The purpose of this master's thesis was to investigate the influence of different temperature and pH conditions on the activity of lipases from selected extracts of seeds and sprouts available on the Slovenian market. We formulated three working hypotheses: first, that lipase activity depends on temperature and is highest at neutral pH; second, that it is higher in seed extracts than in sprouts; and third, that it varies depending on the plant source. We examined seeds and sprouts of black soybeans, mustard, sunflower, wheat, sweet corn, oil radish, nežika beans and sesame seeds and flaxseed sprouts. In the samples, the moisture content or dry matter content was determined, the protein concentration was measured spectrophotometrically, and SDS-PAGE gel electrophoresis was performed. We found that all samples contained proteins ranging from 10 to 72 kDa. The dry matter content was higher in seed samples than in sprouts, and the protein content on dry matter was mostly higher in sprout than in corresponding seeds. The highest protein content was determined in the black soybean seed extract (31,7 mg/mL), and the lowest in mustard sprout extract (0,65 mg/mL). Lipase activity was calculated from spectrophotometric measurements of absorbance at 400 nm at pH 7,2 and temperatures of 15 °C, 25 °C, 37 °C, and 45 °C, as well as at different pH values, pH 4,0, 6,5, 7,2, and 9,0, at temperature of 37 °C. The highest lipase activity was observed in mustard and wheat sprout extracts (0,26 U/mL) at 45 °C. The lowest activity was observed at 15 °C in sweet corn sprout extract (0,0019 U/mL). Lipase activity increased with higher temperature and pH. From these results, we concluded that lipases from the analyzed samples exhibited higher activity in a basic environment (pH 9,0), while acidic conditions (pH 4,0) were the least favorable and resulted in activity below the detection limit.
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