Study On Coffee Aroma Anlysis And Technology Of Preparation Of Coffee Flavor With Maillard Reaction

The different aroma of six kinds of coffee were determined by sensoryevaluation, the electronic nose and GC-MS to establish a standard for providing atheoretical basis to prepare coffee flavor. The coffee flavor was prepared by Maillardreaction and the optimum conditions were determined by PB experiment and uniformdesign. The stability of the product in different food application and the optimumconditions were studied. The main results were as followed:(1) The six kinds of coffee had different aroma characteristics. There were thestrongest caramel and resin flavor in Colombian coffee; Espresso released the mostintense chocolate flavor, fragrance of flowers and grass fragrance; The most obviousfruit aroma appeared in Kenya coffee as well as nutty flavor and spice flavor, charcoalin Vietnam coffee. In terms of general characteristics of volatile flavor, espresso,Javan coffee, Kenya coffee and mandheling coffee were similar, and Vietnam coffeeand Colombian coffee were similar. The chemical compositions of six kinds of coffeesamples were analyzed by GC-MS, combining with others’ studies, so as to determinethe relative ratio of the content of2–furfurylthiol, pyrazine substances and furanketones in the aroma materials of Arabica coffee and Robusta coffee so that thecriteria of coffee flavor was established by the integrated index of sense, theelectronic nose and gas chromatography-mass.(2) According to the PB test, the materials of the coffee flavor of Maillardreaction were lysine (1.17g), methionyl acid (0.20g), phenylalanine (0.56g), tyrosine(0.95), fructose (6g) and glucose (2g). The optimum conditions were determined. Thetemperature, the moisture content and the pH value of this system were respectively110℃,15%and9.5. The range of time was20-60min. The aroma of coffee flavorprepared by the optimum conditions was similar with that of Colombian coffee.Particularly, both were relatively close in terms of floral, fruity and scented grass. Thearoma of coffee flavor had relatively large difference from natural coffee in sensor S1,S2, S5, S6, S7, S10, however, less difference in sensor S3, S4, S8, S9. Two kinds ofpyrazine compounds one furan compound were analyzed by GC-MS in this coffee flavor. The content ratio was5.17:1, which was smaller than that of these substancesin natural coffee.(3) The aroma of coffee flavor used in cakes was affected by the content of sugar,baking time, baking temperature so as to change its flavor. Used in tea, the aroma ofcoffee flavor was influenced with the increase of heating time. Whereas used in icecream, the change of process conditions hadn’t a great impacts on the coffee flavor.