FOOD SCIENCE ›› 2020, Vol. 41 ›› Issue (12): 211-220.doi: 10.7506/spkx1002-6630-20190709-117

• Composition Analysis • Previous Articles     Next Articles

Principal Component Analysis and Cluster Analysis for Evaluating the Free Amino Acid Composition of Inner and Outer Lily Bulb Scales from Different Cultivars

WANG Xinyu, WANG Rongrong, WANG Ting, YANG Lüzhu, LIU Jie, LI Huan, ZHANG Qun, SHAN Yang, DING Shenghua   

  1. (1. Graduate School of Longping Branch, Hunan University, Changsha 410125, China;2. Hunan Provincial Key Laboratory of Fruits and Vegetables Storage, Processing and Quality Safety, Hunan Province International Joint Laboratory on Fruits and Vegetables Processing, Quality and Safety, Agricultural Product Processing Institute, Hunan Academy of Agricultural Sciences, Changsha 410125, China; 3. College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China; 4. Turpan Technology Extention Center of Forestry and Fruit Industry, Turpan 838000, China)
  • Online:2020-06-25 Published:2020-06-22

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Abstract: This study aimed to analyze the differences in the composition of free amino acids (FAAs) in the inner and outer bulb scales of seven cultivars of lily. We determined FAAs by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A systematic evaluation was performed by measurement of taste activity value (TAV) as well as using principal component analysis (PCA) and cluster analysis (CA). The results showed that a total of 21 FAAs were detected in all samples at concentrations ranging from 4.10 to 10.10 mg/g. There were differences in the contents of total free amino acids (TFAAs), essential amino acids (EAAs), flavor amino acids, and medicinal amino acids (MAAs) among different cultivars. On the whole, the content of TFAAs in the inner bulb scale was higher than that of the outer one, with mean values of 7.00 and 6.18 mg/g, respectively. Among all cultivars, the content of TFAAs was higher in Lilium davidii var. unicolor (from Pinglu and Lanzhou), and L. davidii Duchartre, and the lowest in L. regale Wilson. The content of EAAs was high in L. lancifolium Thunb. and L. davidii Duchartre, accounting for more than 10% of TFAAs for both inner and outer bulb scales. Among the flavor amino acids, bitter and umami amino acids were predominant, and both glutamic acid and arginine were the main contributors. MAAs were rich in lily bulbs, accounting for 49.18%–70.15% of TFAAs. Five principal components were extracted through principal component analysis, which together explained 88.803% the total variance and could reflect the comprehensive information about FAAs. According to the comprehensive analysis, the inner bulb scale of L. davidii var. unicolor from Pinglu, and the inner and outer scales of L. davidii Duchartre ranked top three among all samples. The hierarchical cluster analysis divided the inner and outer bulb scales of the seven lily cultivars into five categories, and the results were consistent with the principal component analysis, which could reflect the differences between different lily germplasms.

Key words: lily bulbs, free amino acids, liquid chromatography-tandem mass spectrometry, principal component analysis, cluster analysis

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