Strecker-type Degradation Produced by the Lipid Oxidation Products 4,5-Epoxy-2-Alkenals

Abstract

Strecker degradation is one of the most important reactions leading to final aroma compounds in the Maillard reaction. In an attempt to clarify whether lipid oxidation products may be contributing to the Strecker degradation of amino acids, this study analyzes the reaction of 4,5-epoxy-2-alkenals with phenylalanine. In addition to N-substituted 2-(1-hydroxyalkyl)pyrroles and N-substituted pyrroles, which are major products of the reaction, the formation of both the Strecker aldehyde phenylacetaldehyde and 2-alkylpyridines was also observed. The aldehyde, which was produced at 37 degrees C-as could be determined by forming its corresponding thiazolidine with cysteamine-and pH 6-7, was not produced when the amino acid was esterified. This aldehyde is suggested to be produced through imine formation, which is then decarboxylated and hydrolyzed. This reaction also produces a hydroxyl amino derivative, which is the origin of the 2-alkylpyridines identified. All these data indicate that Strecker-type degradation of amino acids is produced at 37 degrees C by some lipid oxidation products. This is a new proof of the interrelations between lipid oxidation and Maillard reaction, which are able to produce common products by analogue mechanisms.

Model Studies on the Pattern of Volatiles Generated in Mixtures of Amino Acids, Lipid-Oxidation-Derived Aldehydes, and Glucose

“…It seems that aldol condensation reactions of lipid oxidation aldehydes catalyzed by an amino acid are very important in the overall formation of aroma volatiles in such reaction mixtures. Thus, in addition to the degradation of amino acids induced by lipid oxidation products, which has been reported before by Hidalgo and co-workers, 3,4 amino-acid-induced degradations and further reactions of lipid oxidation products may be of considerable importance in thermally processed foods as well. In addition, most of the volatiles identified in this study have been reported as volatile constituents of thermally processed lipidrich food products, 21,29,32 indicating that the mechanisms explained play a role in the formation of food volatiles.…”

Changes in SPME-extracted volatile compounds from Iberian ham during ripening

“…Fat content has a marked effect on the release of the volatile compounds from meat products (Chevance and Farmer, 1999;Carrapiso, 2007), and also has an outstanding influence, as their fatty acid profiles does, on the generation of volatile compounds (Mottram, 1998;Elmore et al, 2002;Hidalgo and Zamora, 2004).…”

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation and fate: an example of the coordinate contribution of lipid oxidation and Maillard reaction to the production and elimination of processing-related food toxicants

“…The formed compound, which was an intermediate in the reaction, was found to be phenylacetaldehyde. 16 Therefore the first step of the formation of PhIP is the Strecker degradation of phenylalanine to produce phenylacetaldehyde (Scheme 2), a step that does not need the presence of creati(ni)ne but is facilitated in 60 the presence of reactive carbonyl compounds derived from carbohydrates, 24,25 lipids, 26 amino acids, 27 or polyphenols 28 (see below). Once phenylacetaldehyde is formed, the reaction between phenylacetaldehyde and creati(ni)ne is produced to form in a first step 2-amino-5-(1-hydroxy-2-phenylethyl)-1-methyl-1H-imidazol-4(5H)-one and then, after dehydration, 2-amino-1-methyl-5-(2-phenylethylidene)-1H-imidazol-4(5H)-one.…”

“…35 However, in the course of lipid oxidation, many compounds analogous to α-dicarbonyl compounds are produced which are able to degrade amino acids similarly to the α-dicarbonyl compounds derived from carbohydrates. 15 The Strecker degradation of amino acids produced by secondary lipid oxidation products was firstly described in 2004 for the formation of phenylacetaldehyde by phenylalanine degradation in the presence of epoxyalkenals, 26 and later extended to other lipid-derived reactive carbonyls. [36][37][38] aldehyde formation by lipid oxidation products is believed to be produced analogously to amino acid degradation by α-dicarbonyl compounds.…”