The Research On The Model System Of Maillard Reaction And The Prepartion Of The Beef Flavoring

The effect on the compounds which have important contributions to the formation of beef aroma were investigated by using model system, when the reaction conditions of Maillard reaction were different. On the basis of the results of the model systems, beef flavoring whose aroma was closed to the natural beef aroma was prepared via Maillard reaction. The volatiles of beef flavoring were analysed by using dynamic headspace sampling(DHS) and gas chromatography-olfactometry- mass spectrometry(GC-O-MS). Dynamic headspace dilution analysis(DHDA) was also applied for the determination of the key aroma-active compounds of the flavoring. At the same time, in order to study the characteristic compounds of the flavoring obtained by this experiment, comparative analysis of different flavorings was carried on.The study on the model system has three parts. The first part, six different model systems reacted in different pH values conditions were composed of thiamine(V_B1), cysteine(Cys), ribose(R) and xylose(X).The results were as follows: the system containing thiamine and cysteine had the highest yield of 2-methyl-3-furanthiol(MF-SH) at pH = 5.5. The system containing thiamine, cysteine, ribose(or xylose) and the system being only composed of cysteine and ribose(or xylose) generated most MF-SH at pH = 5.5, and as the pH value increased, the yield of MF-SH decreased sharply. The system containing thiamine, cysteine, ribose(or xylose) and the system being only composed of cysteine and ribose(or xylose) had the higher yields of 2-furfurylthiol(FF-SH) at the pH≤6.0, the yield of FF-SH decreased significantly when the pH was greater than or equal to 6.5. Compared the four systems aforementioned, the systems containing ribose had the higher yield than the systems containing xylose when the pH was lower than or equal to 5.0. When the pH was greater than or equal to 5.5, the results were on the contrary. The second, different concentrations of methionine and xylose composed of three different model systems reacted in different pH conditions. All the three different model systems had the highest yield of 3-methylthiopropanal at the pH = 6.5. With the increase of the amount of methionine added (the same amount of xylose added), the production of 3-methylthiopropanal increased in three systems. But the increase ratio between them was not a linear relationship. The last part, the effect of various factors on the generation of 4-hydroxy-2,5-dimethyl-3(2H)-furanone(HDMF) were evaluated by orthogonal design. Primary and secondary effects of the order were as follows: rhamnose ﹥arginine﹥pH﹥proline﹥lysine﹥cysteine﹥fructose.On the basis of the results of the model systems, through two orthogonal experiments, the best formula of the beef flavoring via Maillard reaction were obtained. The results were as follows: rhamnose 0.3g, fructose 1.0g, cysteine 0.5g, lysine 0.6g, methionine 0.3g, arginine 0.8g, xylose 1.2g, thiamine 0.8g, salad oil 4g, salt 1g, phosphate buffer 60ml (0.2M, pH = 6.0), reaction temperature 120℃, reaction time 60min. Thirty-three aroma-active compounds were identified by using DHS and GC-O-MS. The key aroma-active compounds identified by DHDA were as follows: 2,3-butanedione, hexanal, nonanal, 1-penten-3-ol, dihydro-2-methyl-3(2H)-furanone, 1-octen-3-one, furfural, pyrrole, 2-methyl-3-furanthiol, (E)-2-heptenal, dimethyl trisulfide, 2-furfurylthiol, acetic acid, 3-methylthiopropanal, (E,E)-2,4-decadienal and 4-hydroxy-2,5-dimethyl-3(2H)-furanone. Among them, the most important odorants were 1-octen-3-one(mushroom), 2-methyl-3-furanthiol (meat, vitamins) and 2-furfurylthiol (roasted, meat).Compared with other different commerical beef flavorings, the flavoring gained from this experiment had more compounds of caramel and fat notes. The compounds of fat note were (E)-2-heptenal, (E,E)-2,4-decadienal, (E,E)-2,4-octadienal and the compounds of caramel note were HDMF, furfural dihydro-2-methyl -3(2H)-furanone.Our research investigated effects of reaction conditions on the formation of compounds which have important contributions to the formation of beef aroma, such as 2–methyl-3-furanthiol, 2-furfurylthiol, 3-methylthiopropanal and so on. On the basis of the results of the model systems, the beef flavoring was prepared. To our knowledge, such study has not been reported in China.In this paper, the key aroma-active compounds were analysed by using GC-O-MS and DHDA. We hoped that the results of this study would be helpful for the preparation of beef flavoring and food flavor analysis.