Studies on the Origin of Carbons in Aroma Compounds from [13C6]Glucose -Cysteine-(E)-2-Nonenal Model Reaction Systems

Abstract

The thermal degradation of lipid oxidation products with amino acids and reducing sugars is known to be important for the characteristic aroma generation in both meat and meat-like process flavorings. SPME(solid phase microextraction)/GC-MS was used to analyze the volatiles produced from a solution of [13C6]glucose, cysteine, and lipid degradation product- (E)-2-nonenal, heated at 130 °C for 90 min. Analysis of the mass spectra showed that the resulting 2-butyl-thiophene and 5-butyldihydro-2(3H)-furanone were 13C6-labeled and hence stemmed from glucose. Glucose and (E)-2-nonenal were equally important for the formation of 2-pentylfuran, whether cysteine was present in the reaction or not. 2-Furanmethanol, (E)-2-(1-pentenyl)-furan, 2-hexanoylfuran, ethanethiol, 5-methyl-2(5H)-thiophenone, 1-methyl-5-mercaptotetrazole, 4-pentyl-pyridine, 2-pentyl-thiophene, and 2-mercaptopropanoic acid were virtually 13C1-13C4 labeled, suggesting an origin from both glucose and cysteine and/or (E)-2-nonenal carbons. Thus, the relative contribution of aldehyde to the C-skeleton of a particular aroma compound changed substantially when both glucose and cysteine were involved in its formation.

Profile of volatile compounds in frankfurters from culled goat meat during cold storage

“…This trend partially conforms the findings of Watanabe et al. (2015), where an increase is associated with the progress of oxidation reactions of UFA and the Maillard reaction (e.g., reaction between glucose, cysteine, and (E)‐2‐nonenal (Diez‐Simon et al., 2019; Song et al., 2019), while the latter decrease depends on its involvement in other chemical reactions, for example, with hydrogen sulfide, where 2‐pentylthiophene is formed, as well as on the slowing of lipid oxidation reactions (Van Ba et al., 2013; Jurado et al., 2009).…”

“…During storage, its content increased to day 21, followed by a decrease to day 42 (except in G100). This trend partially conforms the findings of Watanabe et al (2015), where an increase is associated with the progress of oxidation reactions of UFA and the Maillard reaction (e.g., reaction between glucose, cysteine, and (E)-2-nonenal (Diez-Simon et al, 2019;Song et al, 2019), while the latter decrease depends on its involvement in other chemical reactions, for example, with hydrogen sulfide, where 2-pentylthiophene is formed, as well as on the slowing of lipid oxidation reactions (Van Ba et al, 2013;Jurado et al, 2009). Furan-2-carbaldehyde (furfural) is formed via the Maillard reaction through thermal decomposition or rearrangement of carbohydrates alone (or in the presence of amino acids), where pentose sugars (especially, ribose) and inosine-5′-monophosphate (5′-IMP) play a significant role (Madruga et al, 2010;Watanabe et al, 2015).…”

“…2‐pentylfuran is an alkyl‐furan, mostly produced by auto‐ and thermal oxidation of LA (and other n‐6 FA), oleic, and α‐linolenic acids (in a lesser extent), though it can also be a product of the Maillard reaction (Van Ba et al., 2013; Song et al., 2019). As a product of lipid oxidation, its content is expected to increase form CON to G100, due to the progressively higher fat unsaturation with the increase of goat meat content in GFs (Stajić et al., 2020).…”

“…However, the content of 2‐pentylfuran increased to G50, and then decreased to G100, with significant differences in G100 to CON. This declining trend could be explained by its further involvement as an intermediate in other chemical reactions (e.g., forming of 2‐pentylthiophene) or by the reduced Maillard reaction contributions in frankfurters with the prevailing content of culled goat meat, considering the lower cysteine and glucose contents compared to beef (Van Ba et al., 2013; Fazlani et al., 2019; Mazhangara et al., 2019; Song et al., 2019). During storage, its content increased to day 21, followed by a decrease to day 42 (except in G100).…”

“…From day 21, thiophene was not detected in all treatments which could be explained by the progression of lipid oxidation, whereby unsaturated aldehydes (e.g., (E)‐2‐nonenal) inhibited the formation of thiophene through interactions with its precursors formed in the Maillard reaction (e.g., H 2 S) (Van Ba et al., 2013; Diez‐Simon et al., 2019; Khan et al., 2015; Song et al., 2019). Despite the generally accepted rule that lower pH promotes the formation of sulfur‐containing compounds (Van Ba et al., 2013), the declining pH over time in all treatments (Stajić et al., 2020) resulted in a decrease of thiophene, which corresponds to the trend reported by Van Ba et al.…”