FOOD SCIENCE ›› 2019, Vol. 40 ›› Issue (4): 229-236.doi: 10.7506/spkx1002-6630-20171228-354

• Component Analysis • Previous Articles     Next Articles

Differences in Free Amino Acid Composition of Fruits of Common Olive and Sweet Olive and Their Glutamine Metabolism Characteristics

PENG Zhenfen, YE Qinghua, WANG Wei, XIE Qian, CHEN Qingxi*   

  1. (College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China)
  • Online:2019-02-25 Published:2019-03-05

Abstract: Using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with multivariate statistical analysis, fruits of the common olive ‘Changying’ and the sweet olive ‘Qinglan 1 hao’ were compared for differences in their free amino acid composition. Meanwhile, glutamine metabolism characteristics of the two olive varieties were analyzed. The aim was to provide the basis for understanding the contribution of amino acids to the differential flavor between common olive and sweet olive. By principal component analysis (PCA), partial least squares projection to latent structures discriminant analysis (PLS-DA) and significance analysis, the differential free amino acids between the two varieties were determined and correlation analysis was also conducted. The results showed that there was a difference in free amino acid composition between common olive and sweet olive with respect to the sweet amino acids serine (Ser) and glutamine (Gln) as well as umami glutamate (Glu). The three amino acids were all more abundant in ‘Qinglan 1 hao’ and made greater contribution to the flavor of this variety. Their average contents were in the descending order: Glu > Gln > Ser for both varieties, and their differences between the two varieties were in descending order: Ser > Gln > Glu, overall suggesting that Gln was a more important amino acid. The Gln content of ‘Changying’ was significantly negatively correlated with asparagine synthetase (AS) activity (P < 0.05) and soluble sugar with correlation coefficient (r) of ?0.792 and ?0.711, respectively, whereas no significant correlation with sucrose or reducing sugar was found (P > 0.05). The Gln content of ‘Qinglan 1 hao’ was not significantly correlated with AS activity, while it was highly significantly correlated with sucrose (P < 0.05, r = 0.953) and soluble sugar (P < 0.05, r = 0.791) and negatively correlated with reducing sugar (P < 0.05, r = ?0.780). Hence, the correlations of Gln content with the metabolic enzyme activities and sugars differed between both varieties. In conclusion, free amino acids made different contributions to the flavor of common olive and sweet olive. Notably, Gln could affect the flavor of olive by regulating the activity of AS and sugar metabolism.

Key words: olive, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), differential amino acids, correlation analysis

CLC Number: