Content of free and protein‐binding N^ε‐carboxymethyllysine and N^ε‐carboxyethyllysine in different parts of braised chicken

Abstract

In order to illustrate the levels of advanced glycation end products (AGEs) in Chinese traditional braised chicken, the distribution of free and protein‐binding Nε‐carboxymethyllysine (CML) and Nε‐carboxyethyllysine (CEL) in four parts of processed chicken including chest (X), leg (T), skin (P), and the mixed whole body (M) was investigated. Our results showed that the content of free CML was 1,186.63–1,795.43 ng/g meat and protein‐binding CML was 11,693.91–16,122.90 ng/g meat. Differently, the content of free CEL was 24.81–41.62 ng/g meat and protein‐binding CEL was 270.11–385.49 ng/g meat. It was found that the total contents of CML were 31.5–56.8 folds higher than those of CEL. Protein‐binding AGEs (CML + CEL) were 6.6–9.9 times higher than those of free AGEs (CML + CEL). Pearson's correlation of AGEs and oxidation in four parts of braised chicken were also investigated, and the results showed that oxidation had a significant effect on levels of CEL; especially, the protein carbonyl was negatively correlated with free CEL (p < .05). TBARs value was significantly positively correlated with protein‐binding and total CEL (p < .01). In conclusion, our findings are important for better understanding of the AGEs formation in braised meat.

Investigating changes of proteome in the bovine milk serum after retort processing using proteomics techniques

“…The reason for this situation is heat treatment increased the protein modifications at the molecular level (Gathercole et al., 2017). Protein modifications that occur in bovine milk during heat treatment usually have a negative impact on its nutritional properties, such as the ε‐amino group of the lysine (Lys) residue of the protein side chain can be modified to Nε‐carboxymethyllysine, a type of lysine that reduces the digestibility of the protein (Zhu et al., 2020), thereby decreasing the digestibility and nutritional value of bovine milk proteins. According to the previous report, heat treatment can improve the digestibility of proteins in raw milk through denaturation, but this improvement may be offset by a decrease in protein digestibility due to protein modifications (Wada & Lonnerdal, 2014).…”

Dietary N‐epsilon‐carboxymethyllysine as for a major glycotoxin in foods: A review

“…Chen & Smith 2015;Cheng et al, 2021;Goldberg et al, 2004;Milkovska-Stamenova et al, 2015;Roldan et al, 2015;Scheijen et al, 2016;C. Sun et al, 2012;Uribarri et al, 2010;Zhu, Fang, Cheng, et al, 2020) contain enzyme-linked immunosorbent assays (ELISA), high-performance liquid chromatography-fluorescence spectroscopy (HPLC-FS), liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).…”

Effect of vacuum frying and atmospheric frying on the quality and protein oxidation of squid (Loligo chinensis)

“…The absorbance of the supernatant was determined at 532 nm and the value was presented as milligrams of MDA per kilogram of squid samples. The carbonyl content was determined through 2,4dinitrophenylhydrazine (DNPH) method (Zhu et al, 2020). Samples were dissolved in PBS (20 mM, pH 6.5) to homogenize and centrifuge.…”