Objective:To determine the phase-transition temperature of white vaseline produced by different processes by differen-tial scanning calorimetry ( DSC) in order to analyze the relevance between the melting point and the phase-transition temperature and the relevance between different production processes and the phase-transition temperature. Methods: Hermertic aluminum pans were used to encapsulate the samples, and the testing conditions were optimized. The sample weight was about 10 mg, and the range of measuring temperature was -20-100℃. The heating rate was 5℃·min-1 and the flow rate of nitrogen was 30 ml·min-1 . Results:The phase-transition temperature and the melting point were significantly different. The phase-transition temperature of white vaseline samples produced by different processes was quite different. Conclusion:Melting point determination in the current standard method of white vaseline exists defects, and the composition of white vaseline produced by various processes is quite different.

OBJECTIVETo look for optimum extraction techniques for oleuropein by boiling olive leaves at low temperature and reduced pressure.

METHODAccording 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.

RESULTThe 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%.

CONCLUSIONCompared 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.

Iridoids ; Liquid-Liquid Extraction ; methods ; Olea ; chemistry ; Plant Leaves ; chemistry ; Pressure ; Pyrans ; chemistry ; Technology, Pharmaceutical ; methods ; Temperature