Antioxidants in food systems

It has been known for many years that Maillard Reaction products can behave as antioxidants in food systems (13,14), and they have been shown to inhibit warmed-over flavor development in cooked meat which is caused by the autoxidation of lipids, especially phospholipids. There has been a significant amount of research examining the Maillard reaction products and intermediates from model systems which may have antioxidative properties. 

Niki et al., 2010). Moreover, as a-tocopherol is the most reactive tocol it is also the most unstable and is, of all tocols, the first one consumed. This may decrease its activity as a long-term antioxidant in food systems, and a mixture of tocols is often preferred for antioxidant protection. In general, the optimal concentration of a-tocopherol has been lower than those of other tocols (Kamal-Eldin et ah, 2006 Seppanen et ah, 2010). 

The vitamin C activity of L-ascorbic acid or reduced ascorbic acid (RAA) and its oxidized form, dehydroascorbic acid (DHA) is essentially the same, while D-ascorbic acid (isoascorbic acid or erythroascorbic acid) has little of the vitamin s biological potency (1). The readiness with which RAA is reversibly oxidized to DHA is the basis of its physiological activity, and of its use as an antioxidant in food systems. 

Phenolics are commonly present in both edible and inedible parts of plants. They act as antioxidants in food systems in order to minimize rancidity and protect cells from oxidative stress in the body. With the growing interest in replacing synthetic antioxidants with natural alternatives, many plant materials including tree nuts have been explored for their phenolic contents and antioxidant efficacies. A variety of phenolic compounds such as phenolic acids, llavonoids, and olher polyphenols have been isolated from almond and identified (Table 8.1). 

Kochhar, S.P. Russell, J.B. Detection, estimation, and evaluation of antioxidants in food systems. In Food Antioxidants, Hudson, B.J.F. (Ed.),Elsevier Applied Science New York, 1990 pp. 19-64. 

Literature data support the use of rice bran oil and constituents as antioxidants in food systems. Tocols and oryzanols appear to have different degrees of activity depending on the Upid system evaluated. Oryzanols are more effective in cholesterol systems and tocols the most effective in linoleic acid model systems. The combination of these components greatly enhances the activity of rice bran oil as an antioxidant. Further study is recommended to assess other lipid systems as well as synergistic activities between the oryzanols and tocols. 

The activity of antioxidants in food [ 1 ] emulsions and in some biological systems [2] is depends on a multitude of factors including the localisation of the antioxidant in the different phases of the system. The aim of this study is determining antioxidant distributions in model food emulsions. For the purpose, we measured electrochemically the rate constant of hexadecylbenzenediazonium tetrafluorborate (16-ArN,BF ) with the antioxidant, and applied the pseudophase kinetic model to interpret the results. 

The most common natural antioxidants are tocopherols, ascorbic acid and P-carotene (more often synthetic nature-identical compounds than natural products). Their changes were studied in detail in model systems, fats and oils, but experimental evidence is mainly lacking on more complicated systems, such as natural foods and ready dishes. Still less is known on different antioxidants from spices and from essential oils. These data will probably be obtained gradually. Very little is known about synergism of antioxidants in food products other than edible fats and oils or their regeneration from the respective free radicals and quinones. In mixtures, some antioxidants are preferentially destroyed and others are saved. Some data have already been published, but these complex changes should be studied in more detail. 

PORTER w L (1993) Paradoxical behaviour of antioxidants in food and biological systems, in Williams GM Antioxidants Chemical, Physiological, Nutritional and Toxicological A. ipects, Princeton Scientific, Princeton, N J, 93-122. 

Interestingly, early examples of carotenoid autoxidation in the literature described the influence of lipids and other antioxidants on the autoxidation of carotenoids." " In a stndy by Budowski et al.," the influence of fat was fonnd to be prooxidant. The oxidation of carotenoids was probably not only cansed by molecnlar oxygen bnt also by lipid oxidation products. This now well-known phenomenon called co-oxidation has been stndied in lipid solntions, in aqueons solntions catalyzed by enzymes," and even in food systems in relation to carotenoid oxida-tion." The inflnence of a-tocopherol on the antoxidation of carotenoids was also stndied by Takahashi et al. ° who showed that carotene oxidation was snppressed as... 

The first report on antioxidative effect of MRP was made by Franzke and Iwainsky (3). Shortly afterward Griffith and Johnson (4) reported that the addition of glucose to cookie dough resulted in a better stability against oxidative rancidity during storage of the cookies. Research on antioxidative MRP was then mainly performed by groups in Japan. A symposium on Maillard Reactions in Food held in Uddevalla, Sweden, 1979 included also the aspect of antioxidative properties. The contributions on this subject contained also brief reviews (5, 6, 7). Most of the work has been done on model systems. Some applications in food systems have, however, also been reported (8 - 11). 

Multiphase Systems Antioxidant activity depends very much on the lipid substrate used for evaluation and the hydrophilic/lipophihc nature of the anti-oxidative compound. Solubility and partition properties of the compound in the medium affect the activity of antioxidants in the bulk hpid systems. As most foods cannot be related to bulk oil systems (e.g., meat, fish, eggs, mayonnaise, salad dressings, etc.), evaluation of antioxidants in multiphase systems is more relevant to their physical and chemical nature. Because of the very same reasons, several studies have found that compounds exhibiting strong activity against oxidation of lipids in bulk systems are often inefficient in colloidal and emulsion systems. 

Screening of aniioxidative activity in various model systems is important prior to testing or application of antioxidants in foods. Such model qrstenis are more rapid compared to food storage experiments, and the model systems might even be more infomiaiivc in relation to antioxidant mechanisms. 

The behavior of antioxidants in food and their antioxidative ability can vary markedly, depending on the lipid-containing systems. Food products are predominantly multiphase systems in which the activity of the antioxidants depends on the lipid composition, pH and ionic strength, non-lipid constituents, additives such as emulsifiers, and the presence of metal ions. These factors may affect several important physicochemical properties of the antioxidant, such as interphase transport,... 

Lipid antioxidants can be broadly defined as any compounds serving to inhibit oxidative processes that cause deterioration of food lipids thereby improving the quality and extending the shelf life of the food products. It has been widely accepted that antioxidants for use in food systems must satisfy the following criteria ... 

Frankel, E.N., Natural and biological antioxidants in food and biological systems. Their mechanisms of action, application and implications, Lipid TechnoL, 49, 77, 1995. 

Prakash, B., Singh, R, Kedia, A., and Dubey, N. K. (2012). Assessment of some essential oils as food preservatives based on antifungal, antiaflatoxin, antioxidant activities and in vivo efficacy in food system. Food Research International, 49, 201-208. 

Ethylenediamine hydrochloride is used in topical preparations and is a common sensitizer (Epstein and Maibach 1968). Sensitive patients can react with dermatitis when the ethylenediamine is taken systemically (Provost and Jillson 1967). It may cross-react with ethylenediamine tetraacetate (EDTA) which is used as a preservative in eyedrops and in the cosmetic industry (Raymond and Gross 1969). EDTA is also used as a sequestrant in food systems it acts synergistically to several antioxidants and may be present in fats, oils, salad dressings, meat, seafood, vegetables, beverages, and dairy products (Furia 1972). 

NFPA Health 3, Flammability 1, Reactivity 0 Uses Curing agent for cast PU elastomers, food-contact PU resins epoxy resin curing/hardening agent corrosion inhibitor intermediate for paints, dyes, polymers isocyanate resins polyamides determination of tungsten and sulfates curing system additive for bisphenol A-ep-ichlorohydrin epoxies for food contact antioxidant in food-contact rubber articles for repeated use... 

Uses Additive for high-pressure lubricants and greases plasticizer softener antioxidant in foods preservative, antioxidant for edible fats and oils, greases, in cosmetics, pharmaceuticals, polyolefins and other polymer systems, rubber stabilizer for... 

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