ABSTRACT Bugs are pest insects that, when not adequately controlled, may cause significant losses in the soybean crop. Their damage to grains compromises delivery in the storage unit and storage success. Thus, the objective of this study was to evaluate, during storage, the effect of temperature and moisture content on soybean grain quality with high damage caused by bugs in the crop. The experiment was set in a completely randomized design with a 2 x 4 x 5 factorial design, with two moisture contents (11.75 and 13.84% (w.b.)), four storage temperatures (20, 25, 30 and 35 °C), and five evaluation periods (0, 2, 4, 6 and 8 months). The percentage of damaged/fermented, damaged, fermented, broken grains, and electrical conductivity were analyzed. It can be inferred that bug-damaged soybean grains have reduced quality when stored at higher temperatures and for more extended periods. It is not recommended to store bug-damaged grains in moisture contents of 13.84% (w.b.) at temperatures above 30 °C for longer than four months. Grains stored at 35 °C when not damaged by bugs, ferment after six months of storage. Bug-damaged grains evolve to fermented grains during storage.
Abstract The objective of this study was to evaluate the drying system using a dryer with furnace automatically fed with eucalyptus chips and another dryer manually fed with eucalyptus firewood, as well as assessing the quality of corn grains. Harvest was mechanically performed and the grains were transported by trucks to the storage unit for drying. Corn grain drying was conducted in mixed-flow dryers with a nominal capacity of 100 tons per hour. For air heating, two direct-fired furnaces were used, one automatically fed with eucalyptus chips and the other manually fed with firewood. Corn grains were evaluated for moisture content, apparent specific mass, thousand-grain weight, polycyclic aromatic hydrocarbons (PAHs), electrical conductivity and color. Drying corn grains with direct fire using firewood or chips as fuel causes contamination by PAHs. In general, the use of firewood or chips did not influence the quality of thousand-grain weight, apparent specific mass and color, while the use of chips increased electrical conductivity. It is essential that research advances in this subject, prioritizing the contamination of food, with proven carcinogenic activity, which should be treated as a high risk to public health.
Devido à diversidade das características dos produtos agrícolas e a possível presença de defeitos e impurezas numa determinada quantidade expressiva de grãos, torna-se fundamental conhecer as propriedades físicas destes materiais, com finalidade de auxiliar no dimensionamento e projetos de equipamentos destinados a pós-colheita. Assim, objetivou-se determinar as propriedades físicas para diferentes proporções de grãos de soja, cotilédones e impurezas. O teor de água dos materiais foi determinado em estufa de circulação de ar forçado. Foram determinadas as propriedades físicas: massa específica aparente e unitária, ângulo de repouso, porosidade intergranular e velocidade terminal. As propriedades físicas dos grãos de soja variam quando inseridas diferentes proporções de cotilédones e impurezas. O ângulo de repouso aumenta com a maior quantidade de impurezas finas e a porosidade intergranular aumenta com a presença de impurezas grossas; a massa específica aparente é maior para grãos inteiros, enquanto ocorre incremento da massa específica unitária para as impurezas grossas. Os grãos, cotilédones, vagens e impurezas apresentam variações na velocidade terminal, sendo influenciadas pelo teor de água, forma e tamanho das partículas.
Due to the diversity of the characteristics of the agricultural products and the possible presence of defects and impurities in a certain expressive quantity of grains, it is fundamental to know the physical properties of these materials, in order to assist in the design and design of equipment destined to post-harvest. Thus, the objective was to determine the physical properties for different proportions of soybean grains, cotyledons and impurities. The moisture content of the materials was determined in a forced air circulation oven. The physical properties were determined: bulk and true density, angle of rest, intergranular porosity and terminal velocity. The physical properties of soybeans vary when different proportions of cotyledons and impurities are inserted. The angle of repose increases with the greater amount of fine impurities and the intergranular porosity increases with the presence of coarse impurities; the bulk density is higher for whole grains, while increasing the true density for the coarse impurities. The grains, cotyledons, pods and impurities present variations in terminal velocity, being influenced by the moisture content, shape and size of the particles.