Impact of ultrasonic treatment on volatile components in pumpkin juice by gas chromatography–mass spectrometry and electronic nose

Gas chromatography-mass spectrometry (GC–MS) and electronic nose (E-nose) techniques were used to study the effect of ultrasonic (US) retention on the volatile components of freshly squeezed pumpkin juice. The investigation found that the volatile components in pumpkin juice varied depending on the ultrasonic method (ultrasonic power at 0—400 W, treatment time 0—20 min, and temperature 10—40 ℃). As power increases, temperature decreases, and processing time increases, the number of components detected increases. In particular, the concentration of aroma components in pumpkin juice treated after 200 W, 10 min, and 10 ℃ were 1.21, 0.99, and 1.23 times higher than that in the control group, respectively. The aroma characteristics of pumpkin juice showed that ketones, alcohols and ester compounds are its main aromatic substances. Compared to untreated pumpkin juice samples, ultrasonic treatment resulted in the formation of new compounds or the elimination of compounds present in untreated samples. The results of electronic nose, GC–MS and sensory evaluation showed that ultrasonic better preserved the flavour of pumpkin juice. The results of this study improve our understanding of the application of ultrasonic in enhancing the volatile components of pumpkin juice.