Fundamentals and Applications of High Pressure Processing to Foods

Abstract

In the pursuit of new food preservation procedures to obtain products of high nutritional and sensorial quality that are microbiologically safe, with long shelf life, and with characteristics similar to those of fresh products, the use of high hydrostatic pressure (HHP) has received much focus around the world due its different applications. Thus, maximum interest in exploiting this technology as applied to biological systems has increased in recent years. When applying high pressure (HP) to preservation of foods, microorganisms are inactivated without the use of heat and, therefore, vitamin content, flavor of foods, or color of foods is not affected (Swientek, 1992; Palou et al., 2000b); thus, change is minimal. For this reason, the application of HP is considered a ‘‘cold’’ process (Crawford et al., 1996). Progress of research within the food and pharmaceutical industries has, during recent years, allowed manufacture of products with HP. HP technology has traditionally been employed in areas different from that of foods, as in the case of ceramics, steel and super alloy production, extrusion, and synthetic materials (Hoover et al., 1989). Research regarding the effects of HP on foods and microorganisms was first begun in 1889 by Hite (1899). Hite used equipment that reached 6800 atm (689 MPa) to treat different foods and beverages, such as milk and meat, besides studying the inactivation of some viruses. Among the first tests made with HP are those of Bridgman (1914), who denatured egg protein; Timson and Short (1965), who studied the effect of HP on microorganisms in raw milk; Wilson (1974), who sterilized some low-acid foods; and Elgasim andKennick (1980), who studied the effect of HP on the quality of meat protein 6 years later. In 1990, Meidi-ya Food Co. (Osaka, Japan) introduced to the market apple, strawberry, and kiwi jams, which were sterilized using only HP (Palou et al., 2000b; Mozhaev et al., 1994). Hayashi (1995) presented a list of foods processed by HP that were commercialized in the Japanese market, which included fruit desserts and dressings, mandarin and grape juices, raw squid, and fish sausages (Palou et al., 1999). Some of the foods currently processed by HP that are already commercialized are jams, dressings, jellies,