| Abstract [eng] |
Many vegetable raw materials are rich in phytosterols. These compounds have health-enhancing properties, but the extraction and use of phytosterols in new food development is a process that requires scientific research analysis. The aim of the final master's project is to extract phytosterol glycosides from plant raw materials and apply them in the production of functional yogurt. In order to achieve the goal, the analysis of chemical composition and technological parameters of raw materials was performed, and oil extraction was done in different ways. Purification of phytosterol fractions by solid-phase extraction, isolation by gas, and high-performance liquid chromatography. Prototypes of yogurts were made and their sensory, physicochemical and microbiological analysis was performed. Raw materials of vegetable origin were selected for the study: wheat bran, wheat germ, linseeds, hemp seeds, walnuts, soybeans, and soybean lecithin. First, an analysis of the chemical composition of the raw materials was performed to assess their properties. After this analysis, the highest protein content was found in soybeans and fat in linseeds. Linoleic acid predominated in all tested raw materials, except for linseeds, which had the highest content of α-linolenic acid. The yield of oil from linseeds obtained by supercritical fluid and Soxhlet extraction methods was the highest. While analyzing the composition of phytosterols in the raw materials after solid purification by oil extraction, with gas chromatography method, the only brasicasterol was found in wheat germ and bran, which was 1384.84 µg/ml and 6632.65 µg/ml, respectively. Using high-performance liquid chromatography, the highest levels were found in β-sitosterol in wheat germ - 601.81 µg/ml and in wheat bran - 591.98 µg/ml. The highest content of campesterol was found in wheat germ - 201.97 µg/ml. Low concentrations of stigmasterol were found in all raw materials, and only traces of brasicasterol were found. The most suitable conditions for the extraction of phytosterols are the purification of oil by solid-phase extraction PSA cartridges and the analysis of the obtained samples by the high-performance liquid chromatography method. The most suitable technological and organoleptic indicators of yogurt were obtained using the bacterial culture mixture YC-X11, which consists of Streptococcus thermophilus / Lactobacillus bulgaricus and the number of phytosterols in the product is 1.2 g/100g. After 21 days of assessment, the total number of bacteria in the yogurt was 3.80 CFU/g, pH - 4.24, the distribution of phytosterols was homogeneous, bitterness, tanginess, the intensity of pungent and extraneous odor were weakly expressed. |
