Preheating and Heat Treatment

Preheating and Heat Treatment Preheating and postoperation heat treatment are used to avert or relieve the detrimental effects of the high temperature and severe thermal gradients inherent in the... 

The structural features of ceU wall polysaccharides of carrots have been studied by Stevens and Selvendran (1984) and Massiot et al.(1988). Plat et al.(1991), Ben Shalom et al.(1992) and Massiot et al.(1992) investigated the changes in pectic substances of carrots after blanching, dehydration and extended heat treatment. Data on the changes in ceU waU polysaccharides of canned carrots are lacking. This study aims to investigate the effect of preheating time at low temperature and the addition of CaCL on texture and on the composition of various pectin fractions of carrots canned by conventional and by a new process. 

It is common practice to stabilize full-fat products by preheating the seed, or by extrusion as in the case of full-fat soybean flour (6). Heat treatment deactivates lipases and lipoxygenases... 

ProgrRept, Oct-Dec 1949- To obtain further info about influence of prior heat treatment on ignition delay samples of PETN, preheated at 150° during 5 secs were either reheated for 3 hrs at 90° or stored for 1.5 hrs at 23° i mm pressure. The delay to ignition time of these samples was then detd and it was observed that neither treatment had changed the sensitivity of preheated PETN. Other tests included the effect of mass on ignition time at 250° of NC (13.15% N) and on Cordite N (modified) (See Table C)... 

Acid cleaners based on sulfamic acid are used in a large variety of applications, eg, air-conditioning systems marine equipment, including salt water stills wells (water, oil, and gas) household equipment, eg, copper-ware, steam irons, humidifiers, dishwashers, toilet bowls, and brick and other masonry tartar removal of false teeth (50) dairy equipment, eg, pasteurizers, evaporators, preheaters, and storage tanks industrial boilers, condensers, heat exchangers, and preheaters food-processing equipment brewery equipment (see Beer) sugar evaporators and paper-mill equipment (see also Evaporation Metal surface treatments Pulp). 

Figure 13.2 The influence of heat treatment on the shelf life of freeze-dried tomato powder stored at 23 °C and different water activities (Xext> 420 = 0.9 corresponds to the limit of acceptability)., A, preheated at 40 °C and aw = 0.11 (about 30% of glutamic acid has reacted to fructosylglutamic acid) O, A, unheated. Reproduced from Eichner and Ciner-Doruk577 with permission from Elsevier.

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