One of the main parameters of sunflower seeds is its oil content. This characteristic is mandatory for certifica[1]tion of agricultural products and assessment of their value. IR spectroscopy and pulsed NMR methods are widely used to determine the oil content.The purpose of the research was to scientifically and practically substantiate the possibility of using sunflower oil samples for calibrating NMR analyzers, identifying and assessing the quality of oilseeds and products of their processing based on the NMR method. The comparison of the results of various options for the calibration of a pulsed NMR analyzer for determining the oil content of sunflower seeds was carried out. The first option was to measure the NM relaxation characteristics of oil protons from prepared samples of sunflower seeds, followed by determination of their oil content by exhaustive extraction in a Soxhlet apparatus, construction of a calibration equation based on the obtained data, and entering its coefficients into the program of NMR analyzers.The resulting calibration was the base one, with which other calibration options were compared. The second option was to use for calibrating the NMR analyzer various samples of sunflower oil obtained by pressing from sunflower seeds of the same varieties and hybrids, that were used for the first calibration option, as well as sunflower oil samples purchased in a commercial network. Five samples evenly distributed in the range from 2.000 g to 7.000 g with an accuracy of 0.001 g were taken from each oil sample using laboratory scales, and the amplitudes of proton NMR signals were measured in them. The dependency between the oil mass of the analyzed samples and the amplitude of proton NMR signals in them was graphed. Comparison of the obtained calibration dependences showed their close nature. Mathematical calculations have shown that the use of sunflower oil for the calibration of NMR analyzers does not lead to an increase in the error in the measurement results of the oil content of sunflower seeds compared to the first option of the calibration.The practical significance of the research will considerably simplify the calibration process, reduce the calibration time from 3–4 days to 3–4 hours, and eliminate the use of toxic solvents and additional expensive equipment without a significant change in the error in determining the oil content of sunflower seeds by NMR.

Одним из наиболее перспективных направлений в селекции масличного льна является получение сортов и гибридов с низким содержанием линоленовой кислоты в масле семян. В результате из него можно получить более сбалансированное по жирнокислотному составу масло, придать ему дополнительные функциональные свойства и повысить срок хранения и область применения. В настоящее время для определения жирнокислотного состава масла семян используют хроматографический метод. Недостатками этого метода являются длительность времени применения и разрушающий характер. Известен способ определения массовой доли линоленовой кислоты в масле семян льна с использованием импульсного метода ЯМР, позволяющий оценивать пробы объемом 25 см3. Но данный способ не подходит для оценки перспективных селекционных вариаций малого объема. С целью устранения данного недостатка была разработана специальная конструкция датчика сигналов ЯМР для объема пробы 8 см3, что соответствует объему семян, получаемых с группы однотипных растений льна. Приведены сравнительные результаты измерения массовой доли линоленовой кислоты в масле семян льна импульсным методом ЯМР с использованием штатного датчика сигналов ЯМР-анализатора АМВ-1006М и специально разработанного уменьшенного объема. Выявлено, что применение разработанного датчика позволяет практически в 2 раза повысить точность результатов измерений. Предложенная конструкция позволяет значительно повысить эффективность селекционной работы за счет возможного увеличения количества анализируемых проб и упростить процесс идентификации образцов с требуемым содержанием линоленовой кислоты. One of the most promising directions in oil flax breeding is the production of varieties and hybrids with a low content of linolenic acid in seed oil. As a result, it is possible to obtain a more balanced oil in terms of fatty acid composition, give it additional functional properties and increase the shelf life and range of applications. Currently, the chromatographic method is used to determine the fatty acid composition of seed oil. The disadvantages of this method are the length of the time of application and the destructive nature. A method is known for determining the mass fraction of linolenic acid in flax seed oil using the pulsed NMR method, which makes it possible to evaluate samples with a volume of 25 cm3. But this method is not suitable for assessing promising low-volume breeding variations. In order to eliminate this disadvantage, a special design of the NMR signal sensor was developed for a sample volume of 8 cm3, which corresponds to the volume of seeds obtained from a group of flax plants of the same type. Comparative results of measuring the mass fraction of linolenic acid in flax seed oil by the pulsed NMR method using the standard signal sensor of the AMB-1006M NMR analyzer and a specially designed reduced volume are presented. It was found that the use of the developed sensor makes it possible to almost double the accuracy of the measurement results. The proposed design makes it possible to significantly increase the efficiency of breeding work due to the possible increase in the number of analyzed samples and simplify the process of identifying samples with the required content of linolenic acid.

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.

The article presents the results of the study of the metrological characteristics of NMR analyzers AMV-1006M obtained during their calibration to determine the mass fraction of oleic acid in sunflower seed oil using sunflower seeds and specially developed reference materials (RM) - imitators of the mass fraction of oleic acid in seed oil. When calibrating an NMR analyzer under repeatability conditions, it was found that the relative standard deviations of the measurement results and the limits of the confidence random error of the measurement results using RM simulators are almost 3 times lower than the results of the measurement with use of natural sunflower seeds. When checking the reproducibility of the calibration results using four NMR analyzers, it was found that the reproducibility of the calibration of NMR analyzers using RM simulators of the mass fraction of oleic acid is more than 3 times better than when using sunflower seeds. The data obtained is explained by the fact that RM-simulators have a fairly homogeneous structure, which is formed during their manufacture. Sunflower seeds are a complex heterogeneous system with a heterogeneous structure in the volume of the analyzed sample. The study of the effect of temperature on the calibration results showed that the standard deviation of the measurement results for RM-simulators does not exceed 0.8 % abs., while the using of natural seeds, values of 2.5 % abs. were obtained. Thus, the use of RM simulators can significantly reduce the calibration error of NMR analyzers associated with the effect of temperature. The obtained data confirmed the expediency of using for calibration of the AMV-1006M NMR analyzers precisely CO-simulators of the mass fraction of oleic acid.

Currently, there is an increase in the volume of rapeseed processing, which leads to a natural increase in the production of by-products such as rapeseed lecithin. One of the indicators of the quality of lecithins, which determines the content of physiologically valuable components – phospholipids is the weight fraction of substances insoluble in acetone. The aim of the study is to develop an integrated system for metrological support of an instrumental method for determining the weight fraction of substances insoluble in acetone, contained in rapeseed lecithins, using the pulse NMR method. The main element of this system is standard imitating samples with known metrological values of the mass fraction of substances insoluble in acetone. As a result of the conducted studies of NMR characteristics of natural samples of rapeseed lecithins with different mass fractions of substances insoluble in acetone, the optimal parameters of NM relaxation characteristics of standard imitating samples have been determined. It has been shown that three substances are required to create standard imitating samples, while to simulate the protons contained in the oil phase of rapeseed lecithins two substances are required using spin-spin relaxation time from 77 to 110 ms and a spin-spin relaxation time from 23 to 28 ms, and to imitate phospholipid protons – a substance with a spin-spin relaxation time from 2 to 6 ms is required. On the basis of the study of NMR characteristics of protons contained in samples of chemically inert organic silicon liquids and natural latex, a composition of 6 standard samples-imitators of the mass fraction of substances insoluble in acetone contained in rapeseed lecithins, and a procedure for their use for NMR calibration analyzer AMV-1006 M have been developed.

Developing modern instrumental express methods for monitoring quality parameters requires special attention to the comparability of measurement results with reference methods. This article includes the result of improving the method for determining oleic acid content in sunflower seed oil using pulsed NMR technique. In the conditions of industrial laboratories, different seed quality and temperature have the greatest influence on the accuracy of measuring oleic acid content. It is possible to reduce the influence of different quality by increasing the number of simultaneously analyzed samples. A method for preliminary SHF treatment of seeds was proposed that could significantly reduce the time of seed sample preparation with the temperature below 15°C. Due to the special characteristics of SHF treatment, seeds are heated under certain parameters to the temperature of 20-25°C without loss of moisture contained in the analyzed sample what is especially important for the comprehensive determination of quality parameters of sunflower seeds using pulsed NMR method.To eliminate temperature influence, it was proposed to measure the temperature of each analyzed sample before the analysis. This allowed significant increasing the accuracy of measuring oleic acid content. These solutions were implemented in a sampling device that made a sample with a volume of 25 cm3 and at the same time measured its temperature.

The article presents the results of studying of nuclear magnetic relaxation characteristics of protons, which contain in various organosilicon fluid brands, with the aim of justifying the possibility of their use in the development of simulator reference materials (RMs) of oleic acid mass fraction in sunflower seed oil. The data characterizing the NM-relaxation characteristics of organosilicon liquids, varying in a viscosity index, are provided. Based on the range of changes in the time of spin-spin relaxation of protons containing in oil of sunflower seeds with various mass fraction of oleic acid (157-200 msec) there are select silicon organic fluids, that allow the most accurate simulation of wave-form envelopes of oil protons spin echo signals in the seeds. The simulator reference materials under development are intended for use in the calibration of NMR-analyzers for determination of oleic acid mass fraction in of sunflower seed oil.

The article presents the results of the study of factors affecting the accuracy of the results of measuring the mass fraction of oleic acid in sunflower seed oil using a pulsed NMR method. Analysis of the data obtained during the production tests has revealed factors that reduce the accuracy of the measurement results. The first factor is the different quality of the analyzed samples of sunflower seeds, which is due to the biological characteristics of the seeds and growing conditions. The second factor affecting the error of the measurement results of the quality parameters of sunflower seeds is the difference in the temperature of the seeds being analyzed and the temperature in the laboratory where the used NMR analyzer is installed. Moreover, this factor has the greatest influence on the accuracy of measurements of the mass fraction of oleic acid in sunflower seed oil. The third factor is the human factor, namely, the accuracy of sampling using a sampling cup, which is currently included in the AMV-1006M serial NMR analyzer.In order to eliminate their influence, a special sampling device has been developed. It has been established that the reduction in the influence of the identified factors is achieved by normalizing the volume of the sample of seeds and measuring its temperature. The article presents data characterizing the main nodes of the developed sampling device, as well as the results of determining the mass fraction of oleic acid in oil of sunflower seeds after the introduction of the developed sampling device in the measurement procedure.The developed design of the sampling device is simple to manufacture, has high operational characteristics, allows to increase the accuracy of sampling seeds by volume and significantly improve the accuracy of the results of measuring the mass fraction of oleic acid in oil of sunflower seeds based on the pulsed NMR method.

Исследовано влияние четыреххлористого углерода на ядерно-магнитные релаксационные характеристики протонов, содержащихся в рапсовых лецитинах (РЛ). Выявлено, что добавление CCl4 в многокомпонентную систему, которую представляет собой жидкий РЛ, приводит к ослаблению и разрыву межмолекулярных связей, а при достижении определенного соотношения масс РЛ и CCl4 происходит максимальный разрыв межмолекулярных связей и в системе устанавливается равновесие. Установлено, что при увеличении в системе РЛ–CCl4 массовой доли CCl4 с 1 до 4 происходит перераспределение содержащихся в РЛ четырех компонент: на 33% увеличивается доля 1-й компоненты; доля 2-й снижается на 14,5%; на 1,3% увеличивается доля 3-й; на 17,1% снижается доля 4-й по сравнению с контролем – образцом жидкого РЛ без добавки CCl4. Таким образом, предварительное растворение РЛ в четыреххлористом углероде при соотношении масс 1 : 4 соответственно позволяет максимально высвободить из мицелл содержащиеся в лецитине молекулы фосфолипидов, проявляющих кислотные свойства, и молекулы свободных жирных кислот, что в значительной степени сократит время их взаимодействия с раствором щелочного реагента при определении кислотного числа жидких РЛ. The effect of carbon tetrachloride on the nuclear magnetic relaxation characteristics of protons contained in rapeseed lecithins (RL) has been studied. It is revealed that the addition of CCl4in a multicomponent system, which is a liquid RL, leads to the weakening and rupture of intermolecular bonds, and when a certain mass ratio of RL and CCl4is reached, the maximum rupture of intermolecular bonds occurs and the equilibrium is established in the system. It was found that the redistribution of the four components contained in the RL occurs by increasing the mass fraction of CCl4in the system RL–CCl4from 1 to 4: the share of the 1st component increases by 33%; the share of the 2nd component decreases by 14,5%; the share of the 3rd component increases by 1,3%; the share of the 4th component decreases by 17,1% compared with the control sample of liquid RL without CCl4additive. Thus, the preliminary dissolution of RL in carbon tetrachloride at a mass ratio of 1: 4, respectively, allows the maximum release from the micelles contained in lecithin phospholipids molecules exhibiting acidic properties, and molecules of free fatty acids, which greatly reduce the time of their interaction with the alkaline reagent solution in determining the acid number of liquid RL.

The first part of the article presents the history of creating quantitative NMR analyzers of oil content and humidity of oil crop seeds and their by-products. The developed NMR analyzers differ from similar devices in the availability of metrological support (reference materials (RMs) of approved type) and an extended range of moisture measurement (5–20)%. The main metrological characteristics of the developed NMR analyzer are given. The second part of the article deals with problems solved in the process of carrying out the scientific research work on the development of metrological support for quantitative NMR analyzers. Based on the tasks set, the most optimal substances imitating oil and water components contained in the oil crops and their by-products were selected. The imitation substances in question provide long-term stability of the developed RMs, erewhile being chemically inert to each other, environmentally safe? and allowing an imitation of oil and water in oil crops and their by-products. Organosilicon fluids with (35–40) ms and (95–130) spin-spin relaxation times of protons ms are proposed as an oil imitator. To imitate water, a one-component self-vulcanizing organosilicon compound, which is applied to paper strips with a thin coat, is used in the developed type-approved RMs. In conclusion, the article presents perspective directions of developing RMs of mass fraction imitators of typical fatty acids in the oil of oil crops (sunflower, linseed, and rapeseed).

Изучено влияние массовой доли содержащихся в лецитинах компонентов, проявляющих кислотные свойства, на их ядерно-магнитные релаксационные (ЯМР) характеристики для выявления возможности использования указанных характеристик в качестве аналитического параметра определения кислотного числа лецитинов. В качестве объектов исследования взяты подсолнечные лецитины с различными кислотными числами: 17,8; 24,1 и 30,1 мг КОН/г, значения которых обусловлены различной массовой долей содержащихся в лецитинах свободных жирных кислот (3,5; 4,7 и 5,5% соответственно) и фосфолипидов, проявляющих кислотные свойства, (10,5; 12,0 и 13,0% соответственно). Установлено, что значения ни одной из ЯМР характеристик (время спин-спиновой релаксации и амплитуды сигналов ядерной магнитной релаксации) протонов лецитинов не могут быть выбраны в качестве аналитического параметра для определения кислотного числа, так как они не зависят от кислотного числа лецитинов. На основании полученных данных сделан вывод, что для определения кислотного числа лецитинов с применением импульсного метода ядерного магнитного резонанса необходима специальная пробоподготовка образца лецитина, позволяющая обеспечить: во-первых, различия в значениях ЯМР характеристик протонов свободных жирных кислот и протонов триацилглицеринов, содержащихся в масле, выделенном из лецитина; во-вторых, различия в значениях ЯМР характеристик протонов фосфолипидов, проявляющих кислотные свойства, и протонов других групп фосфолипидов, содержащихся в лецитине. The aim of the research was to study the effect of the mass fraction of components exhibiting acidic properties contained in lecithins on their NMR characteristics in order to identify the possibilities of using these characteristics as an analytical parameter for determining the acid number of lecithins. Sunflower lecithins with different acid numbers were taken as objects of study: 17,8; 24,1 and 30,1 mg KOH/g, the values of which are due to different mass fractions of free fatty acids (3,5; 4,7 and 5,5%, respectively) and different mass fractions of phospholipids, exhibiting acidic properties (10,5; 12,0 and 13,0%, respectively) contained in lecithins. It was established that the values of none of the NMR characteristics – times of spin-spin relaxation and amplitudes of NMR signals of protons of lecithins can not be selected as an analytical parameter for determining the acid number, since they do not depend on the acid number of lecithins. Based on the obtained data, it was concluded that to determine the acid number of lecithins using the pulsed method of nuclear magnetic resonance, special sample preparation of a sample of lecithin is necessary, which allows to ensure, first, differences in the NMR values of the characteristics of free fatty acid protons and triacylglycerol protons contained in oil extracted from lecithin, and, secondly, the differences in the NMR values of the characteristics of protons of phospholipids, exhibiting acidic properties, and protons of other phospho groups lipids contained in lecithin.

The article presents the results of the investigation of NMR characteristics of protons contained in sunflower lecithins. The basic requirements for creating NMR simulant samples of proton characteristics contained in sunflower lecithins are formulated. The results of the investigation of NMR characteristics of organosilicon fluids of various brands are presented in order to select the most effective simulant samples. The composition of simulant samples of NMR proton characteristics contained in sunflower lecithins is developed, the application of which will significantly simplify the process of calibration and verification of NMR analyzers.

It’s been determined that the amplitude of the NMR signals of protons of the solid phase, that is, the amplitude of NMR signals of soap protons (Am), is an analytical parameter characterizing the content of the soap formed, and, consequently, the content of free fatty acids. It’s been revealed that there is a linear dependence between the acid-degree value of oil extracted from sunflower phospholipids and the amplitude of NMR signals of soap protons, which is described by the following equation: A.n.=0,2481× Ам+ 0,4319. A method has been developed for determining one of the main quality indicators of sunflower phospholipids-the acid-degree value of oil extracted from sunflower phospholipids, using the nuclear-magnetic relaxation method, which makes it possible to eliminate the use of toxic solvents, as well as to improve the accuracy of the analysis results.

The article presents the results of the investigation of NMR characteristics of protons contained in sunflower lecithins. The basic requirements for creating NMR simulant samples of proton characteristics contained in sunflower lecithins are formulated. The results of the investigation of NMR characteristics of organosilicon fluids of various brands are presented in order to select the most effective simulant samples. The composition of simulant samples of NMR proton characteristics contained in sunflower lecithins is developed, the application of which will significantly simplify the process of calibration and verification of NMR analyzers.

It’s been determined that the amplitude of the NMR signals of protons of the solid phase, that is, the amplitude of NMR signals of soap protons (Am), is an analytical parameter characterizing the content of the soap formed, and, consequently, the content of free fatty acids. It’s been revealed that there is a linear dependence between the acid-degree value of oil extracted from sunflower phospholipids and the amplitude of NMR signals of soap protons, which is described by the following equation: A.n.=0,2481× А м + 0,4319. A method has been developed for determining one of the main quality indicators of sunflower phospholipids-the acid-degree value of oil extracted from sunflower phospholipids, using the nuclear-magnetic relaxation method, which makes it possible to eliminate the use of toxic solvents, as well as to improve the accuracy of the analysis results.

The article presents the results of the research on the effect of carbon tetrachloride on the change in the nuclear magnetic relaxation characteristics of protons contained in sunflower lecithins

The article presents the results of the research of the possibility of determining the acid number of sunflower lecithins using the method of nuclear magnetic resonance (NMR). The application of the NMR method will greatly simplify the process of determining the acid number of lecithins and eliminate the influence of a human factor on the results of analyzes.