Fahimeh Tooryan; Maryam Azizkhani
Abstract
Introduction: Lipids are valuable foods that operate as the medium of heat transfer to the food and susceptible to oxidation on storage and frying processes. Lipid oxidation is one of the major cause of food quality deterioration during storage for vegetable oils, fats and other food systems. The free ...
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Introduction: Lipids are valuable foods that operate as the medium of heat transfer to the food and susceptible to oxidation on storage and frying processes. Lipid oxidation is one of the major cause of food quality deterioration during storage for vegetable oils, fats and other food systems. The free radical are defined as any chemical species having one or more unpaired electrons is generally responsible for the deterioration and limiting the shelf life of fatty foods. Characteristic changes associated with oxidative deterioration include development of unpleasant tastes and odors as well as changes in color, specific gravity, viscosity and solubility .Moreover, the products of lipid oxidation may be potentially toxic and may lead to adverse effects such as the production of carcinogens, mutagenesis and aging. Autoxidation occurs when molecular oxygen reacts with unsaturated lipids like canola oil. Antioxidants are a group of chemicals affect the process of lipid oxidation at different stages and capable of extending the shelf life of food that contain lipids. In general, food industry have been added and applied the synthetic antioxidants such as BHA (Butylated hydroxyl anisole), BHT (Butylated hydroxyl anisole) and TBHQ (Tert-butyl hydroquinone) during the manufacturing process to retard lipid oxidation and prevent fat oxidative and rancidity. They are used to retard the development of unpleasant flavour caused by the oxidation of unsaturated fatty acids. They retard oxidation of lipids by reacting with free radicals, chelating free catalytic metals and also by acting as oxygen scavengers. However, there is concern about the safety and toxicity of synthetic antioxidants in relation to their metabolism and accumulation in body organs and tissues. Synthetic antioxidants are known among other things to cause impairment of blood clotting, lung damage and to act as tumor promoters. Consumers acceptance of synthetic antioxidants remains negative due to their perceived detrimental effect on human health like carcinogenic effects. Consequently, This has led to an increasing trend and interest in the search for effective natural antioxidant and there has been a tendency towards natural antioxidants and replace of these synthetic antioxidants with natural ones such as phenolic compounds. Finding new resources of vegetal antioxidants in order to use them in food (as an additive or alternative with artificial antioxidants) is an important research subject in the field of food science and technology.Researches on alternative natural products such as aromatic plants extract and essential oil have been extended. Phenolic compounds are defined as substances possessing a benzene ring bearing one or more hydroxyl substituents, including their functional derivatives. There are different sources of phenols such as grapes, olive oil, sorghum, beans, spices and herbs. Aromatic plants are used traditionally in various regions of Iran for their preservation and medicinal properties, in addition to enhancing the aroma and flavor of foods. Aromatic plants components that have antiradical activities were used as natural antioxidant in food and biological products. Carum copticum (C. copticum )is well known and valuable medicinal plant that is used widely in Iranian traditional medicine. In this study C. copticum ,as natural antioxidant, was added to Canola oil for improving its oxidative stability .The aim of this research was to evaluate the antioxidant properties of C. copticum extracts (aqueous and alcoholic),and its antioxidant activity in canola oil
Materials and methods: In this study, aqueous and alcoholic extract of C. copticum fruit was extracted as a natural antioxidant. In the first stage, the amount of phenolic compounds content in extracts were measured. Then to determine antioxidant power and activity of extracts the two methods was investigated, DPPH◦ free radical scavenging and β-carotene/linoleic acid system. Each extract at three concentrations of 200 ppm ,400ppm and 600ppm added to canola oil and storage in a period of 49 days. BHT were added to Canola oil at 100 and 200ppm. Also their oxidative stability in canola oil was investigated by measuring peroxide and thiobarbituric acid values.
Results & discussion: The results showed that, C. copticum has good total phenolic content and in β-caroten bleaching assay, by concentration of 2 mg/ml BHT showed the highest inhibition effect (%96 ± 0.09) and followed CE (%76±0.0). In DPPH◦ free radical scavenging and β-carotene/linoleic acid systems, the sequence of the power of antioxidant activity was BHT then CE in concentration of 400 and 600 ppm. In oven test, all extracts inhibited primary and secondary oxidation products of canola oil. Statistical results revealed that CE in concentration of 600 ppm, did not showed significant difference for PV and TBARS comparing with 200 ppm BHT(p>0.05). But CA and CM had lower antioxidant activity in comparision with 200 ppm BHT (p<0.05). Acocording to results, C. copticum is a potent antioxidant for stabilization of canola oil and can be used as a natural antioxidant. It seems that after complementary test because of appropriate antioxidant activity, C. copticum can be used as natural antioxidant in foodstuff, especially in edible oils to improve the oxidative stability of canola oil.
Eisa Jahed; Hadi Almasi; Mohammad Alizadeh khaled abad
Abstract
Introduction: Due to increasing attention to the environment, as well as consumer demand for healthy, nutritive food products and extended shelf life, in the recent years, the food and packaging industries have paid increasing attention to biodegradable edible packaging prepared from biopolymers such ...
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Introduction: Due to increasing attention to the environment, as well as consumer demand for healthy, nutritive food products and extended shelf life, in the recent years, the food and packaging industries have paid increasing attention to biodegradable edible packaging prepared from biopolymers such as proteins, polysaccharides, and lipids or their combinations. These biodegradable films may act as carrier of wide variety of additives, such as antimicrobial, antioxidant agents, flavors, colorants and spices which improve the functionality of the packaging materials by addition of novel or extra functions. In the present study, an antioxidant/antimicrobial active packaging based on chitosan biopolymer was designed. For this purpose, lignocellulose nanofibers (LCNF) and cellulose nanofibers (CNF) at concentration of 4% were used as reinforcement of biopolymer properties, as well as to control the release of Origanum vulgare subsp. gracile and Carum copticum essential oils (as antioxidant/antimicrobial agent) from the packaging material into the foodstuff.
Materials and methods: The O. vulgare ssp. gracile leaves and C. copticum seeds were obtained from wild plants in mountains of Urmia (Iran). LCNF (average diameter about 55 nm, average length about 2–5 μm, 99% purity) produced from unbleached hardwood pulp through mechanical and acid treatments and CNF (average diameter about 28 nm, average length about 2–3 μm, 99% purity) prepared from softwoods through mechanical disintegration were kindly provided by Nano Novin Polymer Co. (Saari, Iran). Chitosan (medium molecular weight, from shrimp shell with a deacetylation degree of 75–85%), purchased from Sigma-Aldrich (St. Louis, MO, USA). Chitosan based bionanocomposite films incorporated with organic nanofillers and essential oils were developed by solvent casting method. The synthesized films were characterized by XRD and DSC analyses. To determine the prepared films would have potential to be used as an active packaging, water vapor permeability, water solubility, color, transparency, mechanical properties, antimicrobial and antioxidant activity of the films were also evaluated. In order to determine the efficiency of activated nanocomposites, the effect of these films was evaluated on the oxidative stability of rapeseed oil without antioxidants and compared with the effect of TBHQ synthetic antioxidant.
Results & Discussion: The results showed that the addition of essential oils did not have a significant effect on the crystallinity and thermal properties of the films, while organic reinforcement increased the crystalline properties and thermal resistance of nanocomposite films. By applying the essential oils and CNF and LCNF in the structure of the films, the apparent transparency and consequently the amount of light passage from them decreased compared to the control sample. With addition of essential oils separately and in combination, as well as CNF and LCNF in the structure of films, solubility and film permeability decreased compared to pure chitosan film. By adding of two essential oils with a ratio of 50:50, tensile strength (UTS) and strain to break (STB) of films were increased, while organic nanofibers led to an increase in UTS and a significant reduction in STB of nanocomposites. It was also found that active films containing different ratios of essential oil had remarkable antioxidant activity and high antimicrobial activity against E.coli and B.cereus bacteria, which by adding CNF and LCNF these features were reduced due to the role of controlling the release of essential oil compounds by nanofibers. With the numerical optimization of the software, the optimal amount for the essential oils of C. copticum and O. vulgare oils were 2.29 and 2.71% (5% mix) respectively, in combination with the LCNF nanofibers. The results of oxidative stability of Canola oil showed that nanocomposites containing 5% essential oil were considerably able to keep the oil freshness during storage at ambient temperature and delay the oxidation of the oil.
Esmaeil Atayesalehi; Seyedeh Tahereh Nasiri Takami; Reza Esmaeilzadeh kenari
Abstract
Compounds derived from lipid oxidation endangering human health and lead to cardiovascular disease and cancer. The addition of antioxidants is effective in retarding the oxidation of lipids and lipid containing foods. Due to the toxicological effects of synthetic antioxidants, Decrease their use and ...
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Compounds derived from lipid oxidation endangering human health and lead to cardiovascular disease and cancer. The addition of antioxidants is effective in retarding the oxidation of lipids and lipid containing foods. Due to the toxicological effects of synthetic antioxidants, Decrease their use and replacing them with natural antioxidants. This study investigates antioxidant effect of Pimpinella methanolic extract (PME) on inhibition of lipid oxidation in canola oil (CO) in comparison to the canola oil stabilized Tert-butyl hydroquinone (TBHQ). PME was added at 400 and 800 ppm to CO. Color Index (CI), Conjugated diene value (CDV), peroxide value (PV), Acid Value (AV), were determined during 60 days of storage. Different oxidation parameters revealed that methanolic extract of Pimppinella affinisLedeb at concentration of 800ppm was more effective than 400ppm. Results revealed Pimpinella to be a potent antioxidant for stabilization of canola oil. As expected with increasing of the storage time, the oxidative stability of canola oil decreased.
Reza Farhoosh; Hashem Pourazerang; Mohammad Hossein Hadad Khodaparast
Abstract
Measuring the rate of changes in total polar compounds (TPC) content and polar fractions, the oxidative stability of canola oil during frying process as affected by bene kernel oil (BKO, 0.05 and 0.1%) and tert-butylhydroquinone (TBHQ, 100ppm) was investigated. It was observed that the TPC content increased ...
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Measuring the rate of changes in total polar compounds (TPC) content and polar fractions, the oxidative stability of canola oil during frying process as affected by bene kernel oil (BKO, 0.05 and 0.1%) and tert-butylhydroquinone (TBHQ, 100ppm) was investigated. It was observed that the TPC content increased linearly with frying time (R2 > 0.98). The canola oil containing the BKO (especially 0.1%) was significantly capable of increasing oxidative stability. The TPC analysis by high-performance size-exclusion chromatography allowed the separation and quantification of triglyceride polymers (TGP), triglyceride dimers (TGD), oxidised triglyceride monomers (oxTGM), diglycerides (DG), and free fatty acids (FFA) during frying. The ability of the BKO to resist the TGP and oxTGM formations was near to that of the TBHQ, whereas the ability of the BKO to resist the DG and FFA formations was better than that of the TBHQ.
