Abstract: Water-soluble vitamin B complex microcapsules were prepared by spray-drying technique using gelatin as wall material and a mixture of thiamine hydrochloride (vitamin B1), riboflavin (vitamin B2), pyridoxine hydrochloride (vitamin B6), folic acid and nicotinamide as core material. The effects of technological parameters including wall material/core material mass ratio, inlet temperature, and feeding rate on microencapsulation efficiency and microcapsule yield were investigated using an orthogonal array design. The microencapsulation efficiency was determined by fluorospectrophotometry. Characteristics microcapsule shape and granule size distribution) of microencapsulated vitamins B were evaluated by scanning electron microscopy (SEM) and laser particle size analyzer. The results showed that the most significant factor affecting microencapsulation efficiency was wall material/core material mass ratio, followed by inlet temperature and feeding rate. Microcapsule yield was significantly by inlet temperature and little affected by feeding rate and wall material/core material mass ratio. The optimal microencapsulation conditions were obtained as follows: wall material/core material mass ratio 10:1, inlet temperature 170 ℃, and feeding rate 3 mL/min. SEM observations showed that few microcapsules were approximately spherical, and the outer surfaces of most microcapsules had some dents. The mean diameter of microcapsules was 8.93 μm.

Key words: microcapsule, vitamin B complex, spray-drying, gelatin, preparation