EFFECT OF SURFACTANTS ON KINETICS OF DEXTROSE CRYSTALLIZATION

Dextrose (glucose) is a very important food and a medicinal product not produced in Russia. The aim of this investigation is to intensify crystallization of dextrose and its further production for import substitution. Dextrose production technology is characterized by complicacy and durability of crystallization. The stage of crystal nucleation is poorly studied, while common methods to accelerate nucleation and crystal growth have some drawbacks leading to lower dextrose quality and equipment capacity. The experiments to determine the influence of aliphatic alcohols on surface tension of dextrose solutions, nucleation and crystal growth have been carried out. Added surfactants (propanol, butanol, isobutanol, isopropanol) decrease surface tension of dextrose solutions in 2.5 times. For pure dextrose solutions the induction period of nucleation is 210 min but added propanol decreases this period up to 120 min. The induction period is 15-20 min when 0.01% of crystal seeds are addles. The induction period of nucleation is not observed when crystal seeds are added together with propanol. Acceleration of crystallization under the influence of alcohol is observed at the stage of crystal growth as the evidence of a more profound depletion of dextrose solution to DS 60.2-60.3% and a high content of crystal of 11.64-11.88% at the end of crystallization. Crystal size and shape of anhydrous and hydrated dextrose remain stable in the medium of absolute alcohols throughout 12 months of storage. The obtained results are important for the theory and practice of dextrose production as they make it possible to accelerate dextrose crystallization and develop new types of crystal seeds having long storage life.