Physical-chemical characterization of yellow mombin (Spondias mombin L.) foam-mat drying at different temperatures

The objective of this work was to perform foam-mat drying of yellow mombin pulp, verifying the kinetics and mathematical modeling of the process, and characterizing the obtained product with respect to physical and chemical characteristics, compared with the fresh pulp. Foam-mat drying was carried out with the aid of the foam agent Emustab®, at temperatures of 50, 60, 70 and 80 °C. The drying data were analyzed and fitted to four mathematical models (Wang & Singh, Verma, Page and Midilli). Effective diffusion coefficient and activation energy were determined. Titratable acidity, pH, soluble solids content and vitamin C content, as well as the solubility in water of yellow mombin powder and color variance (L*, a*, b*) were analyzed in both fresh and dehydrated pulp. The Wang & Singh model showed best fit at the temperature of 50 °C, whereas the Midilli model showed the best mathematical fit at temperatures of 60, 70 and 80 °C. Net diffusion coefficient and activation energy values were proportional to the drying temperature. Drying of the foam at 60 °C indicated guarantee of quality of yellow mombin pulp with respect to titratable acidity, pH and color of the a* coordinate.Objetivou-se realizar a secagem da polpa dos frutos de cajá em camada de espuma, verificando a cinética e modelagem matemática do processo, e caracterizar o produto obtido quanto às características físicas e químicas, sendo estas comparadas à polpa in natura. A secagem foi realizada em camada de espuma, com auxílio do agente espumante emustab, nas temperaturas de 50, 60, 70 e 80 °C. Os dados da secagem foram analisados e ajustados por quatro modelos matemáticos (Wang e Singh, Verma, Page e Midilli). Foram determinados o coeficiente de difusão efetiva e energia de ativação. Na polpa in natura e desidratada foram analisados o teor de acidez titulável, pH, teor de sólidos solúveis e teor de vitamina C, assim como a solubilidade em água do pó de cajá e análise de variância da cor (coordenadas de L*, a* e b*). O modelo Wang e Singh indicou melhor ajuste para a temperatura de 50 °C e o modelo de Midilli demonstrou o melhor ajuste matemático para as temperaturas de 60, 70 e 80 °C. Os valores do coeficiente de difusão líquida e energia de ativação foram proporcionais à temperatura de secagem. A secagem da espuma a 60 °C indicou garantia da qualidade da polpa do cajá para acidez titulável, pH e coloração da coordenada de a*

Physical-chemical characterization of yellow mombin (Spondias mombin L.) foam-mat drying at different temperatures

ABSTRACT The objective of this work was to perform foam-mat drying of yellow mombin pulp, verifying the kinetics and mathematical modeling of the process, and characterizing the obtained product with respect to physical and chemical characteristics, compared with the fresh pulp. Foam-mat drying was carried out with the aid of the foam agent Emustab®, at temperatures of 50, 60, 70 and 80 °C. The drying data were analyzed and fitted to four mathematical models (Wang & Singh, Verma, Page and Midilli). Effective diffusion coefficient and activation energy were determined. Titratable acidity, pH, soluble solids content and vitamin C content, as well as the solubility in water of yellow mombin powder and color variance (L*, a*, b*) were analyzed in both fresh and dehydrated pulp. The Wang & Singh model showed best fit at the temperature of 50 °C, whereas the Midilli model showed the best mathematical fit at temperatures of 60, 70 and 80 °C. Net diffusion coefficient and activation energy values were proportional to the drying temperature. Drying of the foam at 60 °C indicated guarantee of quality of yellow mombin pulp with respect to titratable acidity, pH and color of the a* coordinate

Isotherms and isostatic heat of foam-mat dried yellow mombin pulp

ABSTRACT Yellow mombin has high nutritional value but is very perishable. Foam mat drying is a method that has been widely used to preserve liquid and semi-solid powdered foods. In this context, the aim of this study was to determine desorption isotherms and isosteric heat of yellow mombin (Spondias mombin L.) foam for different conditions of temperature and water activity. Powdered yellow mombin pulp was obtained by drying in forced-air oven regulated to 60 ° C. The indirect static method was used to determine the isotherms and isosteric heat, whereas water activity (aw) was determined using the Hygropalm-HP23AW-A analyzer. A B.O.D. incubator, set at 10, 20, 30 and 40 °C, was used to control the temperature, and the water activity for each temperature was between 0.220 and 0.832. The experimental data were fitted to mathematical models frequently used to represent the hygroscopicity of agricultural products, and the best model was the Modified Halsey. Integral isosteric heat of desorption of yellow mombin powder, within the water content range of 17.22 to 57.58 (% d.b.), ranged from 3198.56 to 2598.38 kJ kg-1. It was concluded that the equilibrium water content of yellow mombin pulp powder increased with the increment in water activity; desorption isotherms obtained for yellow mombin pulp powder showed sigmoid form and, with the reduction of water content, the isosteric heat increases