Beetroot ketchup as a stable carrier of potential probiotic Lacticaseibacillus rhamnosus K3 and Lactobacillus johnsonii K4: A study on sensory attributes, storage viability, and in vitro gastrointestinal survival

This research aimed to assess the viability of Lacticaseibacillus rhamnosus K3 and Lactobacillus johnsonii K4 in beetroot ketchup during storage and simulated digestion to examine fermentation effects on sensory quality. The findings revealed that both strains maintained viability above 8 log₁₀ CFU/ml during storage, confirming their potential as probiotics. pH levels changed significantly over three-week storage period indicating fermentation's impact on shelf stability. The control sample maintained consistent pH level of 4.6, while pH of ketchup fermented with L. rhamnosus K3 decreased from 3.84 to 3.79, and ketchup fermented with L. johnsonii K4 decreased from 3.96 to 3.69. Sensory evaluations showed statistically significant differences in odor, texture, flavor, and overall quality between samples. Fermentation with L. johnsonii K4 improved sensory attributes, achieving the highest overall quality score with mean value of 7.31 out of 10, compared to 6.28 for the control and 6.23 for the L. rhamnosus K3 fermented ketchup. Survival rate of L. johnsonii K4 was 27 %, compared to 2.8 % for L. rhamnosus K3 in dynamically simulated gastrointestinal system TIM-1. Both fermented ketchups contained over 10⁹ CFU of viable cells. These results demonstrate that plant-based food products can effectively serve as carriers for potential probiotic strains, preserving their viability during storage and digestion, while enhancing sensory quality of food products.