Analysis on the flavor characteristics of Rosa roxbunghii juice with different carbon sources fermented by lactic acid bacteria based on electronic nose and HS-SPME-GC-MS

In order to explore the effects of different carbon sources on the flavor of fermented Rosa roxbunghii juice, the flavor characteristics of R. roxbunghii juice (RRT-YM, RRT-ZT) with different carbon sources (corn flour, sucrose) fermented by Lactobacillus paracasei were analyzed by electronic nose combined with headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that the growth rate of lactic acid bacteria in RRT-YM was faster than that in RRT-ZT. The viable lactic acid bacteria counts reached the highest value of 8.69 lg CFU/g at 3 d, and the pH, soluble solid content and sensory score were 2.98, 2.93% and 24.93 points, respectively. Electronic nose analysis showed that sulfur compounds, terpenoids and aromatic substances accounted for more in RRT-YM than in other groups. The volatile flavor components analysis showed that RRT-YM had 20 types of volatile flavor components, and the contents of terpenoids, alcohols and aldehydes were higher than those of RRT-ZT. Among them, squalene, benzyl alcohol and octyl aldehyde were the unique volatile components of RRT-YM with high content of 5.21 mg/L, 4.24 mg/L and 2.99 mg/L, respectively, which contributed to the sweetness, fruit and citrus flavor of RRT-YM. In conclusion, the flavor of R. roxbunghii juice with corn flour as carbon source fermented by lactic acid bacteria was better.