High-pressure treatment/processing

FDA regulation of, 21 578-579 gelatin in, 12 442 high pressure treatment of, 13 436 processed, 18 32-35 shipping containers for, 18 37 Food Quality Protection Act of 1996 (FQPA), 18 538-539 21 591 minor use pesticides under, 18-539-540 Food refrigeration, 21 558-566 importance of, 21 559 Food Safety and Inspection Service (FSIS), 13 17... 

The self-assembly of caseins may be readily manipulated by processing methods that affect the integrity of native casein micelles and the character of the casein interactions in aqueous media. Examples of such procedures are (Dickinson, 2006) (i) acidification toward the isoelectric point (p/) (pH 4.6-4.8), leading to a neutralization of the net protein charge (ii) enzyme action, as exploited in the production of cheeses and fermented milks (iii) addition of divalent ions, especially, Ca2+ ions (iv) addition of sucrose or ethanol (v) temperature treatment and (vi) high-pressure treatment. 

This method (ultra-high pressure treatment UHP) for the aseptic processing of food stuffs and other organic products still appears to be some way from extended application. 

In 1966, Lundgren [9] observed the existence of an optimum temperature for germination of spores, therefore Clouston and Willis [10, 11] deepened the process of germination and the inactivation of Bacillus pumilius under high-pressure treatment (HPT) and Wills [12] described the sensitivity of spores exposed to radiant energy. 

While the major aim in industrial wheat starch production is to produce a refined grade of A-starch, the production of a purified B-starch may also have commercial significance because of its unique uses, as described later in this chapter. In Europe, a new process was developed to separate B-starch into two fractions a high-purity, small granular starch and a feed fraction.53 The process involves enzyme treatment followed by high-pressure treatment and purification on fine screens, separators and decanters. Large and small wheat starch granules are marketed in Japan.85... 

The addition of mineral salts to alter protein and mineral equilibria in milk is a strategy that has been used to manipulate milk functionality, either alone or in combination with other processing treatments, such as alteration of pH, ultrafiltration, diafiltration, heating and cooling, or static high-pressure treatment. 

Novotna et al. (1999) showed that sensory quality of apple juice subjected to high-pressure treatment was better than that of pasteurized juice in terms of aroma. Lavinas et al. (2008) indicated that high-pressure processing (350-400 MPa, 3 or 7 min) of cashew apple juice reduced the aerobic mesophilic bacteria count to a level below the detection limit yeast and filamentous fungi were also inactivated. The juice could be stored for 8 weeks at 4°C without any significant change in the product quality. 

Laboissiere et al. (2007) showed that high-pressure processing (300 MPa, 5 min, 25°C) could be used to preserve yellow passion fruit pulp, yielding a ready-to-drink juice with improved sensory quality, free from cooked and artificial flavor attributes, as compared to commercial juices. High-pressure treatment did not cause any significant modifications in compounds responsible for aroma, flavor, and consistency. 

A considerable loss of turgor and structural collapse was observed during high-pressure processing of cauliflower and spinach (Prestamo and Arroyo, 1998). High-pressure treatment influenced structure of spinach more extensively than cauliflower since the latter has a harder and less elastic cell structure. The soft parenchyma cell of spinach leaf was completely destroyed after high-pressure treatment (400 MPa, 30 min, 5°C). 

Anema (2008b) showed that application of combined process involving heat and high pressure to skim milk resulted in higher level of whey protein denaturation than that of heat or pressure treatment alone. High-pressure treatment alone decreased the casein micelle size, whereas the change in casein micelle size was not prominent for thermal or combined treatment. 

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