Investigation on taste-active compounds profile of brown sugar and changes during lime water and heating processing by NMR and e-tongue

Brown sugar contains large amount of taste-active compounds. However, the effect of lime water and temperature on brown sugar processing has not been systematically studied. Herein, the NMR and e-tongue were used to analyze the taste-active compounds and taste characteristics of sugarcane juice, syrup and brown sugar. The results showed that during the clarification stage, lime water decreased phenolic acids with simple structure, but increased sugars and umami amino acids, thus increasing the sweetness and umami of sugarcane juice. However, during the evaporation stage, both lime water and high-temperature heating accelerated the Maillard reaction and caramelization of the syrup. During the concentration stage, temperature had the greatest influence on the taste in the processing of brown sugar. Under vacuum heating, it could retain more sugars, amino acids, organic acids and phenols, thus increasing sweetness and umami; meanwhile, it could reduce color, thus reducing bitterness and astringency. These data indicate that the taste-active compounds and taste characteristics of brown sugar can be improved by membrane filtration (without lime water) and vacuum heating.