Effects of air temperature on the physicochemical properties and flavor compounds of roasted red ginseng lateral roots in a jet impingement fluidized bed roaster

摘要

This study aimed to improve the availability of red ginseng lateral roots by applying air jet impingement fluidized bed roasting as a novel processing technology. The effects of air temperature (150 degrees C, 160 degrees C, 170 degrees C, 180 degrees C, 190 degrees C, and 200 degrees C) on the physicochemical properties and flavor compounds of red ginseng lateral roots were investigated. The air roasting time and velocity of the jet impingement fluidized bed roaster were 10 min and 21.68 m s-1, respectively. The moisture content and bulk density significantly decreased, while the total weight loss, expansion index and specific volume significantly increased as the temperature increased (p < 0.05). The extraction yields significantly increased by 38.34% at 200 degrees C compared with unroasted samples (p 0.05). The high-temperature roasted sample had larger and more porous structures on their surfaces than the unroasted sample in the scanning electron microscope images. The major ginsenosides (Re, Rg1, Rb1, Rc, Rb2 and Rd) peaked at 150 degrees C or 160 degrees C, whereas the minor ginsenosides (Rh1 and Rg2) peaked at 190 degrees C or 200 degrees C. Furfural and maltol increased 444 and >10 times in the roasted samples at 200 degrees C and 170 degrees C, respectively, when compared with the unroasted samples.