Heat treatment caused reactions

High hydrostatic pressure (HHP) processing is another method for the preservation of foods. It is a nonthermal preservation technique and causes little or no change in the organoleptic and nntri-tional quality of product unlike most conventional heat treatments. Enzymatic reactions may be enhanced or inhibited by pressure and pressure-induced changes in the enzyme-substrate interaction, changes in the reaction mechanism, the effect on a particular rate-limiting step, or the overall catalytic rate [111],... 

Carbon blacks are the most widely used fillers for elastomers, especially vulcanised natural rubber. They cause an improvement in stiffness, they increase the tensile strength, and they can also enhance the wear resistance. Other particulate fillers of an inorganic nature, such as metal oxides, carbonates, and silicates, generally do not prove to be nearly so effective as carbon black. This filler, which comes in various grades, is prepared by heat treatment of some sort of organic material, and comes in very small particle sizes, i.e. from 15 to 100 nm. These particles retain some chemical reactivity, and function in part by chemical reaction with the rubber molecules. They thus contribute to the crosslinking of the final material. 

The disadvantage of the dilution of extracts is that the flavour concentration is lower and the flavour dose has to be increased. Significant heat treatment can influence the flavour stability in a negative way because oxidation and Maillard reactions are enhanced and the flavour might be less stable. Owing to the fact that flavours are mainly complex mixtures, their rheological properties, particularly in presence of hydrocolloids, fibres or other macromolecules, are often not Newtonian. This can cause problems in the production process. In order to simplify... 

Thiamin is relatively unstable and is easily cleaved by a nucleophilic displacement reaction at its methylene carbon. The hydroxide ion (OH-) is a common nucelophile which can cause this reaction in foods. Thiamin is thus more stable under slightly acid conditions. Thiamin is reported to be relatively stable to pasteurization and UHT heat treatment (<10% losses) and during the storage of pasteurized milk, but losses of 20-40% have been reported for UHT milks stored for long periods of time (1-2 years). The light sensitivity of thiamin is less than that of other light-sensitive vitamins. 

Instantized milk powder normally exhibits low bulk density but higher water dispersibility than conventionally spray-dried powder. However, the extra heat exposure from the agglomeration and redrying treatments causes additional Maillard reaction, whey protein denaturation, and related chemical and physicochemical reactions that tend to lower product quality. 

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