A simple model of the diffusion phenomena taking place during the debittering process of green table olives

Abstract

RESUMENUn modelo simple del fenómeno de difusión que tiene lugar durante el proceso de desamarizado de aceitunas verdes de mesa.Se ha cuantificado el cambio en la concentración de sodio y calcio en la pulpa y en la lejía durante el tratamiento alcalino de aceitunas. La concentración promedio de sodio en la pulpa aumentó de 0,0045 a 0,395 meq Na/g mientras que la de calcio creció de 0,018 a 0,0252 meq Ca/g. La textura de las aceitunas disminuyó casi linealmente de 375 gf a 235 gf durante el tratamiento alcalino. Las aceitunas sufrieron una perdida de azúcares reductores del 25.9%. Se ha propuesto una hipotética y simplificada descripción de la dinámica de los cambios de carga iónica y el desenrrollamiento de las pectinas durante el desamarizado de las aceitunas. También se calculó el coeficiente efectivo de difusión para sodio y calcio usando un modelo de difusión para una placa compuesta. Los coeficientes resultaron en el orden de 10 -12 m 2 /s para la piel y 10 -10 m 2 /s para pulpa. En ambos casos el coeficiente de difusión de Na fue mayor que el de Ca. PALABRAS CLAVE: Calcio -Carga iónica -Difusión -Sodio -Tratamiento alcalino de aceitunas verdes. SUMMARYA simple model of the diffusion phenomena taking place during the debittering process of green table olives.The change in the concentration of sodium and calcium ions in the olive flesh and in the lye during the debittering process was quantified. The average concentration of Na increased from 0.0045 to 0,395 meq Na/g of olive flesh and the concentration of Ca increased from 0.018 to 0.0252 meq Ca/g of olive flesh. The firmness of the olives decreased almost linearly from 375 gf to 235 gf during the alkali treatment. The olives also suffered a 25.9% loss in their initial content of reducing sugars. A hypothetical simplified description of the dynamic of ionic charge changes and unwinding of the pectinic structure during the debittering process of green olives has been proposed. In addition, the A simple model of the diffusion phenomena taking place during the debittering process of green /s for the flesh. In both cases, the diffusion coefficients of Na were larger than the diffusion coefficients of Ca.

Mathematical modelling of mass transfer phenomena for sucrose and lactitol molecules during osmotic dehydration of cherries

“…This could be due to the resistance and barrier to diffusion of sucrose and lactitol molecules offered by the skin of cherries. A similar finding was described by Maldonado et al [26,27,31] where the difference in diffusivity could be due to a more impermeable structure in fruit skin (natural barrier) against the diffusion of compounds.…”

“…This characteristic of the epidermis, in addition the cuticle layer, which covers fruits such as cherries and others, present a barrier effect to the diffusion of substances through it and is different from the diffusion in the mesocarp. Maldonado et al [31] and Zuritz and Maldonado [25] found this when studying sodium diffusivity in olives.…”

“…On the other hand, it can be observed that if the effective diffusion values of Table 1 are compared, the conclusion is reached that the water coefficients in skin and flesh are 2 order of magnitude greater than the coefficients, in skin and flesh of cherries, for soluble solids [31].…”

“…In addition, water loss, sucrose gain, glucose and fructose concentration at different conditions, during osmotic dehydration of pineapple slices was analysed [30]. Whilst, changes in ionic movement for sodium and calcium in olives, through calculation of diffusion coefficients, was quantified [31].…”

Ultrasound-accelerated debittering of olive fruits

“…Permeation of NaOH is a function of the treatment conditions such as lye concentration and temperature, along with olive variety and maturity (Maldonado et al, 2011). UAD increased penetration rate of sodium hydroxide solution in comparison with CD, significantly (Fig.…”