Dynamic changes of physicochemical properties, sensory attributes, and flavor profiles in hawthorn berry juice fermented by lactic acid bacteria strains

Dynamic changes in physicochemical properties, aroma/taste substances, and sensory attributes were investigated in hawthorn juice co-fermented by Lactiplantibacillus plantarum and Lactobacillus casei within 0-60 h. Fermentation significantly improved sensory quality of hawthorn juice and induced obvious color changes (ΔE > 3), with viable cell count reaching more than 7.5 lg CFU/mL after 36 h-fermentation. The sweet, floral, and fruity aroma attributes increased significantly by 73.8%, 10.5%, and 9.9%, respectively, meanwhile, astringency declined after fermentation, thereby improving sensory acceptability. Especially, sweetness increased markedly by 28.3%, which might be related to the cross-modal effect of aroma on taste perception. The number of aroma compounds increased from 17 to 49 after fermentation, and the odor activity values of linalool/α-terpineol were significantly elevated from 395.26/10.58 to 748.67/22.64, which enhanced the fruity/floral aroma and was consistent with sensory results. Although organic acids increased while sugars and amino acids decreased, fermented hawthorn juice exhibited mild acidity, probably due to substance conversion as well as flavor synergy and masking effects. Additionally, 33 compounds were identified as key markers during fermentation, including α-terpineol, hexyl acetate, glycine and citric acid etc. This study provides valuable insights for the development of hawthorn juice with high flavor quality. • 32 aroma compounds were newly detected in hawthorn juice after LAB fermentation. • Fermentation time remarkably affect hawthorn juice flavor with the best at 24-36 h. • LAB enhanced fruity/floral aroma of juice, and decreased bitterness/astringency. • Fermented juice had a mild acid due to compounds conversion or flavor perception. • α-Terpineol, nonanal, glycine, citric acid, etc. were key markers after fermentation.