Metabolic variations of organic acids, amino acids, fatty acids and aroma compounds in the pulp of different pummelo varieties

Pummelo (Citrus grandis Osbeck.) is a major commercial fruit in the world. In this study, samples of three popular varieties, namely "Huangjin", "Sanhong" and "Dongshizao", were collected from three commercial orchards located in China. A total of 153 metabolites in the pulp were annotated and analyzed using UPLC-QTRAP-MS/ MS and GC-MS, and PCA of these metabolites could clearly distinguish the three varieties. The pulp of "Dongshizao" had the most enjoyable taste, and that of "Huangjin" had the strongest aroma. The most important aroma compounds were hexanal, beta-myrcene and trans-2-decene. Amino acids were positively correlated with 18 volatile substances, and also affected the tastes of sweetness, sourness and bitterness. Unsaturated fatty acids accounted for 70% of total fatty acids. The types of sugars and organic acids were similar among different varieties, but differences in the contents of individual substances and sugar/acid ratio contributed to different tastes.