Lipid Oxidation Products Research Articles

The influence of storage conditions on the chemistry and flavor of hoppy ales

Understanding the factors which lead to the (in)stability of the chemistry and sensory of hoppy beer styles such as India Pale Ales (IPAs) has become a major concern for many brewers. Therefore, the evolution of several volatiles under different storage conditions (room temperature, cold storage, forced aging) was investigated in eleven hoppy ales and one lager which were commercially produced in Germany. Compared to the lager, the fresh ales contained higher initial aldehyde levels. Furthermore, the distribution of lipid oxidation and Maillard reaction products differed from those typically found in lager beer. Upon storage, significant increases of some staling aldehydes were observed. Interestingly, the concentrations of some hop aroma volatiles like terpenoids (i.e. linalool and geraniol) were relatively stable throughout storage and counteracted “oxidized” impressions in ales high in these compounds. In comparison, hop aroma in some ales was driven by less stable volatiles such as esters.

Fat Oxidation of Fatty Fish vs. Meat Meal Diets Under in vitro Standardized Semi-Dynamic Gastric Digestion.

Meat and fish are introduced into the diet as a source of protein, but these muscle foods present different fatty acid (FA) compositions and different lipid stabilities. Fatty fish is expected to oxidize due to its higher content of polyunsaturated FA (PUFA), whereas the higher heme-Fe content of red meat will also affect lipid stability. Combining other food ingredients within a meal also influences lipid oxidation, which will not stop after meals intake. This is due to the acidic environment of the stomach together with the presence of metallic ions, a process that is scarcely understood. The goal of this study was to evaluate the oxidation of fatty fish vs. meat meal diets under in vitro standardized semi-dynamic gastric conditions and FA release from the stomach to the duodenum. Meal diets composed by 25% beef meal (BM) or fatty fish meal (FM), 25% fried potatoes, and 50% sugar soft drink were prepared. Proximate composition, FA and amino acid profiles, and meals quality indices were evaluated. Their differences in composition led to different total gastric digestion time of 242.74 (BM) and 175.20 (FM) minutes. Using the INFOGEST semi-dynamic gastric model, 4 gastric emptying (GE) were simulated in both meals. In each GE, FA profile and lipid oxidation products (LOPs) formation were assessed. As a result, more than 50% FA release to the duodenum occurred in GE1, whose percentage decreased with the time of digestion. FM exhibited the highest LOPs formation, which corroborates the high peroxidizability index measured for this meal diet. Higher LOPs formation occurred in the later GEs, which released less FA. This suggests that higher times of residence in the stomach increase FA oxidation. This study shows a higher formation of LOPs during digestion of FM using a whole meal approach. These results relate to its richness in PUFAs compared to BM. Despite higher LOPs formation, FM digests that reached duodenum still contain higher content of unoxidized PUFAs compared with BM and a desirable ω3/ω6 PUFAs ratio of ~0.43. LOPs formation in PUFA-rich meals could be reduced if those meals have a low caloric value, avoiding large times of residence in the stomach and consequently high levels of oxidation.

Effects of Sweet Potato Powder Selected Based on the Polar Paradox Hypothesis on Oil Oxidation in the Preparation of Deep-Fried Croquettes.

This study investigated whether sweet potato powder (SPP) and purple SPP (PSPP) could prevent oil oxidation during deep-frying. A volume of soybean oil was repetitively used for deep-frying croquettes coated with either SPP or PSPP. An aliquot of the fried oil was collected (SPP and PSPP oils) before and after each frying to analyze moisture and lipid oxidation products (LOPs). With increasing numbers of frying, the moisture content in oils significantly increased without an appreciable difference between SPP and PSPP oils. The total oxidation values reflecting primary and secondary LOPs also significantly increased. However, the values were higher for PSPP oils despite the much higher antioxidant activity of the polar extracts from PSPP compared to SPP. This was attributed to the presence of transition metals. PSPP oils seemed to have association colloids whose interfaces were occupied more with polar antioxidants, thereby transition metals were easily reduced and their pro-oxidative activity increased. The polar paradox hypothesis stating that polar antioxidants are more effective in preventing lipid oxidation in bulk oil is not always applicable to real foods due to various food matrices.

Oxidative stress in metabolic diseases: current scenario and therapeutic relevance.

The metabolic syndrome is a clustering condition of increased abdominal obesity in concert with hyperglycemia, insulin resistance, hypertension, and dyslipidemia. It confers higher risk of metabolic diseases such as diabetes and ischemic heart disease and has been observed to be associated with high morbidity and mortality. It is a progressive pathological process for diabetes-induced complications and appears to be multifactorial in origin. Several preclinical, clinical, and epidemiological reports have shown a persistent link between the metabolic syndrome and oxidative stress. There is pronounced imbalance between pro-oxidants and anti-oxidants with increased production of oxidizing molecules, depletion of anti-oxidants, and consequently accumulation of protein and lipid oxidation products in the cell in metabolic syndrome. The increased cellular pro-oxidant activity also results in altered molecular pathways, mitochondrial dysfunction, deregulation in cell cycle control, chromosomal aberrations, inflammation, and overall decreased biological activity as well as impairment of the antioxidant systems. Here, the focus of our review article will be on the formation of oxidative species, the interplay between metabolic syndrome and oxidative stress, and its potential implications in therapeutic approaches.

Determination of Optimum TBARS Conditions for Evaluation of Cow and Sheep Milk Oxidative Stability

Having a complex fatty acid profile, milk is the subject of several oxidation processes that are different to those in other food matrices. Considering this, is important to appreciate the degradation status of milk using rapid and simple methods to quantify the main degradation products. The aim of this study was to adapt a simple and rapid method for determination of milk oxidative stability and to quantify malondialdehyde, one of the lipid oxidation products. Four parameters (trichloroacetic acid concentration—TCA, antioxidant type, incubation time, and thiobarbituric acid—TBA concentration) were modified to establish the best experimental sequence. It was concluded that the relevant results were obtained by precipitating milk proteins using 20% TCA; incubating samples for 90 min with 0.8% TBA, without adding antioxidant; and registering absorbance at three different wavelengths (450, 495, and 532 nm). This method was successfully applied to cow and sheep milk samples and the absorbance values obtained provided information about degradation of fatty acids for both milk types. The Pearson correlation showed a positive relationship between the fatty acid profiles of milk samples and the absorbance values that characterized their oxidation pattern during storage.

Nuclear Magnetic Resonance Spectroscopic Analysis of the Evolution of Peroxidation Products Arising from Culinary Oils Exposed to Thermal Oxidation: An Investigation Employing 1H and 1H-1H COSY and TOCSY Techniques.

Scientific warnings on the deleterious health effects exerted by dietary lipid oxidation products (LOPs) present in thermally stressed culinary oils have, to date, not received adequate attention given that there has been an increase in the use and consumption of such oil products in everyday life. In this study, high-resolution 1H nuclear magnetic resonance (NMR) analysis was used to characterize and map chemical modifications to fatty acid (FA) acyl groups and the evolution of LOPs in saturated fatty acid (SFA)-rich ghee, monounsaturated fatty acid (MUFA)-rich groundnut, extra virgin olive, and macadamia oils, along with polyunsaturated fatty acid (PUFA)-rich sesame, corn and walnut oils, which were all thermally stressed at 180 °C, continuously and discontinuously for 300 and 480 min, respectively. Results acquired revealed that PUFA-rich culinary oils were more susceptible to thermo-oxidative stress than the others tested, as expected. However, ghee and macadamia oil both generated only low levels of toxic LOPs, and these results demonstrated a striking similarity. Furthermore, at the 120 min thermo-oxidation time-point, the discontinuous thermo-oxidation episodes produced higher concentrations of aldehydic LOPs than those produced during continuous thermo-oxidation sessions for the same duration. On completion of the thermo-oxidation period, a higher level of triacylglycerol chain degradation, and hence, higher concentrations of aldehydes, were registered in culinary oils thermally stressed continuously over those found in discontinuous thermo-oxidized oils. These findings may be crucial in setting targets and developing scientific methods for the suppression of LOPs in thermo-oxidized oils.

APPLICATION OF ANALYTICAL CHEMISTRY AND CONTROL METHODS IN OXIDATION PROCESSES STUDIES OF CHEMICAL, FOOD BIOTECHNOLOGICAL AND PHARMACEUTICAL TECHNOLOGIES

Technological parameters, namely temperature and duration of β-carotene extraction process from filamentous fungus Blakeslea trispora biomass via vegetable oils with various fatty acid compositions and various contents of natural antioxidants (refined deodorized sunflower, high-oleic sunflower, corn and sesame) have been investigated. Statistical models of β-carotene dependences, as well as analytical numbers, characterizing content of free fatty acids (acid number) and primary products of lipid oxidation (peroxide number) content, in oil extracts of the specified refined deodorized oils, from temperature and extraction duration have been built.
 Rational parameters of β-carotene extraction from Blakeslea trispora biomass with selected extractants (refined deodorized sunflower, high-oleic sunflower, corn and sesame oils) have been determined to control extract's technological properties. It has been proven that usage of these refined deodorized oils as extractants practically does not affect on the target product content in oil extracts of biomass, but it does affect on analytical numbers of extracts, characterizing content of free fatty acids, peroxides and hydroperoxides. The highest content of free fatty acids in β-carotene, containing biomass extraction with sunflower oil, has been observed. The minimum content of free fatty acids in extracts with corn and sesame oils has been be achieved. The highest content of primary products of β-carotene lipid oxidation (peroxides and hydroperoxides), containing biomass extraction by sunflower oil, has been observed. The minimum content of free fatty acids in extracts with usage of sesame oil has been achieved.
 It is possible to predict β-carotene content, as well as acid and peroxide numbers of oil extracts from biomass in specified refined deodorized oils, depending on temperature and extraction process duration, using obtained approximation dependences.

Interaction between secondary lipid oxidation products and hemoglobin with multi-spectroscopic techniques and docking studies

This study aimed to explore the effect of secondary lipid oxidation products (SLOPs) on hemoglobin (Hb) in chicken model. The fluorescence quenching technique and molecular docking were employed, and the apparent binding constants Ksv and the binding site numbers of SLOPs with Hb were calculated. The results revealed that three SLOPs (hexanal, benzaldehyde, and 2-pentanone) obviously promoted the oxidation of Hb, which is consistent with the change of Hb hydrophobicity, particle size, polydispersity index and zeta potential. The SLOPs strongly quenched the intrinsic fluorescence of Hb and triggered the alterations in the Hb structure. Hydrophobic interaction was the main force between SLOPs and Hb. Among the three SLOPs, hexanal demonstrated more stronger oxidation on Hb, which is closely related to its hydrophobic ability and structure characteristic, especially 10 μM hexanal is more prone to form an obvious unfolded structure and caused molecular aggregation than lower concentrations.

Regulation of lipid peroxidation in mitochondria by nitroglycerine

The mechanisms of lipid oxidation under the application of nitroglycerine (NG) were studied in isolated rat heart and liver mitochondria. Dose-dependent formation of diene conjugates (DC), leukotriene C4 (LTC4) and thromboxane B2 (TxB2) was shown. To disclose the mechanisms regulating lipid peroxidation in mitochondria, we studied the effect of NG application on the formation of prooxidants (H2O2 and free Fe2+), as well as xanthine oxidase and mtNOS activity as main sources of ROS and RNS. Based on the correlation dependences, we have found that DC, LTC4, and TxB2 formation was strongly dependent on hydroperoxide production and free divalent iron release in mitochondria. Also, DC formation exhibited the dependence on Ca2+ uptake in mitochondria. No dependence of lipid oxidation on xanthine oxidase activity was found. In heart, but not liver mitochondria, DC, LTC4, and TxB2 exhibited strong dependence on mtNOS activity, but were independent of nitrosothiols formation. This indicated that lipid oxidation was independent of direct protein nitrosylation caused by NG application. No dependence of lipid oxidation on mtNOS activity in liver was found, which agreed with much higher mtNOS activity in heart mitochondria, and suppression of mtNOS activity in liver mitochondria at high doses of NG. So, we came to the conclusion that under NG application ROS overproduction and free Fe2+ release promoted both enzymatic and non-enzymatic lipid oxidation in heart and liver mitochondria. Also, we hypothesized that RNS overproduction due to the elevated mtNOS activity in the heart could largely contribute to lipid peroxidation and promote much faster increase in the formation of lipid oxidation products in heart as compared to liver mitochondria, especially at high doses of NG. Obtained correlation dependences allowed us disclose free iron, hydroperoxide, and mtNOS activity as principal factors affecting lipid peroxidation in mitochondria under NG application.

Role of Maillard Reaction Products as Antioxidants in Washed Cod and Washed Turkey Muscle Oxidized by Added Hemoglobin

AbstractThe ability of Maillard reaction products (MRPs) to inhibit hemoglobin (Hb)‐mediated lipid oxidation is examined in washed cod muscle (WCM) and washed turkey breast muscle (WTM). Lipid peroxides and thiobarbituric acid reactive substances (TBARS) are used as markers of primary and secondary lipid oxidation products, respectively. MRPs inhibits Hb‐mediated lipid oxidation in WCM (p < 0.01) but are weakly inhibitory in WTM. α‐tocopherol concentration is 24‐fold greater in WCM compared to WTM. The elevated α‐tocopherol content of WCM may partly explain the enhanced antioxidant effectiveness of MRPs in WCM, noting that MRPs and α‐tocopherol act synergistically in the scavenging of free radicals. MRPs are more effective in inhibiting lipid oxidation in WCM at pH 6.6 compared to lower pH values. Antioxidant effectiveness of MRPs diminishes when stored refrigerated but not with frozen storage. MRPs obtained by 3 h heating contains more Maillard reaction intermediates than 2 h heating, which better inhibits LOOH formation (p < 0.01). These intermediates decrease faster during refrigerated compared to frozen storage. These studies suggest elevated pH and sufficient endogenous tocopherols are required for low concentrations of MRPs to protect highly unsaturated lipid in washed muscle from oxidation by hemoglobin.Practical Applications: This study shows that the maillard reaction products (MRPs) can be used to inhibit the oxidation of tocopherol‐rich meat products, and the MRPs stored in the frozen condition for a certain period also have antioxidant activity.

Antioxidation effect of alginate beads containing thyme, rosemary or geranium essential oils in lard and coconut oil

SummaryThe alginate beads encapsulated thyme (AT), rosemary (AR) and geranium (AG) essential oils (EOs) were prepared to inhibit lipid oxidation in lard and coconut oil. The result showed that beads dried in hot air oven (45 °C) encapsulated higher amount of EOs than drying by desiccation method. Sachets containing AT, AR and AG were applied in PET bottles containing lard and coconut oils and stored at 45 °C. The DPPH scavenging activities of AT, AR and AG were 85.39%, 78.26%, and 78.12%, respectively. During storage, released EOs reduced PV and TBARS of lard and coconut oil and did not affect their colour acceptability scores. From PV, FFA and TBARS, AT at 0.50 g exhibited the best results in terms of lipid oxidation inhibition, although encapsulation percentage and release were significantly lower than AG and AR. Porous in alginate beads could entrap lipid oxidation products, including volatile compounds and water vapour. Besides, the hydrophilic property of polymer matrix led to water absorption, which lower aw value. In week3, the odour acceptability scores of control lard failed, while those packed with AT, AR and AG were acceptable. Alginate beads containing EOs can be used to extend the storage life of lard and coconut oil.

Lipids Peroxidation Products in Young Men with Type 1 Diabetes Mellitus

The aim of this research was to assess the level of lipid oxidation products level and the antioxidant defense state in young male patients with type 1 diabetes mellitus (T1DM) depending on the disease duration. Materials and Methods: A total of 57 men of young reproductive age (average age of 30.25±8.51 years) with T1DM and an unsatisfactory glycemic profile, depending on the disease duration, were divided into 2 groups. Group 1 included 29 men (average age of 27.69±6.92 years) with a T1DM duration <5 years (2.72±1.61 years) and HbA1c level of 11.37±2.74%. Group 2 included 28 men (average age of 32.89±9.28 years) with a T1DM duration ≥5 years (12.93±5.69) and HbA1c level of 10.19±2.18%). The control group consisted of 28 men of the same age (29.71±4.59 years). Spectrophotometric/spectrofluorometric methods and enzyme immunoassay were used. Results: We found a significant increase in the values of CDs (by 2.04 times, P<0.0001), KD and CT (by 2.38 times, P<0.0001), TBARs (by 1.17 times, P=0.001), SB (by 2.6 times, P<0.0001), and retinol (by 1.44 times, P<0.0001) in Group 1 compared to the control group. In Group 2, there was a statistically significant increase in the levels of CDs (by 2.59 times, P<0.0001), KD and CT (by 2.94 times, P<0.0001), TBARs (by 1.49 times, P=0.001), SB (by 3.27 times, P<0.0001), and retinol (by 1.4 times, P=0.001) compared to the control group. The differences between the two groups with different duration of T1DM were characterized only by the CDs level, which was increased in Group 2 patients with a T1DM duration of ≥5 years (by 1.27 times, P=0.048) compared to Group 1 patients with a T1DM duration of < 5 years. Conclusion: LPO parameters can serve as additional laboratory markers that characterize the course of T1DM and can be used to develop potential prevention and therapy strategies.

Effects of lysosomal low-density lipoprotein oxidation by ferritin on macrophage function

We have previously demonstrated that low-density lipoprotein (LDL) can be oxidized by iron in the lysosomes of macrophages. Some of the iron content of lysosomes might be delivered through autophagy of ferritin (the main iron-storage protein in the body). We have now investigated the effects of ferritin-mediated LDL oxidation on macrophage function. The addition of ferritin to human THP-1 cells and human monocyte-derived macrophages increased lysosomal lipid peroxidation, as shown by LPO-Foam, a fluorescent probe targeted to lysosomes. Incubating THP-1 cells with ferritin and native LDL or LDL aggregated by sphingomyelinase, to allow their endocytosis and delivery to lysosomes, led to the formation of lysosomal ceroid (an advanced lipid oxidation product), indicative of lysosomal LDL oxidation. Incubating THP-1 cells with ferritin and LDL caused metabolic activation of the cells, as shown by increased extracellular acidification and oxygen consumption measured by a Seahorse analyzer. LDL oxidized by ferritin in lysosomes might be released from macrophages when the cells die and lyse and affect neighboring cells in atherosclerotic lesions. Adding LDL oxidized by ferritin at lysosomal pH (pH 4.5) to macrophages increased their intracellular reactive oxygen species formation, shown using dihydroethidium, and increased apoptosis. Ferritin might therefore contribute to LDL oxidation in the lysosomes of macrophages and have atherogenic effects.

Impact of Heating Temperature and Fatty Acid Type on the Formation of Lipid Oxidation Products During Thermal Processing.

Thermal treatment of lipids rich in fatty acids contributes to the formation of lipid oxidation products (LOPs), which have potentially harmful effects on human health. This study included soybean oil (SO), palm oil (PO), olive oil (OO), and lard oil (LO) as the research objects, with an aim to investigate the impact of heating temperature and fatty acid type on the generation of LOPs (α-dicarbonyl compounds, malondialdehyde (MDA), α,β-unsaturated aldehydes, and 16 volatile aldehydes). Results showed that LOPs increased significantly (p < 0.05) with the increase in temperature (100 ~ 200°C). Furthermore, the amount of 2,3-butanedione (159.53 μg/g), MDA (3.15 μg/g), 4-hydroxy-hexenal (3.03 μg/g), 2-butenal (292.18%), 2-pentenal (102.26%), hexanal (898.72%), and 2,4-heptadienal (E, E) (2182.05%) were more at 200°C in SO rich in polyunsaturated fatty acids (PUFAs) than other oils. Results from heat map analysis indicated that the 2, 4-heptadienal, and glyoxal related to the myristic acid of oil. Moreover, the MDA was in close association with PUFAs. Based on the effect of temperature and fatty acid type on the generation of LOPs, this study could serve as a control method to reduce harmful LOPs.

Novel Urinary Metabolites of Aldehydic Lipid Oxidation Products From Heated Soybean Oil Revealed by Aldehyde Abatement and Metabolomic Fingerprinting

ObjectivesHeated cooking oils are a constitutive component of contemporary human diets and a common ingredient in animal feed. Aldehydes, as the most reactive lipid oxidation products (LOPs) in heated oils, are widely considered as a contributor to the adverse health effect associated with heated oil consumption. Aldehydes-derived metabolites in biofluids are valuable for monitoring the exposure of the aldehydes from heated oils, but the efforts for their identification were hampered by the high reactivity of aldehydes as well as the chemical complexity caused by the coexistence of other LOPs in heated oils. To address this challenge, this study investigated the aldehydes-derived metabolites through the metabolomic fingerprinting of mouse urine samples from feeding heated oils with and without aldehyde abatement. MethodsThe heated soybean oil (HSO) was prepared by heating the control soybean oil (CSO) at 185°C for 6 h with constant air flow (50 ml/min). Both HSO and CSO were then mixed with the silica gel with piperazine side chain to remove their aldehyde content, producing the silica gel-treated HSO (HSO-si) and the silica gel-treated CSO (CSO-si), respectively. The urine, serum, fecal samples were collected from the C57BL/6 mice fed with 4 diets containing CSO, CSO-si, HSO, HSO-si, and then analyzed by the liquid chromatography-mass spectrometry (LC-MS) metabolomic analysis. ResultsThe silica gel treatment dramatically reduced the aldehyde contents in HSO. Novel urinary metabolites formed by the reactions between 2,4-decadienal and lysine were identified through the metabolomic comparison between the HSO samples and the samples from 3 other treatment groups. ConclusionsThe identification of novel urinary metabolites of aldehydic LOPs warrants further biochemical examination on the chemical and metabolic processes responsible for their formation. These metabolites could become the biomarkers for monitoring the exposure of aldehydes in humans and animals. Funding SourcesThe research is partially supported by the NIFA project MIN-18–125.

Effect of gamma irradiation on the primary and secondary products of lipid oxidation in raw chicken meat, stored under different temperatures and packaging – a meta-analysis

Abstract A meta-analysis on the effect of gamma irradiation on lipid oxidation products in raw chicken meat subjected to different temperatures of storage and packageing was carried out. A total of 11 studies were examined in regard to the peroxide value (POV) and thiobarbituric acid reactive substances (TBARS). The high heterogeneity in the studies was decisive for the selection of the random effects model applied on the raw mean difference (effect size) for the analysis of the data. The results of the meta-analysis showed that gamma irradiation increased the contents of the primary (POV) and secondary products (TBARS) of lipid oxidation in the raw chicken meat (P&lt;0.001). Further, meta-regression and the examined covariates indicated significant influence of the dose of radiation on the formation of POV (P&lt;0.001), whereas TBARS contents tended to depend on the package of the meat. In most of the studies included in the meta-analysis, the contents of the lipid oxidation products remained in acceptable levels and the treatment with gamma rays did not affect negatively the high nutritive value of the meat.

Effects of Peroxyl Radicals on the Structural Characteristics and Fatty Acid Composition of High-Density Lipoprotein from Duck Egg Yolk

In this study, high-density lipoprotein (HDL) from duck egg yolk was subjected to oxidation with a system based on 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH)-derived peroxyl radicals. The effects of peroxyl radicals on the protein carbonyl, free sulfhydryl, secondary/tertiary structure, surface hydrophobicity, solubility, particle size distribution, zeta potential and fatty acid composition of HDL were investigated by using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Fourier-transform infrared spectroscopy (FTIR), circular dichroism (CD), fluorescence spectroscopy, dynamic light scattering and ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The results indicated that the content of protein carbonyl was significantly increased, that of free sulfhydryl was obviously reduced, and the ordered secondary structure was also decreased with increasing AAPH concentration. In addition, the surface hydrophobicity and solubility of HDL showed apparent increases due to the exposure of hydrophobic groups and aggregation of protein caused by oxidation. The fatty acid composition of HDL exhibited pronounced changes due to the disrupted protein–lipid interaction and lipid oxidation by AAPH-derived peroxyl radicals. These results may help to elucidate the molecular mechanism for the effect of lipid oxidation products on the oxidation of duck yolk proteins.

Inhibitory effects of chitosan grafted chlorogenic acid on antioxidase activity, and lipid and protein oxidation of sea bass (Lateolabrax japonicus) fillets stored at 4 °C.

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.

Effects of the BHA and basil essential oil on nutritional, chemical, and sensory characteristics of sunflower oil and sardine (Sardina pilchardus) fillets during repeated deep-frying

This study was to evaluate the BHA and basil essential oil on the quality attributes of deep-fried sardine fillets and frying oil. The extent of lipid oxidation was monitored by measuring peroxide value (PV), thiobarbituric acid reactive substances (TBARS), TBA, and changes in free fatty acids. Sensory analysis and color values upon the frying period were also determined. PV, FFA, TBA, and TBARS values in fish fillets and frying oil have peaked and then decreased at the end of frying except for the control. BEO showed the highest sensory scores compared to others. As a result, it is not possible to make a clear judgment about the effect of the natural or synthetic antioxidants on all lipid oxidation products that may occur during frying both fish fillets and frying oil. This study suggests that secondary oxidation products in frying oil and the sensorial quality of fish fillets can be better controlled by using basil essential oil.

Maternal Oxidized Soybean Oil Administration in Rats during Pregnancy and Lactation Alters the Intestinal DNA Methylation in Offspring.

As a food contaminant, oxidized oil or lipid oxidative products have been proven to exert toxicological effects on the growth and development of animals and humans. Research shows that maternal oxidative stress damage might transmit to another generation by epigenetic modulation. However, current evidence is still not clear on the mechanism of the effects of dietary oxidized oil during pregnancy on the two generations. This study employed a rat model fed with oxidized soybean oil (OSO) during pregnancy and lactation to explore the effects of the oxidative degree (0, 200, 400, and 800 mequiv of O2/kg) on the placental RNA methylation and DNA methylation in offspring jejunum. The results showed that following the ingestion of OSO, the placental genes of different m6A methylation were significantly enriched to nutrient metabolic processes and hormone activity. In addition, the intestine in offspring hypofunctioned observably, such as reducing the height of villi and the level of anti-inflammatory cytokine. Furthermore, maternal intake of OSO during pregnancy can damage the intestinal barrier function of offspring by inhibiting the proliferation and differentiation of intestinal epithelial cells and reducing the activity of intestinal DNA methyltransferase. In conclusion, this study reinforces the assertion that maternal OSO consumption during gestation and lactation negatively affects the placental health and intestinal development of suckling pups.