Volatile and non-volatile profiles in jujube pulp co-fermented with lactic acid bacteria

Jujube has become a popular food because of its abundant nutritional elements, but its main consumption in dried form exhibits challenging industrial processing. In current study, the effect of lactic acid bacteria co-fermentation with a mixture of Lactobacillus plantarum, Lactobacillus rhamnosus GG, and Streptococcus thermophilus on volatile and non-volatile profiles of jujube pulp was investigated, with the aim to discover potentially novel products. Using headspace solid phase microextraction coupled with gas chromatography-mass spectrometry, most acids and alcohols in jujube were significantly increased before 12-h fermentation. Seven active aromas, identified by gas chromatography–olfactometry and odor activity values were altered significantly after fermentation. A total of 36 significantly differential non-volatiles were identified using ultrahigh-performance liquid chromatography coupled with quadrupole-orbitrap mass spectrometry and multivariate statistical analysis during fermentation. These non-volatiles were mainly involved in the amino acid and lipid metabolism pathways. Using Spearman correlation analysis, we found that the relative expression of 13 non-volatiles exhibited significant correlations with 7 active aroma compounds after fermentation. This study identified the metabolic differences in fermented jujube and provides clues that could improve the sensory quality of lactic acid bacteria co-fermentation products.