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A B S T R A C TWe conducted a detailed experimental investigation of the effect of CO 2 injection on the electrical conductivity of water bearing porous media, needed for an improved geophysical monitoring of CO 2 storage reservoirs. Therefore, we developed an experimental set-up that allows to investigate electrical characteristics of the injection process as well as the impact of dissolved CO 2 on pore water conductivity. We found that a gaseous, fluid and supercritical pure CO 2 phase bears no relevant conductivity at pressures up to 13 MPa and temperatures up to 50 • C. When CO 2 dissolves in pore water, pressure-dependent dissociation processes can double the pore water conductivity, that can be used in leakage detection. This is quantified by an adaptation of Archie's law. The empirical adaptation and the experimental data are confirmed by combined geochemical-geoelectrical modelling. Furthermore, water-saturated sand samples were investigated while CO 2 displaced the pore water at pressures up to 13 MPa and temperatures up to 40 • C. A decrease in electrical conductivity by a factor of up to 33 was measured, corresponding to a residual water saturation of 14-19%. Qualitatively, a decrease was also demonstrated under supercritical conditions. As an integrative interpretation, a conceptual model of electrical rock properties during CO 2 sequestration is presented.

The effects of traditional pasteurization (low pasteurization, conventional pasteurization, hot filling) and alternative pasteurization (pulsed electric fields, high pressure processing), followed by ultrasonication on the carotenoid content, carotenoid profile, and on the in vitro carotenoid bioaccessibility of orange juice were investigated. There was no significant difference in the total carotenoid content between the untreated juice (879.74 µg/100 g juice) and all pasteurized juices. Significantly lower contents of violaxanthin esters were found in the high thermally-treated juices (conventional pasteurization, hot filling) compared to the untreated juice, owing to heat-induced epoxy-furanoid rearrangement. The additional ultrasonication had almost no effects on the carotenoid content and profile of the orange juices. However, the in vitro solubilization and the micellarization efficiency were strongly increased by ultrasound, the latter by approximately 85.3–159.5%. Therefore, among the applied processing techniques, ultrasonication might be a promising technology to enhance the in vitro bioaccessibility of carotenoids and, thus, the nutritional value of orange juice.

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