Development of a LC-ESI/MS/MS assay for the quantification of vanillin using a simple off-line dansyl chloride derivatization reaction to enhance signal intensity

Elucidating the Odor-Active Aroma Compounds in Alcohol-Free Beer and Their Contribution to the Worty Flavor

Alcohol-free beers (AFBs) brewed by cold-contact fermentation exhibit a flavor reminiscent of wort which affects consumer acceptability. The aims of this study were to identify the odor-active compounds in AFB and elucidate the contribution of these to the overall aroma and worty character of the beer. Using a sensomics approach, 27 odor-active aroma compounds were identified and quantitated using gas chromatography-mass spectrometry. The most odor-active compound was methional (boiled potato-like aroma), followed by 3-methylbutanal (cocoa-like), (E)-β-damascenone (apple, jam-like), 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone (curry, spicy-like), and phenylacetaldehyde (floral, honey-like). The important contribution of these flavor compounds to the worty and honey aroma of AFB was determined by sensory assessment of the recombinate in a beer-like matrix with omission tests. The role of 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone in AFB aroma was reported for the first time. The outcomes from this study are of relevance for the brewing industry to design strategies for the reduction of the wortiness of AFB.

A colorimetric assay for vanillin detection by determination of the luminescence of o-toluidine condensates

Vanillin (4-hydroxy-3-methoxybenzaldehyde), a food additive with rich milk flavor, is commonly used in the food, beverage and cosmetic industries. However, excessive consumption of vanillin may cause liver and kidney damage. Therefore, methods for detecting and controlling the level of vanillin in food, especially in infant powder, have important practical significance. In this study, we established a colorimetric assay for vanillin detection. The detection was performed under high-temperature and acidic conditions, which can induce the reaction of the aldehyde group of vanillin with the amino group of o-toluidine. The resulting product had a maximum absorption at 363 nm, which was quantified by a UV spectrophotometer. This assay had a limit of detection (LOD) of 1 pg mL⁻¹ and a linear range between 1 μg mL⁻¹ and 100 μg mL⁻¹. The average recoveries at three spiked levels were in the range from 91.1% to 101.6% with a relative standard deviation (RSD) of 4.62% ~ 7.27%.

Offline derivatization LC–MS/MS method for simultaneous estimation of vanillin and vanillic acid in guinea pig plasma

Aim: Vanillin used as a positive control substrate of aldehyde oxidase activity gets metabolized to vanillic acid. Low MW and low sensitivity in negative ion mode are challenges with these analytes. Our objective was to develop a simple offline derivatization LC–MS/MS method to address these challenges. Methodology/results: A simple dansyl chloride derivatization of the phenolic groups on vanillin and vanillic acid was adopted to enable easy ionization in commonly used acidic mobile phases. Calibration curves were linear over the concentrations of 4.88–1250 nM with an LLOQ of 0.64 fmoles on column for both analytes. Conclusion: The qualified method was successfully applied to simultaneously measure vanillin and vanillic acid in plasma and urine from a guinea pig pharmacokinetic study.

Pharmacokinetics of vanillin and its effects on mechanical hypersensitivity in a rat model of neuropathic pain

The analgesic effects of vanillin on neuropathic pain was evaluated using thermal sensitivity and mechanical allodynia using the sciatic nerve constriction model (n = 30 rats). To determine the pharmacokinetics of vanillin, rats (n = 6/administration route) received either 20 or 100 mg/kg of vanillin i.v. and p.o., respectively. For the pharmacodynamic study, baseline levels for hyperalgesia and allodynia were taken for 5 days prior to surgery. Following surgery each group (n = 6 rats/group) received either vanillin (50 mg/kg or 100 mg/kg), morphine (2 mg/kg or 6 mg/kg) or the vehicle only. Pharmacokinetic results following p.o. administrations are C(max) 290.24 ng/mL, T(max) 4 h, relative clearance 62.17 L/h/kg and T(1/2) 10.3 h. The bioavailability is 7.6%. Mechanical allodynia was decreased on treatment days 1, 2, 3, 5 (p < 0.003) and not on day 4 (p > 0.02) with 50 mg/kg vanillin, whereas at 100 mg/kg p.o. a decrease was noted only on days 7 and 8 (p < 0.003). No effect on hyperalgesia was seen following vanillin administration. In conclusion, vanillin is bioavailable and seems to have an alleviating effect on mechanical allodynia, and not on hyperalgesia, when evaluated with a chronic constriction nerve injury rat model of neuropathic pain.