Microencapsulation of beta-carotene in pea protein wall system

Beta-carotene was microencapsulated in pea protein isolate wall system with and without maltodextrin using emulsification technology and spray drying. Effects of various factors including mass ratio of wall to core materials, and wall composition on microcapsule properties such as microstructure, particle size distribution, and moisture content, beta-carotene retention, and release time were determined. Uniform spherical microcapsules with smooth surfaces were observed from SEM image of the microcapsules. The average particle size ranged from 4.3 to 7.1 mum in radius determined by a computerized image analysis system. The half time of oxidation was extended 8 weeks. The wall to core ratio had significant effects (P < 0.05) on drying yield, particle size, moisture content, and beta-carotene retention during storage of pea protein based, beta-carotene containing microcapsules. The wall composition (with different levels of maltodextrin content in the wall system) had significant effects (P < 0.05) on particle size and beta-carotene retention during storage. The release of beta-carotene from swelling microcapsules could be controlled by altering the wall material with respect to the heat treatment of pea protein and to the composition of wall materials. The results confirmed that microencapsulation is an efficient method to preserve beta-carotene from oxidation. The results suggested that pea protein or pea protein combined with maltodextrin could be used as good microencapsulating agents for food ingredients, nutraceuticals, and pharmaceuticals.