Toward High-Throughput Analysis of Aroma Compounds Using Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry: Screening of Key Food Odorants in Various Foods

Research progress in the synthesis of stable isotopes of food flavour compounds

Stable isotope dilution analysis (SIDA) is a quantitative method widely used in the determination of food flavour components because of its high efficiency and precision. However, many stable isotope reagents cannot be purchased through commercial channels. In this paper, the basic principle of stable isotope dilution analysis is introduced and its historical progress in food flavour analysis are examined. Then, the preparation methods of stable isotope analysis of food flavour compounds in recent years were compiled. In the literature reviewed, from 2012 to 2022, there were 185 stable isotopes of food flavour compounds used for food flavour analysis, of which 126 compounds can be purchased commercially and 59 compounds must be prepared in the laboratory. This review aims to present the methods used in the synthesis of stable isotopes to facilitate the development of food flavour analysis using stable isotope technology.

Toward Unified Flavor Quantitation in Cocoa-Based Products

Because food flavor is perceived through a combination of odor and taste, an analytical method that covers both dimensions would be very beneficial for mapping the consistent product quality over the entirety of a manufacturing process. Such a method, so-called "unified flavor quantitation", has been successfully applied to several different food products in recent years. The simultaneous detection of aroma and taste compounds by means of ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) enables the analysis and quantification of an enormously large number of compounds in a single run. To evaluate the limits of this method, chocolate, a high-fat, complex matrix, was selected. In 38 distinct commercial chocolate samples, 20 flavor-active acids, aldehydes, and sugars were analyzed after a simple, rapid extraction step followed by derivatization with 3-nitrophenylhydrazine using a single UHPLC-MS/MS method. The results obtained highlight the great potential of the "unified flavor quantitation" approach and demonstrate the possibility of high-throughput quantitation of key aroma- and taste-active molecules in a single assay.

Integrated metabolomics and transcriptomic analysis reveals metabolic changes of flavor compounds of Camellia assamica host plant after parasitized by Viscumarticulatum

Tea is one of the most popular beverages, it has many health benefits and flavor properties due to the presence of numerous secondary metabolites. Camellia assamica is also a main source of tea, which is mainly planted in the regions of southwest China. In this study, a non-targeted and targeted metabolomics analysis and sensory evaluation on tea leaves with and without mistletoe (Viscum articulatum) was carried out using liquid chromatography-mass spectrometry. RNA-seq-based transcriptomic analysis was conducted in parallel on the same samples, subsequently gene expression and metabolic differentiation were also investigated. Tea leaves with mistletoe presented much lower contents of (-)-catechin, (-)-epicatechin, (-)-gallocatechin gallate and (-)-epicatechin gallate, but significantly higher levels of free amino acids including Arg, Asp, GABA and Gln than that without mistletoe. Transcriptomic analysis also confirmed the main differentially expressed genes (DEGs) containing phenylpropanoid and flavonoid biosynthesis were down-regulated, but genes of amino acid biosynthesis were up-regulated. qRT-PCR analysis further revealed that the relative expression of CsCHS, CsC4H, CsANS, CsLAR, and CsF3H was hindered, while CsglyA and CsilvE expression was increased.