On the production of glucose and fructose syrups from cashew apple juice derivatives

Abstract

a b s t r a c tThe cashew crop is an important agro-economic activity in many equatorial areas, although less than 10% of the cashew apple production is exploited industrially. This work focuses on two aspects: obtaining food-grade syrups from cashew apple juice and studying fixed bed adsorption dynamics to separate fructose from glucose. Syrups obtained by concentrating clarified cashew apple juice under vacuum showed similar characteristics to a reference food-grade syrup, with a higher content in fructose, which may contribute to a higher sweetening power with less caloric intake. Adsorption equilibrium studies were performed with synthetic solutions of fructose and glucose by frontal analysis under the concentration range found in the syrups (10-120 g/L) at 30, 40 and 60°C, using the cation exchange resin Dowex MTO 99Ca. Fructose was more strongly adsorbed than glucose, with measured selectivities ranging from 1.50 to 2.25. Resistance to mass transfer was significant and thought to be due to resin crosslinkage. Glucose and fructose breakthrough curves using cashew apple syrup as feed were practically identical to those measured with synthetic solutions, which leads us to believe that high-fructose syrups may be readily obtained by using current continuous chromatographic units, such as SMB.

Competitive effect of glucose–fructose adsorption in a fixed‐bed chromatographic column

“…The straight line was observed and the slope representing the ratio of axial dispersion and fluid interstitial velocity, or the inverse of Péclet number, is shown in Table . The value of D ax / v L was less than 0.01, confirming the small extent of dispersion and hence the plug flow pattern . The determined Péclet number was then used in the simulation of breakthrough curve profiles of glucose and fructose.…”

“…The linear isotherm model and the Langmuir isotherm model generally used for the adsorption of a solute in liquid solution , were tested to determine the best fit of the experimental data. The mathematical models are expressed in Eqs.…”

“…A dispersed plug flow model and linear driving force (LDF) model, both in the dimensionless forms of time and axial coordinate, were used to demonstrate the dynamic behavior of both fluid and stationary phases in a single chromatographic column [4,[19][20][21][22][23][24][25]. These models assumed: (i) isothermal operation, (ii) convection and axial dispersion, (iii) constant fluid properties and flow rate, (iv) instantaneous equilibrium at the external surface of the adsorbent particles, and (v) negligible external film resistance.…”

Kinetics and equilibria of the chromatographic separation of maltose and trehalose

“…Moreover, the resin had a higher affinity for trehalose than for maltose. According to Ramos , the higher affinity for trehalose can be calculated by the following equation: …”

Chromatographic Separation of Isomaltooligosaccharides on Ion-Exchange Resins: Effect of the Cationic Form

“…The key to the design and optimization of SMB units relies on the accurate determination of adsorption isotherms of the components of the mixture to be separated on the stationary phase packing the columns. For linear adsorption equilibrium, which is generally the case of saccharides on ion-exchange resins, fundamental equilibrium and mass transport experiments are usually conducted in SMB individual preparative columns by applying concentration steps or injecting pulses of either a tracer or the adsorbates of the mixture (Azevedo and Rodrigues 2006;Ramos et al 2011;Chilamkurthi et al 2012).…”