Obtainment of High-Fructose Solutions from Cashew (Anacardium occidentale) Apple Juice by Simulated Moving-Bed Chromatography

The simulated moving-bed (SMB) technology has been successfully used in separations in the petrochemical, food, and fine chemicals industries. This work is intended to demonstrate the possibility of using this technology to obtain high-fructose solutions from the cashew apple juice, which may represent an attractive economic alternative for its industrial exploitation. The cashew tree is a native tropical plant abundant in Northeastern Brazil, the commercial value of which relies mainly on the processing of its nut. Despite the high nutritional value of the penduncle of the fruit, the cashew apple, approximately 90% of the crop spoils on the soil. Simulation and experimental results are presented for SMB separation of fructose from glucose, both present (˜40 kg/m³) in the aqueous phase of concentrated cashew apple juice. Kinetic and equilibrium data for fructose and glucose on packed columns using cation-exchange resins are reported. Experimental results for SMB operation at 30°C indicate purities close to 90% in each product (fructose-rich extract and glucose-rich raffinate). Simulated predictions of the unit performance and internal profiles agree well with experimental data. To increase the added value and versatility of the products, either an isomerization step for the raffinate or diverse SMB fluid–solid flow rate ratios may be applied. In this way, a wide range of products may be obtained, from nearly pure fructose to 42, 55, and 90% solutions, which are the standard high-fructose syrup concentrations. If solids content is conveniently raised to the standards of commercial high-fructose syrups, these products may be used as food additives, thus confirming a potentially attractive use of the cashew apple juice.

Keywords:

• Cashew juice
• Fructose
• Simulated moving bed

ACKNOWLEDGMENTS

Financial support from Capes (process 1140/96-5), Brazil, and project PRAXIS XXI/3/3.1/CEG/2644/95, Portugal, are gratefully acknowledged.