RESUMO O estudo da cinética de secagem é de fundamental importância para a modelagem matemática, a qual tem sido muito usada no projeto e em análise dos processos de transferência de calor e de massa, durante a secagem. Buscou-se, então, avaliar a capacidade de ajuste de nove modelos matemáticos comumente utilizados para descrever o processo de secagem em sementes de crambe (Crambe abyssinica Horts), através de um delineamento inteiramente casualizado com três repetições, em que os tratamentos são constituídos de cinco teores de água (0,11; 0,13; 0,17; 0,25 e 0,28 decimal b.s) e cinco temperaturas do ar de secagem (30; 40; 50; 60 e 70 ºC). Para verificação do ajuste dos modelos estudados fez-se análise de regressão não-linear, pelo método Quasi-Newton. De acordo com os dados obtidos conclui-se que: o modelo da Aproximação por Difusão é o que melhor se ajusta aos dados de secagem obtidos; o aumento da temperatura de secagem promove maior taxa de remoção da água do produto; o coeficiente de difusão apresenta valores da ordem de 0,18 x 10-10 e 3,92 x 10-10 m2 s-1 e a energia de ativação para a difusão líquida foi da ordem de 4,97 kJ mol-1.

The heating and drying of various types of food using microwave improve the economy of time and energy. The physiological quality variation of the seeds submitted to microwave drying is known to some extent. In this context, some authors have reported excellent performance using this technique, on germination rates, after drying. The commercial use of microwave drying in seeds is irrelevant, which motivates more extensive research on the benefits and challenges of this technique that can increase its insertion in the post-harvest handling steps of agricultural products. Corn is a product of high worldwide relevance. Therefore, the use of microwaves in its drying process has excellent potential to arrive at significant savings in its production. Thus, this study is aimed to evaluate the effects on the physiological quality of the seeds submitted to different drying conditions, using the microwave radiation. To that end, corn seeds, with a water content of 20% on wet basis (w.b.), were dried at 40, 50, and 60 °C, at power ratings of 0, 0.6, and 1.2 W/g; in the vacuum condition. Drying occurred continuously, with intermittent power, until the seeds reached the 12% wet basis; in this condition, the seeds could be stored with secure. Germination tests performed shortly after drying showed that the temperature of 40 °C at a power of 0.6 W/g had a reduction in drying time of approximately 5 h when compared to conventional drying (40 °C and 0.0 W/g). The evaluation of the physiological quality of the seeds showed no significant difference in the germination, vigor, and longevity indices of the treated seeds.

The prediction of seed longevity (P50) is traditionally performed by the use of the Probit model. However, due to the fact that the survival data are of binary origin (0,1), the fit of the model can be compromised by the non-normality of the residues. Consequently, this leads to prediction losses, despite the data being partially smoothed by Probit and Logit models. A possibility to reduce the effect of non-normality of the data would be to apply the principles of the central limit theorem, which states that non-normal residues tend to be normal as the n sample is increased. The Logit and Probit models differ in their normal and logistic distribution. Therefore, we developed a new estimation procedure by using a small increase of the n sample and tested it in the Probit and Logit functions to improve the prediction of P50. The results showed that the calculation of P50 by increasing the n samples from 4 to 6 replicates improved the index of correctness of the prediction. The Logit model presented better performance when compared with the Probit model, indicating that the estimation of P50 is more adequate when the adjustment of the data is performed by the Logit function.

The use of seeds with high physiological quality allows rapid growth and establishment of seedlings in the field to be obtained. Therefore, the accuracy of the information obtained during the determination of the physiological quality of seeds is of great importance. The objective was to use generalized linear models, investigating which link function (Probit, Logit and Complementary log-log) is suitable to predict T50 and uniformity during germination of soybean and corn seeds. To perform the experiments, we used seeds from five commercial hybrids and/or cultivars of corn and soybean. The germination speed was calculated by counting the germinated seeds and the results were expressed in the form of proportions. Germination uniformity was calculated by the difference in the times required for germination. The best model was selected according to the criteria of the test of Deviance, AIC and BIC. The Logit model showed accurate results for most cultivars. The evaluation of germination in the form of proportions considering the assumption of binomial response is satisfactory, and the choice of the link function is dependent on the characteristics of each lot and/or species evaluated. The use of this methodology makes it possible to estimate any germination time and uniformity.

O crambe apresenta potencial de cultivo para as regiões tropicais, sobretudo, para o Centro-Oeste brasileiro, podendo ser considerada como uma opção à tão limitada lista de espécies disponíveis para a safrinha. Contudo, a expansão da área de cultivo desta Brassicacea somente ocorrerá com o fornecimento de sementes de qualidade, e para isso os conhecimentos sobre os procedimentos de secagem são relevantes. Este trabalho foi realizado com a finalidade de avaliar a qualidade fisiológica de sementes de crambe submetidas à secagem. Para tanto, foram avaliadas sementes com cinco teores de água (10; 12; 15; 20; 22% b.u), submetidas a cinco temperaturas de secagem do ar (30; 40; 50; 60 e 70 ºC). Os testes utilizados para análise foram: teste de germinação, primeira contagem da germinação, comprimento de plântulas e condutividade elétrica. Conclui-se que a temperatura entre 40 a 60 ºC propiciaram melhor desempenho fisiológico nos testes de viabilidade e vigor de sementes de crambe. A temperatura de 70 ºC foi prejudicial ao desempenho fisiológico das sementes de crambe. Teores de água acima de 12% b.u. sob faixas de temperaturas entre 40 a 60 ºC, podem interferir positivamente na quebra de dormência das sementes de crambe