Oligomerization of reactive carbonyls in the presence of ammonia-producing compounds: A route for the production of pyridines in foods

Abstract

The reactions of different lipid-derived reactive carbonyls with ammonia-producing compounds were studied to investigate the formation of pyridines in foods. 2-Alkyl, 3alkyl-, and 2,5-dialkylpyiridines were produced by oligomerization of short-chain aldehydes in the presence of ammonia. Thus, acetaldehyde/crotonaldehyde mixtures and 2,4-alkadienals were the main responsible for the formation of 2-alkylpyridines; acrolein or 2,4-alkadienals were needed for the formation of 3-alkylpyridines; and 2alkenals were responsible for the formation of 2,5-dialkylpyridines. On the contrary, 2,6-dialkylpyridines were produced by cyclization of unsaturated ketones. Reactions pathways for formation of these pyridines are proposed, and confirmed by isotopic labelling experiments. Aldehydes and ketones required for their formation are produced in the course of lipid oxidation. Therefore, pyridine formation seems to be an additional consequence of the lipid oxidation pathway. This new knowledge can employed for the optimization of reactions to achieve the desired targeted flavor generation during food processing.

Formation of heterocyclic aromatic amines with the structure of aminoimidazoazarenes in food products

“…When the pyridines produced by an aldehyde were studied comparatively in the presence of creatinine, ammonia, and other ammonia-producing compounds, the amount of pyridines obtained with creatinine was always lower than the amount of pyridines obtained with other ammonia-producing compounds (Zamora, Lavado-Tena, & Hidalgo, 2020). The reason is that creatinine is able to react with the reactive carbonyls in addition to generate the ammonia needed for producing the pyridine.…”

“…However, they are produced to a significant extent as a consequence of carbonyl-amine reactions when lipid-derived reactive carbonyls are involved (Zhang et al, 2018). Formation pathways for these pyridines have been proposed very recently (Zamora, Lavado-Tena, & Hidalgo, 2020).…”

“…They have been suggested to be produced by cyclizations and oligomerizations of lipidderived short-chain reactive aldehydes produced in the presence of ammonia and ammonia-producing compounds. In fact, short-chain unsaturated aldehydes are not stable when heated in the presence of ammonia, and the formation of pyridines is rapidly observed (Zamora, Lavado-Tena, & Hidalgo, 2020).…”

Different Effects of Vitamin C-Based Supplements on the Advance of Linseed Oil Component Oxidation and Lipolysis during In Vitro Gastrointestinal Digestion

“…Indeed, in the headspace of DLAsc1–2 and DLVC1–4 samples, significantly increased concentrations of 3-ethyl-pyridine were found, together with 2-ethyl-pyridine, the latter not being detected in the rest of digests. Both compounds are known to be derived from reactions between 2,4-heptadienals and amino compounds [ 55 ].…”

Conversion of 5-Hydroxymethylfurfural into 6-(Hydroxymethyl)pyridin-3-ol: A Pathway for the Formation of Pyridin-3-ols in Honey and Model Systems

“…Pyridines are typical food flavors, which are produced as a consequence of processing . The formation pathways of alkylpyridines seem to be related to the cyclizations and oligomerizations suffered by lipid-derived aldehydes in the presence of ammonia-producing compounds . In addition, formation of alkylpyridiniums has been described in roasted coffee by trigonelline decomposition .…”