Preparation and bioactivity of probiotic-fermented lotus seed and lily bulb beverage

Introduction Lotus seeds and lily bulbs are rich in active components, including polysaccharides, flavonoids, polyphenols, and saponins, which exhibit a range of biological activities such as antioxidant, anti-inflammatory, and immune-regulating properties. Consequently, lotus seeds and lily bulbs find extensive applications in the food and cosmetics industries. Method First, lotus seeds, lily bulbs, and their mixtures were fermented using 19 probiotic strains including Saccharomyces and Lactobacillus. The fermentation methods and strains were screened by comparing the total polysaccharide and total flavonoid contents in the fermentation products under different strains and fermentation methods. Second, single-factor and response surface optimization methods were employed. Using Design-Expert 10 software for Box-Behnken experimental design, with free radical scavenging rate as the response value, three factors affecting the polysaccharide content of the lotus seed and lily bulb fermentation broth were investigated: fermentation time, material concentration, and temperature. Third, the safety of the fermentation products under optimized conditions was evaluated using the chicken embryo chorioallantois membrane as an alternative model for in vitro eye irritation testing. Fourthly, LPS-induced mouse macrophage cell line RAW264.7 monocytes were used as a cellular inflammation model, H 2 O 2 -induced human immortalized keratinocytes (HACAT) as a cellular oxidation model, and mouse melanoma cells B16-F10 to evaluate the in vitro anti-inflammatory, antioxidant, and melanin-inhibiting effects of the fermented products. H 2 O 2 -induced zebrafish embryos were employed as an animal oxidation model, copper sulfate-induced zebrafish as an animal inflammation model, and zebrafish larvae to assess the in vivo anti-inflammatory, antioxidant, melanin-inhibiting, and skin-whitening effects of the fermented products. Additionally, the TCC method and K-B disk diffusion method were used to test the inhibitory effects of the fermented products against common acne-causing pathogens such as Staphylococcus aureus, Propionibacterium acnes, and Staphylococcus epidermidis. Result Lactobacillus plantarum L-08 was selected as the dominant strain for fermentation from a pool of 20 probiotics. The optimized fermentation conditions were established as follows: fermentation temperature of 28°C, a feed-to-liquid ratio of 1:35, fermentation time of 48 h, and an inoculation rate of 1%. Probiotic fermentation significantly enhanced the antioxidant and anti-inflammatory biological activities of the lotus seed lily mixed fermentation broth. In cellular experiments, the safe concentration range of the lotus seed lily fermentation broth for various cell types was determined to be between 0.625 and 10%. In the HACAT cell oxidation model, the lotus seed lily fermentation broth significantly increased total antioxidant capacity. In the RAW 264.7 macrophage model, it effectively inhibited the production of inflammatory mediators. In the B16-F10 melanoma cell model, it inhibited melanin synthesis pathways, demonstrating significant whitening effects. In zebrafish injury experiments, the lotus seed lily mixed fermentation broth significantly improved the total antioxidant capacity of zebrafish within the concentration range of 2.5–10%, while also exhibiting anti-inflammatory effects. In chicken embryo chorioallantois membrane experiments, the lotus seed lily mixed fermentation broth did not induce significant damage to the chorioallantoic membrane vessels, thereby proving its safety. A comparative analysis between unfermented group and probiotic fermented group verified that probiotic fermentation significantly enhanced the antioxidant and anti-inflammatory biological activities of the lotus seed lily mixed broth. Discussion Lotus seed and lily hybrid fermentation liquid has antioxidant and anti-inflammatory biological activity, and has exhibited low cytotoxicity with cell viability above 90%, which can expand its application in health care, cosmeceutical application.