•Glycation reduced gastric digestibility and altered gastric digested peptides.•Gastric and gastrointestinal digested peptides profiles were substantially changed by glycation.•Glycation showed less influence on β-CN digestibility due to its intrinsic disordered structure.•Non-crosslinked AGEs affect the digestion process to a lesser extent than crosslinked ones.α-Dicarbonyl compounds, which are widely found in common consumed food, are one of the precursors of advanced glycation end products (AGEs). In this study, the effect of glycation derived from glyoxal (GO), methylglyoxal (MGO) or butanedione (BU) on the in vitro digestibility of β-casein (β-CN) and β-lactoglobulin (β-Lg) was investigated. Glycation from α-dicarbonyl compounds reduced the in vitro digestibility of studied proteins in both gastric and intestinal stage. In addition, glycation substantially altered the peptides released through gastric and gastrointestinal digestion, as detected by liquid chromatography electrospray-ionization tandem mass spectrometry (LC-ESI-MS/MS). Crosslinked glycation structures derived from BU considerably reduced the sensitivity of glycated β-Lg towards digestive proteases, albeit to a lesser degree in glycated β-CN due to its intrinsic unordered structure. By contrast, non-crosslinked AGEs that formed adjacent to enzymatic cleavage sites did not block the enzymatic reaction in several cases, as evidenced by the corresponding digested peptides modified with glycation structures. These findings expand our understanding of the nutritional influence of α-dicarbonyl compounds and health impact of relevant dietary AGEs.Download high-res image (298KB)Download full-size image

The aim of this study was to produce diacylglycerols (DAG) by chemical glycerolysis of soybean oil at low temperatures. Solvents and low-frequency ultrasonic irradiation were introduced to enhance the reaction. Three operation modes, namely mechanical stirring, magnetic stirring and ultrasonic irradiation, were compared. In the solvent-free system, DAG formation was not observed in any of the three operation systems. DAG were formed when reactions were incubated in tertiary alcohols for all of the three operation systems. Interesting observations were found in the acetone system. Although DAG formation was negligible under mechanical stirring with classical propeller, a total of 52.0 ± 2.2% DAG was obtained when ultrasonic irradiation was used. The same content of DAG can also be obtained under magnetic stirring; however, a 4-h reaction was required. Acetone dosage (solvent:oil, wt:wt) 3:1 and 40 W ultrasonic power were suitable for the reaction system under the conditions studied.