Correction of the Carbohydrate Composition of Raw Materials for Microbial Transformation Based on Microbial Consortia

Abstract

Introduction. Fermentative processing of plant raw materials is traditionally carried out using native (epiphytic) microflora, which is located on the surface and represented by lactic acid microorganisms. During this process, the carbohydrates in the raw material are metabolized into lactic acid. This process does not always result in optimal product quality as the raw material often lacks carbohydrates, the optimal conditions for the development of the target microflora are hard to achieve, the microflora might be inhibited by contaminants, etc. Lactic acid microbial consortia can act as a good alternative to spontaneous fermentation of cabbage as this method creates good conditions for the microbial synergistic interaction. Such fermentation process can be controlled by adjusting the carbohydrate composition of the substrate. The research objective was to develop an analytical approach to determine the minimum required degree of change in the native carbohydrate composition of substrate that would ensure the synergy of lactic acid microorganisms. Study objects and methods. The fermentation process was performed using white cabbage of Slava variety and such strains of lactic acid microorganisms as Lactobacillus casei VCM 536, Lactobacillus plantarum VCM B-578, and Lactobacillus brevis VCM B-1309, as well as their paired consortia. The raw material was subjected to grinding, and the epiphytic microflora was removed to create optimal conditions for the development of the lactic acid microflora. Results and discussion. The study made it possible to define the dynamics of carbohydrate fermentation in white cabbage by various strains of lactic bacteria and their paired consortia during processing. Mathematical models helped to describe the dynamics of glucose and fructose fermentation. The experiment also demonstrated the changes that occurred in the interaction within the paired consortia during fermentation. The paper introduces a new approach to determining the minimum required degree of change in the native carbohydrate composition required to ensure synergy of lactic acid microorganisms in paired consortia. Conclusion. The research defined the necessary amounts of carbohydrate needed to shift the integral factor of mutual influence towards sustainable synergy for three paired consortia. Consortium L. brevis + L. plantarum + 3.65 g/100 g of fructose proved to be the optimal variant for industrial production of sauerkraut from white cabbage of Slava variety. The developed approach can improve the existing industrial technologies of fermentation and create new ones.

Keywords

• fermentation
• white cabbage
• lactic acid microorganisms
• consortia
• model medium
• carbohydrate digestion