Natural antioxidants in foods

Dry clean tanshen rhizomes were powdered and extracted with hexane for three days at room temperature. The hexane solution was kept overnight and then filtered. After removal of the solvent a residue was obtained which was separated into seven colored fractions by column chromatography with silica gel. Miltirone was isolated by preparative tic from fraction 1 (light red) using hexane ethyl acetate (4 1) followed by benzene-acetone (20 1). The product obtained was recrystallized from ethylacetate, m.p. 100-101°C. Its structure was confirmed by mass spectrum, NMR, IR and UV spectra which agree quite closely with those of Ho et al [76], Miltirone showed antioxidant behavior comparable to that of the commonly used phenolics BHT and BEA [77], The antioxidant activity of miltirone in lard at 100°C was determined with a Rancimat. Miltirone and other related compounds may have the potential of being used as natural antioxidants in food and cosmetics. 

Many countries have regulations regarding the type of antioxidants permitted for use and also on the maximum allowable limits in foods. The snack food companies must be aware of local regulations regarding the use of synthetic and natural antioxidants in foods. 

Frankel, E.N. Natural antioxidants in foods and biological systems. Their mechanism of action, applications and implications. Lipid Technology 7, 77-80 (1995). 

Polyphenols are the most important phytochemicals found in a variety of fruits, vegetables, and plant-based foods. Currently there is an increasing interest for the separation, characterization, and valorification of these compounds due to their bioactive properties, health benefits, and potential use as natural antioxidants in foods, pharmaceuticals, and cosmetics. 

Biopolymers Natural Antioxidants in Foods Polymers, Synthesis... 

CHOPRA M, MCLOONE u L, o neill m, WILLIAMS N and THURNHAM DI (1996) Fruit and vegetable supplementation - effect on ex vivo LDL oxidation in hiunans , in Kumpulainen, J T and Saonen, J T (eds), Natural Antioxidants and Food Quality in Atherosclerosis and Cancer Prevention, Cambridge, Royal Society of Chemistry, 150-55. 

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. 

JASWIR I, MAN Y B c and KITTS D D (2000) Use of natural antioxidants in refined pahn olein during repeated deep-fat frying, Food Res Int, 33, 501-8. 

Lairon, D. and Amiot, M.J., Flavonoids in food and natural antioxidants in wine, Curr. Opin. Lipidol., 10, 23, 1999. 

Lopez-Velez M, Martmez-Martmez F and Del Valle-Ribes C. 2003. The study of phenolic compounds as natural antioxidants in wine. Crit Rev Food Sci Nutr 43(3) 233—244. 

The use of antioxidants in food products is governed by regulatory laws of the individual country or by internal standards. Even though many natural and synthetic compounds have antioxidant properties, only a few of them have been accepted as generally recognised as safe (GRAS) substances for use in food products by international bodies such as the Joint FAOAVHO Expert Committee on Food Additives (JECFA) and the European Community s Scientific Committee for Food (SCF). 

Bohm, FI. et al., Flavonols, flavone and anthocyanins as natural antioxidants of food and their possible role in the prevention of chronic diseases, Z. Ernahrungsw., 37, 147, 1998. 

Zia-ur-Rehman, Habib, F., Shah, W. H. (2004). Utilization of potato peels extract as a natural antioxidant in soy bean oil. Food Chem., 85(2), 215-220. 

Oxidation of chromans has been extensively studied, especially of those which resemble the tocopherols which act as antioxidants in nature and in food. The behaviour of a-tocopherol (vitamin E, 547) and many simpler model compounds under oxidizing conditions varies with the oxidizing agent. Among the many products formed are the o- and p-quinones (609) and (610), the spiran (611) and dimer (612). A detailed account is available (81HC(36)59). 

The use of antioxidants in foods, pharmaceuticals, and animal feeds (direct feed additives), as well as their use in food-contact surfaces (indirect additives) is closely regulated by the governments of several countries. Antioxidants are approved only after extensive extraction, toxicological, and feeding studies. The list is relatively limited. Although antioxidants have been used for several decades and some occur naturally in food substances, intensive lesearch in continuing, pardy accelerated by the growing use of unsaturated oils in numerous food products. 

Asharani, V. T., Jayadeep, A., and Malleshi, N. G. (2010). Natural antioxidants in edible flours of selected small millets. Int. ]. Food Prop. 13, 41-50. 

Wanasundara, U.N., Amarowicz, R. and Shahidi, F. 1996. Partial Characterization of Natural Antioxidants in Canola Meal. Food Res. Internat., 28, 525-530. 

Amr, A.S. 1991. Effectiveness of synthetic and potential natural antioxidants in improving the stability of sheep s anhydrous butterfat during long-term storage. J. Sci. Food Agric. 55, 75-85. 

Dugan, L.R. 1980. Natural antioxidants. In Auto-oxidation in Food and Biological Systems (M.G. Simic, M. Karel, eds.), pp. 261-282, Plenum Press, New York. 

Chromatography techniques with different detectors followed by skillful sample preparation are usually applied to quantify these antioxidants in natural sources. These techniques offer sensitive and specific analysis methods for most of the antioxidants. This is the first book that particularly covers and summarizes the details of sample preparation procedures and methods developed to identify and quantify various types of natural antioxidants in plants and food products. In the book, the principle of quantification methods for natural antioxidant-rich phytochemicals is introduced and current methods used in the determination of antioxidants in different sources are reviewed and summarized by experts in the field. As a handbook of analysis of natural antioxidant-rich phytochemicals, the book provides useful information for many researchers in this area to learn ideal analysis methods for the antioxidants they are examining. The book may also serve as a lecture resource for courses in food analysis, functional foods, and nutrition. 

Ascorbic Acid and Ascorbic Acid Esters and Saits Vitamin C or ascorbic acid is widespread in nature but sparingly associated with fats of oils because of its hydrophilic nature (95). Ascorbic acid in the free form, salts of sodium and calcium, and esters of stearic and palmitic are commonly used as antioxidants in foods. Erythorbic acid is the D-isomer of naturally present L-ascorbic acid (Figure 10) and is often used as an antioxidant in dried fruits and a cure... 

Other Phenolic Antioxidative Compounds from Plants Higher plants are rich in a myriad of phenolic compounds in their secondary metabolite pool. Among these, phenolic acids and polyphenolic derivatives are found to be the most important series of hydrophilic-hydrophobic antioxidative compounds naturally present. In foods, these polyphenolic compounds act as radical scavengers... 

Antioxidative compounds naturally present in food are not covered under present regulations obviously, it is not a controlled substance as it is part of the raw material of food processing. However, if an antioxidative compound isolated from a natural source is to be added to food, the compound should comply with the appropriate regulations and safety clearances. 

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