Preparation and characterization of water/oil/water emulsions stabilized by polyglycerol polyricinoleate and whey protein isolate.
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 microm in diameter depending on the concentrations of PGPR and WPI. It was shown that most of the W/O/W droplets were small (<5 microm) in size but a small population of large oil droplets (d > 20 microm) 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-microm 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.
Mun
Saehun
S
Center for Agricultural Biomaterials and Dept. of Biosystems and Biomaterials Science and Engineering, Seoul Natl. Univ., Seoul 151-742, Korea.
Choi
Yongdoo
Y
Rho
Shin-Joung
SJ
Kang
Choon-Gil
CG
Park
Chan-Ho
CH
Kim
Yong-Ro
YR
D002368:Castor Oil / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004655:Emulsions / Q000737:chemistry*; D005990:Glycerol / Q000031:analogs & derivatives* / Q000737:chemistry; D008894:Milk Proteins / Q000737:chemistry*; D012277:Ricinoleic Acids / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D000067816:Whey Proteins
D004655:Emulsions; D008894:Milk Proteins; D012277:Ricinoleic Acids; D000067816:Whey Proteins; C029243:glyceran polyricinoleic acid ester; D014867:Water; D002368:Castor Oil; D005990:Glycerol