title: [Study on the encapsulation technique of high purity gamma-linolenic acid, part 1--saponification reaction and saponification value].
abstract: OBJECTIVE
  To measure the saponification value and fatty acid formation of evening primrose oil, to study the effects of pH value on production yield and fatty acid formation during the saponification reaction, and to provide rationales for the selection of raw material, the enhancement of production yield of saponification, and the encapsulation of gamma-linolenic acid with urea.
  
  
  METHODS
  To measure fatty acid's formation with gas chromatographic method and to measure the saponification value.
  
  
  RESULTS
  The content of gamma-linolenic acid is 7%-10% in evening primrose oil. The content of gamma-linolenic acid is inversely correlated with that of unsaturated fatty acid. The saponification value, the amount of KOH for saponification of evening primrose oil, and the pH value for subsequent isolations of oils are determined. From the measurement of fatty acids of evening primrose oil in two different cultivation locations, the content of gamma-linolenic acid is determined to be 7%-10%, unsaturated oils account for 90%.
  
  
  CONCLUSIONS
  The saponification value of evening primrose oil is between 180-200, pH value of isolated oil is 1.5-2.0 after saponification reaction. Fatty acids mainly include palmitic acid, stearic acid, oleic acid, linolic acid and gamma-linolenic acid.
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: D005228:Fatty Acids, Essential / Q000737:chemistry* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D008041:Linoleic Acids; D031665:Oenothera biennis / Q000737:chemistry*; D019301:Oleic Acid / Q000032:analysis; D019308:Palmitic Acid / Q000032:analysis; D010938:Plant Oils / Q000737:chemistry / Q000302:isolation & purification; D010946:Plants, Medicinal / Q000737:chemistry; D012639:Seeds / Q000737:chemistry; D013229:Stearic Acids / Q000032:analysis; D013678:Technology, Pharmaceutical / Q000379:methods*; D014508:Urea; D017965:gamma-Linolenic Acid / Q000032:analysis*
chemical_list: D005228:Fatty Acids, Essential; D008041:Linoleic Acids; D010938:Plant Oils; D013229:Stearic Acids; D019301:Oleic Acid; D019308:Palmitic Acid; C028498:evening primrose oil; C031183:stearic acid; D017965:gamma-Linolenic Acid; D014508:Urea