title: Identification and Quantitation of 2-Acetyl-1-pyrroline in Manuka Honey (Leptospermum scoparium).
abstract: Manuka honey from New Zealand is known for its exceptional antibacterial activity, which is due to high amounts of the 1,2-dicarbonyl compound methylglyoxal (MGO). MGO in manuka honey is formed via non-enzymatic dehydration from dihydroxyacetone (DHA) during honey maturation. MGO and DHA are highly reactive substances, leading to a variety of unique chemical reactions. During Strecker reaction between proline and MGO, 2-acetyl-1-pyrroline (2-AP), an important aroma compound, is formed. Using liquid-liquid extraction and gas chromatography-mass spectrometry analysis, 2-AP was identified unambiguously in manuka honey for the first time. Quantitation was carried out via external matrix calibration, using a synthetic 2-AP standard and artificial honey. The 2-AP concentration in 11 commercial samples of manuka honey ranged from 0.08 to 0.45 mg/kg. For manuka honey samples containing MGO in concentrations above 250 mg/kg, significantly higher amounts of 2-AP were found when compared to non-manuka honeys. When high amounts of MGO were artificially added to non-manuka multifloral honey, an increase of the 2-AP concentration from 0.07 to 0.40 mg/kg after 12 weeks of storage at 37 °C was observed, concomitant with a significant increase in the concentration of 5-hydroxymethylfurfural (HMF). No increase of 2-AP was found during storage at ambient temperature. 2-AP together with MGO can be a suitable parameter for the quality control of manuka honey.
authors.affiliation: Institute of Food Chemistry, Technische Universität Dresden , D-01062 Dresden, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Rückriemen
authors.affiliation: Institute of Food Chemistry, Technische Universität Dresden , D-01062 Dresden, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Schwarzenbolz
authors.affiliation: Institute of Food Chemistry, Technische Universität Dresden , D-01062 Dresden, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Adam
authors.affiliation: Institute of Food Chemistry, Technische Universität Dresden , D-01062 Dresden, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Henle
mesh_terms: D002851:Chromatography, High Pressure Liquid; D061353:Food Storage; D006722:Honey / Q000032:analysis*; D031649:Leptospermum / Q000737:chemistry*; D009520:New Zealand; D011758:Pyrroles / Q000032:analysis*; D011765:Pyruvaldehyde / Q000032:analysis
chemical_list: D011758:Pyrroles; D011765:Pyruvaldehyde; C426303:2-acetyl-1-pyrroline
keywords: 2-acetyl-1-pyrroline; 5-hydroxymethylfurfural; Maillard reaction; Strecker degradation; aroma; manuka honey; methylglyoxal