Analysis and comparison of staminate flowers components in five Chinese walnut varieties

In this study, five kinds of walnut staminate flowers, from China were compared in terms of conventional nutrients and secondary metabolites. The correlation between amino acids and varieties was determined using the principal component analysis (PCA). Results show that the cellulose, protein, ash, fat and VC contents of walnut staminate flowers are 50.94−65.90, 19.28−25.12, 4.83−6.41, 0.95−2.61 and 5.21−21.35 mg/100 g, respectively. Walnut staminate flowers are rich in minerals and has a potassium content as high as 26.55−37.22 mg/g. The contents of flavonoids and polyphenols in the secondary metabolites of walnut staminate flowers are 85.94−117.98 and 25.01−62.31 mg/g, respectively. Amongst specify, the contents of ellagic acid and juglone, which are recognised to have anticancer activity, are (78.20 ± 21.69) and (63.48 ± 16.34) mg/100 g, respectively, and the contents of polysaccharides and saponins are 0.61−1.58 and 6.50−11.85 mg/g, respectively. The PCA shows that amino acids can distinguish the different varieties of walnut staminate flowers.