Detection of total amino acids of Pholidota cantonensis Rolfe. from Fujian province by ninhydrin colorimetric method

ObjectiveTo optimize the detection condition of amino acids in Pholidota cantonensis Rolfe.from different producing areas of Fujian province by solvent reflux extraction and ninhydrin colorimetric method.

MethodsThe content of total amino acids was determined by ninhydrin colorimetric method with glycine as reference; the effect of different influence factors on detection were studied to determine the optimal detection conditions; on the basis of single factor experiment, L9 (34) orthogonal test was used to investigate the effects of solvent dosage, solvent concentration, extraction time and extraction times on the extraction process of total amino acids from Pholidota cantonensis.The optimal extraction process was optimized based on these indexes.

ResultsThe optimum detection conditions were: wavelength 568 nm, ninhydrin (2%) volume 3 mL, pH 6, buffer solution 2 mL, water bath heating temperature 80 ℃ and heating time 40 min.The optimal ultrasonic extraction conditions were as follows: alcohol concentration 85%, alcohol amount 35 mL, extraction time 60 min, and twice extraction.The contents of total amino acids in four different producing areas in Fujian province were as follows: Yongtai county, Shanghang county, Pingnan county and Yongchun county.

ConclusionsThe ninhydrin colorimetric method is simple, accurate, reliable and reproducible.The optional extraction is stable and feasible, which can provide a basis for quality evaluation control, the determination and further development of Pholidota cantonensis.In the collected samples, the best quality of Pholidota cantonensis from Yongtai county is obtained.