Preparation and Characterization of Water/Oil/Water Emulsions Stabilized by Polyglycerol Polyricinoleate and Whey Protein Isolate |
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Authors: | Saehun Mun Yongdoo Choi Shin-Joung Rho Choon-Gil Kang Chan-Ho Park Yong-Ro Kim |
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Affiliation: | Authors Mun, Rho, and Kim are with Center for Agricultural Biomaterials and Dept. of Biosystems and Biomaterials Science and Engineering, Seoul Natl. Univ., Seoul, 151-742, Korea. Author Choi is with Molecular Imaging and Therapy Branch, Natl. Cancer Center, Goyang-si, 410-769, Korea. Authors Kang and Park are with Ottogi Research Center, Anyang, Korea. Direct inquiries to author Kim (E-mail: yongro@snu.ac.kr). |
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Abstract: | ABSTRACT: In this study we tried to prepare stable water-in-oil-in-water (W/O/W) emulsions using polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier and whey protein isolate (WPI) as a hydrophilic emulsifier. At first, water-in-oil (W/O) emulsions was prepared, and then 40 wt% of this W/O emulsion was homogenized with 60 wt% aqueous solution of different WPI contents (2, 4, and 6 wt% WPI) using a high-pressure homogenizer (14 and 22 MPa) to produce W/O/W emulsions. The mean size of final W/O/W droplets ranged from 3.3 to 9.9 μm in diameter depending on the concentrations of PGPR and WPI. It was shown that most of the W/O/W droplets were small (<5 μm) in size but a small population of large oil droplets (d > 20 μm) was also occasionally observed. W/O/W emulsions prepared at the homogenization pressure of 22 MPa had a larger mean droplet size than that prepared at 14 MPa, and showed a microstructure consisting of mainly approximately 6 to 7-μm droplets. When a water-soluble dye PTSA as a model ingredient was loaded in the inner water phase, all W/O/W emulsions showed a high encapsulation efficiency of the dye (>90%) in the inner water phase. Even after 2 wk of storage, >90% of the encapsulated dye still remained in the inner water phase; however, severe droplet aggregation was observed at relatively high PGPR and WPI concentrations. |
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Keywords: | PGPR stabilization W/O emulsion W/O/W emulsion WPI |
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