Efeito da temperatura sobre a cinética de secagem e a cor do tomate italiano

Abstract

This study evaluated the influence of temperature on drying kinetics and color of Italian tomato of sliced and cut into quarters using different dehydration strategies based on laboratory-convective dried and convective oven drier. The mathematical modeling of drying curves and the effective diffusivity were evaluated. It was verified that tomatoes dried in the laboratory-scale drier presented lower drying time. In addition, the drying time of sliced tomatoes were lower than the cut ones. The proposed drying model presented a satisfactory fitting of the experimental data, showing that the use of global kinetic models presents an alternative to predict the drying profiles at different temperature. It was verified that Deff for tomatoes dried in convective laboratory-scale drier were higher than for oven convective drier, in both cuts. The drying time has strong influence in darkening of the sample and it was verified a tendency in increase the red saturation index with the temperature. The best product quality was obtained using convective laboratory-scale drier at lower drying times. The tomato cut in four parts showed characteristics of final product similar to those sliced tomatoes. However, the slices tomato dried at temperature of 60 °C showed less drying time.Keywords: laboratory-scale drier; oven drier; effective diffusivity; color parameters. resumo Este estudo avaliou a influência da temperatura na cinética de secagem e na cor de tomate italiano cortados em fatias e em quarto partes usando diferentes estratégias de desidratação usando secador convectivo em escala piloto e estufa com circulação de ar. A modelagem matemática das curvas de secagem e da difusividade efetiva foram avaliadas. Foi verificado que os tomates secos em secador em escala de laboratório apresentaram um menor tempo de secagem. Além disso, o tempo de secagem dos tomates cortados em fatias foi inferior ao daqueles cortados em partes. O modelo de secagem proposto apresentou um ajuste satisfatório dos dados experimentais mostrando que o uso do modelo de cinética global apresenta uma alternativa para predizer perfis de secagem em diferentes temperaturas. Foi verificado que os valores de difusividade efetiva dos tomates secos em secador em escala de laboratório foram superiores aos daqueles secos em estufa convectiva em ambos os cortes. O tempo de secagem apresentou grande influência no escurecimento das amostras e foi verificado uma tendência ao aumento do índice de saturação vermelho com a temperatura. A secagem no secador em escala laboratorial apresentou melhor qualidade do produto final e menores tempos de secagem. Os tomates cortados em quatro partes apresentaram características semelhantes aos cortados em fatias. Todavia, os tomates cortados em quatro partes secos a 60 °C foram secos em menores tempos.Palavras-chave: secador em escala laboratorial ; estufa; difusividade efetiva; parâmetros de cor. BBR -Biochemistry and Biotechnology Reports

Effect of drying temperature on the physicochemical characteristics, bioactive compounds, and antioxidant activity of “Palmer” mango peels

“…The results show that the increase in temperature reduced the drying time, increasing the rate of water loss mainly at the beginning of the process. The significant effect of temperature on the drying curves is noticeable, where drying time showed a decreasing behavior with increasing air temperature, an expected effect, also observed by several researchers for numerous agro‐industrial products such as tomato, pineapple, oiti pulp, and prickly pear pulp (Durigon, Mazutti, Mossi, & Treichel, 2013; Machado, Souza, Junqueira, Saraiva, & Teixeira, 2012; Madureira, Figueirêdo, Queiroz, & Silva Filho, 2011; Sousa et al, 2011).…”

“…In a study conducted with Cucumis metuliferus peels, adjusting mathematical models to the experimental data of drying kinetics, the Page model showed satisfactory fit(Barros et al, 2020).The results show that the increase in temperature reduced the drying time, increasing the rate of water loss mainly at the beginning of the process. The significant effect of temperature on the drying curves is noticeable, where drying time showed a decreasing behavior with increasing air temperature, an expected effect, also observed by several researchers for numerous agro-industrial products such as tomato, pineapple, oiti pulp, and prickly pear pulp(Durigon, Mazutti, Mossi, & Treichel, 2013;Machado, Souza, Junqueira, Saraiva, & Teixeira, 2012;Madureira, Figueirêdo, Queiroz, & Silva Filho, 2011;Sousa et al, 2011).Both temperature and air speed influence the drying process, accelerating, or delaying it. Nunes, de Castro, dos Santos Moreira, deSousa, and da Silva (2014), studying the drying kinetics of jaboticaba pulp in a tray dryer with temperature ranging from 50, 60, and 70 C, concluded that in the convective drying of jaboticaba pulp the higher the temperature, the shorter the drying time, justified by the higher drying rate.It was verified that the drying time varied significantly, from 390 to 90 min, for temperatures of 40 and 80 C, respectively.…”