Lipid Oxidation In Foods Research Articles

Antioxidants in Food: Mere Myth or Magic Medicine?

The powerful action of antioxidants in preventing premature lipid oxidation in food suggests that the same compounds, when consumed with the daily diet, could unfold antioxidative/anti-aging effects in the human body. Therefore, it has been hypothesized that antioxidants are helpful in preventing various diseases. More detailed chemical and physiological examination of antioxidants shows, however, that the extrapolation of in vitro data to in vivo behavior may be misleading. Indeed, such a procedure fails to take into account the mismatch between most in vitro models (e.g., cell cultures) and in vivo systems. For example, the physiological relevance of pro-oxidative and other physiological activities of antioxidants have been largely underestimated. Actually, contrary to the antioxidant hypothesis, clinical trials testing the health benefits of dietary antioxidants have reported rather mixed or negative results. Many clinical studies have not taken into account the nutrikinetic and nutridynamic nature of antioxidants. Further, oxidative stress is not only an inevitable event in a healthy human cell, but responsible for the functioning of vital metabolic processes, such as insulin signaling and erythropoietin production. In the light of recent physiological studies it appears more advisable to maintain the delicate redox balance of the cell than to interfere with the antioxidant homeostasis by a non-physiological, excessive exogenous supply of antioxidants in healthy humans.

The Potential Application of Plant Essential Oils/Extracts as Natural Preservatives in Oils during Processing: A Review

The present work summarizes recent investigations carried out about the usage of natural antioxidants in lipid-rich food during processing. Synthetic antioxidants have been used as food additives to retard lipid oxidation and development of off-flavor for over 50 years. However, the literature has expressed safety concerns and health risks (toxic and carcinogenic effects) associated with the use of synthetic antioxidants recently. Natural antioxidative substances from the polyphenols of edible plants are believed to be safer and may provide with additional health benefits and more effective compared to synthetic antioxidants. Due to the fact that natural antioxidants are additives that people mixed with food and consumed for centuries, they are known to be safe by the consumer. Therefore, it is an area worth to investigate due to consumer concerns about health. In the literature, there are many studies showing that the natural antioxidants have important antioxidant effect. Plants (oil seeds, cereals, vegetables, fruits, herb and spices), compounds from animal source (peptides and amino acids), enzymes and some microorganisms are important natural antioxidants. Plant extracts have been widely used to retard lipid oxidation in foods during frying and accelerated storage processes. They were found as strong antioxidant sources due to their high contents of phenolic compounds. There are countless studies about natural antioxidants. However, they have not been investigated completely by means of toxicology.

Application of ESR spin label oximetry in food science

Lipid oxidation attributed to the presence of oxygen has long been a focal area for food science research due in early years mainly to its broad impact on the quality and shelf stability. The need to effectively strategize interventions to detect and eventually eliminate lipid oxidation in food remains as evidence on nutritional and health implications continue to accumulate. Electron spin resonance (ESR) spin label oximetry has been shown capable of detecting dissolved oxygen concentration in both liquid and gaseous phases based on the collision between oxygen and stable free radicals. This review aimed to summarize not just the principles and rationale of ESR spin label oximetry but also the wide spectrum of ESR spin label oximetry applications to date. The feasibility to identify in very early stage oxygen generation and consumption offers a promising tool for controlling lipid oxidation in food and biological systems.

Egg Yolk Phosvitin and Functional Phosphopeptides—Review

Phosphopeptides are among the most interesting biomolecules with characteristic molecular structure and functions. They usually contain clusters of phosphoserines, which can effectively bind calcium and iron, and inhibit formation of insoluble calcium phosphates or iron complexes. Therefore, phosphopeptides can increase calcium or iron bioavailability and prevent lipid oxidation in foods. Milk protein casein has been currently used by industry to produce phosphopeptides. Egg yolk phosvitin is considered as the most phosphorylated protein found in the nature. Phosvitin from egg yolk can be much better source for producing phosphopeptides with varying sizes and functions than casein because it contains much greater number of phosphates in the molecule than casein. However, still phosvitin has not been subjected to considerable attention with regard to bioactive peptides production.

Improving meat quality through natural antioxidants

Nowadays, consumers are demanding more natural foods, obliging the industry to include natural antioxidants in foods. Natural antioxidants have been used instead of synthetic antioxidants to retard lipid oxidation in foods to improve their quality and nutritional value. This review discusses some aspects of recent research on antioxidant activity of plant extracts and natural compounds to improve meat quality. Many herbs, spices, and their extracts have been reported as having high antioxidant capacity, such as some plants of the Lamiaceae family, e.g., oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.), and sage (Salvia officinalis L.). The antioxidant activity of these plants is attributed to their phenolic compound content, which includes volatile compounds also known as essential oils. Several factors that cause some differences on the antioxidant activity of plant extracts include: type of solvent used during extraction, measurement method, and number of samples. Some studies have demonstrated that shelf-life and meat quality can be improved by using natural antioxidants in some stages of meat production. The main effects of these compounds are reducing microbial growth and lipid oxidation during storage. Nevertheless, more research is needed to determine antimicrobial activity of natural antioxidants in meat during storage, identify the main metabolic pathway of these compounds, and its effect on other meat quality parameters.

Physical Structures in Soybean Oil and Their Impact on Lipid Oxidation

The oxidation of edible oil yields both primary and secondary oxidation products (e.g., hydroperoxides, carbonyls, hydrocarbons, and epoxides), which produce undesirable sensory and biological effects. Consequently, the suppression of lipid oxidation in food matrices is of great importance. The rate and extent of lipid oxidation in many heterogeneous foods are strongly affected by the physicochemical characteristics of water-oil interfaces. This study examined the ability of dioleoylphosphatidylcholine (DOPC) and water to form association colloids within bulk oil, as well as their impact on lipid oxidation kinetics. Attenuation was used to show the DOPC and water concentrations at which association colloids existed without altering the optical properties of the oil. Interfacial tension and fluorescence spectrometry showed the critical micelle concentration (CMC) of DOPC in stripped soybean oil was around 650 μM at room temperature. Small-angle X-ray scattering (SAXS) and fluorescence probes showed that water had a very strong impact on the properties of the association colloids formed by DOPC. Measurement of primary and secondary lipid oxidation products revealed that the association colloids formed by DOPC had a pro-oxidant effect. The characterization of association colloids could provide a better understanding of the mechanisms of lipid oxidation in bulk oils and provide insights into new antioxidant technologies.

Interference of sodium caseinate in the TBARS assay

One of the most common methods of measuring lipid oxidation in foods is the quantification of malonaldehyde by reaction with 2-thiobarbituric acid (TBA) in the so called TBA-reactive substances (TBARS) assay. Different variants of the TBARS assay include those in which the food sample reacts directly with the TBA reagent and those that involve collection of a distillate from the food before reaction with TBA. Interference of sodium caseinate (NaCas) in a TBARS assay involving direct reaction of TBA with a food sample was observed while exploring the possible retardation of lipid oxidation in sliced turkey meat coated with a NaCas-containing edible film. This short report shows the extent of interference encountered and illustrates the importance of validating the TBA method for particular applications.

Application of Artificial Neural Networks to Predict the Oxidation of Menhaden Fish Oil Obtained from Fourier Transform Infrared Spectroscopy Method

Oxidation is a major cause of deterioration in fish oil, leading to considerable losses of quality and nutritional value. To date, the available methods to monitor lipid oxidation in foods are based on chemical analysis. Fourier transform infrared spectroscopy (FTIR) is an alternative technique for the study of molecular structure and compositional changes in a wide range of foods. The objectives of this study were to use attenuated total reflectance-FTIR for evaluating oxidative quality and application of artificial neural network analysis (ANN), a mathematical model, to predict the oxidative values of Menhaden fish oil. The oil was stored in the presence of light at room temperature. The oxidation was measured for primary and secondary oxidative change; peroxide value (PV) and anisidine value (AnV), respectively, using FTIR were compared with chemical analysis each day during the 3 weeks of storage. The wavenumber and absorbance values of FTIR spectra were applied to predict the oxidative values of the oil by using ANN. Inputs consisted of wavenumber and absorbance outputs were composed of PV and AnV. It was found that changes in the region between 3,500 and 1,700 cm-1 and absorbance were related to PV and AnV of the chemical analysis (R2 > 0.85). FTIR spectroscopy with the aid of ANN demonstrates its potential as an alternative and rapid technique rather than a conventional method for prediction of food lipids oxidation.

Electron spin resonance spectroscopy: a promising method for studying lipid oxidation in foods

AbstractOxidative reactions that involve lipids are among the most important causes of deterioration of foods and affect both their shelf life and their organoleptic and nutritional properties. Radicals are intermediate key‐constituents in these reactions. Their detection is therefore essential in order to understand and predict early stages of these destructive oxidations. Several Electron Spin Resonance (ESR) methodologies (direct and indirect) make it possible to identify, quantify and measure the reactivity of radical species formed during oxidative‐reductive reactions. They are also used to evaluate the antiradical activity of antioxidants delaying lipid oxidation. An overview on the use of different ESR methodologies to study lipid oxidation in foods is reported in this paper.

Relationships between Free Radical Scavenging and Antioxidant Activity in Foods

Numerous attempts have been made to relate the free radical scavenging capacity of compounds to their antioxidant activity in foods even though antioxidant activity is dependent on both physical and chemical properties. The objective of this study was to compare the free radical scavenging activity of various compounds to their ability to inhibit lipid oxidation in foods. The order of free radical scavenging activity of polar compounds was ferulic acid > coumaric acid > propyl gallate > gallic acid > ascorbic acid as determined by a modified oxygen radical absorbance capacity, while the order of nonpolar compounds was rosmarinic acid > butylated hydroxytoluene >or= tert-butylhydroquinone (TBHQ) > alpha-tocopherol as determined by the 2,2-diphenyl-1-picrylhydrazyl assay. Of these compounds, only propyl gallate and TBHQ were found to inhibit lipid oxidation in cooked ground beef as determined by thiobarbituric acid reactive substances, while only propyl gallate, TBHQ, gallic acid, and rosmarinic acid inhibited lipid oxidation in an oil-in-water emulsion as determined by lipid hydroperoxides and headspace hexanal. These data indicate that the free radical scavenging assays tested have limited value in predicting the antioxidant activity in complex foods.

Study of the DPPH [rad]-scavenging activity: Development of a free software for the correct interpretation of data

Antioxidants are important because they prevent lipid oxidation in food, and decrease the adverse effects of reactive species on normal physiological functions in humans. A wide variety of in vitro chemical models have been developed to assess the ability to prevent oxidative damages; amongst the chemical tests that measure radical scavenging capacity, the DPPH assay is one of the most widely employed method. EC 50 (concentration required to obtain a 50% antioxidant capacity) is typically employed to express the antioxidant activity and to compare the antioxidant capacity of various samples; however its measurement requires some care, because of the non-linear relation between antioxidant concentration and antiradical activity. In this work a statistical software was developed in order to apply different linearising transformations in the study of DPPH -scavenging properties of antioxidants. The software was also implemented to perform the determination of outliers, the calculation of the EC 50 values and the comparison of the curves, and of their corresponding straight lines, obtained from the regression analysis of the data. First, the analysis of the DPPH -scavenging activity was performed on standard molecules and then applied to different food extracts. The regression models employed in this work (probit, logit and angular regressions) appeared to be equivalent and to fit well the antiradical activity curves obtained for both standard molecules and food extracts; probit regression was finally chosen to discuss the results and to introduce a new parameter characterising these curves.

Antioxidant Activity of Polyphenols from Sea Buckthorn Fruits (Hippophae rhamnoides)

Lipid oxidation in foods can be retarded by the addition of antioxidants. Certain plants rich in compounds with antioxidant activity manifest an increasing interest in food industry because they retard oxidative degradation of lipids. Sea buckthorn (Hippophae rhamnoides), alcoholic extract was investigated for antioxidant activity. Sea buckthorn fruits were extracted with ethanol using a Soxhlet extractor and the crude extract was analyzed in order to establish total soluble phenolics and the antioxidant activity. The alcoholic extract of Sea buckthorn was found to contain phenols with antioxidant activity. The extract was studied for 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), superoxide anion and hydroxyl radical scavenging activity. The extract was also studied for lipid peroxidation assay by thiobarbituric acid-reactive substances (TBARS) method. The results indicated that Sea buckthorn annihilates free DPPH radicals, the superoxide anion and the hydroxyl radical and it has an inhibitory effect upon lipid peroxidation process.

PATHOGEN CONTROL BY ANTIOXIDATIVE CHARACTERISTICS OF CUMINUM CYMINUM AND ROSMARINUS OFFICINALIS ESSENTIAL OILS

PATHOGEN CONTROL BY ANTIOXIDATIVE CHARACTERISTICS OF CUMINUM CYMINUM AND ROSMARINUS OFFICINALIS ESSENTIAL OILS

Use of edible films based on whey protein isolate to protect foods rich in polyunsaturated fatty acids

Whey protein isolate (WPI) films acting as oxygen barriers can be used to delay lipid oxidation in foods with high content in polyunsaturated fatty acids (PUFA). The aim of this work was to study as to what extent WPI films are capable of delaying lipid oxidation in vegetable oil, as an example of a food rich in PUFA. The effect of plasticizer type (glycerol or sorbitol) and content (30, 40, 50 and 60%), as well as film thickness (60, 100 and 180 μm) and relative humidity (50 or 75%) were analyzed. In order to evaluate the film protective capability, specially designed methacrylate cells and an accelerated test of oxidative rancidity were used. Results obtained showed that WPI films delayed the rancidity in vegetable oil. Films with sorbitol were more effective than films with glycerol, providing a protection as effective as aluminum foil. Both plasticizer content and film thickness affected its protective capacity significantly. The thickest films with the lowest plasticizer content provided the greatest protection against lipid oxidation. Plasticizer content affected film protection much more intensively than thickness. WPI films presented a more effective protection at 50% RH than at 75% RH.

Dietary advanced lipid oxidation endproducts are risk factors to human health

Lipid oxidation in foods is one of the major degradative processes responsible for losses in food quality. The oxidation of unsaturated fatty acids results in significant generation of dietary advanced lipid oxidation endproducts (ALEs) which are in part cytotoxic and genotoxic compounds. The gastrointestinal tract is constantly exposed to dietary oxidized food compounds, after digestion a part of them are absorbed into the lymph or directly into the blood stream. After ingestion of oxidized fats animals and human have been shown to excrete in urine increase amounts of malondialdehyde but also lipophilic carbonyl compounds. Oxidized cholesterol in the diet was found to be a source of oxidized lipoproteins in human serum. Some of the dietary ALEs, which are absorbed from the gut to the circulatory system, seems to act as injurious chemicals that activate an inflammatory response which affects not only circulatory system but also organs such as liver, kidney, lung, and the gut itself. We believe that repeated consumption of oxidized fat in the diet poses a chronic threat to human health. High concentration of dietary antioxidants could prevent lipid oxidation and ALEs generation not only in foods but also in stomach condition and thereby potentially decrease absorption of ALEs from the gut. This could explains the health benefit of diets containing large amounts of dietary antioxidants such those present in fruits and vegetables, or products such as red-wine or tea consuming during the meal.

MEASURING OXIDATIVE STABILITY OF STRUCTURED LIPIDS BY PROTON NUCLEAR MAGNETIC RESONANCE

ABSTRACT The oxidative stability of enzymatically modified oils (structured lipids) and their unmodified counterparts were assessed using proton nuclear magnetic resonance (1H NMR) spectroscopy. This methodology was used to monitor relative changes in the proton absorption pattern of the fatty acids of oils during storage at 60C. Relative changes of aliphatic to olefinic (Rao) and aliphatic to diallylmethylene (Rad) proton ratios during oil oxidation were determined by 1H NMR spectroscopy. An increase in Rao and Rad values was obtained over the entire storage period. The oxidative stability of oils was also evaluated using conjugated dienes (CD) determination, 2‐thiobarbituric acid reactive substances (TBARS) and headspace volatile analysis. A highly significant correlation (r = 0.930–0.992; P ≤ 0.005) existed between the CD values and changes in Rao and Rad during oxidation of all oils. The correlation coefficient between TBARS and changes in Rao and Rad values was in the range of 0.779–0.983 (P ≤ 0.05). A high correlation (r = 0.948–0.996; P ≤ 0.005) was found between hexanal content and Rao and Rad of oils. Propanal content was also highly correlated (r = 0.950–0.990; P ≤ 0.005) with Rao and Rad.PRACTICAL APPLICATIONSAssessment of the extent of lipid oxidation in food is of much interest to producers and scientists alike. Proton nuclear magnetic resonance spectroscopy provides a valuable tool for quantitation of oxidation of food lipids. This procedure was used for evaluating the oxidative state of structured lipids. The procedure is rapid and nondestructive, requires a small amount of material, and may be considered as “green” because it uses a very minimum amount of solvent and is readily applicable to edible oils and oils extracted from food and biological samples.

Role of Physical Structures in Bulk Oils on Lipid Oxidation

Lipid oxidation is important to food manufacturers especially when they increase unsaturated lipids in their products to improve nutritional profiles. Unfortunately, the number of antioxidants available to food manufacturers to control oxidative rancidity is limited and the approval of new antioxidants is unlikely due to economic barriers in obtaining government approval for new food additives. Therefore, new antioxidant technologies are needed for food oils. This paper reviews the current knowledge of lipid oxidation in foods with emphasis on how physical properties of food systems impact oxidation chemistry. In particular, the role of association colloids in bulk oils on lipid oxidation chemistry is discussed in an attempt to understand mechanisms of oxidation. Increasing the understanding of how physical properties impact lipid oxidation could lead to the development of novel antioxidant technologies that not only protect the oil against oxidation and increase shelf-life but also allow food manufacturers to include more nutritionally beneficial fatty acids in their products.

食品中の脂質の酸化生成物による風味変化

脂質に含まれる多価不飽和脂肪酸は構造的に酸化されやすく, 食品においては調理加工や保存の過程などで酸化をうける。その結果, 生じた脂質酸化生成物には食品の風味を損なう, 毒性を有するなど, 食品の品質に悪影響をもたらすものがある。大豆においては, リノール酸がリポキシゲナーゼによって酸化されて生成するリノール酸13S-ヒドロペルオキシドから豆臭の主成分であるヘキサナールが生ずる。大豆種子に存在する3種のリポキシゲナーゼアイソザイムのうち, L-2アイソザイムがヘキサナール生成に最も寄与し, L-3アイソザイムは逆にヘキサナール生成に寄与せず, 逆にヘキサナール生成を抑制する。一方, 魚においては, 従来, トリメチルアミンが魚臭の主成分であるとされてきたが, イコサペンタエン酸やドコサヘキサエン酸などの酸化劣化に由来する多くのカルボニル化合物が存在すること, これらの化合物はさまざまなにおいを有しており, これらのにおいが相まって魚臭となっていることが明らかとなった。

Antioxidant Properties of Kilned and Roasted Malts

Compounds possessing antioxidant activity play a crucial role in delaying or preventing lipid oxidation in foods and beverages during processing and storage. Such reactions lead to loss of product quality, especially as a consequence of off-flavor formation. The aim of this study was to determine the antioxidant activity of kilned (standard) and roasted (speciality) malts in relation to phenolic compounds, sugars, amino acids, and color [assessed as European Brewing Convention units (degrees EBC) and absorbance at 420 nm]. The concentrations of sugars and amino acids decreased with the intensity of the applied heat treatment, and this was attributed to the extent of the Maillard reaction, as well as sugar caramelization, in the highly roasted malts. Proline, followed by glutamine, was the most abundant free amino/imino acid in the malt samples, except those that were highly roasted, and maltose was the most abundant sugar in all malts. Levels of total phenolic compounds decreased with heat treatment. Catechin and ferulic acid were the most abundant phenolic compounds in the majority of the malts, and amounts were highest in the kilned samples. In highly roasted malts, degradation products of ferulic acid were identified. Antioxidant activity increased with the intensity of heating, in parallel with color formation, and was significantly higher for roasted malts compared to kilned malts. In kilned malts, phenolic compounds were the main identified contributors to antioxidant activity, with Maillard reaction products also playing a role. In roasted malts, Maillard reaction products were responsible for the majority of the antioxidant activity.

Antioxidant Mechanisms of Caseinophosphopeptides and Casein Hydrolysates and Their Application in Ground Beef

Caseinophosphopeptides (CPP) and casein hydrolysates have been shown to bind prooxidant metals such as iron, but their effectiveness as metal chelators to inhibit lipid oxidation in foods has still not been fully investigated. Thus, the antioxidant activity of CPP and casein hydrolysates was studied in phosphatidylcholine liposome model systems. CPP (< 1.0 mg/mL) and casein hydrolysates (0.3-1.7 mg/mL) were effective inhibitors of TBARS development when oxidation was promoted by ferric/ascorbate. High amounts of CPP (> 1.0 mg/mL) were prooxidant, whereas casein hydrolysates were observed to be only antioxidative. In the presence of peroxyl radicals, casein hydrolysates were more effective scavengers than enriched CPP (3-15 mM). In cooked ground beef, TBARS formation was inhibited 75, 39, and 17% by 0.5% enriched CPP, casein hydrolysates, and low molecular weight casein hydrolysates, respectively, after 4 days of storage. The results show that CPP and casein hydrolysates are promising sources of natural antioxidants for foods.