title: Preparation of monodisperse aqueous microspheres containing high concentration of l-ascorbic acid by microchannel emulsification.
abstract: Monodisperse aqueous microspheres containing high concentrations of l-ascorbic acid with different concentrations of sodium alginate (Na-ALG) and magnesium sulfate (MgSO4) were prepared by using microchannel emulsification (MCE). The continuous phase was water-saturated decane containing a 5% (w/w) hydrophobic emulsifier. The flow rate of the continuous phase was maintained at 10 mL h(-1), whereas the pressure applied to the disperse phase was varied between 3 and 25 kPa. The disperse phase optimized for successfully generating aqueous microspheres included 2% (w/w) Na-ALG and 1% (w/w) MgSO4. At a higher MgSO4 concentration, the generated microspheres resulted in coalescence and subsequent bursting. At a lower MgSO4 concentration, unstable and polydisperse microspheres were obtained. The aqueous microspheres generated from the MCs under optimized conditions had a mean particle diameter (dav) of 14-16 µm and a coefficient of variation (CV) of less than 8% at the disperse phase pressures of 5-15 kPa.
authors.affiliation: a Food Engineering Division, National Food Research Institute , Ibaraki , Japan .
authors.forename: Nauman
authors.initials: N
authors.lastname: Khalid
authors.forename: Isao
authors.initials: I
authors.lastname: Kobayashi
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Neves
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Uemura
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Nakajima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nabetani
mesh_terms: D000464:Alginates / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods; D045703:Emulsifying Agents; D004655:Emulsions / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions; D008278:Magnesium Sulfate / Q000737:chemistry; D008863:Microspheres; D009997:Osmotic Pressure; D010316:Particle Size; D011312:Pressure; D012964:Sodium / Q000737:chemistry; D014783:Viscosity; D014867:Water / Q000737:chemistry*
chemical_list: D000464:Alginates; D045703:Emulsifying Agents; D004655:Emulsions; D006603:Hexuronic Acids; D007477:Ions; D014867:Water; D008278:Magnesium Sulfate; D020723:Glucuronic Acid; D012964:Sodium; D001205:Ascorbic Acid
keywords: l-Ascorbic acid; magnesium sulfate; microchannel emulsification; microencapsulation; monodispersity; sodium alginate