Study On The Degradation And Control Of Barbaloin In The Process Of Aloe

Aloe barbadensis Miller is an herbaceous plant which is widely used in medicinal,cosmetic and health care. The chemical composition of Aloe barbadensis Miller is complexand the main active components are anthraquinones and polysaccharides. Barbaloin is thehighest content of anthraquinones from aloe vera and also a potential allergenicity which isoften used as one of the most important indexes in the quality control of aloe products.Barbaloin is not stable, which can oxidize into aloe-emodin and other unknown substancessubjected to various factors. To solve the problems of unstablity, easy to allergies and highresidual of barbaloin, the main objective of this paper studied about the degradation ofbarbaloin in different conditions and applied into the process of aloe vera, conducted apreliminary structure analysis of the degradation products. In this case, it could provide ascientific basis for the better development and utilization of the aloe products.Firstly，the high performance liquid chromatography method (HPLC) was used to isolatethe degradation compounds of barbaloin. The optimal testing condition of7compoundsincluding barbaloin and its degradation compounds was determined through keepingadjustment of mobile phase proportion.Secondly, the HPLC was used to determine the transformation of barbaloin underdifferent treatment including temperature, pH, pH regulator, accessories which was commonlyused in aloe products and metal ions. The result showed that high temperature, alkalinecondition, calcium chloride, carboxymethyl cellulose, Fe3+and Mg2+could accelerate thedegradation of barbaloin significantly, the acidic conditions and Pb2+could inhibit the thedegradation of barbaloin. The degradation rate of barbaloin could reach90%in5minutes inalkaline condition and heat treatment，so it could be used as a rapid and efficient technologyto remove the barbaloin. The degradation kinetics of barbaloin under70℃-97℃was studiedand the degradation process was a first-order kinetic reaction. The linear regression equationbetween InK and1/T was Y=-5762.3X+11.976, the linear correlation coefficients was0.9701, Ea was47.91KJ/mol，InK0was11.976. The kinetic equation could predict thedegradation of barbaloin accurately under the range of experimental temperature and time, thecorrelation value between prediction result and experimental value was0.9959.The difference of degradation compounds were compared under different conditions. Thebarbaloin degradated into three kinds of compounds incoulding aloe-emodin. Two kinds ofdegradation compounds produced under alkaline condition, but no aloe-emodin. There wasonly one main degradation compound under acidic condition. The kinds of main degradationcompounds of barbaloin solutions which were added into accessories and mental ions werethree, incoulding a little amount of aloe-emodin. The degradation of barbaloin in aloe powderwas almost the same with the barbaloin standard solution. The sodium citrate was added intothe aloe vera gel at the process of blanching, the content of barbaloin in the aloe vera gel wasless than0.1mg/kg, which could reach the requirements of the international standard.Compared with the original process, adding citric acid products have no significant differentin sensory. Finally, preliminary study was done on the structure of the main degradation compounds.Results showed that the main degradation compounds of barbaloin were isobarbaloin,aloe-emodin,10-hydroxy aloin B and10-hydroxy aloin A, two other unknown products wereisomers.The result of this study showed that the content of barbaloin and aloe-emodin couldreduce effectively by adding citric acid in the process of aloe products so as to ensure thesafety of aloe products.