title: Heat-induced formation of mepiquat by decarboxylation of pipecolic acid and its betaine derivative. Part 1: Model system studies.
abstract: This study describes, for the first time, the role of pipecolic acid betaine and pipecolic acid, naturally present in some foods, in the formation of the plant growth regulator N,N-dimethylpiperidinium (mepiquat) under dry thermal conditions. The formation of mepiquat and intermediate compounds was investigated in model systems using high performance liquid chromatography-quadrupole/time-of-flight mass spectrometry. Mepiquat is released with a yield of up to 0.66mol% after thermal treatment (>150°C) of pipecolic acid betaine. Similar conversion rates are attained with the congener piperidine-2-carboxylic acid (dl-pipecolic acid), albeit in the presence of alkylating agents, such as choline, glycine betaine or trigonelline, that are fairly widespread in food crops. These new pathways to mepiquat indicate that the occurrence of low levels of this thermally induced compound is probably more widespread in processed foods than initially suspected (see Part 2 of this study on the occurrence of mepiquat in selected foodstuffs).
authors.affiliation: College of Food Science and Engineering, Jilin University, 130062 Changchun, China; Nestlé Research Centre, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland. Electronic address: yuan_yuan@jlu.edu.cn.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Nestlé Research Centre, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland. Electronic address: adrienne.tarres@rdls.nestle.com.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Tarres
authors.affiliation: Nestlé Research Centre, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland. Electronic address: thomas.bessaire@rdls.nestle.com.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bessaire
authors.affiliation: Nestlé Corporate Quality Management, CO-QM, Avenue Nestlé 55, 1800 Vevey, Switzerland. Electronic address: richard.stadler@nestle.com.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Stadler
authors.affiliation: Nestlé Research Centre, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland. Electronic address: thierry.delatour@rdls.nestle.com.
authors.forename: Thierry
authors.initials: T
authors.lastname: Delatour
mesh_terms: D001622:Betaine / Q000737:chemistry; D002853:Chromatography, Liquid; D003653:Decarboxylation; D005511:Food Handling; D006358:Hot Temperature; D013058:Mass Spectrometry; D010875:Pipecolic Acids / Q000737:chemistry*; D010880:Piperidines / Q000032:analysis*
chemical_list: D010875:Pipecolic Acids; D010880:Piperidines; D001622:Betaine; C049449:mepiquat
keywords: Choline; Decarboxylation; Glycine betaine; Mepiquat; Methyl transfer; Model systems; Pipecolic acid; Pipecolic acid betaine; Trigonelline