Title:
Sensory characteristics and consumer acceptability of beef stock containing glutathione Maillard reaction products prepared at various conditions.

Abstract:
The sensory characteristics and consumer acceptability of beef soup samples containing 9 types of glutathione Maillard reaction products (GMRPs) were investigated to examine the effects of the GMRPs produced under different reaction conditions on the flavor of the beef soup. The sensory characteristics of the beef stocks were examined using descriptive analysis. In consumer testing, 50 consumers evaluated the overall acceptability and flavor intensities of beef odor, salty taste, beef flavor, and seasoning flavor in the beef soup samples. It was found that the reaction conditions, including sugar type and pH, affected the sensory characteristics of the beef stock containing the GMRPs. The samples containing the GMRPs reacted at pH 7 were characterized with strong beef flavor, chestnut flavor, and cooked rice flavor. However, the GMRP reacted with xylose at pH 7 (XM7) was significantly stronger in beef-related sensory characteristics than the GMRPs reacted with glucose or fructose at pH 7 (GM7 and FM7). The samples containing the GMRPs reacted at pH 3 had strong acid-related attributes whereas the GMRPs reacted at pH 11 exhibited strong sulfur-related attributes and a bitter taste. Overall, the beef soup containing XM7, which was perceived as having a strong beef odor and flavor, was rated the highest consumer acceptability score. This suggests that XM7 has feasibility as a flavor enhancer. To elucidate its effectiveness further, it is required to apply XM7 in various food systems at varying levels and to compare its flavor enhancing effects with other flavor enhancers such as monosodium L-glutamate in future studies. Practical Application: This study characterized sensory attributes of glutathione Maillard reaction products (GMRPs) reacted under various conditions and evaluated their potential as a flavor enhancer by examining consumer acceptability of beef stock containing the GMRPs. This study showed that the GMRP reacted with xylose at pH 7 had strong 71 beef flavor and the highest consumer acceptability score. The results of this study will provide valuable information for understanding sensory aspect of flavors generated by Maillard reaction of GSH and sugars, since most studies on Maillard reaction focused on chemical reactions. Also, the outcome of this study will help flavor and food industries' efforts to develop a new flavor enhancer for use in a variety of processed food products.