| Summary: | 碩士 === 國立宜蘭大學 === 食品科學系碩士班 === 108 === In the food industry, meat flavor is often simulated by simply blended with natural extracts, or isolated and identified the components in meat by GCMS, then reconstructed and reformulated the meat flavor with related chemicals or by thermal reaction through Maillard reaction. The most popular one is the thermal reaction. The meatlike process flavor is the one through thermal reaction. The meatlike process flavor is prepared by using two or more flavor precursors and heated under specific conditions to carry out the Maillard reaction. The benefits of using meatlike process flavor are reduction of manufacture cost, compensation the aroma defects of the food itself and giving the food a desired and attractive meaty aroma. In this study, the types and composition ratios of meatlike process flavors were determined by Xu (2014). It was used to investigate the effect of reaction conditions, such as heating time, heating temperature and the condition of pH, on the flavor profile of meatlike process flavors manufactured by Maillard reaction under model systems. The volatile compounds in the product was analyzed by HS-SPME-GCMS. The browning intensity of the product was monitored by the ELISA reader. Descriptive test and consumer test were applied to understand the characteristics of the product, the intensity of the meat flavor, and to find out the consumer's preference for the product. Finally, through statistical analysis to comprehensively determine the relationship between the sensory characteristics of the product, volatile substances and the overall acceptance of the consumer. The results showed that in the pH 7 and 120°C mode system, the amount of most flavor compounds increased over the time heating, but the types of volatiles does not change much. At 30 min of heating time, the mercaptans were the most abundant compounds in the model system, which perceived like pork soup, baking and stewing notes. When the heating time was extended over 60 min, the amount of thiophenes increased sharply, the aroma of which was related to pork, baking, smoky, dried meat, sauce. The total amount of volatile compounds began to increase at 90 min, and the flavor profile corresponding to umami. When the heating time reached 120 min, the thiophenes increased with the largest extent, the furans decreased, and its aroma was related to barbecue and salty. In terms of overall consumer acceptance, the overall acceptance of the sample with a reaction time of 30 min was the highest, but the statistical significant of all products was not different. In the pH 7 and 60 min mode system, different reaction temperatures mainly affect the type of volatile compounds and their thermal stability. When heated at 80°C and 100°C, aldehydes are the majority products, which has chicken flavor characteristics, and the product at 100°C has broth, stew, salt, and fresh flavor. At 120°C, the volatile compounds synthesized are mainly furans, mercaptans and thiophenes, and the products at 120°C are with dried pork and sauce connotation. At 140°C, almost all types of volatiles are at their maxmum quantity, eg. the aldehydes, mercaptans, thiophenes and furans, and pyrazines and ketones began playing an important role in aroma profile. Products at 140°C have smoky, barbecue, burnt flavor and pungent flavor, which was the most unacceptable product for consumers. In the 120°C and 60 min mode system, the pH of the reaction has a crucial influence on the types and yields of the reaction products, with a slightly change the aroma characteristics altered dramatically. The formation of mercaptans and furans were facilitated in the acid environment. The products of pH 4 have the aroma characters of pork soup, salty, sauce, chicken, stew and smoky, and that of pH 6 has cooking characteristics. The products in the model system of pH 8 are mainly thiophenes. It has dried meat, burnt, grilled, and roasty nunance. Under condition of pH 10, the maximum amounts of volatile compounds are produced, the majority components are pyrazines and thiazoles, and It is the most unacceptable product for consumers with pungent, odor and plastic odors.
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