High hydrostatic pressure/temperature modeling of frankfurter batters.

The impact of high pressure/temperature treatment on structure modification and functional sensory properties of frankfurter batter was investigated. The degree of solubilization of meat proteins, particularly of myosin, was identified as a key process with significant effect on the batter's structural properties. The maximal solubilization level was at 200 MPa/40 °C IT for all formulations which was found to be treatment time dependent. The impact of the pressurizing gradient - PG=40 MPa/s and PG=2.5 MPa/s was investigated and estimated to have a significant effect on the protein network and functional properties, respectively. These were improved at low PG (2.5 MPa/s) as a phenomenon of secondary network formation parallel to the main matrix. Batter secondary-structure characteristics were found to be ionic-strength dependent. According to SDS-PAGE analysis, the major role in the solubilization, aggregation and gelation processes occurring in the aqueous phase was due to the myosin S-1 and S-2, N-terminal, C-terminals, the MLC and actin during the high pressure/temperature treatment.

Molecular effects of high-pressure processing on food studied by resonance Raman.

Pressurization may cause unwanted side effects including color or texture changes of fish and meat. The color changes of poultry, pork, and smoked salmon were studied by CIE L*, a*, b* system, and resonance Raman (RR). High-pressure processing (HPP) of pork and chicken meat resulted in significant color modification at pressures higher than 270 and 280 MPa, respectively. RR spectra were taken after a high-pressure treatment of pork meat. According to the RR-data, deoxymyoglobin is the dominating myoglobin species in pork meat. High-pressure treatment causes conformational changes resulting in a stabile nonnative ferrous myoglobin species while the ferrous myoglobin state is maintained. High-pressure treatment causes a decrease of the relative RR intensities of astaxanthin by salmon as probed with 514 nm. RR spectra excited at 413 nm revealed a heterogeneous broadening of astaxanthin bands accompanied by the formation of deoxymyoglobin or deoxyhemoglobin. The broadening is interpreted as the degradation products of astaxanthin. Obviously, the high-pressure treatment of smoked salmon triggers redox processes of astaxanthin and the heme protein.