Abstract:

In this study; Mineralogical, geochemical and physical properties of calcined and flux calcined diatomite produced by using diatomite belonging to the diatomite quarry in the Seydiler Region (Iscehisar, Afyonkarahisar) and the performance of diatomite samples were investigated for the bleaching process of vegetable oils. In X-ray diffraction (XRD) studies, natural diatomite is mostly composed of amorphous silica, contains low proportion of opal-CT/cristobalite, tridymite and quartz minerals, on the other hand, bleaching earth is mostly composed of smectite mineral and it has been determined contain a small amount of illite, quartz, feldspar and dolomite minerals. SiO2 content which is one of the most important factors in the economic use of diatomite was determined as 89,132% which is above the desired rate for commercial use. Oil bleaching performances of diatomites were carried out in sunflower and canola oils. In sunflower oil, diatomite cultivars, which were closest to the control group values (L* 77.09; a*-6.21; b*43.23) in terms of brightness, red color and yellow color; It was determined that natural diatomite (15 min; L* 73.39) in terms of brightness, calcined diatomite (15 min; a*-6.29) in terms of red color and flux calcined diatomite (30 min; b*35.64) in terms of yellow color. Different values were also determined in canola oil. In line with these results; According to the applied bleaching process times these diatomite types may change their color lightening levels and it has been determined that can be obtained close values to commercial bleaching earth which is widely used in food technology.

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