ORIGINAL PAPER Mass Transfer Modeling During Osmotic Dehydration of Hexahedral Pineapple Slices in Limited Volume Solutions I. I. Ruiz-López & R. I. Castillo-Zamudio & M. A. Salgado-Cervantes & G. C. Rodríguez-Jimenes & M. A. García-Alvarado Received: 23 January 2008 / Accepted: 30 May 2008 / Published online: 26 June 2008 # Springer Science + Business Media, LLC 2008 Abstract The study of mass transfer during osmotic dehydration process in limited volume solutions was carried out to evaluate the diffusion coefficients of sucrose and water in the osmotic treatment of hexahedral pineapple slices. The experimental osmotic dehydration kinetics for pineapple slices of two different sizes were conducted at 25 °C using a 1:1 solution to fruit weight ratio. The analytical solution of a 3D mass transfer model considering a limited volume of osmotic solution (i.e., an osmotic media of variable solute concentration) was used for describing the mass transfer in osmotic dehydration of pineapple slices. This model was fitted to the experimental kinetics by means of nonlinear regression to obtain the diffusion coefficients. Additionally, the diffusion coeffi- cients were evaluated considering an infinite volume of osmotic solution (i.e., an osmotic media of constant solute concentration). Results showed that the proposed model may be fitted accurately to the experimental osmotic dehydration kinetics and allows the estimation of diffusion coefficients when solute concentration in the osmotic media varies along the process. Keywords Diffusion . Mass transfer . Modeling . Osmotic dehydration Introduction Osmotic dehydration is a mass transfer process where water is partially removed from foods, mainly fruits and vegeta- bles, by soaking them in hypertonic solutions. The driving force for the water diffusion into solution is the difference between osmotic pressures of the hypertonic solution and the food. As the cell wall acts as a semi-permeable membrane, the water loss is accompanied by the simulta- neous counter diffusion of solutes from the solution into the product. Additionally, it has been reported that osmotic dehydration helps to prevent some undesirable quality changes on foods: promotes stabilization of color by reducing non-enzymatic browning reactions (Moreno- Castillo et al. 2005; Pereira et al. 2006) and improves the texture and flavor of the food (Bidaisee and Badrie 2001). Therefore, a good understanding of the osmotic dehydration kinetics is required to set the desired dehydration or impregnation levels during the process (Shi and Le Maguer 2002). With the purpose of describing the mass transfer phenomena during the osmotic dehydration of foodstuffs, many authors have used either empirical or mechanistic models. Empirical models include the Weibull probabilis- tic model (Cunha et al. 2001), power models (Alakali et al. 2006), and exponential power models (Moreno-Castillo et al. 2005). Nevertheless, even when the empirical models may describe satisfactorily the experimental Food Bioprocess Technol (2010) 3:427–433 DOI 10.1007/s11947-008-0102-x I. I. Ruiz-López (*) Chemical and Biochemical Engineering Department, Instituto Tecnológico de Tuxtepec, Av. Dr. Víctor Bravo Ahuja S/N, 68350 Tuxtepec, Oaxaca, México e-mail: irvingisrael@hotmail.com R. I. Castillo-Zamudio Colegio de Postgraduados, Campus Veracruz, Km. 88.5 Carretera Federal Xalapa-Veracruz, 91700 Veracruz, Veracruz, México M. A. Salgado-Cervantes : G. C. Rodríguez-Jimenes : M. A. García-Alvarado Chemical and Biochemical Engineering Department, Instituto Tecnológico de Veracruz, Av. Miguel Ángel de Quevedo 2779, 91897 Veracruz, Veracruz, México