The effects of ultra‐high pressure (UHP) on 25 starches were characterized via microscopy and DSC. Furthermore, the swelling behaviour, digestibility, paste viscosity and gel formation was determined. With few exceptions B‐starches were shown to be more pressure resistant than A‐ and C‐type starches. The pressure range in which the gelatinization occurs is typical for the corresponding starch. Only some starches (e.g. waxy corn starch) show the extensive swelling and almost complete desintegration of the granules, which usually is observed after a heat gelatinization. Typical for a UHP‐gelatinization is, that most starches show very little swelling and maintain their granular character. These starches develope very little viscosity at normal paste concentrations and form pastes of smooth texture, resp. rigid gels at concentrations above 15%. Due to the limited swelling without any resp. very little solubilization of the amylose obviously the retrogradation occurs within the granules, which probably is a further reason for the quite different paste and gel properties of UHP‐gelatinized starches in comparison to heat gelatinized ones.

Pectinesterase, lipase, polyphenol oxidase, lipoxygenase, peroxidase, lactoperoxidase, phosphatase and catalase have been examined at distinct conditions within a pressure range of 0.1 to 900 MPa, temperatures from 25ЊC to 60ЊC, pH 3 to 7, and time of treatment of 2 min to 45 min. Results in model buffers made it possible to rank the enzymes according to their pressure induced inactivation in the following order: lipoxygenase, lactoperoxidase, pectinesterase, lipase, phosphatase, catalase, polyphenol oxidase, peroxidase. A combination of pressure with moderate temperature increased the degree of enzyme inactivation. Pressure treatment of real food systems showed a protective effect of food ingredients on the pressure inactivation of most enzymes evaluated. For example sucrose protected pectinesterase from inactivation by pressure while lactoperoxidase and lipoxigenase were as stable in milk as in buffer.

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