A B S T R A C TThe objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol -1 .Cinética e propriedades termodinâmicas relacionadas à secagem dos frutos de pimenta Cabacinha R E S U M O Objetivou-se, neste trabalho, determinar e modelar a cinética de secagem dos frutos de pimenta Cabacinha para diferentes temperaturas do ar de secagem, bem como obter as propriedades termodinâmicas envolvidas no processo de secagem do produto. A secagem foi realizada em condições controladas de temperatura (60, 70, 80, 90 e 100 °C) utilizandose três amostras de 130 g de frutos, as quais foram pesadas periodicamente até atingirem massa constante. Os dados experimentais foram ajustados a diferentes modelos matemáticos frequentemente utilizados na representação da secagem de frutos. O coeficiente de difusão efetivo, calculado a partir do modelo matemático da difusão líquida, foi utilizado para obtenção da energia de ativação, entalpia, entropia e energia livre de Gibbs. O modelo de Midilli foi o que apresentou os melhores ajustes aos dados experimentais da secagem dos frutos de pimenta Cabacinha. A elevação da temperatura de secagem promoveu: o aumento nos valores da taxa de remoção de água dos frutos, do coeficiente de difusão efetivo e da energia livre de Gibbs além de redução no tempo de secagem dos frutos, nos valores da entalpia e a entropia. A energia de ativação para a secagem dos frutos de pimenta foi de 36,09 kJ mol -1 .

Drying is one of the most important steps of the post-harvest of pepper seeds and must be performed carefully so as not to impair the quality of seeds. The study of thermodynamic properties provides information about the behavior of water in agriculture products and the energy requirement for removal thereof during the drying process. Based on the above, this study aimed to determine and evaluate the thermodynamic properties for different equilibrium moisture contents in pepper seeds of the variety 'Cabacinha'. Seeds with an initial moisture content of 22.7% on dry basis (d.b.) were subjected to drying at 40 °C, until reaching moisture content of 3.9% (d.b.). Based on the obtained results, it is concluded that the integral isosteric heat of desorption, the Gibbs free energy, the differential enthalpy and entropy increase with the reduction of the moisture content of pepper seeds. The Gibbs free energy showed positive values, indicating that the process of desorption is not spontaneous. The theory of the enthalpy-entropy compensation can be applied to the desorption process, since this is controlled by enthalpy.

R E S U M OA higroscopicidade de sementes fornece informações essenciais para otimização de processos de secagem, armazenamento e desenvolvimento de embalagens. O objetivo neste trabalho foi determinar as isotermas de dessorção das sementes de pimenta (Capsicum chinense L.), variedade Cabacinha, para diferentes condições de temperatura e atividade de água utilizando-se o método estático indireto, sendo a atividade de água (aw) determinada por meio do equipamento Hygropalm Model Aw1. Aos dados experimentais foram ajustados modelos matemáticos frequentemente utilizados para representação da higroscopicidade de produtos agrícolas. Para uma atividade de água constante o aumento da temperatura reduz o teor de água de equilíbrio higroscópico das sementes de pimenta. As isotermas de dessorção apresentam formato sigmoidal do tipo II. Os modelos de Cavalcanti Mata, Chen Clayton, Chung Pfost, Chung Pfost Modificado, Henderson e Henderson Modificado são adequados para representar a higroscopicidade das sementes de pimenta Cabacinha para a faixa de temperatura de 10 a 40 °C e atividade de água de 0,213 a 0,975. Hygroscopicity of pepper seeds (Capsicum chinense L.) A B S T R A C TThe hygroscopicity in seeds provide essential information to optimize the drying process, storage and packaging development. The objective of this study was to determine the sorption isotherms of pepper seeds (Capsicum chinense L.), variety Cabacinha for different conditions of temperature and water activity. The sorption isotherms were determined at temperatures of 10, 20, 30 and 40 °C using the static indirect method and the water activity (aw) for each moisture content of seeds was determined by Hygropalm Model Aw1 equipment. The mathematical models often used to represent the hygroscopicity of agricultural products were adjusted to experimental data. For a constant water activity, increase in temperature decreased the equilibrium moisture content of pepper seeds. The desorption isotherms exhibit sigmoidal shape of type II. The models of Cavalcanti Mata, Clayton Chen, Chung Pfost, Modified Chung Pfost, Modified Henderson and Henderson are suitable to represent the hygroscopicity of seeds of pepper Cabacinha for the temperature range of 10 to 40 °C and water activity of 0.213 to 0.975. Palavras-chave:cabacinha isotermas de dessorção modelagem matemática

Information regarding the correlation between characters are of great importance to simultaneous traits selection in breeding programs. However, quantification and interpretation of the correlations magnitude do not imply in direct and indirect effects. In this context, the path analysis is presented as an alternative and viable tool for the selection process. The objective of this study was to evaluate the phenotypic, genotypic and environmental correlations between eight major agronomic characters in pepper lines (C. chinense L.) and its consequences in direct and indirect effects by path analysis. Eight agronomic traits were assessed under field conditions in 22 C. chinense L lines. According to the results, there is a genetic variability among the evaluated lines, whose yield per plant (PY) and total number of fruits (NF) variables are highly correlated with high direct effect on pepper lines yield. The selection of pepper lines with high yield can be accomplished through direct selection or using a suitable selection index, being advantageous to select lines with other characteristics, such as appropriate scion height and diameter for conducting manual and mechanized harvesting. The use of the constant k is efficient to reduce the variance of path coefficients, providing better estimation of the effects that affects yield.