Food biochemical reactions induced

In addition to microbial contamination, there are changes in the food macroscopic properties that also induced biochemical reactions and chemical alterations in tissues, such as changes in the volatile profile [6] and... 

Many biochemical reactions can be induced by temperature increase in foods Maillard reactions, vitamin degradation, fat oxidation, denaturation of thermally unstable proteins (resulting in variation of solubility or of the germinating power of grains, for example), enzyme reactions (which can either be promoted or inhibited), and so on. Some of these biochemical reactions generate components suitable, for example, for their sensory properties (flavor development) others may be more or less undesirable for nutritional or potential toxicity reasons (vitamin losses, changes in color, taste or aroma, formation of toxic compounds). All the reactions are linked to the simultaneous evolution of product composition, temperature and water content (or chemical potential, or water activity), these factors varying diflferently from one point to another, from the center to the surface of the products. 

One factor contributing to crop losses caused by ozone is the development of abnormal pigments which are viewed as discolored areas on foliage of ozone-sensitive cultivars. Such discoloration is esthetically unacceptable on leafy food crops and probably causes a reduction in the nutritional value of all foliar components used for food and feed. Biochemical and physiological reactions responsible for ozone-induced discolorations have not... 

During the processing of foods, several chemical reactions affect the structure of some amino acids reactions with reducing sugars and polyphenols, interaction of the side chains of the amino acids, oxidation, etc. In some cases, these chemical modifications do not seem to change the nutritional availability of the amino acids involved, while in other cases, they do. In all cases, the presence of the newly formed molecules induces biochemical and physiological changes. 

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