Properties and volatile profile of process flavorings prepared from d-xylose with glycine, alanine or valine by direct extrusion method

This study investigated the production of process flavorings by direct extrusion method using a model system consisted of 80% (w/w) d-xylose and glycine, alanine, or valine at 20% (w/w). The extruder's barrel temperatures were controlled at 65, 80, and 50 °C. The aroma compounds in the obtained products were analyzed by gas chromatography-mass-spectrometry (GC-MS). Some properties relevant for food application including solubility, water absorption index, and oil absorption capacity were also determined. Characteristics and color profiles of the extruded flavorings were similar to the process flavorings obtained by conventional method (reflux method). Process flavorings using valine presented the highest L* value (lightness, 59.65), water absorption index, water solubility index, and oil absorption capacity at 3.26 and 1.76 g/g sample, and 2.72 g oil/g, respectively. Use of glycine resulted in the highest frequency of just-about-right for the taste (60%), while alanine gave the highest frequency for odor (53.3%). The extruded flavorings exhibited sweet, sour, and meaty flavor with 13 and 12 volatile compounds from glycine and alanine. When valine, the higher molecular weight amino acid in the bitter group was used, 37 volatiles with more complex flavor profiles were found, among of which, the compound 5-methyl-2-phenylhex-2-enal, which exhibits a chocolate odor, was also present. Sweet and meaty process flavorings could be produced by direct extrusion using d-xylose and glycine, alanine, and valine, with low moisture content at only 5% by weight. The information obtained about their physical, taste and sensory properties, volatile profiles, are beneficial for further use in industrial applications.