Preparation and Key Aroma Components Analysis of Jujube Flavor Fermented Juice

Jujube is rich in nutrition, and there are numerous jujube flavored processed foods made from dried jujube, among which fermented products have attracted much attention. To study the flavor characteristics of co-fermented jujube juice, a mixed culture fermentation agent composed of Lactobacillus plantarum and Pichia pastoris was constructed. The preparation process of fermented jujube flavor juice was optimized through single factor and response surface design experiments. The two pre-treatment methods, headspace solid phase micro-extraction (HS-SPME) and solvent-assisted flavor evaporation (SAFE), were used for gas chromatography-mass spectrometry olfactometry (GC-MS-O) and aroma extraction dilution analysis (AEDA) to identify the key aroma components of fermented jujube flavor juice under the optimized process. The results showed that the optimized parameters for fermented jujube flavor juice preparation process were inoculation amount of 3.0%, pre-inoculation pH 4.75, fermentation time 18.17 h (18 hours and 10 minutes), fermentation temperature 33.9 ℃, and fermentation rotation speed 120 r/min, with the highest sensory score 8.27. Through GC-MS analysis, a total of 48 volatile components were detected, mainly including 12 acid compounds and 10 ester compounds. GC-O analysis showed that HS-SPME had a good extraction and enrichment effect on the aroma components of fermented jujube flavor juice. Finally, through AEDA, β-damascenone, phenylethyl alcohol, phenylacetaldehyde, ethyl tetradecanoate, methyl dodecanate, pentanol, hexanoic acid, cedrol, and methyl decanoate were identified as the key aroma components in fermented jujube flavor juice.