Effect of heating treatment on in vitro digestibility of protein and 5-hydroxymethylfurfural formation in pork meat

In this paper, effects of different boiling times on protein digestibility in pork meat were investigated by in vitro digest model.Moreover, degree of modification of pork protein by boiling treatment was examined through 5-hydromethylfurfural ( HMF) content as indicators.Results showed that in vitro digestibility of pork protein increased after boiling treatment for 10 to240 min.Moreover, the content of free amino group increased firstly and then decreased with the increase of boiling time.Color analysis indicated that color of pork samples became dark, and L^*a^*b^*values increased after boiling treatment. Boiling in water ( greater than 120 min) caused great change of color value, which was above 4.0 and influenced appearance of pork samples.The content of intermediates HMF increased with the increase of boiling time, which indicated degree of modification of protein increased.The variation trend was consistent with that of in vitro digestibility of protein in pork meat.Thus, heat treatment significantly improved the in vitro digestibility of proteins in pork, while overheating treatment affected the color and protein digestibility of pork.So, 5-HMF formation and color indexes are proposed as useful indicators for monitoring damage of protein during the heating treatment of pork.