Enhancing lactose crystallization in aqueous solutions by soluble soybean polysaccharide

- Soluble soybean polysaccharide (SSPS) enhanced lactose crystallization.
- The enhancement was more significant at low SSPS concentrations.
- The enhancement was more significant at seeded than unseeded conditions.
- SSPS enhanced lactose crystallization by facilitating nucleation.
- The structure and purity of lactose crystals were not affected by SSPS.

Increasing the crystallization rate without compromising purity is critical to lactose recovery from cheese whey. In this study, soluble soybean polysaccharide (SSPS), a low viscosity polysaccharide, was studied for the impact on lactose crystallization. SSPS was dissolved at 0-1.0% w/w in 40% w/w lactose solutions to study spontaneous and seeded (with 0.5% w/w lactose crystals) crystallization at 30 °C. The addition of SSPS enhanced the crystallization that was the most significant at 0.1% w/w SSPS, resulting from the facilitation of nucleation. Further addition of SSPS to 0.5% and 1.0% w/w increased sample viscosity and reduced the crystal growth and therefore yield. The purity and structure of lactose crystals were not affected by addition of SSPS, based on DSC, FTIR, and XRD. A high (54.7%) yield of lactose crystals in 24 h after adding 0.1% SSPS and 0.5% w/w seed showed the great potential of SSPS to facilitate lactose recovery.