Distinct Quality Changes of Garlic Bulb during Growth by Metabolomics Analysis

Garlic-specialized metabolites contribute to both spicy flavor and healthy function of garlic. Their accumulation pattern and regulatory mechanism vary greatly at different environments and maturities. Herein, metabolomics models were built to evaluate and predict the quality and chemical composition variances of four garlic varieties in two regions at six growth stages. A total of 91 metabolites were identified, and their accumulation pattern during growth in three varieties of garlic in Shandong was similar but obviously distinct from that planted in Heilongjiang. Active metabolism for organosulfur compounds and amino acids was observed, and most metabolites with the "γ-glutamyl-" group were the storage compounds of nitrogen and sulfur in garlic because they increased remarkably during growth. The levels of functional components in garlic varied among different stages, and reliable prediction models for these compounds were provided, which may give a new idea for the estimation of garlic quality and confirmation of the best harvest time.