Food oxidation

Experimental evidence in humans is based upon intervention studies with diets enriched in carotenoids or carotenoid-contaiifing foods. Oxidative stress biomarkers are measured in plasma or urine. The inhibition of low density lipoprotein (LDL) oxidation has been posmlated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Since carotenoids are transported mainly via LDL in blood, testing the susceptibility of carotenoid-loaded LDL to oxidation is a common method of evaluating the antioxidant activities of carotenoids in vivo. This type of smdy is more precisely of the ex vivo type because LDLs are extracted from plasma in order to be tested in vitro for oxidative sensitivity after the subjects are given a special diet. 

The OSI was primarily developed for oil or fat samples. It is possible to use the method on lipids extracted from foodstuffs however, such lipids may not have the same oxidative stability as the food since the physical structures are different. Additionally, muscle foods oxidize rapidly at elevated temperature due to physical and chemical alterations during cooking thus, this method probably will not be useful with raw meats. 

At q 7 1, this flux is nonzero even at the stationary conditions. However, in the fuUy conjugate system (q = 1), the rate of the food oxidation decreases and J2 = 0 at the stationary state. Thus, the respiration control system in the mitochondria of living organisms determines the rate J2 of the oxidation of alimentary substrates, depending on the variations in the ADP and ATP concentration ratio—in other words, in the driving force Xj of the conjugate process. Obviously, the maintenance of a constant sta tionary ATP concentration, even though low, at q 7 1 needs a nonzero rate of the oxidation of alimentary substrates. 

Use Nutrition, color fixing, flavoring and preservative in meats and other foods, oxidant in bread doughs, abscission of citrus fruit in harvesting, reducing agent in analytical chemistry. The iron, calcium, and sodium salts are available for biochemical research. 

Use Pyrotechnics, explosives, matches, specialty fertilizer, reagent, to modify burning properties of tobacco, glass manufacture, tempering steel, curing foods, oxidizer in solid rocket propellants. 

Free radicals (R, ROO% etc.) can be defined as any chemical species having one or more unpaired electrons, a wide definition that covers hydrogen atoms, transitions metals, the oxygen molecule itself, etc. One of the major areas in which carbon free radicals and oxygen free radicals are involved is lipid oxidation that determines the quality and shelf life of foods. Oxidative rancidity leads to the production of spoiled off-flavor products and is commonly associated with the organoleptic appraisal of food products. ... 

Antioxidants play an important role in the deceleration of lipid oxidation reactions in foodstuffs. According to FDA they are defined as substances used as preservatives, with the aim to reduce spoilage, rancidity or food discoloration, which are derived from oxidations. Addition of antioxidants in foodstuffs is either intentional (direct addition into product) or symptomatic (migration of antioxidants from packaging material into product). The right and effective use of antioxidants depends on the understanding of (a) the chemistry of oils and fats, and (b) the mechanism of oxidation and their operation as substances, which result in food oxidation (Table 13.12). ... 

Active packaging systems exist, in which a chemical, present inside the container, absorbs oxygen or removes the products of food oxidation. 

It is nontoxic and is used as a moisturizing agent in foods. Oxidation of this substance within the hver produces pyruvic acid, which can be used by the body to supply energy. Give the structure of pyruvic acid. 

The reduced coenzymes NADH and FADH2 are end products of the citric acid cycle. In the final stage of food oxidation, the hydrogen ions and electrons carried by these coenzymes combine with oxygen and form water. 

Schwarz, K. 19(i2. In Symposium on Foods Oxidative Deterioration of Food Lipids (If. W. iSchultz, ed.), Chapter 20. Mack Printing Co., Easton, Pennsylvania. Schwarz, K., and Foltz, C. M. 1900. Federation Froc. 19, 421. 

Uses Bleaching agent for household and industrial use, laundry detergents, textile processing, foods oxidizing agent in cosmetics denture cleaner stain remover/deodorizer for carpets dyestuffs oxidation reagent mild antiseptic Manuf./Distrib. ABCR http //www.abcr.de,... 

In milk, as in many odier foods, oxidative reactions are a prime cause of flavor deterioration and loss in nutritional quality (1). Spontaneous oxidation in milk giving rise to oxidized flavor (off-flavor) is a well-described phenomenon (2 3), i diich is supposed to proceed dependii on factors inherent in die milk itself. These inherent factors include fatty acid conq>osition, content of low-molecular weight antioxidants, pro- and anti-oxidative enzyme systems, and transition metal ion content. Moreover, external factors such as handling, agitation, tenq>erature, exposure to light, and contamination by metals and microorganisms are known to trigger additional deteriorative oxidative reactions in milk. 

The methods of the molecular spectroscopy rightfully occupy one of the leading places in the study of the peroxide compounds stracture. The IR spectroscopy is successfully used to establish the structure of the synthesized peroxides as well as for their identification and kinetic studies [ 1 ]. The IR spectra play the role of indicator of the oxidative stability and peroxide value in the foods oxidative modification... 

Cysteine and methionine are particularly sensitive to oxidation, as are histidine, arginine, tryptophan and phenylalanine. In foods, oxidation mainly takes place in suHur-containing amino acids (cysteine, cystine and methionine). Cysteine can be oxidised to cystine or even to cysteic acid, but the oxidation by hydroperoxides in foods does not go so far. Methionine is oxidised to... 

Edible coatings are films formed directly in the food surface by inunersion of the food product in the coating solution (Krochta and De Mulder-Johnston, 1997). Therefore, coatings are part of food products to protect or enhance them in some characteristic and they can be directly eaten or removed before consumption Moreover, edible coatings can be improved by the addition of active substances to form active food packaging, enhancing functional or specific properties of foods, such as the control of food oxidation and microbial growth (Cuq et al., 1995 Han, 2001 Jarimopas et al., 2007). 

Bartosz, G. 2014. Food Oxidants and Antioxidants Chemical, Biological, and Functional Properties. Boca Raton CRC Press. 

Bioactivity potency of lycopene is dependent on the extent of degradation due to isomerization and oxidation. The main causes of lycopene degradation during food processing are oxidation and isomerization. Determination of the extent of lycopene isomerization would provide better insights into the potential health benefits of processed food products. In processed foods, oxidation is a complex process and depends upon many factors, such as processing conditions, moisture, temperature, and the presence of pro- or antioxidants and of lipids. The characterization and quantification of isomers would be desirable to more accurately assess the bioactivity than just the total lycopene content with no knowledge of its isomeric composition. 

One of the characteristic reactions of lipids which are exposed to oxygen is the formation of peroxides. Indeed, among non-enzymic chemical reactions which take place in the environment at ambient temperatures, the oxidation of unsaturated compounds is perhaps the most important both from an industrial and a medical point of view. In biological tissues, uncontrolled lipid peroxidation causes membrane destruction and is increasingly regarded as an important event in the control or development of diseases (section 8.11). In food, oxidation (either enzymically or chemically catalysed) can have desirable as well as adverse consequences (section 8.15). 

---