Drying kinetics and effective diffusion of watermelon seeds

Abstract

ResumoAs sementes de melancia (Citrullus lanatus) apresentam elevado teor de água, e necessitam passar pelo processo de secagem para assegurar o armazenamento e manter a viabilidade da Research, Society and Development, v. 9, n. 4, e16972887, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i4.2887 2 semente. Neste cenário, o estudo da cinética de secagem permite a descrição do processo por meio de modelos matemáticos e obtenção de informações, que auxiliam na compreensão do fenômeno em questão. Assim, objetivou-se ajustar estatisticamente oito modelos matemáticos, a fim de selecionar o que melhor representasse o comportamento da secagem da semente de melancia, determinar o coeficiente de difusão, a energia de ativação e a taxa de secagem das sementes em diferentes temperaturas. As sementes foram secas em um secador experimental nas temperaturas de 40; 45; 50; 55 e 60 °C, com velocidade do ar de 0.8 m s -1 , em quatro repetições. Para os ajustes dos modelos fez-se análise de regressão não-linear, pelo método de Gauss-Newton. Conclui-se que os modelos que melhor representam a cinética de secagem de sementes de melancia são Aproximação da difusão para as temperaturas de 40; 50 e 55 °C, e Page para 55 e 60 °C. As maiores taxas de secagem são observadas nas temperaturas mais elevadas. Os coeficientes de difusão apresentaram magnitude de 7.69684x10 -10 e 1.27585x10 -9 para o intervalo de 40 a 60 °C. E a energia de ativação foi de 12.2641 kJ mol -1 . Palavras-chave:Coeficiente de difusão; Energia de ativação; Taxa de secagem, Teor de água;Temperatura. AbstractStudying the drying kinetics allows describing the process by mathematical models and obtaining information that helps to understand the phenomenon in question. Considering that watermelon (Citrullus lanatus) seeds have high moisture content and need to be subjected to drying, the objective was to select the model that best represents the drying behavior of watermelon seeds and determine the diffusion coefficient, activation energy and drying rate of these seeds at different temperatures. The seeds were dried in an experimental dryer at temperatures of 40, 45, 50, 55 and 60 °C, with air velocity of 0.8 m s -1 , in four replicates. The models were fitted with non-linear regression analysis using the Gauss-Newton method. It was concluded that the models that best represent the drying kinetics of watermelon seeds are Approximation of Diffusion for temperatures of 40, 50 and 55 °C and Page for 55 and 60 °C.The highest drying rates are observed at the highest temperatures. The diffusion coefficients presented magnitude of 7.69684×10 -10 and 1.27585×10 -9 for the range from 40 to 60 °C, and the activation energy was 12.2641 kJ mol -1 .

Drying kinetics and mass transfer parameters of mung beans dried using a convective dryer

“…It can be considered an intermediate value, as the variation range is 12.7-110.0 kJ mol -1 for most food products (Zogzas et al, 1996). A lower activation energy corresponds to easy moisture removal from the material subjected to drying (Kosasih et al, 2020) because the activation energy is the energy barrier that must be overcome to start the mass diffusion from the wet material (Li et al, 2019;Xie et al, 2017), and variations are commonly found, as it can be influenced by the shape of the product, initial and final moisture content, chemical composition, structure, and the imposed drying conditions (Siqueira et al, 2020b).…”

Rapid and nondestructive watermelon (Citrullus lanatus) seed viability detection based on visible near‐infrared hyperspectral imaging technology and machine learning algorithms

“…Figure 5a shows that there were the effective wavelengths obtained from the Vis‐NIR range (463–1000 nm) that corresponds to the O–H, C–H (third overtone of resins and polysaccharides), and N–H stretching (third overtone of amino acids) (Ru et al., 2019). Currently, there are few studies on detecting seed compound substance contents to certain seed conditions (Albishri et al., 2013; Köçeroğlu et al., 2020; Siqueira et al., 2020). To test the watermelon seeds’ condition, this study used different methods to select useful information.…”

“…Therefore, watermelon seeds with unknown storage conditions might result in the waste of financial, and natural resources and a reduction of watermelon products (De Vitis et al., 2020; Jin et al., 2022). It is also possible that native seeds are not always ready for usage straight away after their harvesting season and frequently require a storage period before delivery to practitioners (Siqueira et al., 2020). Hence, it is of the essence to ascertain the viability of watermelon seeds’ status to prevent the loss of farmers in their agricultural sectors.…”

Estudo experimental e numérico do perfil de aquecimento de um forno solar aplicado à secagem

“…No entanto, a secagem de produtos agrícolas é uma operação que demanda um alto consumo energético e por isso a influência da temperatura, cinética e velocidade do ar de secagem vem sendo alvo de estudos nos últimos anos (Alves et al, 2014;Taşeri et al 2018;Santos et al, 2020a;Santos et al, 2020b;Siqueira et al, 2020;Almeida et al, 2020;Rigueto et al, 2020). Partindo disso, a aplicação de uma fonte energética alternativa pode contribuir para redução de custo operacionais relacionados a secagem.…”