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Analiza właściwości fizykochemicznych i charakterystyka spektrofotometryczna wybranych olejów roślinnych
Introduction. Vegetable oils are a known source of mono- and polyunsaturated fatty acids (MUFA and PUFA). The growing demand for vegetable oils, rich in unsaturated fatty acids, increases the use of new oil plants to obtain them. In this study, the physicochemical properties (density, pH, refractive index, dynamic viscosity, contact angle, surface tension, color) were examined, a spectroscopic analysis was carried out and antioxidant properties were determined. In order to determine the indicated parameters, simple and easily accessible analytical methods were used, which provide key information about the prop erties of oils and serve as indicators for assessing their quality. Six commercially available oils were se lected for the study: evening primrose seeds (Oenothera paradoxa), milk thistle seeds (Silybum maria num), pumpkin seeds (Cucurbita oleo), linseed (Linum usitaissimum L.), winter camelina seeds (Camelina silvestris) and black cumin seeds (Nigella sativa). Results and conclusions. The conducted research provided significant insights into the relationship between the determined parameters of vegetable oils. The positive correlation between density and refrac tive index also highlights the influence of fatty acid composition on these properties. The observed diversi ty of colors of the oils tested highlights the unique composition of dyes characteristic of each oil. It was found that the pH of vegetable oils is a key indicator reflecting the level of acidity in the oil. The correla tion between contact angle and surface tension revealed complex surface interactions.
Characteristics of Langmuir monomolecular monolayers formed by the novel oil blends
Abstract The aim of this work was to assess the physical properties of Langmuir monolayers of three new oil blends “RBWg” (obtained by mixing rapeseed oil, black cumin oil, and wheat germ oil), “REp” (rapeseed oil and evening primrose oil), and “CRb” (camelina oil and rice bran oil), as well as to characterize the molecular dynamics of their protons using low-field nuclear magnetic resonance (LF NMR) method. The studied blends are rich in oleic acid (C18:1), linolenic acid (C18:2), and α-linolenic acid (18:3). The chromatographically determined ratio of n6 to n3 fatty acids was found to be in the range of 5.18–5.27. The appropriate n6/n3 fatty acid ratio was also confirmed by FT-IR analysis. The spin–lattice relaxation rate (R 1) and spin–spin relaxation time (R 2) measured by LF NMR method were similar for the RBWg and REp blends but different from the third oil blend (CRb), which indicates lower proton mobility in CRb. The observed changes in the properties of monolayers of oil blends suggest that the refined rice bran oil in the CRb blend also significantly changes the viscoelastic properties of this blend. The results obtained in this study provide a theoretical basis for the development of a well-balanced approach to using oils in food production technology.