## 1 Introduction  
Braised pork is a traditional Chinese cuisine made from pig meat, which is quite popular among ordinary people due to its mellow taste and fatty but not greasy characteristics. There are several kinds of braised pork, such as Maoist braised pork (peppery taste), Dongpo braised pork (soft and refreshing), and Shanghai braised pork (sweet salty palatability). However, in order to reach a perfect color and flavor, too much sugar need to be added added during the cooking of braised pork. This may not only result in the decline of the nutritional value of the food itself but also excessive sugar consumption has been identified as the major cause of excessive caloric intake and is the main dietary determinant of obesity or other civilization diseases.  
Recent researches have focused on the new sweeteners or seasonings as substitutions for sugar in food formulas [1; 2]. However, these sweeteners cannot produce intense aroma and color compared with the white granulated sugar. It is well known that Maillard reaction plays an important role in the generation of aroma and taste-active compounds of processed food [3]. Complete Maillard reaction products (MRPs) are usually used for savory flavoring [4]. They have been favored by consumers over the years and are found to be intriguing by researchers because of their rich fragrance. However, since most of the flavor components in MRPs are volatile, it is difficult to maintain the stability of flavored end products for application, especially during the heating treatment of cooking. The loss of aroma and fragrance makes MRPs limited in the application. During the initial stage of Maillard reaction, neither aromas nor melanoids are produced but significant non-volatile aroma precursors-Maillard reaction intermediate (MRI) are formed [5]. When heated, MRI undergoes dehydration and fission as the Maillard reaction progresses and generates colorless reductones and heterocyclic compounds [6]. Hence, the braised sauce with MRI as a flavoring additive cannot exhibit its flavor during primary processing or storage at room temperature but generates desirable flavor and color during cooking.  
However, there is lack of deep research on braised sauce with added MRI. Thus, the MRI from xylose-L-cysteine was prepared in an aqueous phase and its applications in braised pork were tested by gas chromatography-olfactometry (GC-O) with aroma extraction dilution analysis (AEDA) and odor activity values (OAV). Xylose, an albotenose, is one of the reaction precursors. It is also mainly used as an ideal sweetener because of its physical characteristics, such as being a non-digestible sugar and having zero calories. L-cysteine (cys) was an important precursor for the formation of sulphur compounds and has been extensively used in the manufacturing of reaction flavors. Many researches have been reported to detect aroma-active compounds using GC-O [7; 8; 9; 10; 11; 12]. In addition, in order to obtain the more comprehensive analysis of flavor compounds, solid phase microextraction (SPME) and simultaneous distillation and extraction (SDE) pre-treatment methods were compared.  
During this study, two types of braised pork were prepared, cooked with self-made braised sauce added with MRI (A) and white granulated sugar (B), respectively. The objectives of the present study were (1) to compare the sensory characteristics and aroma attributes of the two kinds of braised pork by descriptive sensory analysis, (2) to analyze and compare the volatile compounds by SPME/SDE-GC-MS, (3) to screen the characteristic aroma-active compounds as determined by AEDA and OAV, and (4) to assess through the above analysis and whether the self-made braised sauce containing MRI was recommended for new cooking methods for braised pork.