Antioxidants from barley husks impregnated in films of low-density polyethylene and their effect over lipid deterioration of frozen cod (Gadus morhua)

BACKGROUND: The changes in quality of cod fillets packaged in films with and without antioxidants during 12 months of frozen storage at ? 20 °C were investigated in the present study. The following parameters were determined in order to study lipid hydrolysis and primary and secondary lipid oxidation in the samples during frozen storage: peroxide value, conjugated dienes, conjugated triene hydroperoxides, free fatty acids, totox value, thiobarbituric acid‐reactive substances and p‐anisidine value. RESULTS: Films containing antioxidants isolated from barley husks were effective in slowing down lipid hydrolysis and primary and secondary lipid oxidation processes. Secondary lipid oxidation reached maximum values in the 12th month of storage in control samples and samples packaged with antioxidant‐containing film. Maximum lipid hydrolysis and lipid oxidation values for control cod samples were significantly higher than the maximum values found in samples packaged with antioxidant‐containing film. CONCLUSION: The results confirm the efficacy of natural antioxidants derived from barley husks in slowing down lipid hydrolysis and increasing the oxidative stability of cod flesh. They also demonstrate the potential usefulness of natural antioxidants extracted from barley husks in the development of active packaging films for food preservation. Copyright © 2011 Society of Chemical Industry     

Lipid damage during frozen storage of Atlantic halibut (Hippoglossus hippoglossus) in active packaging film containing antioxidants

The use of peroxide value (PV), free fatty acids (FFA), thiobarbituric acid reactive substances (TBARS) and p-anisidine value (PA) proved suitable for studying lipid hydrolysis and primary and secondary lipid oxidation in samples of Atlantic halibut throughout frozen storage. After twelve months, the FFA values in the samples packaged with the film containing natural antioxidants (extracted from barley husks) were similar to the FFA value in the control sample after 9 months. Maximum peroxide value in the samples packaged with the antioxidant-containing film was found one month after the maximum value observed in the control sample. After six months, the concentration of malondialdehyde in the control sample was approximately 30–50% higher than in samples packaged in film containing antioxidants. The results confirm the efficacy of natural antioxidants derived from barley husks and antioxidant active packaging film in slowing down lipid hydrolysis and increasing the oxidative stability of Atlantic halibut flesh.     

Effect of a Polyphenol–Vacuum Packaging on Lipid Deterioration During an 18-Month Frozen Storage of Coho Salmon (<Emphasis Type="Italic">Oncorhynchus kisutch</Emphasis>)

A packaging system combining a polyphenol-rich film and vacuum (PPRF–VP) was applied to farmed coho salmon (Oncorhynchus kisutch) muscle for an 18-month storage (−18 °C). For it, two different concentrations of polyphenol compounds (namely, p-coumaric and ferulic acids) obtained from a barley husk extract were applied (PPRF–VP conditions) and compared to vacuum packaging without polyphenol presence (vacuum control; VP condition) and to packaging in the absence of vacuum and polyphenols (control; CP condition). The study was addressed to lipid hydrolysis and oxidation development and to lipid changes related to nutritional value. Both PPRF–VP conditions provided an inhibitory effect (p < 0.05) on conjugated diene and fluorescent compound formation in frozen salmon. Compared to CP condition, vacuum packaging (PPRF–VP and VP conditions) led to lower (p < 0.05) peroxide and anisidine values and to an inhibitory effect (p < 0.05) on α- and γ-tocopherol losses. No effect (p > 0.05) of polyphenol presence and vacuum packaging could be inferred on free fatty acid formation (hydrolysis development) and on polyunsaturated fatty acid retention (polyene index assessment). A low rancid odour development was observed in all kinds of fish samples, this being lower (p < 0.05) in fish kept under vacuum (PPRF–VP and VP) conditions.     

水包油乳液中油脂氧化稳定性的研究进展

随着消费者对不饱和脂肪酸及其产品营养价值越来越重视,不饱和脂肪酸富集食品已经成为食品工业发展的趋势。水包油(oil-in-water,O/W)乳液是食品油脂最常见的存在形式,也是必需脂肪酸、脂溶性营养素和风味物质的有效载体。然而,富含不饱和脂肪酸的O/W乳液食品在加工和贮藏过程中极易氧化,引起风味恶化、营养损失,甚至形成威胁人类健康的有毒化合物。因此,如何提高乳液中油脂的氧化稳定性是食品工业中亟待解决的问题。然而,消费者对天然食品需求的提高,又限制了合成抗氧化剂和氢化等传统抗氧化方法的使用。本文综述了O/W乳液中油脂氧化的机制、影响因素和调控机制,重点概述了食品分散体中油-水界面的理化性质如何影响油脂氧化稳定性这一基础研究,为高稳定性乳液体系和新型功能食品的开发提供新思路和理论支持。     

Effect of HPMC–Anthocyanin Packaging Color and Oxygen Permeability on Salmon Oil Preservation

Antioxidant food packaging films were successfully developed by incorporation of anthocyanin compound (liquid extract from natural sources) into hydroxypropyl methylcellulose matrix. Film color and oxygen barrier properties were measured. Red color of films containing anthocyanin compound (AC) showed good control of light transmission in comparison with control (transparent) films. Barrier properties of these films showed that addition of AC decreased oxygen permeability, possibly due to hydrogen bonding between polymer OH groups and those of anthocyanin compound. The effectiveness of bioactive films was investigated by packaging salmon oil. Changes in oil color, headspace oxygen consumption, conjugated dienes, polyene index, and C–H stretching vibration of cis-double bond (=CH) showed that, in general, AC films improved salmon oil stability. Films with 2, 3, and 4 % (v/v) AC offered the best protection against lipid oxidation due to improved barrier properties against light and oxygen.     

Rancidity development during the frozen storage of farmed coho salmon (Oncorhynchus kisutch): Effect of antioxidant composition supplied in the diet

A commercial diet including synthetic antioxidants (BHT–ethoxyquin mixture) (diet I) was provided to coho salmon (Oncorhynchus kisutch) in parallel with two diets including natural antioxidants (tocopherol isomers–rich mixture, diet II; tocopherol isomers-rosemary extract mixture, diet III). A comparative study of the rancidity development in the corresponding frozen (−18 °C) products was undertaken. When compared to fish fed with diet I, individuals corresponding to diet II showed a greater (p < 0.05) retention of primary (conjugated dienes and peroxides content) and secondary (anisidine and thiobarbituric acid indices) lipid oxidation compounds that led to a lower interaction compound formation (fluorescence ratio ranges: 0.33–0.50 and 0.55–0.85, for diet II and diet I individuals, respectively); likewise, a higher polyene index (1.99–2.14 and 1.72–1.97, respectively) and lower oxidised taste scores (0.0–0.6 and 0.0–2.4, respectively) were obtained. No effect (p > 0.05) on lipid hydrolysis development (free fatty acid formation) could be found as a result of employing different diets.     

Development of new active packaging films coated with natural phenolic compounds to improve the oxidative stability of beef

The aim is to develop active packaging films containing natural antioxidants and to evaluate their capacity to enhance the oxidative stability of beef during refrigeration. The antioxidant activity of a natural extract obtained from a brewery residual waste was evaluated and compared with that of a commercial rosemary extract and two synthetic antioxidants (BHT and propyl gallate). Different concentrations of each antioxidant were also added directly to beef samples, resulting in a reduction in lipid oxidation of up to 70–80% relative to the control. Active antioxidant films coated with PVPP-WS extract reduced lipid oxidation by up to 80%, relative to the control, during cold storage. The use of active packaging films containing natural extracts could improve the oxidative stability of meat products and should therefore be of great interest in the food industry.     

Prevention of lipid oxidation in muscle foods by milk proteins and peptides: A review

Muscle foods (especially fresh meat, precooked, and restructured meat products) are highly prone to lipid oxidation, which ultimately leads to certain problems, viz. discoloration, off-flavor, drip losses, loss of essential fatty acids and vitamins, and generation of toxic products. These problems can be minimized with the help of various agents and or techniques such as use of natural/synthetic antioxidants, metal chelating agents, physical conditions, vacuum packaging, and encapsulation techniques. Among these, the role of synthetic antioxidants is quite debatable due to certain health risks to humans. Among the natural molecules, milk proteins and their bioactive peptides offer a promising potential for the meat industry. Various forms of milk proteins and peptides including caseinates, whey proteins, skim milk, and milk co-precipitates can be used to prevent lipid oxidation in meat products either in the form of added ingredients or as edible coatings. However, in addition to prevention of lipid oxidation, they also provide nutritional benefits and improve the technological processing and shelflife of meat and meat products. This review focuses on the utilization, mechanism of action, and efficacy of milk proteins and peptides to inhibit lipid oxidation in muscle food products.     

桑椹多酚对广式腊肠贮藏过程中脂质降解和氧化特性的调控作用

脂质氧化和水解是形成腊肠特征风味的重要途径,但过度氧化会造成腊肠品质的劣变。桑椹多酚是一类天然抗氧化剂,被证实可以有效缓解腊肠储藏过程中的氧化反应,然而其通过调控腊肠脂质氧化和水解来改变腊肠风味的相关机制还鲜有研究报道。鉴于此,该研究将桑椹多酚提取物（1 g/kg）加入到肉糜中,制成广式腊肠,跟踪28 d的储藏过程中腊肠的脂质氧化代谢产物（共轭二烯、共轭三烯、TBARS和己醛）以及脂肪酸（中性脂肪酸、游离脂肪酸和磷脂）的组成变化。研究发现,桑椹多酚主要通过抑制脂质次级代谢产物（己醛和丙二醛）来延缓腊肠的脂质氧化。经过28 d的储藏期后,桑椹腊肠中己醛与丙二醛的含量较对照组分别下降63.10%与28.05%。此外,储藏过程中桑椹多酚还可以有效抑制腊肠储藏过程中游离脂肪酸、磷脂的释放。经过28 d的储藏期后,与对照组相比,桑椹腊肠的游离脂肪酸含量下降了9.59%。同时,桑椹多酚还可以减少风味物质中醛类物质的产生和积累。综上所述,桑椹多酚主要通过延缓腊肠储藏过程中脂质的降解及次级氧化过程来调控产品的风味。     

Vibrational spectroscopic analysis of hake (Merluccius merluccius L.) lipids during frozen storage

Vibrational spectroscopy (mid FTIR and FT-Raman) was used to monitor lipids extracted from hake fillets during frozen storage. Kramer shear resistance was used as a marker of texture changes and lipid damage was also investigated by following the development of conjugated dienes and free fatty acids by spectrophotometric methods. Results show that the intensity of the free fatty acid carboxylic ν(CO) band measured by ATR-FTIR spectroscopy can be used for monitoring the development of lipid hydrolysis in hake lipids. Changes in the Raman ν(CC) stretching region (1658 cm⁻¹ band), partially attributed to conjugated dienes development, were the only observed spectroscopic alterations related to lipid oxidation of hake lipids during frozen storage at −10 °C. The high correlation of free fatty acids with instrumental texture and the disappearance of the ν_as(PO₂⁻) band are consistent with membrane lipid hydrolysis being one of the factors directly related with toughening of lean fish flesh.     

Lipid oxidation-related characteristics of gim bugak (Korean fried cuisine with <Emphasis Type="Italic">Porphyra</Emphasis>) affected by frying oil

The effect of frying oil on the lipid oxidation, antioxidants, and in vitro antioxidant activity of gim bugak was studied. Bugak was prepared by pan-frying at 180 °C in unroasted sesame, soybean, extra virgin olive, or palm oil. The degree of lipid oxidation based on conjugated dienoic acid and p-anisidine values was higher in the bugak fried in soybean or sesame oil with high contents of polyunsaturated fatty acids and tocopherols. However, the oil oxidation was lower in olive and palm oils, which showed higher degradation of tocopherols and polyphenols than in sesame or soybean oil during frying. Although the bugak fried in palm oil contained less antioxidants than that fried in soybean or sesame oil, the in vitro antioxidant activity was not different (p > 0.05). Results suggest that palm oil can replace unroasted sesame oil for the preparation of gim bugak with improved lipid oxidative stability and health functionality.     

Phenolic Compounds and Plant Phenolic Extracts as Natural Antioxidants in Prevention of Lipid Oxidation in Seafood: A Detailed Review

Lipid oxidation is the principal cause of quality loss in seafood, which is known to contain high amounts of polyunsaturated fatty acids. Such quality deterioration, associated with the development of off‐flavor as well as lowering of nutritive value, can be retarded by incorporation of additives having antioxidative properties. The use of synthetic antioxidants has long been practiced in retarding lipid oxidation. However, due to the potential health concerns of synthetic antioxidants, polyphenolic compounds, which are found in different plants and their manufactured by‐products, have been used as an alternative natural antioxidants to retard lipid oxidation in different seafood systems. Both pure phenolic compounds and crude plant phenolic extracts have been successfully used in delaying oxidation in fish muscle, fish oil, and fish oil‐in‐water emulsions. This article reviews in detail the phenolic antioxidants and their natural sources as well as focuses on the role of pure phenolic compounds and crude plant phenolic extracts on the prevention of lipid oxidation in different seafood systems.     

Phenolic Profiles and Antioxidant Properties of Apple Skin Extracts

ABSTRACT:  Lipid oxidation, especially the oxidation of polyunsaturated fatty acids, is a significant issue in the food industry impacting both food quality and health of consumers. Apple skin was investigated as a source of natural antioxidants. The phenolic compound composition and antioxidant properties of 21 selected apple genotypes were evaluated. The lipid stabilizing ability of the apple skin extracts was examined using an aqueous emulsion system of methyl linolenate. The total phenolic concentrations determined by high-performance liquid chromatography tandem mass spectrometry of methanolic extracts of skins of the apple genotypes varied from 150 to 700 mg/100 g DW. The antioxidant capacity measured by Folin–Ciocalteu (16.2 to 34.1 mg GAE/100 g DW), ferric reducing antioxidant power (1.3 to 3.3 g TE/100 g DW), oxygen radical absorbance capacity (5.2 to 14.2 g TE/100 g DW), and percent inhibition of oxidation of methyl linolenate (73.8% to 97.2%) varied among the apple genotypes. The apple skin extracts, specifically the crab apple varieties such as "Dolgo," were revealed to be effective inhibitors of oxidation of polyunsaturated fatty acid in a model system and thus can be considered as a potential source of natural food antioxidants.     

Chemical changes during farmed coho salmon (Oncorhynchus kisutch) canning: Effect of a preliminary chilled storage

A relevant farmed fish species (coho salmon; Oncorhynchus kisutch) was studied as a raw material for the canning process. The effects of preliminary chilling storage and thermal treatment (cooking and sterilisation) on the chemical constituents (lipids and non-protein nitrogen compounds) of the canned fish were analysed. An increasing previous chilling time led to an important autolysis (K value) development, and to an increasing formation of free fatty acids, and interaction compounds (fluorescence and browning assessments) (p < 0.05) in the canned product. The thermal treatment led to the formation of volatile amines (total and trimethylamine), free fatty acids, secondary lipid oxidation compounds (anisidine and thiobarbituric acid values) and interaction compounds in canned fish. Interaction compound assessment was found the most useful tool to study the lipid oxidation and non-enzymatic browning developments, while the K value showed to be an interesting index for assessing the freshness stage of the raw material employed.     

Trends in the use of natural antioxidants in active food packaging: a review

The demand for natural antioxidant active packaging is increasing due to its unquestionable advantages compared with the addition of antioxidants directly to the food. Therefore, the search for antioxidants perceived as natural, namely those that naturally occur in herbs and spices, is a field attracting great interest. In line with this, in the last few years, natural antioxidants such as α-tocopherol, caffeic acid, catechin, quercetin, carvacrol and plant extracts (e.g. rosemary extract) have been incorporated into food packaging. On the other hand, consumers and the food industry are also interested in active biodegradable/compostable packaging and edible films to reduce environmental impact, minimise food loss and minimise contaminants from industrial production and reutilisation by-products. The present review focuses on the natural antioxidants already applied in active food packaging, and it reviews the methods used to determine the oxidation protection effect of antioxidant active films and the methods used to quantify natural antioxidants in food matrices or food simulants. Lastly consumers’ demands and industry trends are also addressed.     

The effect of natural antioxidants on haemoglobin-mediated lipid oxidation during enzymatic hydrolysis of cod protein

Heating and changes in pH often practised during fish protein hydrolysis can cause lipid oxidation. The effect of natural antioxidants towards haemoglobin-mediated lipid oxidation during enzymatic hydrolysis of cod proteins was investigated. Different variants of a washed cod model system, containing different combinations of haemoglobin and natural antioxidants (l-ascorbic acid and Fuscus vesiculosus extract), were hydrolysed using Protease P “Amano” 6 at pH 8 and 36 °C to achieve 20% degree of hydrolysis. Lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS) were analysed periodically during the hydrolysis process. The in vitro antioxidant activity of the final products was investigated. Results indicate that oxidation can develop rapidly during hydrolysis and antioxidant strategies are preferable to produce good quality products. Oxidation products did not have an impact on the in vitro antioxidant activity of the hydrolysates. The natural antioxidants inhibited oxidation during hydrolysis and contributed to the antioxidant activity of the final product.     

The effects of natural antioxidants and lighting conditions on the quality of salmon (Salmo salar) fillets packaged in modified atmosphere

The effect of lighting conditions (darkness, a low‐UV colour‐balanced lamp and supermarket fluorescents), along with the application of natural antioxidants (rosemary extract and ascorbic acid) on shelf‐life of salmon (Salmo salar) fillets packaged in modified atmosphere and stored at 1 ± 1 °C was studied. Darkness and lighting with low‐UV colour‐balanced lamps led to an extension of shelf‐life compared with conventional light, as assessed by a* values, lipid oxidation (TBARS value) and sensory evaluation. The application of natural antioxidants on the surface of MAP salmon fillets gave rise to a delay of lipid oxidation as well as an improvement of the sensory quality, mainly in the case of conventional lighting conditions. Copyright © 2005 Society of Chemical Industry     

Light effects on lipid oxidation,antioxidants, and pigments in dried laver (Porphyra) during storage

Effects of light on lipid oxidation, antioxidants, and pigments in dried laver (Porphyra) were studied during storage at 40°C and at a water activity of 0.75 for 15 days. Lipid oxidation was evaluated by measuring peroxide value (POV) and conjugated dienoic acid (CDA) contents, whereas fatty acid composition was analyzed by gas chromatography. Contents of polyphenols, tocopherols, porphyran, chlorophylls, carotenoids, and phycobilins were also monitored. The POV and CDA contents of dried laver lipids increased during storage, whereas contents of eicosapentaenoic acid, pigments, and antioxidants decreased. Light accelerated lipid oxidation as well as degradation of antioxidants and pigments during storage of dried laver. Chlorophyll and polyphenols were the most rapidly degraded among all pigments and antioxidants, respectively, and light had the strongest effect on their degradation. Lipid oxidation of dried laver due to light was highly dependent on the content of a-tocopherol among all minor compounds.     

Antioxidants Release from Solvent-Cast PLA Film: Investigation of PLA Antioxidant-Active Packaging

The release study of natural antioxidants, i.e., ascorbyl palmitate and α-tocopherol, and synthetic phenolic antioxidants including butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate, and tert-butylhydroquinone (TBHQ) from polylactic acid (PLA) film into food simulants were accomplished. PLA antioxidant films were placed in contact with 95, 50, and 10 % ethanol at 40 and 20 °C. Released antioxidants were regularly measured by high-performance liquid chromatography system for 60 days. Ascorbyl palmitate was completely degraded during film preparation and is not a suitable antioxidant for PLA antioxidant-active packaging. The diffusion coefficient (D) and partition coefficient (K) of antioxidants were calculated based on obtained data. Diffusion of the antioxidants from PLA to the simulants showed a Fick’s behavior with the diffusion coefficient (D) value between 10^?9 and 10^?11 cm² s^?1 with 0–100 % of release. Faster and higher release of antioxidants occurred at 40 °C according to Arrhenius law. At 40 °C, TBHQ in 95 % ethanol decomposed to 2-tert-butyl-1,4-benzoquinone and other quinone derivatives, and α-tocopherol in 50 % ethanol decomposed to some unknown neoformed compounds. Antioxidants molecular weight, Log P, simulant polarity, and temperature were the most influencing factors on antioxidants release rate from PLA films in contact with food simulants. The D and K coefficients of studied antioxidants from PLA in three food simulants and two temperatures can be used to create PLA antioxidant-active packaging to continually control the oxidation reactions in diverse foodstuffs to ensure higher food qualities. The PLA antioxidant-active packaging approach also permits to reduce the amounts of directly added antioxidants in foods to provide safer foods.     

Effect of the addition of air-classified barley flours on the lipid stability of bakery products

Whole grains are a potential source of dietary antioxidants, and their phenolic compounds play a potential role in the prevention of lipid oxidation. In the present study, the barley coarse fraction was tested as a source of phenolic compounds to minimize lipid oxidation in bakery products (tarallini) during storage. The content of phenolic compounds in wheat and barley flours and in their mixtures was evaluated by capillary electrophoresis. Three recipes of tarallini were formulated containing different levels of barley coarse fraction (0, 20, 50%, w/w) and either extravirgin olive oil or sunflower oil. Samples were stored for 6 months and analysed every 3 months. The peroxide value was used to establish the primary oxidation state; secondary oxidation products were also evaluated (oxidized fatty acid and diene and triene conjugated by UV). All samples showed an increase in lipid oxidation during storage. The increase in peroxide values after 6 months was in the range of 183–574%. Tarallini prepared with sunflower oil showed the highest lipid oxidation. Antioxidant effects were not observed with the coarse fraction phenolic compounds.