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The course of the conversion of methanol with water vapour was followed on a low-temperature Cu-Zn-Cr-Al catalyst at pressures of 0.2 and 0.6 MPa. The kinetic data were evaluated together with those obtained at 0.1 MPa and the following equation for the reaction kinetics at the given conditions was derived: r = [p(CH3OH)p(H2O)]0.5[p(H2)]-1.3.

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Maize grits with or without starchy additives (native wheat starch, distarch phosphates, soluble fiber) were extruded through a single-screw laboratory extruder Brabender KE 19/25 with a controlled barrel temperature in three zones and in a head, die diameter 4 mm, comprising a compression ratio of the screw of 2:1. The purpose was to influence resistant starch (RS) content together with improving/saving key physicochemical properties by controlling extrusion cooking variables (water addition into feed of 5-20%, screw speed 80-120 rpm, temperature, mass fraction of the additive in the dry premix 0-50%). The influences of most starchy additives were negligible. Pre-gelatinized cross-linked starch and soluble fiber nutriose influenced significantly the process pressure, where a low value exhibited high values RS. Based on the data of 48 trials, 7 mathematical optimization models were computed. High RS content worsened the expansion ratio. To obtain a RS content of 1%, it was necessary to decrease expansion ratio to 1.7 where the breaking strength was acceptable. The result of minimizing resistant starch content created an expansion ratio from 2.6 to 2.7, a breaking strength 1 N/mm 2 and a RS content (maximum) of 0.2%.

HINKOVÁ A., BUBNÍK Z., POUR V., HENKE S., KADLEC P. (2005) caramel) depended partially on the filtration temperature (15-17°C for egg blend, 40°C for amaranth, and 50-70°C for caramel) but mostly on the character of the medium filtered.