title: [Study on the encapsulation technique of high purity gamma-linolenic acid, part 1--Single factor, and two-factor tests for encapsulation process].
abstract: OBJECTIVE
  To study the effects of all factors during the process of urea encapsulation of gamma-linolenic acid on the purity and yield.
  
  
  METHODS
  To observe the material proportions, time, temperature and purity using single-factor and two-factor tests.
  
  
  RESULTS
  Single-factor test showed that the optimal ratio of all materials (oil, urea and 95% ethanol) was 1:3:8. A 30% purity after single encapsulation process was obtained, at the best temperature range was - 15 degrees C-20 degrees C, for 24 hours. Two-factor test showed that the optimal ratio of oil, urea and ethanol was 1:3:8, where the concentration of ethanol was 90%-95%. The purity reached 90% or higher, with three-time encapsulation process.
  
  
  CONCLUSIONS
  An optimized process was identified where material ratios, encapsulation time, temperature, and ethanol concentrations were determined using single-factor and two-factor tests.
authors.affiliation: Central China University of Science & Technology, Wuhan 430074, China.
authors.forename: Feng-Xia
authors.initials: FX
authors.lastname: Liu
authors.forename: Gang
authors.initials: G
authors.lastname: Xue
authors.forename: Qiu-Hua
authors.initials: QH
authors.lastname: Gao
authors.forename: Wei-Xia
authors.initials: WX
authors.lastname: Gao
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Zhang
mesh_terms: D000431:Ethanol; D005228:Fatty Acids, Essential / Q000737:chemistry / Q000302:isolation & purification; D008041:Linoleic Acids; D031664:Oenothera / Q000737:chemistry; D031665:Oenothera biennis; D010938:Plant Oils; D010946:Plants, Medicinal / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods; D013696:Temperature; D014508:Urea; D017965:gamma-Linolenic Acid / Q000008:administration & dosage* / Q000302:isolation & purification
chemical_list: D005228:Fatty Acids, Essential; D008041:Linoleic Acids; D010938:Plant Oils; D000431:Ethanol; C028498:evening primrose oil; D017965:gamma-Linolenic Acid; D014508:Urea