Food products antioxidants role

A common misnomer used on food products and even in the press is antioxidant minerals. Let s debunk this term now. Minerals themselves do not actually have antioxidant capacity but rather become attached to enzymes that do. In this role, the mineral is called a cofactor, which means that it allows an enzyme or protein to perform antioxidant work. Among the most frequently mentioned minerals in this category is selenium, which enables the peptide glutathione—the main antioxidant made in our bodies—to act as an antioxidant. Manganese, magnesium, iron, zinc, and copper are other dietary minerals having roles with enzymes involved in antioxidant functions. Many superfruits are particularly enriched with these minerals. 

In a test-tube method called ORAC (oxygen radical absorbance capacity), freeze-dried agaf powder scored the highest ORAC level yet determined among fruits, a result that incited a storm of marketing literature declaring that a af products have the highest antioxidant health value of any food. The bad news is that there are limitations to that ORAC value as we know it (see Appendix A). Antioxidant properties determined in test tubes are unlikely to have the same antioxidant roles in the human body. Further, the comparisons of aqa ORAC with other fruits are not valid since the fruit preparations were not identical across all tests. 

Because minerals are an integral part of many enzymes, they play an important role in food processing, e.g., in alcoholic and lactic fermentation, meat aging, and dairy food production. Many compounds used as food additives or for rheological modification of some foods contain metallic cations in their structure. A number of these compounds function as antimicrobials, sequestrants, antioxidants, flavor enhancers, and buffering agents, and sometimes even as dietary supplements (Table 4.4). 

Vitamin activity in foods and food products serves as an example where typical problems arise with traditional liquid solvent extraction and then where SFE has been used to address these concerns [30]. In addition to the routine assay of food products, there is a considerable amount of research being conducted on the role of carotenoids and xanthans as antioxidants in the human body. This antioxidant-role may address many health concerns such as aging and various diseases. The "friendly-extracting-environment" of SFE has some merit of consideration for such studies, particularly with regard to the lesser possibility of oxidation of the analytes during the sample preparation step. 

The antioxidant activity of different food products has been linked to their preventive role in cardiovascular disease [68 86 98 99]. Many of them are fruit and vegetables, although cereals, herbs and spices also show important antioxidant activity. Processed fruit products also provide important antioxidant protection as has been described for orange and lemon juice, [100], grape juice [91], grape pomace [101] and red wines [102-107]. Very pronounced in vitro antioxidant activity has been demonstrated in tea [99 108] and olives [27]. Many herbs and spices containing antioxidant constituents can be useful to prevent rancidity of meat and fish products [109-112]. Fibre also has antioxidant activity, mainly due to the presence of phenolic metabolites linked to the polysaccharides [87]. Thus, the antioxidant activity of barley leaves [93], pineapple peel fibre [113] and rice-hull [114] have been described. 

There is only scarce evidence confirming the toxic influence of hydroperoxides from the diet. The toxicity of thermo-oxidized frying fats on humans is better verified. The toxicity of oxidized cholesterol, especially at temperatures higher than lOO C and in the presence of unsaturated lipids, has attracted particular attention, as has the role of oxy fltosterols. Antioxidants continue to be the subject of intensive researches and discussions (Pokomy et al., 2001). Their activity in food is different than in vivo. Although no clear understanding of the prooxidant activity of antioxidants exists, supplementation of antioxidants to food products and to animal organisms does take place. 

Nowadays, it is generally acceptable that antioxidants play an important role not only in food industry, increasing the shelf life of food products and improving the stability of lipid-containing foods, but also in preventing radical-induced diseases such as cancer and atherosclerosis. From nutraceuticai viewpoint, these tropical spices might be one of the important foodstuffs which provide human health benefits. 

The conclusions about the role phenol plays as an antioxidant in real food systems are often reached by comparing the oxidative behaviour of food samples with different contents of phenolic compounds. The variations in phenolics are usually obtained by using products made from different raw materials (e.g. malts containing different levels of polyphenols for production of beer (Andersen et al, 2000)). However, using different raw materials not only affects the levels of phenols, but also affects the levels of transition metals and enzymes which can have profound effects on the oxidative behaviour of the finished product. It is, therefore, often advantageous to study the oxidative behaviour of samples derived from a single batch of production where the level of phenols has either been increased by addition or decreased... 

In meat curing, nitrite is traditionally used for developing the pink, heat-stable pigment. Its other important role is the inhibition of the outgrowth of Clostridium botulinum spores in pasteurized products and, in some countries, in several types of smoked fish. Nitrite also serves as an antioxidant and contributes positively to the development of the flavor of cured-meat. The undesirable side-effect, however, is the reaction of nitrite with amino groups of food constituents, leading to the formation of NNCs. 

The more effective a termination step is, the shorter will be the propagation cycle and the less product will be produced per initiation event. In the limiting case, if each initiation event was terminated, then no product would be produced. This is the role of antioxidants added to many products and most processed food. These additives scavenge free radicals produced by the reaction of oxygen with C-H bonds and prevent them from participating in oxidation propagation cycles—thus oxidative degradation is stopped or slowed markedly. 

Taking into account the important role of balance in oxidant-antioxidant phenomena for human health and interrelation between internal and external factors, evaluation of oxidant-antioxidant state of human body fluids and natural resources of antioxidants is essential for therapy and prevention of diseases and adverse effects of environment. Thus, analysis of ready-made food and production processes monitoring are of great importance. 

Plants represent a very important role in human nutrition, due to the large quantities of proteins, carbon hydrates, lipids, vitamins, antioxidants and mineral salts that its can supply. Sometimes the nutritional aspect can be associated with the flavour and fragrance of the extracts producing a high value products. In recent years one can observe an increase in research for natural sources, in particular from plant matrices, of additives with application in the food, cosmetic and pharmaceutical industries. 

There is increasing evidence that in addition to the traditional antioxidative vitamins, other compounds may also have important antioxidative functions in the human body. The antioxidant vitamins C and E, together with other antioxidants from products such as tea, wine and other foods of vegetable origin may thus play a critical role in the reduction or in the delay of the onset of degenerative diseases, including coronary heart diseases (CHD) (Biesalski, 1999). It is not yet well established as to what extent antioxidants have protective properties beyond the levels obtained through a balanced diet (Halliwell, 1997 Stahelin, 1999). 

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