Development of a method for temperature control of sunflower seeds in determining the content of oleic acid NMR

Abstract

Processing oil seeds with a modified fatty acid composition requires the development of new ways to control quality indicators. One of the solutions is express control of the mass fraction of oleic acid in oil of sunflower seeds using the NMR method. Production tests of this method showed the necessity for temperature control of samples before analysis for a long time, if the sample of temperature is less than 15 ° C, which significantly increases the analysis time. The article presents data of changing in the weighted average time of spin-spin relaxation of protons contained in sunflower seeds with different mass fractions of oleic acid in seed oil from their temperature. It was found that a decrease in the sample temperature by 1 ° C leads to a decrease in the weighted average time of spin-spin relaxation of protons seeds with a different mass fraction of oleic acid by 2.3 mc. To reduce the time of thermostating of the sample, we proposed the method of SHF-treatment of sunflower seeds. During the tests we identified the optimal energy of SHF-treatment (in our case it was 360 W) for the test sample of 100 g weight. The selected weight of the sample can significantly reduce the influence of the factor of different quality of samples and is minimal to obtain comparable results. SHF-treatment allows uniform heating of samples without evaporation of moisture from their surface and without changing the internal structure of the sample.