Edible fats and oils

Most fats and oils consist of triacylglycerides (recently also denoted as triacylglycerols cf. 3.3.1) which differ in their fatty acid compositions to a certain extent. Other constituents which make up less than 3% of fats and oils are the unsaponifi-able fraction (cf. 3.8) and a number of acyl lipids e. g., traces of free fatty acids, mono- and diacyl-glycerols. 

The term fat generally designates a solid at room temperature and oil a liquid. The designations are rather imprecise, since the degree of firmness is dependent on climate and, moreover, many fats are neither solid nor liquid, but are semi-solid. Nevertheless, in this chapter, unless specifically emphasized, these terms based on consistency will be retained. 

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Nickel also is an important iadustrial catalyst. The most extensive use of nickel as a catalyst is ia the food iadustry ia connection with the hydrogenation or dehydrogenation of organic compounds to produce edible fats and oils (see Fats and FATTY oils). 

The biggest use of chlorine dioxide is in bleaching wood pulp. In some mills, much of the chlorine and hypochlorite has been replaced by chlorine dioxide to reduce the amount of chlorinated by-products. Chlorine dioxide is also used to bleach textiles, flour, and edible fats and oils. 

Shortening, table oils, margarine, and other edible fats and oils, n.e.c. ... 

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. 

SHAHIDI F, WANASUNDARA p K J P D and WANASUNDARA u N (1997) Changes in edible fats and oils during processing , J Food Lipids, 4 199-231. 

Ultrasonically assisted extraction is also widely used for the isolation of effective medical components and bioactive principles from plant material [195]. The most common application of low-intensity ultrasound is as an analytical technique for providing information about the physico-chemical properties of foods, such as in the analysis of edible fats and oils (oil composition, oil content, droplet size of emulsions, and solid fat content) [171,218]. Ultrasonic techniques are also used for fluids characterisation [219]. 

German Society for Fat Science (2001) Bleaching of edible fats and oils. 

There is as yet no agreed international list of permitted food colours. Thus a food dye that is permitted in one country may be considered unacceptable in another. The synthetic food colorants permitted in the European Union are listed in Table 1.8 [60]. All were originally introduced as acid dyes for wool many years ago. Furthermore, more than thirty colorants of natural origin are permitted in most countries. The natural carotenoid dyes are of outstanding importance for colouring edible fats and oils. These yellow to red methine dye structures occur in many families of plants and animals, including vegetables, berries,... 

Gillespie AM, Walters SM. 1989. Semi-preparative reserve phase FIPLC fractionation of pesticides from edible fats and oils. Journal of Liquid Chromatography 12(9) 1687-1704. 

Lea, C.H. 1946. The determination of the peroxide values of edible fats and oils The iodi metric method. J. Soc. Chem. Ind. 65 286-291. 

Sardine oil has similar fatty acids to other edible fats and oils and also contains longer-chain co-3 polyunsaturated fatty acids, such as eicosapentaenoic acid and docosahexanoic acid. Table 2 indicates that the principal polyunsaturated fatty acids of sardine oil are in the co-3 family. 

It is important to prevent the oxidation of edible fats and oils and of foods that contain oils to maintain their quality and safety. Oxidation of fats and oils can be initiated by heat, light, and metals in the fats and oils. The oxidation products from oils, which include hydroperoxides and cyclic peroxides, decompose to produce a variety of volatile compounds, which result in undesirable flavors and odors in oils (131-134). Oils damaged by oxidation also have been reported to cause biological problems, such as diarrhea, growth depression, and tissue damage in living organisms. 

S Pokomy, J Coupek, J Pokomy. Analysis of inhibitors in edible fats and oils by gel chromatography. J Chromatogr71 576-579, 1972. 

The RP-HPLC system was tested on the fractionation of OPPs and OCPs, from edible fats and oils of both animal and vegetal origin. When acetonitrile was used, the most polar OPPs eluted rapidly but tailed on this column, whereas the relatively nonpolar OCPs were retained the longest. Additional cleanup on miniature Florisil columns is required for the dirtier samples. A UV detector was used to determine the elution patterns of standards (78). The same system was used for the fractionation of OPP residues in processed bay foods prior to the final determination by GC without further cleanup but using a MS detector (66). 

Accurate determination of the amount of solid fat in edible fats and oils is an essential requirement for process control in food industry during hydrogenation, interesterification and blending. Moreover, important physical properties, such as hardness, heat resistance, mouth-feel and flavor release, can be predicted via measurements of solid fat content at different temperatures using low resolution (low-field) NMR. 

Stearic acid is a long chain SFA present, to varying degrees, in virtually all edible fats and oils. Table IV provides the fatty acid composition of fats and oils commonly consumed by humans. The most abundant food sources of stearic acid in the American diet are beef fat and cocoa butter (chocolate). Cocoa butter is valued by chocolate manufacturers because it remains solid at room temperature but dissolves quickly at body temperature, a unique characteristic of chocolate that is due largely to stearic acid. During the last few decades as cocoa butter prices and supplies have fluctuated, food companies began looking for alternative oils that could provide equivalent amounts of stearic acid in order to retain the desirable physical characteristics. Several... 

FATTY ACID COMPOSITION (%) OF EDIBLE FATS AND OILS... 

Winters, R. L. (1990), in World Conference Proceedings, Edible Fats and Oils Processing, Basic Principles and Modern Practices, David, R., ed., American Oil Chemists Society, Champaign, IL, pp. 402-405. 

Suzuki, S. and Oshima, S. 1970. Influence of blending of edible fats and oils on human serum cholesterol level. Jpn. J. Nutr. 28, 3-9. 

Zschau, W. (2001) Bleaching of edible fats and oils IX. Legal and analytical aspects of bleaching. From the working group Technologies of industrial extraction and processing of edible fats . Eur. J. Lipid Sci. Technol., 103, 117-122. 

Kanematsu, H., Maruyama, T., Niiya, I., Amamura, A. and Matsumoto, T. (1973) Changes in the steroid content of edible fats and oils during commercial processing. J. Japan Oil Chem. Soc., 22, 814-817. 

Internationally too, measures have been established to protect consumers and ensure the authenticity of the foods they purchase, namely the standards of the Codex Alimentarius ( food code ). These will be described in this section and in particular as they relate to edible fats and oils. However, in order to put this into context, some background information will be given first on the Codex Alimentarius organization and how it works. 

Contaminants and the Codex Committee on Food Labelling. The activities of these committees will clearly have a bearing upon the development of standards for edible fats and oils by the CCFO. 

Contents of individual fatty acids in the fat of a species can vary by over 100 percent. Table 34.2 summarizes general fatty acids contents of the major edible fats and oils, and Table 34.3 does likewise for industrial fats and oils. 

Sobstad, G. E., Animal fats The effect of process technology on fat quality, in World Conference Proceedings Edible Fats and Oils Processing Basic Principles and Modern Practices, D. R. Erickson (Ed.), pp. 31-36, AOCS, Champaign, IL, 1990. 

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