No abstract

Microencapsulation of hydrophobie (oc-tocopherol) and hydrophilic (ascorbic acid) vitamins by native (non-modified) and modified soy protein isolate (SPI) was carried out using a spray-drying technique. Proteins' functional properties were modified by acylation and cationization reactions in aqueous alkaline media. The results obtained demonstrated that SPI modification resulted in decreased emulsion droplet size and viscosity. Ali preparations with ascorbic acid (M) had lower viscosity and microparticle size than those with oc-tocopherol (T). Moreover, grafting of fatty acid chains ta SPI by acylation improved its amphiphilic character and affinity with hydrophobie substances. Thus, the microencapsulation effi ciency of T was increased from 79.7% ta 94.8% and the microencapsulation efficiency of M was reduced from 91.8% ta 57.3% compared ta native SPI. Conversely, attachment of quaternary ammonium cationic groups ta proteinic chains by cationization, increased SPI solubility and favored the M microencapsu lation. This study illustrated that an appropriate modification of SPI can improve the microencapsulation efficiency of suitable active cores.