Microencapsulation of Water-Soluble Isoflavone and Physico-Chemical Property in Milk

This study was carried out to investigate the addition of water-soluble isoflavone into milk by means of microencapsulation technique. The yield of microencapsulation, sensory attributes, and capsule stability of water-soluble isoflavone microcapsules in milk were measured. Coating materials used was polyglycerol monostearate (PGMS), and core material was water-soluble isoflavone. The encapsulation yield of water-soluble isoflavone with PGMS was 67.2% when the ratio of coating material to core material was 15 : 1. The rate of water-soluble isoflavone release from capsules was 18, 19, and 25% when stored at 4,20, and $30^{\circ}C$ for 12 days in milk, respectively. In sensory evaluation, beany flavor and color of microencapsuled water-soluble isoflavone added milk were significantly different from uncapsuled water-soluble isoflavone added milk, however, bitterness was not significantly different. In vitro study, micro-capsules of water-soluble isoflavone in simulated gastric fluid with the range of 3 to 6 pHs were released 3.0∼15.0%, however, the capsules in simulated intestinal fluid with pH 7 were released 95.7% for 40 min incubation time. In conclusion, this study provided that PGMS as coating materials was suitable for the microencapsulation of water-soluble isoflavone, and the capsule containing milk was almost not affected with sensory attribute.