Formation Of Secondary Oxidation Products Research Articles

Exploring the Physicochemical, Antioxidant and Sensory Properties of the Flavoured Virgin Olive Oil With Chavir Extract During Storage

ABSTRACTThis study aimed to study the impact of Ferulago angulata (Schlecht) Boiss (known as an antioxidant known as Chavir) extract, obtained through ultrasound‐assisted extraction (UAE), on the physicochemical, antioxidant and sensory properties of virgin olive oil (VOO) during a 90‐day storage period at room temperature. For this purpose, different concentrations of Chavir extract (100, 200 and 300 ppm) were added to VOO. Key parameters, including total phenol content (TPC), extract composition by HPLC‐DAD and quality indicators like acidity value (AV), p‐anisidine value (p‐AV) and UV indices (parameters: K232, K270 and ΔK), were determined. AVs increased overall during the storage period, but adding Chavir extract at 300 ppm appeared to counteract the rise in free fatty acids, suggesting a potential role in reducing hydrolysis. p‐AVs decreased in unflavoured and flavoured samples, indicating reduced oxidation in Chavir‐flavoured VOO. K232 values exhibited a decline in the presence of flavouring agents and their concentrations. In contrast, the values of K270 showed an increase over the storage period, which indicated the formation of aldehyde and ketones in the second oxidation step. All samples maintained ΔK values below permissible limits (≥ 0.01), signifying good stability. The sensory evaluation emphasised positive attributes such as bitterness, fruitiness and pungency, indicating the high quality of VOO. The addition of Chavir extract further enhanced all of these positive characteristics, particularly at the 300 ppm concentration. However, a gradual decline was observed in all these attributes over time. Notably, the Chavir extract played a crucial role in delaying the formation of secondary oxidation products, which contribute to negative attributes like rancidity in VOO. Moreover, adding Chavir extract increases oxidative stability, infuses the positive qualities in VOO and provides valuable insights into its potential applications for enhancing the overall quality of VOO during storage. This enhancement not only helps maintain high quality and nutritional value but also makes the product more appealing to consumers.

Reduction of toxic aldehydes in heated flaxseed oil using sesame and perilla protein enzymatic hydrolysates.

Reducing ability of sesame meal protein enzymatic hydrolysates (SMH) and perilla protein enzymatic hydrolysates (PMH) on the content of toxic aldehydes including acetaldehyde, formaldehyde, 2-hydroxylhexenal (HHE), and 2-hydroxyl nonenal (HNE), were evaluated in heated flaxseed oil at concentrations ranging from 0.01 to 1.0g. Adding SMH and PMH decreased the formation of secondary oxidation products and toxic aldehydes during heating. In particular, HHE and HNE were not detected, even at 0.01g of protein concentration. Free radical scavenging activities in heated flaxseed oil significantly increased when 1.0g of SMH and PMH were added (p < 0.05). Some volatiles including 2-ethylpyridine, pyrazines, and trimethylamine were formed or increased substantially in flaxseed oils with higher concentrations of SMH and PMH. In general, SMH showed higher antioxidative activity and reducing ability on the toxic aldehydes than PMH. Plant protein enzymatic hydrolysate could control the formation of toxic aldehydes during oxidation of ω-3 edible oil.

Evaluating the Kinetics and Molecular Mechanism for Biomimetic Metabolic Activation of PAHs by Surface-Enhanced Raman Scattering Spectroscopy.

Biomimetic cytochrome P450 for chemical activation of environmental carcinogens is an efficient in vitro model for evaluating their mutagenicity and ultimately acquiring the metabolites that cannot be easily accessed by conventional routes of organic synthesis. Different kinds of mutagen derived from polyaromatic hydrocarbons (PAHs) by metalloporphyrin/oxidant model systems have been reported, but the underlying molecular mechanisms are poorly understood. Herein, we have for the first time demonstrated an effective surface-enhanced Raman scattering (SERS) protocol to study the dynamics and biomimetic metabolic behaviors of pyrene (Pyr) in the presence of various oxygen donors. Quantitative information on the relative concentration of Pyr and its metabolites in the biomimetic system can be extracted from the SERS spectra. On the basis of our results, we conclude that the oxidative metabolism of Pyr is highly influenced by the types and concentrations of oxygen donors, leading to the formation of 1-hydroxypyrene and dioxygenated products. Besides, the addition of an appropriate amount of an organic solvent can promote the formation of secondary oxidation products. These results offer valuable insights into the dynamics of PAHs metabolism and the regulation of their metabolic pathways in biomimetic activation. In comparison to traditional liquid chromatography-mass spectrometry, the present SERS approach is more suitable for high-throughput evaluation of the metabolic process and kinetics of PAHs. We anticipate that this approach will enable a more general and comprehensive tracking of metabolic dynamics and molecular mechanisms involved in the biomimetic activation of other xenobiotics, such as procarcinogens, promutagens, and drugs.

Oxidative stability and compositional characteristics of oil from microwave irradiated black cumin seed under accelerated oxidation condition

The present work evaluated the impact of microwave pre-treatment on the storage stability, fatty acids and triacylglycerol contents in black cumin seed oil (BCO) during storage at 62 ºC. During storage, the oxidative indicator values (free acidity, peroxide value, p-anisidine value, TOTOX, specific extinctions and thiobarbituric acid) for the oils increased faster in untreated oil samples than in the microwaved samples. The degradation rate of polyunsaturated fatty acids (PUFAs) and triacylglycerol species (LLL and OLL) during storage were higher in untreated samples compared to treated ones, indicating that oxidation proceeded more slowly in the treated samples. During storage, the generation of hydroperoxides, their degradation and the formation of secondary oxidation products as investigated by FTIR, were lower in the treated oils. In conclusion, microwave pre-treatment prior to oil extraction reduced the oxidative degradation of oil samples, thereby increasing the storage stability of BCO.

Extraction of bioactives from brown seaweed using sub and supercritical fluids: Influence of the extract on the storage stability of fish oil enrich mayonnaise

This study aimed at extracting lipophilic and hydrophilic compounds from Nordic brown seaweed Fucus vesiculosus and to evaluate the extract’s ability to maintain the physical and oxidative stability of fish oil-enriched mayonnaise (80% fat, 1:4 fish oil: rapeseed oil) during storage (dark, up to 28 days). Three different types of extracts were obtained, one using supercritical carbon dioxide (lipophilic extract) and two using subcritical water extraction (hydrophilic extracts)—one on dry seaweed (Subcritical water extract (SCWE) and one on the residue from supercritical carbon dioxide extraction after extracting the lipophilic compounds (Subcritical water extract (SCWER). The extracts were characterized with respect to their antioxidant composition and in vitro antioxidant properties. Moreover, the extracts were added in concentrations of 2 g/kg mayonnaise, both individually or in combination to study synergistic effects between antioxidants with different polarity and locations in the mayonnaise system. Results showed that both types of extractsdelayed the oxidation of lipids; The hydrophilic extracts (SCWE and SCWER) were able toretard the formation of hydroperoxides, and subsequent formation of secondary oxidation products. However, no synergetic effect was found for the hydrophilic and hydrophobic extracts when they were applied in different phases of the mayonnaise. The metal chelating ability is suggested to be responsible for the observed better performance of the hydrophilic extracts. However, further studies are required to understand which specific components in the extract have contributed to metal chelating ability. In conclusion, the findings of the present study suggest hydrophilic and hydrophobic compounds from the Nordic seaweed F. vesiculosus can retard lipid oxidation in mayonnaise.

Antibacterial and Antiproliferative Activities of Azadirachta indica Leaf Extract and Its Effect on Oil-in-Water Food Emulsion Stability.

The present study aims to identify and quantify the phenolic compounds of Azadirachta indica leaf extract using HPLC-MS and to evaluate the antioxidant, antibacterial (against different Gram-positive and negative bacteria) and in vitro anti-proliferative activities of this extract (against breast, human liver and cervix adenocarcinoma-derived cells). The application of this extract as a natural antioxidant for food preservation was also tested on oil-in-water food emulsions for the first time in the present work in order to determine the use of Azadirachta indica leaves as a natural additive to preserve the food against lipid oxidation and rancidity. The results obtained revealed that 50%-aqueous ethanol leaf extract showed the best extraction yield (25.14%), which was characterized by a high content in phenolic compounds and strong antioxidant activity. Moreover, this leaf extract inhibited the growth of the bacterial strains tested (Staphylococcus aureus, Escherichia coli, Salmonella paratyphi and Micrococcus luteus) and showed better anti-proliferative activity against breast and cervix adenocarcinoma-derived cells than human liver cancer cells after 48 h of treatment. Additionally, Azadirachta indica leaf extract showed almost similar effects as gallic acid solutions (0.25% and 0.5%) in preserving the oxidation of oil-in-water food emulsions and prevented the formation of secondary oxidation products (malondialdehyde) as well. The results obtained suggested that extracts of Azadirachta indica leaves are a potential source of antioxidant and antibacterial compounds and pointed to the potential of these natural extracts as therapeutic agents.

Variations in Antioxidant Capacity, Oxidative Stability, and Physicochemical Quality Parameters of Walnut (Juglans regia) Oil with Roasting and Accelerated Storage Conditions.

Walnut oil, like all vegetable oils, is chemically unstable because of the sensitivity of its unsaturated fatty acids to the oxidation phenomenon. This phenomenon is based on a succession of chemical reactions, under the influence of temperature or storage conditions, that always lead to a considerable change in the quality of the oil by promoting the oxidation of unsaturated fatty acids through the degradation of their C-C double bonds, leading to the formation of secondary oxidation products that reduce the nutritional values of the oil. This research examines the oxidative stability of roasted and unroasted cold-pressed walnut oils under accelerated storage conditions. The oxidative stability of both oils was evaluated using physicochemical parameters: chemical composition (fatty acids, phytosterols, and tocopherols), pigment content (chlorophyll and carotenoids), specific extinction coefficients (K232 and K270), and quality indicators (acid and peroxide value) as well as the evaluation of radical scavenging activity by the DPPH method. The changes in these parameters were evaluated within 60 days at 60 ± 2 °C. The results showed that the levels of total phytosterols, the parameters of the acid and peroxide value, K232 and K270, increased slightly for both oils as well as the total tocopherol content and the antioxidant activity affected by the roasting process. In contrast, the fatty acid profiles did not change considerably during the 60 days of our study. After two months of oil treatment at 60 °C, the studied oils still showed an excellent physicochemical profile, which allows us to conclude that these oils are stable and can withstand such conditions. This may be due to the considerable content of tocopherols (vitamin E), which acts as an antioxidant.

Characterization of free fatty acids photo‐oxidation under UV radiations: A stepwise Raman study

AbstractLipid peroxidation (LPO) is an oxidative deterioration when oxidants such as reactive oxygen species attack lipids that contain double bonds especially polyunsaturated fatty acids (PUFAs). The mechanism of LPO is composed of three steps: initiation, propagation, and termination. It can result from several reaction pathways: (1) auto‐oxidation, (2) enzymatic oxidation, or (3) photo‐oxidation. UV solar exposition is a major concern in skin research, dermatology, and cosmetic science. Skin surface lipids (SSLs) and stratum corneum (SC) lipids are among the first skin components exposed to external insults such as UV radiations. Fatty acids represent a major lipid class in SSLs and SC. The aim of this paper is to study the photo‐oxidation of fatty acids under UV solar radiations using Raman spectroscopy. Vibrational spectroscopies are useful techniques to follow the LPO in its different stages of oxidation: (1) the initiation step by following the CH2/CH3 stretching bands ratio that decreases due to the hydrogen abstraction in alpha position; (2) the propagation step where primary oxidation products are formed such as hydroperoxides, which was evaluated by following the 1165/1640 cm−1 ((δ(OH) and ν(CO))/ν(CO)) ratio that increases during oxidation process; and finally, (3) the termination step that is marked by the formation of aldehydes, alcohols, ketone, trans secondary oxidation products, and others, which was monitored by following the 1730/1640 cm−1 (ν(CO) (ald.)/ν(CO) (acid)) ratio and the trans ν(CC)/cis ν(CC) ratio that increase indicating the formation of secondary oxidation products. To our knowledge, this work is the first to put together different spectral descriptors enabling to follow, step by step, the different modifications of free fatty acids structures during the oxidation process.

Oxidation of Pear Seed Oil During Storage

The effects of storage on the oxidative deterioration of crude Pear Seeds Oil (PSO), obtained by soxhlet extraction, were studied. Oxidation was monitored after 6 months via several analytical techniques: peroxide value, iodine value, free fatty acids, Fourier-transform infrared spectroscopy (FTIR), and Gas chromatography–mass spectrometry (GC-MS). The slow detorioration of the oil was an indication that oxidation was strongly dependent on temperature, oxygen availability and the presence of Cu2+. The mass spectra from the GC-MS results reveal the formation of secondary oxidation products, thereby denoting a transformation of primary hydroxyperoxides. This assertion is further strengthen based on the increasing value of the total Saturated Fatty Acids (SFA) from 26.09 to 29.44 % and a corresponding decrease for Unsaturated Fatty Acid (UFA) from 71.28 to 68.80 %. Other physicochemical analysis, shows that an average Iodine value recorded a reduction from 40.377 to 39.193 at a rate of 2.9 %, free fatty acid also recorded an increase at 15.18 %. Furthermore, the acid value also recorded a 2.60 % reduction. An increase in the peroxide value from 6.243 to 7.452 at a rate of 16.22 %, is a confirmation of possible formation of secondary oxidation products as revealed by the GC-MS mass spectra. Therefore the need to pay close attention during production, transportation as well as the presence of possible Cu2+ is key to addressing slow oxidation that is capable of impairing the quality of the oil.

STUDY OF THE OXIDATION KINETICS OF VEGETABLE OILS AT DIFFERENT TEMPERATURES

In this paper, oxidation was studied using the example of 4 types of vegetable oils: linseed, sunflower, corn and safflower. The kinetics of oxidation of vegetable oils at room temperature was studied. The peroxide value of sunflower, corn and flaxseed oils steadily increased during oil storage compared to safflower oil.The kinetics of oxidation of vegetable oils at different temperatures was also studied. Among the studied samples at 100 °C, for linseed, rapeseed and safflower, the acceleration of the growth of peroxide formation is significantly higher than for olive, corn and sunflower by 2-3 times.The growth rate of the peroxide value in sunflower, olive and corn oil increased significantly at temperatures above 1000C. According to the results of the study of the temperature dependence of the rate of oxidation of vegetable oils, it is recommended in the production process in order to achieve greater oxidative stability of oils, the temperature regime for linseed oil should not exceed 60 ° C, for sunflower oil - 80 ° C.With a further increase in temperature above the identified values, the rate of formation of secondary oxidation products increases, which reduce the taste of linseed oil.

Studying the influence of berry extracts on the quality and safety indicators of half-smoked sausages

In order to prevent oxidative damage, an experiment was conducted to determine the effectiveness of berries extracts (Aronia melanocarpa Elliot and Ribes nigrum L.) in the production of half-smoked sausages. The recipe of half-smoked sausages with a polycomponent composition of raw materials includes semi-fat pork with muscle tissue, tendon-free lean pork, tendon-free Muscovy duck meat, side pork, hydrated bamboo fiber. Berry extracts (Aronia melanocarpa Elliot and Ribes nigrum L.) at concentrations of 0.2–0.5 % to the weight of crude minced meat were added to the examined samples of minced meat. Sample No. 1 was a control, that is, made without the addition of extracts of berries. During the storage of products with extracts, an acidic number, a peroxide number, a thiobarbituric number, and the predefined indicators of microbiological safety were determined. The addition of chokeberry extract in the amount of 0.2–0.5 % to the minced meat weight significantly slows down the hydrolytic oxidation of lipids in finished products, effectively inhibits the peroxide oxidation of fat. The use of blackcurrant extract also has an antioxidant effect but is weaker. Stabilizing the peroxide oxidation of lipids in half-smoked sausages has the effect of inhibiting the formation of secondary oxidation products, which is confirmed by the results reported here. The amount of secondary oxidation products was the smallest at the end of the shelf life of the product with a concentration of chokeberry extract of 0.5 % and was 0.197±0.001 mg MA/kg, which is 3.74 times lower than that in the control. The addition of extracts of chokeberry and black currant reduces microbiological contamination and has a bacteriostatic effect. The most effective is the introduction of chokeberry extract in the amount of 0.05 %, which reduces the oxidative damage to fat by more than three times.

Effects of bioactive compounds upon the deterioration of the chilled mechanically deboned poultry meat during storage

Mechanically deboned poultry meat is a valuable protein containing raw material widely used for the production of meat products. However, it does not have a high resistance to oxidation; therefore, various antioxidants including those of natural origin are used in its composition. The article provides information on the advisability of using rosemary extract and dihydroquercetin to stabilize lipids and interrupt hydrolytic and chain oxidative processes in mechanically deboned poultry meat. The permissible storage time for mechanically deboned poultry meat using the rosemary extract and dihydroquercetin in a chilled state is 96 hours. Research has been carried out on the oxidative processes of the fatty complex of mechanically deboned poultry meat during the refrigerated storage period. Antioxidants prevent the accumulation of peroxides: in the samples with their use, the peroxide number reaches critical values on 6-7 day of storage, without their use - on 3 day of storage. For all samples, a gradual increase in the acid number has been observed; however, for samples without antioxidants its values reach a critical level on the 4 day of storage, with the use of antioxidants - on the 7 day. The active formation of secondary oxidation products has begun from the second day of storage and reached the limit of permissible values in samples without antioxidants after 3 days of storage. In samples with antioxidants, the thiobarbituric number reaches a critical value on the 6 day. It has also been shown that the use of antioxidants contributes to the preservation of sensorial indicators (colour, odour) improving the quality of products. The efficiency of using the rosemary extract and dihydroquercetin as inhibitors of the oxidation of mechanically deboned poultry meat has been confirmed.

The Influence of Acid Whey on the Lipid Composition and Oxidative Stability of Organic Uncured Fermented Bacon after Production and during Chilling Storage.

The aim of this research was to evaluate the effect of acid whey on changes in the fatty acid profile, oxidative stability, physico-chemical parameters, and microbiological and sensory quality of traditional organic uncured fermented Polish bacon after production and during chilling storage. Three different treatments of fermented bacon were produced: C—control bacon with a nitrite curing mixture; T—bacon with a nitrate curing mixture; and AW—bacon with acid whey and NaCl. The acid whey used in the production of uncured fermented pork bacon positively changed the sensorial characteristics, directly after the ripening process, and had a positive effect in terms of a decrease in the pH of the product. All of the fermented bacon treatments in general were of good microbiological quality. A higher lactic acid bacteria (LAB) level was observed in the AW treatment after the fermentation process, and the bacteria number did not change during storage, whereas in the C and T treatments, the LAB level increased during storage (p < 0.05). The application of acid whey did not limit the formation of secondary oxidation products (TBARS) during bacon ripening (1.68 mg MDA kg−1), but had a reduced value during storage time (0.73 mg MDA kg−1). The highest polyunsaturated fatty acid (PUFA) levels, after ripening and after four weeks of refrigerated storage, were found in the C treatment. In the AW treatment, it was found that the PUFA level increased; likewise, the content of n-3 and n-6 fatty acids increased, while saturated fatty acids (SFAs) decreased during storage (p < 0.05). The opposite tendency was observed in the C treatment. After four weeks of storage, the PUFA/SFA ratio was the lowest in the nitrate treatment, and higher values of the PUFA/SFA ratio were obtained in the acid whey and nitrite treatment (p < 0.05).

Effect of Frying and Roasting Processes on the Oxidative Stability of Sunflower Seeds (Helianthus annuus) under Normal and Accelerated Storage Conditions.

The effect of different cooking processes such as frying and roasting on the oxidative stability of sunflower seeds was evaluated under accelerated oxidation and normal storage conditions. The fatty acid composition by GC-MS showed a higher amount of linoleic acid in fried samples due to the replacement of the seed moisture by the frying oil. On the other hand, roasted samples presented a higher oleic acid content. DSC and TGA results showed some decrease in the thermal stability of sunflower seed samples, whereas PV and AV showed the formation of primary and secondary products, with increasing oxidation time. Roasted sunflower seeds showed seven main volatile compounds characteristic of the roasting process by HS-SPME-GC-MS: 2-pentylfuran, 2,3-dimethyl-pyrazine, methyl-pyrazine, 2-octanone, 2-ethyl-6-methylpyrazine, trimethyl-pyrazine, and trans,cis-2,4-decadienal, whereas fried samples showed six volatile characteristic compounds of the frying process: butanal, 2-methyl-butanal, 3-methyl-butanal, heptanal, 1-hexanol, and trans,trans-2,4-decadienal. The generation of hydroperoxides, their degradation, and the formation of secondary oxidation products were also investigated by ATR-FTIR analysis. The proposed methodologies in this work could be suitable for monitoring the quality and shelf-life of commercial processed sunflower seeds with storage time.

Interfacial activity of phenolic-rich extracts from avocado fruit waste: Influence on the colloidal and oxidative stability of emulsions and nanoemulsions

The effects of phenolic-rich extracts from avocado peels (AP) and seeds (AS) on the colloidal and the lipid oxidative stability of oil-in-water (O/W) emulsions/nanoemulsions were evaluated. For this purpose, the interfacial tension (IFT) of avocado oil droplets in the presence of extracts and surfactants (low methoxyl pectin, LMP; Tween 80, T80), individually or combined, was assessed. Individually, T80 led to the lowest IFT values (4.25 ± 0.02 mN/m), followed by AS and AP extracts (9.27 ± 0.86 mN/m and 12.31 ± 0.10 mN/m, respectively) and LMP (14.88 ± 0.05 mN/m). Regarding particle size, the emulsions containing AP and AS extracts were smaller (1.45 ± 0.10 μm and 1.11 ± 0.03 μm, respectively), and stabler, than blank emulsions (4.05 ± 0.51 μm). Conversely, the extracts, especially AS extract, reduced the stability of nanoemulsions causing a 24-fold particle size increase. Nevertheless, AP and AS extracts reduced the formation of secondary oxidation products in emulsions/nanoemulsions. These findings provide novel insights into the potential use of avocado waste.

Effect of sesamol on the physical and chemical stability of plant-based flaxseed oil-in-water emulsions stabilized by proteins or phospholipids.

Plant-based polyphenols are increasingly being explored as functional ingredients in emulsified food systems. In this study, the effects of sesamol on the physical and chemical stability of flaxseed oil-in-water emulsions stabilized by either phospholipids (sunflower) or proteins (whey or pea) were investigated. In the absence of sesamol, the protein-based emulsions displayed better physical stability than the phospholipid-based ones, which was related to their smaller particle diameter and higher particle charge. For the phospholipid-based emulsions, sesamol addition did not improve their physical stability, but it did inhibit lipid oxidation. In particular, it decreased the formation of secondary oxidation products, with a 65% reduction in TBAR formation compared to the control after 8 days of storage. For the protein-based emulsions, sesamol addition reduced particle aggregation and inhibited lipid oxidation, reducing the secondary oxidation products by around 85% after 19 days of storage. The inhibitory efficiency of sesamol in the pea protein-based emulsions was comparable to that in the whey protein-based ones. The effects of sesamol on the physical and chemical stability of the emulsions were related to its partitioning between the oil, water, and interfacial layers. This study suggests that adding sesamol to plant-based emulsions may improve their physical and chemical stability, thereby extending their shelf life.

Antioxidants Effect of Two Aminomethyl Derivatives of 2-Methoxyphenol on Thermal and Storage Oxidative Stability of Coconut Oil

The antioxidants effect of two aminomethyl derivatives of 2-methoxyphenol: 4,6-di[(morpholin-4-yl)methyl]-2-methoxyphenol (DMMMP) and 5-[(pyrrolidin-1-yl)methyl]vanillic acid (PMVA) on enhancing thermal and oxidative storage stability of coconut oil was performed using tert-butylhydroxyquinone (TBHQ) as a comparative standard. The efficacy on thermal stability test was carried out by heating at 180 oC for 1, 3, and 6 hours, while the efficacy on the storage stability test was performed using an accelerated method by heating at 60oC for 5 weeks. The concentrations for MDMMP was 200, 350, and 500 ppm; for PMVA was 200, 275, and 350 ppm; and for TBHQ was 200 ppm. Free fatty acid (FFA) level, peroxide value (PV), and p-anisidine value (p-AV) were used as parameters to assess the level of oxidative stability of coconut oil. The results showed that the addition of DMMMP 200, 350, and 500 ppm, and PMVA 200 and 275 ppm did not inhibit FFA, peroxide, and aldehyde formation. In thermal stability study, PMVA (350 ppm) could inhibit the free fatty acid release, and formation of secondary oxidation products compounds on thermal stability comparable to TBHQ (200 ppm) addition, but only TBHQ that could inhibit peroxide formation for 6 h. In storage stability, DMMMP (all concentration) could not delay the fatty acid release, while PMVA (all concentration) and TBHQ (200 ppm) delayed that for 2 and 5 weeks, respectively. DMMMP (all concentration) delayed peroxide formation for 2 weeks, while PMVA (all concentration) and TBHQ (200 ppm) delayed peroxide formation for 5 weeks. All compounds only delay the formation of secondary oxidation products for 1 week. In conclusion, the efficacy of PMVA as an antioxidant against thermal and storage oxidative stability of coconut oil is higher than DMMMP but lower than TBHQ.

How To Stabilize ω-3 Polyunsaturated Fatty Acids (PUFAs) in an Animal Feeding Study?-Effects of the Temperature, Oxygen Level, and Antioxidant on Oxidative Stability of ω-3 PUFAs in a Mouse Diet.

Substantial studies have shown that ω-3 polyunsaturated fatty acids (PUFAs) have various health-promoting effects; however, there are inconsistent results from animal studies that showed that ω-3 PUFAs have no effects or even detrimental effects. Emerging research suggests that oxidized ω-3 PUFAs have different effects compared to unoxidized ω-3 PUFAs; therefore, lipid oxidation of dietary ω-3 PUFAs could contribute to the mixed results of ω-3 PUFAs in animal studies. Here, we prepared an AIN-93G-based, semi-purified, powder diet, which is one of the most commonly used rodent diets in animal studies, to study the oxidative stability of fortified ω-3 PUFAs in animal feed. We found that lowering the storage temperature or the addition of a certain antioxidant, notably tert-butylhydroquinone (TBHQ), helps to stabilize ω-3 PUFAs and suppress ω-3 oxidation in the animal diet, while reducing the level of oxygen in the storage atmosphere is not very effective. The addition of 50 ppm of TBHQ in the diet inhibited 99.5 ± 0.1% formation of primary oxidation products and inhibited 96.1 ± 0.7% formation of secondary oxidation products, after 10 days of storage of the prepared diet at a typical animal-feeding experiment condition. Overall, our results highlight that ω-3 PUFAs are highly prone to lipid oxidation in a typical animal-feeding experiment, emphasizing the critical importance to stabilize ω-3 PUFAs in animal studies.

The Effects of Dietary Inclusion of Bilberry and Walnut Leaves in Laying Hens' Diets on the Antioxidant Properties of Eggs.

Simple SummaryEggs are considered common dietary sources of n-3 polyunsaturated fatty acids (PUFA), but they are susceptible to quality deterioration. In order to reduce oxidation, the best strategy is the addition of antioxidants to hens’ diets. Walnut and bilberry co-products, rich in phenolic compounds, are produced in agricultural industries, and are a valuable source of antioxidants for animal nutrition. The dietary inclusion of bilberry and walnut leaves as natural sources of antioxidants in poultry diets led to the accumulation of nutrients with antioxidant activity in the egg yolk, and the susceptibility of the yolk to lipid peroxidation during storage improved. The results of the present study showed that including bilberry and walnut leaves in laying hens’ diets enhanced the oxidative stability of the egg yolk and retarded the lipid peroxidation process during storage.The purpose of this study was to examine the effects of dietary inclusion of walnut and bilberry leaves (WL and BL), as sources of natural antioxidants in poultry diets, on the enrichment of antioxidant nutrients in the egg yolk and on the susceptibility of the yolk to lipid peroxidation during storage. The experiment was conducted on 32-week-old TETRA SL LL laying hens, which were assigned to three dietary treatments with 30 birds each. Each treatment was replicated 10 times with three chicks per replicate pen. Experimental dietary treatments differed from control diet (C) by addition of 0.5% BL supplement or 1% WL supplement. The phytoadditives were not significant contributors to the productive parameters. The addition of BL and WL in laying hens’ diets significantly increased the total polyphenol content, and the zinc, lutein and zeaxanthin concentrations in the egg yolks. In regards to the oxidative stability parameters, a significant decrease in the concentrations of primary oxidation products formed in the egg yolk of experimental groups was seen, proving an efficient inhibition effect of the phytoadditives on peroxyl radical formation. A significant correlation was observed between primary oxidation products and total polyphenol content of the egg yolks, where zinc, lutein and zeaxanthin are the bioactive compounds that inhibit the formation of secondary oxidation products.

Investigation of the Effects of Repeated Frying on the Quality of Vegetable Oil

Refined vegetable oil (Kings brand), was purchased from Mile 3 Market, Port Harcourt, Nigeria and was repetitively used in frying Akara balls for a period of 24 hours, at intervals of four hours per day, for six days. The effect of heat and repetitive use for frying on quality of the oil was monitored by the measurement of the physico-chemial parameters of the oil after each frying period. The density, % free fatty acid, viscosity, peroxide value and iodine value of the fresh and used oil were determined to investigate the level of deterioration. The results obtained show that the values of the parameters increased with frying time except that of iodine value which decreased with frying time. The free fatty acid value increased from 0.06 -.56%, density increased from 0.900-0.910 g/ml, viscosity increased from 23.33-28.31mm²/s, peroxide value increased from1.988-4.879meqO₂/Kg and iodine value decreased from 43.35 – 29.83wijis. These changes are attributed to the destruction of the chemical structures of the triacylglycerols and formation of new products in the oil by heat. The increase in the density and viscosity shows that as frying progressed, denser and higher molecular weight compounds are formed thereby rendering the used oil more viscous. The increase in peroxide values may be due the formation of peroxides as the primary products of oxidation. The formation of peroxides leads to loss of unsaturation in the oil which is seen as a reduction in iodine value of the oil. The sweet aroma of the oil was also lost as frying progressed as a result of de-esterification of the oil and formation of secondary oxidation products that impart off-flavours to the oil. The findings show that repeated use of vegetable oil for frying leads to deterioration/degration of the oil.