[Grading of Gastrodia elata pieces based on quality constant].

The grade of Gastrodia elata pieces is evaluated by quality constant evaluation method.Fifteen batches of G. elata pieces collected were measured for their appearance and morphological indexes. The contents of gastrodin,p-hydroxybenzyl alcohol,barrisoside A,B and E were taken as index components for the content determination. The traditional grading standards were combined with modern quality control indicators,and the quality constants were calculated to grade the pieces.The results showed that the quality constants of 15 batches of G. elata ranged between 143. 3 and 1 027. 3. If the percentage mass constant( ≥80%) was the first grade,the percentage mass constant between 50%-80% indicated the second grade,and the remaining percentage mass constant indicated the third grade. The quality constant of the first gradepieces was sality,that of the second grade pieces ranged between 513. 0-821. 0,and that of the third grade pieces was <513. 0. On the basis of the study for the grading method of quality constants,and the natural morphology and cutting characteristics of the pieces,a grading model for the quality constants of the pieces cut along texture was established,which made the method scientific,rational as well as " personalized". The model method is applied in grading G. elata pieces,so as to specify the grading method,further enrich the study data of the grading evaluation of G. elata pieces and provide a useful reference for the grading evaluation of G. elata pieces. Meanwhile,the grading method of mass constants could be further applied and promoted to prove its rationality,scientificity and practicability.