The viability of seeds passing through the appropriate conditions of harvest and post-harvest storage and the step. The objective of this study was to evaluate the physiological potential of sunflower seeds under different storage conditions (25 °C and 50%, 20 °C and 60%, 30 °C and 40% RH air) using different packages (permeable and impermeable). Physiological assessments were carried seeds in zero, three and six months of storage times and analyzed by the average test were compared by Tukey test at 5% probability. Under the conditions of 20 °C and 60% RH, and 25 °C and 50% RH in air and impermeable packaging obtained the best quality results. The physiological potential of sunflower seeds was affected by drying temperatures and storage conditions. The drying air temperature above 45 °C negatively affected the quality of sunflower seeds. Permeable and waterproof packaging not guaranteed the quality of sunflower seeds during storage. The quality of sunflower seeds stored up time of three months was negatively affected. The conditions of 20 °C and 60% RH air were more favorable for the preservation of physiological quality of sunflower seed during the storage time.

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Given the prominence of sunflower on the national scenario and the importance of drying steps in postharvest, this study aimed to evaluate the drying kinetics of sunflower seeds in an oven with forced air convection in different temperatures. Thus, mathematically describe and determine the effects of drying on shrinkage of seeds. The experimental design was completely randomized, factorial (4x3), four air drying temperatures (45, 55, 65 and 75 °C) and three replications. Drying was carried out until the seeds water content reached equilibrium. The air temperature and flow were monitored with a psychrometer, and a hot wire anemometer, respectively. It has been found that the drying time was significantly (P<0.05) reduced with increasing temperature of the air drying. The model of Wang and Sing was that better adjusted to experimental drying data. Effective diffusivity of sunflower seed ranged from 2.83 to 2.93x10 -6 m 2 s -1 , while the isosteric heat of adsorption, 3,725.176 to 3,773.082 kJ kg -1 . Reducing water content influenced the shrinkage of sunflower seeds, with emphasis on temperatures above 55 °C. The model Corrêa was that better adjusted to experimental data of sunflower seeds volumetric shrinkage. KEYWORDS:Dryer, optimization, post-harvest. CINÉTICA DE SECAGEM, MODELAGEM MATEMÁTICA E CONTRAÇÃO VOLUMÉTRICA DE SEMENTES DE GIRASSOL (HELIANTHUS ANNUUS L.)RESUMO: Diante do destaque da cultura do girassol no cenário nacional e da importância da etapa de secagem para a pós-colheita, este trabalho teve como objetivo avaliar a cinética de secagem de sementes de girassol, em estufa com circulação de ar convectivo e forçado em diferentes temperaturas, descrever matematicamente e determinar os efeitos da secagem na contração volumétrica das sementes. O delineamento experimental utilizado foi inteiramente casualizado, fatorial (4x3), sendo quatro temperaturas do ar de secagem (45, 55, 65 e 75 °C) e três repetições. A secagem foi realizada até o teor de água das sementes entrarem em equilíbrio higroscópico. A temperatura e o fluxo do ar foram monitorados com auxílio de um psicrômetro e um anemômetro de fio quente, respectivamente.

The storage of sunflower seeds in an adequate position to guarantee the quality and regulate the supply of raw material for the industries for the production of oils and bran. The objective of this study was to evaluate the yield of sunflower seed oil after drying and during storage in three conditions (25 0 C and 50%, 20% and 60 0 C, 30 0 C and 40%) in different packing (permeable and impermeable). Quality assessments of seed and oil yield were performed in zero, three and six months of storage times and analyzed by the average test were compared by Tukey test at 5 % probability. In storage there were greater reductions in oil, with the increase of storage temperature of 20 °C to 30 °C and reducing the relative humidity from 60% to 40%. Under these conditions, the yield of oil decreased from 65% to 17%. Waterproof packaging positively influenced the quality of sunflower seeds stored. The conditions of 25 °C and 50% RH air storage were more favorable for the quality of the seeds. The increase in time of storage under conditions of 30 °C and 40% RH air adversely affecting the quality of seeds. It was concluded that to increase the oil yield of sunflower seeds, the best storage conditions were 25 0 C and 50% RH air.