Abstract:This study aimed to clarify the change of myofibrillar protein-bound Nε -（carboxymethyl）lysine（MP-bound CML）after simulated gastrointestinal digestion by fluorescence microscope，sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE），tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis（Tricine-SDS-PAGE）and particle size analyzer.After gastrointestinal digestion，the hydrolyzed products were divided into four classes by ultrafiltration according to molecular weight（greater than 5 kDa，between 3 kDa to 5 kDa，between 1 kDa to 3 kDa and less than 1 kDa）.The contents of CML in different molecular weight components was determined by high performance liquid chromatography-triple quadrupoletendem mass spectrum （HPLC-QQQ-MS/MS）.Results showed that the particle size of MP-bound CML was gradually decreased during the simulated gastrointestinal digestion in vitro.After digestion for 360 min in intestinal phase，the particle size of MP-bound CML hydrolysates was concentrated in the range of 100 nm to 1 000 nm.The molecular weight were mainly less than 17 kDa.Bound CML with molecular weight less than 5 kDa accounted for 68.5%of MP-bound CML hydrolysates.In particular，bound CML with molecular weight less than 1 kDa accounted for 8.9%.This finding would provided some basic support for exploring the mechanism of intestinal absorption of protein-bound advanced glycation end-products（AGEs）in foods.