N,N-dimethylpiperidinium (mepiquat) Part 2. Formation in roasted coffee and barley during thermal processing

• Published in: Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment Chemistry, analysis, control, exposure & risk assessment, 2014-02, Vol.31 (2), p.234-241
• Main Authors: Wermann, Silke, Theurillat, Viviane, Verzegnassi, Ludovica, Hofmann, Jocelyne, Kuchenbecker, Ralf, Constable, Anne, Delatour, Thierry, Stadler, Richard H
• Format: Article
• Language: English
• Subjects: Amino acids; Barley; beans; Biological and medical sciences; cereals; Chemical reactions; Coffee; Coffee - chemistry; color; Correlation analysis; Food Analysis; Food industries; Food science; Fundamental and applied biological sciences. Psychology; grain foods; heat treatment; Hordeum - chemistry; Hordeum vulgare; Hot Temperature; lysine; Maillard reaction; mepiquat; Molecular Sequence Annotation; N,N-dimethylpiperidinium; Piperidines - chemistry; pizza; Plant Growth Regulators - chemistry; ready-to-eat foods; roasting; surveys; Temperature effects; thermal treatment; trigonelline
• ISSN: 1944-0057; 1944-0049; 1944-0057
• DOI: 10.1080/19440049.2013.871585

Previous work in model systems has demonstrated that mepiquat can be formed under typical roasting conditions from the amino acid lysine via the Maillard reaction and trigonelline, the latter alkaloid serving as a methyl donor. This study shows for the first time that mepiquat is formed in low mg kg –¹ amounts during the coffee roasting process and consequently can be detected in roast and ground as well as soluble coffee up to levels of 1.4 mg kg –¹. Darker roast coffees contain relatively higher amounts of mepiquat versus light roasted beans, with an excellent correlation of mepiquat formation to roast colour (r ² = 0.99) in robusta beans. A survey of 20 of the major green coffee origins (robusta and arabica coffees) showed the absence of mepiquat (