Qualidade fisiológica e perfil de ácidos graxos do óleo bruto de sementes de niger após a secagem

Abstract

With a prediction of the depletion of fossil fuel sources, the search for renewable energy sources, the use in the pharmaceutical, food and various other industries, has been intensified in the studies with agricultural products with significant amount of oil in its composition. However, in addition, it is necessary that the oil also has good quality. As with some crops, depending on the harvest season, the product is susceptible to climatic conditions, making natural drying in the field unfeasible. In view of this, the niger needs to go through the artificial drying process, in order to reduce its water content, maintain its quality and ensure storage security. For the successful implementation of culture it is necessary to use quality seeds and vigor tests are important in assessing the physiological potential of seeds because complement the information obtained in the germination test. Thus, the objective of this work was to study the physiological quality of niger seeds, as well as the fatty acid profile of the crude oil extracted after drying under different air temperature conditions. For the experiment, were used niger seeds (Guizotia abyssinica Cass.) harvested with approximately 19% moisture content, wet basis (w.b.) cultivated in Dourados / MS. Drying was carried out at temperatures of 40, 50, 60 and 70 ºC until the moisture content was 8.5 ± 1% (w.b.). The physiological properties of niger seeds were determined by the following tests: germination, germination speed index, mean germination time, cold, accelerated aging with saturated solution, emergence and emergency speed index. For the extraction of the oil content in the seeds, the direct hexane method was used. The technique of gas chromatographic separation with flame ionization detector (GC-FID) was used to determine the fatty acid profile. The experiment was set up in a completely randomized design. For the experimental average data analysis of variance and regression was performed using the software SISVAR. By means of a joint analysis of the data, it can be concluded that: drying air temperatures of 40 and 50 ºC do not compromise the physiological quality of niger seeds. The temperature of 70 ºC promotes the lowest values in the tests evaluated. In general, the drying temperatures employed do not promote large changes in the fatty acid profile of niger oil.