Influence of glycation on microencapsulating properties of soy protein isolate-lactose blends.

ABSTRACT

BACKGROUND: There is increasing interest in developing encapsulating materials from vegetable proteins as an abundant alternative for animal proteins or petroleum-derived polymers. Relationships between emulsifying and microencapsulating properties of soy protein isolate or blends with carbohydrates have not been well characterised. The influence of glycation between soy protein isolate and lactose prior to emulsification on the emulsifying and microencapsulation properties of their blends was investigated in this work. RESULTS: Analysis of the emulsion characteristics indicated that the glycation resulted in a decreased size of emulsion droplets, enhanced emulsion stability, and decreased apparent viscosity, suggesting improvement of emulsifying properties. In the spray-dried emulsions, the treatment with increasing degree of glycation from 0 to 13% progressively increased the retention efficiency from 96.4 to 98.3%. The glycation with an appropriate degree of glycation significantly decreased mean droplet size of the reconstituted emulsions, and increased the dissolution rate and capacity. However, the storage stability of the powders at 75% relative humidity was decreased by the glycation, though to a limited extent. CONCLUSION: Glycation improves the encapsulation efficiency, redispersion and dissolution properties of soy protein isolate-lactose blends, but slightly accelerated the storage instability of the spray-dried emulsions. The improvement of microencapsulation properties has been related to that of the emulsifying properties.