Effects of fermentation by lactic acid bacteria with flocculating activity on the structure and physicochemical...

The sour liquid method is considered to produce starch with superior physicochemical properties that are more appropriate for producing traditional oriental foods. However, the actual production process is often affected by external environmental factors, and the fluctuation of the bacterial community in sour liquid can significantly affect the production of starch and the quality of the final product. LAB in sour liquid plays a major role in starch production. Therefore, it is important to explore the effect of LAB fermentation with flocculating activity on the structure and properties of starch. We investigated the effect of fermentation by Schleiferilactobacillus harbinensis LJ5 with flocculating activity on the structure and physicochemical properties of pea starch. During the 72 h of fermentation, amylose content of pea starch first increased and then decreased slightly. Amylopectin long chains decreased significantly after fermentation, while short chains increased significantly. Fermented pea starch granules exhibited obviously pocked and dimpled surfaces, and S. harbinensis LJ5 was observed to adhere to the surface of starch granules. Relative crystallinity and short-range order degree of pea starch significantly increased as fermentation progressed, whereas the crystal structure (C-type) remained unchanged. Fermented samples exhibited enhanced pasting viscosity, breakdown, setback, and gelatinization enthalpy compared with native pea starch, while also having lower pasting temperature. Fermentation also improved the gel textural properties of pea starch. In conclusion, this study provides a theoretical basis for future industrial production of starch by the sour liquid method of fermentation with pure species of microorganisms.