Optimization of lactic fermentation parameters of sugar beet (Beta vulgaris L.) puree with Lactobacillus plantarum and Lactobacillus casei

The increasing demand for probiotic fermented plant products rich in bioactive and prebiotic compounds prompted a study on the lactic fermentation of sugar beet. The objective was to create a functional probiotic product by exploring the synergy between probiotics and media. The lactic fermentation process utilized two strains, Lactobacillus plantarum and Lactobacillus casei, which were evaluated at different concentrations in both single (Phase A) and mixed (Phase B) applications. Critical parameters analyzed included fermentation duration, CSL, whey, and glucose syrup, with a focus on their impacts on betaine levels, probiotic viability, antioxidant capacity, pectin content, sugar, lactic acid, and acetic acid. Through response surface methodology, optimal conditions were determined: for the A-L. casei sample, conditions comprised 4.78% inoculation, 9.64% syrup, 1% whey, and a fermentation period of 39.96h, resulting in 1.833 mg/ml of betaine and an antioxidant activity of 491.5 µm. The A-L. plantarum sample exhibited 5% inoculation under similar conditions, yielding 1.863 mg/ml of betaine. In the mixed B sample, the optimal conditions were identified as 4.90% inoculation (with 32.28% L. plantarum and 25.03% L. casei), producing 1.38 mg/ml of betaine after 66.28h. These optimized samples hold significant potential as ingredients for the development of functional products.