Rapid, High-Throughput Quantitation of Odor-Active 2-Acetyl Azaheterocycles in Food Products by UHPLC–MS/MS

Abstract

A rapid, high-throughput method for the quantitation of the 2-acetyl azaheterocycles, 2-acetyl-1-pyrroline, 2-acetyl-1,4,5,6-tetrahydropyridine, 2-acetylpyrazine, and 2-acetyl-2-thiazoline, in different food products, by liquid chromatography–tandem mass spectrometry (LC–MS/MS), was developed. The quick extraction by bead beater homogenization, fast derivatization by 3-nitrophenylhydrazine (40 °C, 2 h), and efficient LC separation make this method suitable for high-throughput analysis. As established in this study, the highly precise LC–MS/MS method applies to different food products or beverages without requiring further adjustment. The analysis was performed with sample amounts of 0.2–0.5 g, and limit of quantitation values of 0.6, 0.5, 0.6, and 1.0 μg/kg were obtained for 2-acetyl-1-pyrroline, 2-acetyl-1,4,5,6-tetrahydropyridine, 2-acetylpyrazine, and 2-acetyl-2-thiazoline, respectively. Thus, it was possible to quantitate the analytes in the range of their odor thresholds.

Isotope-Coding Derivatization for Quantitative Profiling of Reactive α-Dicarbonyl Species in Processed Botanicals by Liquid Chromatography–Tandem Mass Spectrometry

“…29 Apart from odor-active shortchain α-DCs (DA, 2,3PD), some 2-acetyl azaheterocycles 48 (2AP, 2ATP) could be found at trace levels (<0.3 μg/g) in Dazao, Heizima and Zhigancao, corroborating the generation of volatile odorants responsible for food aromas by dry heating 34 or honey frying the raw products. 48,49 Thus, most medicinal products may release considerable amounts of reactive α-DCs, and the spectrum strongly depends upon the food ingredients, additives, and processing parameters (temperature, moisture, pH, time, etc.). Even so, it is still under debate how food-derived α-DCs contribute to the endogenous pool and whether the ubiquitous α-DC metabo-lites impact health in vivo.…”

“…47 Although only trace amounts of α-DCs occur in Zhigancao (honey-fried licorice root), more dicarbonyl species have been observed in this traditional decoction pieces, which can be assumed to arise from heated honey 5,16 as the excipient in the unique Paozhi processing. 29 Apart from odor-active shortchain α-DCs (DA, 2,3PD), some 2-acetyl azaheterocycles 48 (2AP, 2ATP) could be found at trace levels (<0.3 μg/g) in Dazao, Heizima and Zhigancao, corroborating the generation of volatile odorants responsible for food aromas by dry heating 34 or honey frying the raw products. 48,49 Thus, most medicinal products may release considerable amounts of reactive α-DCs, and the spectrum strongly depends upon the food ingredients, additives, and processing parameters (temperature, moisture, pH, time, etc.).…”

Flavor of tea (Camellia sinensis): A review on odorants and analytical techniques

“…Moreover, NMR is an excellent tool to obtain chemical structure information of compounds and has been widely used in tea taste analysis (Kaneko et al, 2006;Scharbert, Holzmann, et al, 2004;Scharbert, Jezussek, et al, 2004). Except for distinguishing the structural differences of flavor isomers using 1D or 2D NMR, recently, Frank et al validated a quantitative 1H-NMR spectroscopy (qNMR) method as a precise tool for the rapid quantitation (∼15 min) of food-related target compounds with low molecular weight in reference materials and natural isolates such as nucleotides, polyphenols, or cyclic peptides (Bosl et al, 2021;Frank et al, 2014;Kauz et al, 2021).…”

“…Except for distinguishing the structural differences of flavor isomers using 1D or 2D NMR, recently, Frank et al. validated a quantitative 1H‐NMR spectroscopy (qNMR) method as a precise tool for the rapid quantitation (∼15 min) of food‐related target compounds with low molecular weight in reference materials and natural isolates such as nucleotides, polyphenols, or cyclic peptides (Bosl et al., 2021; Frank et al., 2014; Kauz et al., 2021).…”

Volatile Organic Compounds, Evaluation Methods and Processing Properties for Cooked Rice Flavor

“…Therefore, Drying and low-temperature storage of harvested rice can effectively increase the content of 2-AP in cooked rice, and improve the taste quality of cooked rice (Liu et al 2021 ). Some researchers illustrated that 2-AP was produced by the Maillard reaction after rice is cooked with rising temperature, as the physicochemical reactions between amino acids and carbohydrates or their degradation products in cooked rice will generate 2-AP (Hofmann and Schieberle 1998 ; Bösl et al 2021 ). For instance, the concentrations and odor activity values in cooked basmati rice is 610 μg/kg and 83,516 respectively (Buttery et al 1994 ).…”