Metabolism analysis for enhanced nutritional profile of chestnuts subjected to anerobic solid-state fermentation by probiotic lactic acid bacteria

The improved nutritional composition of anaerobic solid-state fermentation (SSF) with broken dried chestnut by probiotic lactic acid bacteria (LAB), namely Lactobacillus casei strain CU (CU) and Lactobacillus fermentum strain KF5 (KF5) was evaluated. Preliminary sensory evaluation results showed that fermented chestnut had unique flavor characteristics between perception of sour and of chestnut. The number of LABs in fermented chestnut samples was not less than 8 log(10) cfu/g under the condition of 40 days storage at 4 degrees C. Chestnut fermented with KF5 had a slightly better antioxidant activity to reduce the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical of 87% than the unfermented control (70.12%). Significant increases of 10.53% and 21.16% in protein digestibility of samples were observed following SSF with CU and KF5, respectively. The extracts of the fermented chestnut showed a less intense band just below 25 kDa in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The gas chromatography-mass spectrometer (GC-MS) extracellular metabolite analysis showed that the complex macromolecules in chestnut was degraded into simple sugars, organic acids, amino acids, and fatty acids. The findings of the study provide the possibility of using fermented chestnuts as potential healthy functional food. Practical applications At present, the application scope of modern chestnut preservation technology is not very wide, which is limited by cost and other factors. Therefore, the development of in-depth processing technologies of chestnut is one of the important ways to have a positive influence on the chestnut market. Nowadays, people focus on functional foods that can give full play to the body's defensive function, regulate physiological rhythm, prevent diseases, and promote rehabilitation, rather than just satisfying appetite or nutrition. Consumer attention to consume probiotic foods contributing to the maintenance of a good state of health through their biologically active ingredients has been significantly increased. This topic combines the characteristic resources of chestnut with selected probiotic lactic acid bacteria (LAB) through food biotechnology and uses anaerobic solid-state fermentation (SSF) technology to develop healthy functional food with high nutritional value and in line with people's consumption concept: chestnut products with good nutritional flavor and probiotic functional, which further improves the nutritional value of products.