Comparative UHPLC-Q-Orbitrap HRMS-Based Metabolomics Unveils Biochemical Changes of Black Garlic during Aging Process

Abstract

Aged black garlic (BG) is a functional food in global markets; however, very few studies have ventured into comprehensive profiling of BG metabolomes during the aging process. Herein, we exploited UHPLC-Orbitrap HRMS for a comparative metabolomics analysis. During the heat treatment, organosulfur compounds such as allicin, diallyl disulfide, ajoene, S-allyl-l-cysteine (SAC), and γ-glutamyl-SAC were downregulated. Plenty of glycerophospholipids together with shikimate, aromatic amino acids, and vitamin B6 vitamers were significantly augmented; tryptophan was however consumed to generate downstream products manifested in nicotinate metabolism and aminobenzoate degradation. These secondary metabolites serve as signaling mediators or protectants against extreme thermal exposure. Besides, Heyns compounds and Amadori-rearrangement byproducts with potential mutagenic effects were concentrated. Together, our findings expand the known metabolome space of BG processing and better elucidate the reactivities of the key metabolites. We provide in-depth insights into the biochemical changes of BG that enable further functional or toxicological investigations of this popular food.

Keywords: Maillard reaction; functional food; glycerophospholipids; organosulfur; phytochemicals; plant metabolome; thermal treatment.