Dehydrated rancidity

Lipid oxidation is responsible for rancidity, development of off-fiavors, and the loss of fat-soluble vitamins and pigments in many foods, espedaUy in dehydrated foods. Factors which affect oxidation rate include moisture content, type of substrate (fatty acid), extent of reaction, oxygen content, tanperature, presence of metals, presence of natural antioxidants, enzyme activity, UV light, protein content, free amino... 

Studies of autoxidation and rancidity in relation to off-flavour production in foods cannot be overemphasized. Rancidity development in food products such as milk, meat, dehydrated food, potato chips, fruits and vegetables is a prime concern of food chemists. The process of autoxidation and rancidity not only involves cis to trans isomerization but also production of many other compounds, such as peroxides and hydroperoxides. IR spectroscopy has been used sucessfully to follow the autoxidation process qualitatively and quantitatively. Bands at 2.93, 3.2, 5.72 and 10 to 11 have been associated quantitatively with hydroperoxides, free acid, C=0, and cis to trans isomerization, respectively. Analysis by IR absorption was found to be more sensitive to changes than a qualified taste panel and considerably more sensitive than determination of peroxide values (O Connor, 1956). 

Polysaccharide films and coatings are used to extend the shelf life of fruits, vegetables, seafood, meats and confectionary products by preventing dehydration, oxidation rancidity, surface browning and oil diffusion and in some specific cases can improve the physicochemical, nutritional and sensorial properties of the products. The... 

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