EFFECTS OF HIGH-PRESSURES TREATMENT ON STARCHES

The effects of ultra-high pressure (UHF) on 25 starches were character ized via microscopy and DSC. Furthermore, the swelling behaviour, dige stibility, 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 o ccurs is typical for the corresponding starch. Only some starches (e.g . waxy corn starch) show the extensive swelling and almost complete de sintegration of the granules, which usually is observed after a heat g elatinization. Typical for a UHF-gelatinization is, that most starches show very little swelling and maintain their granular character. Thes e starches develope very little viscosity at normal paste concentratio ns and form pastes of smooth texture, resp. rigid gels at concentratio ns above 15%. Due to the limited swelling without any resp. very littl e solubilization of the amylose obviously the retrogradation occurs wi thin the granules, which probably is a further reason for the quite di fferent paste and gel properties of UHF-gelatinized starches in compar ison to heat gelatinized ones.