Effects of Different Particle Sizes of Ultrafine Indica Rice Flour and Lactobacillus casei on the Fermentation and Flavor Characteristics of Danling Dongba.

This study aimed to enhance the flavor and quality of Danling Dongba, a traditional fermented rice product, by preparing ultrafine indica rice flours using fluidized bed airflow crushing. Flours with particle sizes of 20.16, 17.16, and 12.22 μm were fermented with Lactobacillus plantarum 550 (L. plantarum 550), Lactobacillus fermentum GF1800 (L. fermentum GF1800), and Lactobacillus paracasei S6 (L. paracasei S6) under optimized conditions. The 12.22 μm flour showed the best performance, with a water absorption index of 2.32 g/g, solubility of 2.05%, swelling power of 9.26 g/g, and peak viscosity of 7632.53 cP. Solid-phase microextraction coupled with GC × GC-MS revealed that Lactobacillus fermentation increased volatile flavor compounds from 42 (unfermented) to 72. Notably, L. plantarum 550 enhanced fruity esters such as ethyl caprylate (1.18%), while L. paracasei S6 enriched milk-like ketones such as 3-hydroxy-2-butanone (1.54%). These findings demonstrate that optimizing flour fineness and Lactobacillus strains can significantly improve the flavor complexity of Danling Dongba, offering a scientific basis for its standardized production and industrial development.