Analysis of fermentation characteristics, nutritional and flavor profiles of <i>Xuxiang</i> kiwifruit juice fermented by different lactic acid bacterial strains, and changes in antioxidant activity after <i>in vitro</i> digestion

Abstract

Abstract BACKGROUND Kiwifruit is nutrient‐rich but prone to postharvest spoilage. Conventional juicing results in a significant loss of bioactive compounds, which limits its functional value. RESULTS Xuxiang kiwifruit juice was fermented using three lactic acid bacterial strains: Limosilactobacillus fermentum , Lactobacillus acidophilus and Weissella . The highest fermentation performance was observed in juice fermented with L. acidophilus : the viable cell count in the L. acidophilus group was significantly higher by 3.54% compared to the Weissella ‐fermented group, reaching (2.8 ± 0.5) × 10 9 CFU mL −1 ( P &lt; 0.001). The total acidity increased by 87.01% relative to the unfermented sample, achieving 20.59 ± 0.01 g L −1 ( P &lt; 0.001). After 32 h of fermentation, the total phenolic content increased by 28.94% compared to the control, reaching 3.03 ± 0.03 g L −1 ( P &lt; 0.001), while the vitamin C content represented a 3.22% improvement over the Weissella group ( P &lt; 0.001). The succinic acid content increased by 24.32% compared to the unfermented control, reaching 1.12 ± 0.01 mg mL −1 ( P &lt; 0.0001). Notably, ethyl palmitate was produced during fermentation with L. acidophilus , contributing to a creamy aroma. During fermentation with Weissella , the contents of glutamate and glycine were increased, and the ABTS radical scavenging activity increased by 27.89% compared to the unfermented control, reaching 95.06 ± 1.22% ( P &lt; 0.0001). During fermentation with L. fermentum , the flavonoid content increased dramatically by 135.29% relative to the unfermented control, reaching 0.8 ± 0.05 g L −1 ( P &lt; 0.0001). After in vitro digestion, the ABTS radical scavenging capacity increased by 11.90% compared to the control, reaching 83.19 ± 1.27% ( P &lt; 0.01), and superoxide dismutase activity increased by 3.82%, reaching 30 736 U mL −1 ( P &lt; 0.05). Fermentation with L. fermentum elevated key aroma compounds, including ( E )‐2‐hexen‐1‐ol (22.54 ± 0.03%), 1‐nonanol (1.32 ± 0.02%) and ( E )‐1‐(2,6,6‐trimethyl‐1,3‐cyclohexadien‐1‐yl)‐2‐buten‐1‐one (4.06 ± 0.02%). This resulted in an enriched flavor profile characterized by grassy, floral and citrus, rose and honey notes, along with an enhanced perception of berry‐like sweetness. CONCLUSION The three lactic acid bacterial strains exhibited distinct functional advantages during kiwifruit juice fermentation, and L. fermentum demonstrated superior overall performance in both flavor compatibility and functional preservation. These results provide a technical basis for the development of high‐quality probiotic kiwifruit beverages. © 2025 Society of Chemical Industry.

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