Determination the Quantitative and the Average Degree of Polymerization of Proanthocyanidins in Peanut Skin Extract with Ultraviolet Spectrophotometry
Objective To establish a method for detecting the quantitative and the average degree of polymerization of proanthocyanidins in peanut skin extracts by UV spectrophotometry.Methods The molar concentration of proanthocyanidins can be measured by modified vanillin method in acetic acid solvent,and then the mass concentration of proanthocyanidins is determined by vanillin method in methanol solvent.By using these two reactions,the average degree of polymerization of proanthocyanidins can be determined.Results The liner range of the molar concentration scope of the optimized colorimetric conditions is 0.025 ~ 0.126 μmol/ ml.The average recovery is 98.81% and RSD is 1.86% (n =6).The average degree of proanthocyanidin A1 and A2 are consistant with the theoretical values.Conclusion The method is simple,accurate,rapid and reliable for determining the quantitative and the average degree of polymerization of proanthocyanidins in peanut skin extracts.
peanut skinproanthocyanidinscontentaverage degree of polymerization