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

Recent studies show the immense capacities of the unified quantitation of aroma and taste compounds using liquid chromatography-mass spectrometry (LC-MS). The goal of this study was to highlight the broad application of this unified method. Thus, a stable isotope dilution analysis quantification method of the most important key food odorants in various food categories by LC-MS was developed. Using the well-known derivatization agent 3-nitrophenylhydrazine for carbonyl derivatization and a newly developed approach for alcohol and thiol derivatization, a method for the quantitation of 20 key food odorants was established. Intraday precision was determined to be ≤26%, and interday precision was between 24 and 31%. Limits of quantitation were determined between 0.014 and 283 µg/kg. The work shows that a wide array of aroma compounds can be analyzed accurately by LC-MS.

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

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.

Bioavailability and Biological Effects of 2- O-ß-d-Glucopyranosyl-carboxyatractyligenin from Green Coffee in Caenorhabditis elegans.

Targeted analysis of Coffea arabica and Coffea canephora green coffees (total sample size n = 57) confirmed 2- O-ß-d-glucopyranosyl-carboxyatractyligenin (6) as the quantitatively dominating carboxyatractyligenin derivative. Its abundance in Arabicas (2425 ± 549 nmol/g, n = 48) exceeded that in Robustas (34 ± 12 nmol/g, n = 9) roughly by a factor of 70. Coffee processing involving heat (e.g., steam treatment and decaffeination) reduced concentrations of 6 and increased those of the decarboxylated derivative. The bioavailability of compound 6 in Caenorhabditis elegans was demonstrated by ultraperformance liquid chromatography-tandem mass spectrometry analysis of extracts prepared from nematode cultures incubated in a liquid medium containing 6. A toxicity assay performed to assess the impact of 6 in vivo showed a 20-fold higher median lethal dose (LD50 = 11.7 ± 1.2 mM) concentration compared to that of the known phytotoxic adenine-nucleotide transporters inhibitor carboxyatractyloside (2, LD50 = 0.61 ± 0.05 mM), whereas 1 mM 6 and 0.1 mM 2 were sufficient to decrease the survival of wild type C. elegans, already 10-20-fold lower doses reduced reproduction. Because the insulin/insulin-like growth factors signaling cascade (IIS) is a key regulator of life span and stress resistance, the impact of compound 6 on the survival of long-living daf-2 C. elegans was tested. As the susceptibility of these nematodes to 6 was as high as that in wild type, an impact on central metabolic processes independent of IIS was suggested. Analysis of the in vivo adenosine triphosphate (ATP) content of adult C. elegans revealed no changes after 1 and 24 h, but a 50% reduction after treatment with 1 mM 6 during the entire postembryonic development. These data speak for a developmental-stage-dependent modulation of the ATP pool by 6.