Investigation Of Maillard Reaction Type Time-temperature Indicator Monitoring Dietary AGEs At Consumer End

Dietary advanced glycation end products(AGEs)are the important source of endogenous AGEs.and the accumulation of endogenous AGEs is suggest to associated with the progress of diabetes as well as other chronic diseases.Therefore,it is necessary to strengthen the monitor of dietary AGEs.Nevertheless,there is still no effective means for dietary AGEs control at the consumer end.A Maillard reaction type time-temperature indicator(TTI)was built up to monitor dynamic changes of dietary AGEs.For consumers,the variation of dietary AGEs content could be obtained by observing the colour of TTI.and the fluorescent AGEs are selected as the marker of AGEs.(1)Preliminary study of Maillard reaction type TTIThe variation of colour and fluorescent AGEs was assayed in the reaction system with amino acids and monosaccharides.The generation rule of colour and fluorescent AGEs was similar.But the colour of food would cover up the variation of colour in reaction system.A Maillard reaction type TTI was built up to monitor dynamic changes of dietary AGEs.The result of screening experiment of Maillard reaction type TTI was shown that the optimized TTI reaction system consisted of 0.4 M lysine and 0.3~0.5 M xylose(diluted in pH 7.0 phosphate buffer).The end point of TTI was the absorbance of 1.2.The color change of TTI was clearly visible(colorless,yellow,orange,brown until dark brown)with the accumulation of time and temperature.(2)Dynamics and capability of Maillard reaction type TTITTI system was built with different concentration xylose included TTI-1(0.3 M xylose),TTI-2(0.4 M xylose)and TTI-3(0.5 M xylose).The activation energies of TTI-1,TTI-2 and TTI-3 were 96.17 kJ/mol,87.98 kJ/mol and 83.55 kJ/mol respectively.According to the principle of matching TTI with food quality,the range of activation energies of AGEs in food system matched with TTI system were 71.17 kJ/mol ~121.17 kJ/mol,62.98 kJ/mol ~112.87 kJ/mol and 58.55 kJ/mol ~108.55 kJ/mol respectively.According to the result of storage experiment,the reaction of TTI system was slow to respond in the cold and dark environment.But the TTI still occurred visible color change with the extension of time.Hence TTI need separate package between lysine and xylose in storage time.When TTI was actived,lysine and xylose mixed by mechanical force.(3)TTI monitoring AGEs in food model systemThe change of fluorescent AGEs was assayed in food model system(lysine/glucose system).The activation energy of fluorescent AGEs was 118.18 kJ/mol.According to the principle of matching TTI with food quality,the difference of activation energies between TTI-1 and fluorescent AGEs was 22.01 kJ/mol(less than 25.00 kJ/mol).It explained that TTI-1 could monitor fluorescent AGEs content in food model system.Non-isothermal test was also shown that TTI-1 could monitor the change of fluorescent AGEs perfectly.(4)TTI monitoring AGEs in foodThe change of total fluorescent AGEs was assayed in instant soy milk powder.The activation energy of total fluorescent AGEs was 93.78 kJ/mol.According to the principle of matching TTI with food quality,the difference of activation energies between TTI-1 and total fluorescent AGEs was 2.39 kJ/mol(less than 25.00 kJ/mol).It illustrated that TTI-1 could monitor total fluorescent AGEs content in instant soy milk powder.Other high AGEs foods were also assayed.The activation energies of soy sauce,milk powder,eight-treasure gruel and soybean paste were 75.55 kJ/mol、106.12 kJ/mol、62.95 kJ/mol and 81.04 kJ/mol respectively.According to the principle of matching TTI with food quality,TTI-1 was most suitable for monitoring total fluorescent AGEs content in milk powder,and TTI-3 was most suitable for monitoring total fluorescent AGEs content in soy sauce,eight-treasure gruel and soybean paste.And the design of TTI ensured the accuracy and security of application in instant soy milk powder.The Maillard reaction type TTI system was composed with lysine and xylose.The color change of the TTI was clearly visible during short time heating process.The TTI can be used to monitor dietary AGEs content and give an effective way for consumer to know AGEs content in food.