title: [Boiling extraction of oleuropein at low temperature and reduced pressure].
abstract: OBJECTIVE
  To look for optimum extraction techniques for oleuropein by boiling olive leaves at low temperature and reduced pressure.
  
  
  METHODS
  According to single factor experiment (SFE) design, the effects of seven factors, the impact of seven factors, type of solvent, temperature, time, ratio of material to liquid, ethanol concentration, vacuum degree and extraction times, on extraction yield of oleuropein were investigated. Based on the results of SFE, four more important factors, temperature, time, ratio of material to liquid and ethanol concentration, were selected in L9 (3(4)) orthogonal experiment (OE) to compare with those extracted with traditional methods.
  
  
  RESULTS
  The optimum conditions for boiling extraction of oleuropein at low temperature and reduced pressure were as follows: temperature 60 degrees C, time 20 min, ratio of material to liquid 1:30 and ethanol concentration 85%. The conditions presented an extraction yield of 5.90%.
  
  
  CONCLUSIONS
  Compared with traditional extraction methods and the ultrasound assisted extraction method, boiling extraction techniques at low temperature and reduced pressure were so quick and efficient that it has a good application prospect.
authors.affiliation: Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, National Engineering Laboratory for Biomass Chemical Utilization, Key and Open Laboratory on Forest Chemical Engineering, State Forestry Administration, Key Laboratory of Biomass Energy and Material, Jiangsu Province, Nanjing 210042, China. xpjdzh@163.com
authors.forename: Pujun
authors.initials: P
authors.lastname: Xie
authors.forename: Lixin
authors.initials: L
authors.lastname: Huang
authors.forename: Caihong
authors.initials: C
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: You
authors.forename: Chengzhang
authors.initials: C
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
mesh_terms: D057888:Iridoid Glucosides; D039823:Iridoids; D059625:Liquid-Liquid Extraction / Q000379:methods; D031658:Olea / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D011312:Pressure; D011714:Pyrans / Q000737:chemistry*; D013678:Technology, Pharmaceutical / Q000379:methods*; D013696:Temperature
chemical_list: D057888:Iridoid Glucosides; D039823:Iridoids; D011714:Pyrans; C002769:oleuropein