The nutritional quality and flavor profiles of Sandiao soup made by the traditional refinement process

Sandiao soup is a classic feature of Huaiyang cuisine. This study analyzed the changes in Sandiao soup’s nutritional components and flavor compounds during its production via the traditional refinement process, with a focus on determining the changes in the pH, salinity, color, calorific value, and amino acid and nucleotide composition of the soup during the suspension part of this process. The changes in the main components and flavor compounds of Sandiao soup were analyzed using an electronic tongue and electronic nose and by gas chromatograph–ion mobility spectroscopy (GC-IMS). As the simmering time of the soup increased, its pH decreased, salinity and solid content increased, clarity increased, and brightness decreased, correlating with the highest sensory score. In addition, as the suspension time of the soup increased, its nucleotide content increased (particularly its concentration of inosine monophosphate and guanosine monophosphate, which are significant flavor components in the soup), and the concentration of free amino acids increased, with the concentrations of alanine and glutamic acid being the highest. Principal component analysis revealed that the taste of the soup changed during the suspension process. GC-IMS analysis identified 35 flavor compounds in the soup and showed that aldehydes (particularly nonanal and hexanal), alcohols, ketones, and esters made the greatest contributions to the flavor. The best results in terms of color, flavor, and other organoleptic indicators were achieved when the stock was processed three times. Overall, the results show that Sandiao soup becomes enriched in nutritional components and key flavor compounds as the suspension time during its processing increases.