxygen-to-oxidizable lipid ratio is strictly controlled. We use data pertaining to headspace oxygen concentration, and to primary and secondary lipid oxidation products to develop a model based on reaction kinetics, including not only the classical reaction scheme (starting from an unsaturated lipid, LH) but also radical initiation from hydroperoxides, which is thought to be an effect that is overlooked in the classical description of the initiation step.We were able to describe the course of the reactions in these emulsions using the same reaction rate constants for all emulsions, with the exception of the two related to radical-based initiation. In Tween 20- and Tween 80-stabilized emulsions, initiation stems most probably solely from decomposition of hydroperoxides; this implies that lipid oxidation in these emulsions is co-determined by the initial (“pre-existing”) hydroperoxide concentration. In protein-stabilized emulsions, on the other hand, lipid radical initiation is probably linked to reactions involving proteins (co-oxidation reactions), whereas initiation through decomposition of hydroperoxides seems less important, if at all. From this, we can conclude that the difference between both types of emulsions with regard to lipid oxidation mechanisms is related to differences in radical initiation.The developed model can serve as a unified basis for understanding lipid oxidation in emulsions, through which additional effects beyond the bare reaction kinetics, such as mass transfer effects, can be identified and used to e.g., quantify antioxidant effects, which is part of follow-up research.

Effects of Seed Roasting Temperature on Sesame Oil Fatty Acid Composition, Lignan, Sterol and Tocopherol Contents, Oxidative Stability and Antioxidant Potential for Food Applications.

Roasting is a key step for preparing sesame oil that leads to important changes in its organoleptic properties and quality. In this study, white sesame seeds were roasted for 20 min in an electric oven at different temperatures (120, 150, 180, 210, 250 and 300 °C). The oils extracted from unroasted and roasted seeds were compared for their chemical composition: fatty acids (including trans isomers), phytosterols, lignans (sesamin and sesamolin), tocopherols and total phenolic compounds, as well as their oxidative stability and antiradical capacity. There were no obvious differences in the oil densities, refractive indexes or iodine values, but the saponification values were affected by temperature. Relevant primary and secondary lipid oxidation were observed at T > 250 °C, resulting in a higher p-anisidine value and K232 as well as K268 values. Roasting improved oil yield (from 33.5 to 62.6%), increased its induction period (from 5.5 to 10.5 h) and enhanced the total phenolic content (from 152 to 194 mg/100 g) and antiradical activity of the extracted oil. Depending on roasting temperature, a gradual decline was recorded in total amounts of phytosterols (up to 17.4%), γ-tocopherol (up to 10.6%), sesamolin (maximum of 27.5%) and sesamin (maximum of 12.5%). All the investigated oils presented a low quantity in triglyceride polymers, clearly below the maximum tolerated quantity according to the European regulation. The optimal roasting temperature for obtaining high nutritional grade oil within the permissible values was 210 °C. The unsaponifiable components (including lignans and sterols) extracted from roasted seeds have been shown to be natural additives to fresh meatball products to extend shelf life. The results of this study may help to boost the nutritional content of plant-based diets by allowing for the use of roasted sesame seed oil and its components.

Investigation on thermal analysis and FTIR microscopic characteristics of artificially-oxidized coal and chronic naturally-oxidized coal during secondary oxidation

To reduce mine fire risk and ensure efficient resource utilization, an in-depth research must be conducted on the secondary oxidation of coal. Accordingly, the macroscopic oxidation characteristics and microscopic composition of newly-mined coal, artificially oxidized coal (the newly-mined coal oxidized at 70 °C and 180 °C) and repeated-mined coal (oxidized naturally over 10 years) were evaluated in this study. And these coal samples were labeled N, N-70, N-180, and R, respectively. The parameters indicating the oxidation characteristics of coal were analyzed by simultaneous thermal analysis-Fourier transform infrared spectroscopy (STA-FTIR) and Shimazu Fourier transform infrared spectrometry (FTIR-8400) from the perspective of coal thermal reaction and functional groups. The experimental results suggest that the temperature T2 required by N-70, N-180, and R to reach the oxidation stage was lower than that of N. In addition, CO and CO2 gases were released earlier from these coals than from N. The same release was earlier for N-180 and N-70 compared to that for R. Compared with N, the content of hydroxyl and aliphatic hydrocarbons in N-70, N-180 and R after the initial oxidation decreases, and the decrease of N-70, N-180 was greater than that of R. The content of oxygen-containing functional groups (-COOH, C=O, -COO-) increased significantly, and the increase for N-70, N-180 was greater than that of R. These results indicate that coal was more prone to secondary oxidization after primary oxidation. This is because the coal absorbed heat released during the primary oxidation and subsequently had a higher activity. The artificially-oxidized coal in the laboratory absorbed more heat and generated more oxygen-containing functional groups (-COOH, C=O, -COO-) than the chronic naturally-oxidized coal in the mine face, resulting in a higher risk of spontaneous combustion during secondary oxidation.

Effect of Rosemary Extract on Lipid Oxidation, Fatty Acid Composition, Antioxidant Capacity, and Volatile Compounds of Salted Duck Eggs.

The purpose of our study was to determine the impact of rosemary extract in duck eggs, as determined by in vitro antioxidant capacity, lipid oxidation, fatty acid profiles, and flavor analyses. Three groups of salted duck eggs were compared: A control group and group enriched with 0.1% and 0.5% (w/v) rosemary extracts for 28 days of salting. In a time-dependent manner, the radical scavenging activity and reduction power of eggs with 0.5% (w/v) rosemary extract were significantly higher those of the control at 28 days after salting. The fatty acid profiles of salted egg were significantly affected by rosemary extract and salting time. Palmitic acid was the most abundant fatty acid in salted egg treated with rosemary extract, followed by linoleic acid and arachidonic acid. Furthermore, the treated eggs contained more docosahexaenoic acid than the control ones. And the treated eggs also have a considerable impact on the lipid oxidation process (primary and secondary oxidation). As a result, rosemary extract can be used as a natural antioxidant spice to prevent oxidation and extend the shelf life of eggs during storage. Furthermore, flavor research using solid phase microextraction - gas chromatography - mass spectrometry and an electronic nose demonstrated that adding rosemary extract to salted eggs could give them a distinct flavor.

Chitosan/guar gum nanoparticles to stabilize Pickering emulsion for astaxanthin encapsulation

Pickering emulsions stabilized by biopolymers have been gaining increasing attention in recent years. In this work, chitosan/guar gum (CS/GG) nanoparticles were formed by hydrogen bond interactions between amino of CS and hydroxyl of GG. The surface charge and aggregation degree of CS/GG nanoparticles could be regulated by pH value to yield Pickering emulsion of superior quality. Emulsions had optimal physical stability at pH 6.0 and oil fraction of 0.6, with the lowest creaming index of 1.81 ± 0.21% after six months of storage at 4 °C. Contents of primary and secondary oxidation products stored at 37 °C for 30 days in Tween 80-stabilized emulsion are almost 1.46 and 1.66 times that of CS/GG-stabilized Pickering emulsion. These results indicated that CS/GG-stabilized Pickering emulsion had better lipid oxidation stability than Tween 80-stabilized emulsion. In addition, the retention rate of astaxanthin of CS/GG-stabilized astaxanthin Pickering emulsion (85.9 ± 0.57%) was higher than Tween 80-stabilized astaxanthin emulsion (66.12 ± 0.71%) stored at 37 °C for 30 days. This result indicated that the stability of CS/GG-stabilized astaxanthin-loaded Pickering emulsion was better than Tween 80-astaxanthin emulsion. This study provides a framework for applying Pickering emulsions formed using polysaccharide particles in functional foods.

Species Specificity and Selection of Models for Drug Oxidations Mediated by Polymorphic Human Enzymes.

Many drug oxygenations are mainly mediated by polymorphic cytochromes P450 (P450s) and also by flavin-containing monooxygenases (FMOs). More than 50 years of research on P450/FMO-mediated drug oxygenations have clarified their catalytic roles. The natural product coumarin causes hepatotoxicity in rats via the reactive coumarin 3,4-epoxide, a reaction catalyzed by P450 1A2; however, coumarin undergoes rapid 7-hydroxylation by polymorphic P450 2A6 in humans. The primary oxidation product of the teratogen thalidomide in rats is deactivated 5'-hydroxythalidomide plus sulfate and glucuronide conjugates; however, similar 5'-hydroxythalidomide and 5-hydroxythalidomide are formed in rabbits in vivo. Thalidomide causes human P450 3A enzyme induction in liver (and placenta) and is also activated in vitro and in vivo by P450 3A through the primary human metabolite 5-hydroxythalidomide (leading to conjugation with glutathione/nonspecific proteins). Species differences exist in terms of drug metabolism in rodents and humans, and such differences can be very important when determining the contributions of individual enzymes. The approaches used for investigating the roles of human P450 and FMO enzymes in understanding drug oxidations and clinical therapy have not yet reached maturity and still require further development. SIGNIFICANCE STATEMENT: Drug oxidations in animals and humans mediated by P450s and FMOs are important for understanding the pharmacological properties of drugs, such as the species-dependent teratogenicity of the reactive metabolites of thalidomide and the metabolism of food-derived odorous trimethylamine to non-odorous (but proatherogenic) trimethylamine N-oxide. Recognized differences exist in terms of drug metabolism between rodents, non-human primates, and humans, and such differences are important when determining individual liver enzyme contributions with substrates in in vitro and in vivo systems.

NMR Analysis of Lipid Oxidation in Flaxseed Oil-in-Water Emulsions.

The formation of linolenic (Ln) and linoleic (L) acyl oxidation products during storage of flaxseed oil (FO)-in-water emulsions was monitored using proton nuclear magnetic resonance (1H NMR) spectroscopy, as well as chemical analytical methods and gas chromatography. Emulsions containing 10% FO and 1% Tween 60 were prepared by homogenization and then stored at 37 °C in the dark for 21 days under accelerated oxidation conditions (500 μmol ferrous sulfate). The induction time of the emulsions, after which rapid lipid oxidation was first observed, was 5-7 days, as shown by increases in peroxide values and hydroperoxide concentrations determined by NMR spectroscopy. Analysis of the hexanal and propanal concentrations during storage by HS-SPME-GC indicated that the oxidation of Ln and L acyls in the emulsions occurred simultaneously. The oxidation products originating from the Ln and L acyls were monitored using 1H NMR spectroscopy throughout the oxidation process. These results also showed that the Ln and L acyls oxidized simultaneously, and isomers of hydroperoxy-cyclic hydroperoxides (HCPs), Z,E-conjugated dienic hydroperoxides (ZECDHPs), and E,E-conjugated dienic hydroperoxides (EECDHPs) were the major primary oxidation products. Aldehydes were observed after 7 days, which was taken to be the start of the propagation stage, with the formation of a significant amount of oxygenated α, β-unsaturated aldehydes (OαβUAs). Based on the concentrations of hydroperoxides originating from the Ln and L acyls, our results suggested that the loss rate of L acyls was parallel to that of Ln acyls. This result was consistent with Ln acyls adopting a tighter packing at the oil-water interface in the emulsions than L acyls. This hypothesis was supported by the NMR relaxation time data. A good correlation between the isomer concentrations of ZECDHPs and HCPs in Ln acyls and between ZECDHPs and EECDHPs in L acyls was shown, with the mole ratios between them being 1.2 and 1.1, respectively. Droplet size and microstructure analyses showed that droplet aggregation occurred from 11 days onwards, which was attributed to polar oxidation products located at the oil droplet surfaces promoting coalescence. Zeta-potential measurements indicated that the droplets became more negative during storage, which was attributed to the accumulation of anionic reaction products at the droplet surfaces.

Research of changes in quality indicators of fish pate with non-traditional raw materials

Taking into account the results of literature research on the nutritional value of quail eggs, it was found that the development of technology of fish pates with their use is relevant and has practical significance in the technology of production of fish products. The article presents the results of chemical composition, organoleptic evaluation and physico-chemical changes of fish pate with the addition of non-traditional raw materials and setting their shelf life. The expediency of combining freshwater fish with plant and animal raw materials to expand the range of biologically valuable food products is shown. Positive general impressions, harmonious, fishy and sweet-salty taste, showed the feasibility of combining quail eggs and vegetable raw materials with freshwater fish, as evidenced by high performance in appearance, taste and smell. According to the consistency of fish pate smeared and quite dense. It was found that in the experimental sample during storage are hydrolytic spoilage, which indicates the intensive hydrolysis of lipids and the accumulation of free fatty acids in these samples. In the prototypes, the hydrolytic damage gradually increases and only reaches the critical point by the end of the shelf life. Oxidative processes in the lipids of fish pastes were studied by changes in the accumulation of primary oxidation products – peroxides and secondary products – carbonyl compounds. According to the dynamics of changes in the peroxide content of lipids in pate, it was found that the control sample is not subject to storage for 5 days as well as the test sample, the fat content deteriorates and is characterized as non-storage. It has been experimentally established that the addition of non-traditional raw materials allows not only to improve the technology of pate production, but also to solve the problem of obtaining a product of high nutritional value. The authors found that the developed technology of fish pate will significantly expand the range of functional products based on natural ingredients, which will to some extent expand the current problem of processing raw materials in inland waters of Ukraine.

Does water addition during the industrial milling phase affect the chemical-sensory quality of olive oils? The case of cv. Arbequina oils

At olive oil industrial extraction, water addition is a practice overcoming the formation of thick pastes. The effect of water addition (0 to 6.2%, kgadded water/kgolives), during the industrial milling of cv. Arbequina olives, on the oils’ chemical-sensory quality, was evaluated. Despite the extra virgin olive oil classification, compared with the water incorporation (1.2–6.2%), extraction without water addition resulted into oils that showed less primary oxidation (lower peroxide values and K232), greater total phenolic content (+12–22%) and higher oxidative stability (+22–31%). No water addition increased the oils secoiridoids content (+5–13%), mainly oleacein (+27–79%). Oils extracted without water addition had a more intense ripe fruity sensation (≥ +11%) but lower fruit intensities (at least −4%). Thus, the quality and stability of the cv. Arbequina oils can be favoured if extracted without adding water during the olives industrial milling.

Preparation and characterization of lipophilic antioxidative peptides derived from mung bean protein

This study aimed to prepare and characterize antioxidative hydrolysate and its lipophilic peptides derived from mung bean protein. Our results indicated that the hydrolysate prepared with 120 min hydrolysis (MPH) possessed superb DPPH, ABTS radical scavenging activity and metal ion-chelating activity with IC50 values of 11.19 ± 0.02, 18.06 ± 0.18 and 3.78 ± 0.59 µg/mL, respectively. MPH could also effectively retard lipid oxidation for oil-in-water emulsion (up to 50%) and linoleic acid (up to 94%), as well as for bulk oil. Interestingly, the lipophilic peptide fraction (MPHP) extracted from MPH could suppress the formation of primary (up to 50%) and secondary oxidation products (up to 90%) in bulk oil. Ten lipophilic peptides identified from MPHP using LC-MS/MS possessed high amounts of hydrophobic amino acids and histidine, which might favor peptides interacting and/or forming hydrogen bonds with lipid radicals. These findings provide a new perspective for lipophilic peptides in fortifying lipids as natural antioxidants.

Thermal oxidation stability of different multi-element oleogels via 1H NMR spectroscopy

In this study, 1H nuclear magnetic resonance was used to track the evolution of oxidation products of different multi-element oleogels (DMEOs) during temperature-accelerated oxidative degradation. The nutritional properties of the DMEOs were also indirectly explored. Oleogels prepared using sitosterol/lecithin oleogelator showed higher nutritional properties than those prepared using carnauba wax or ethyl cellulose oleogelators. Only a small amount of primary oxidation product hydroxide, (Z,E)-conjugated dienic systems, and (E,E)-conjugated dienic systems were produced from all oleogels upon accelerated oxidation. Furthermore, no 1H signal peaks of secondary oxidation products, such as aldehydes or ketones, were detected. However, very small amounts of primary alcohols (−CH2OH–), secondary alcohols (−CHOH–), and epoxides were identified. Moreover, resveratrol loading and surfactant addition effectively stabilized the internal structure and unsaturated fatty acid acyl content of the oleogels.