Optimization of strains for fermentation of kiwifruit juice and effects of mono- and mixed culture fermentation on its sensory and aroma profiles

Improvement of physicochemical characteristics, bioactivity, flavor and metabolic profiles of mango juice fermented by Limosilactobacillus reuteri

The aim of this study was to explore the alterations in physicochemical characteristics, bioactivity, flavor and metabolic profiles of mango juice fermented by Limosilactobacillus reuteri FJG2526 (L. reuteri FJG2526). The results exhibited that L. reuteri FJG2526 had strong adaptability in mango juice, and reduced the total sugar, polyphenolics and flavonoids content of mango juice. L. reuteri FJG2526 fermentation ameliorated the flavor profiles of mango juice, particularly promoted the production of acids, alcohols, and esters. Moreover, 107 metabolites in the mango juice were drastically altered after 48 h L. reuteri FJG2526 fermentation by metabolomic analysis, including 73 remarkably upregulated metabolites and 34 remarkably downregulated metabolites, primarily involving amino acid metabolism. In addition, L. reuteri FJG2526 fermentation also enhanced the ability to scavenge DPPH and OH free radicals of mango juice, and inhibited lipase and α-glucosidase activities. This study offers new insights into the mango juice fermentation and will contribute to the application of L. reuteri in functional juices.

Fermentation with Bacillus natto and Bifidobacterium improves the functional, physicochemical properties, and taste qualities of coix seed-natto

Coix seed-natto (CS-natto) is a nutritious food rich in various functional components such as nattokinase (NK), and the strains' fermentation is crucial for enhancing its quality. This work utilized Bacillus natto GUTU09 (B9) and Bifidobacterium animalis subsp. lactis BLH1 or BLH6 to ferment soybeans that were soaked in a saccharified liquid made from CS, resulting in the preparation of CS-natto, studied the physicochemical and functional characteristics during fermentation, and analyzed the correlation of various indicators. Finally, an electronic tongue analysis was conducted on CS-natto. The results indicated that fermentation significantly increases NK and antioxidant activity in CS-natto, with NK activity in BLH6-B9 natto reaching 425.00 FU/g. Co-fermentation notably enhanced the content and composition of phenolic substances. Furthermore, the study revealed that the organic acid and soy isoflavone content in co-fermentation were significantly higher than in single-strain fermentation. Fermentation could elevate the levels of amino peptide nitrogen and soluble peptides. Additionally, the addition of Bifidobacterium exhibited a synergistic effect on the fermentation of B9 to produce natto. Correlation analysis indicated that Bifidobacterium promoted B9 to produce NK. The BLH1 encouraged the conversion of organic acids. Daidzein and daidzin were positively correlated (P<0.01), suggesting a potential mutual conversion. Finally, electronic tongue analysis indicated that co-fermentation could effectively enhance the taste. The results indicated that CS-natto could serve as an improved dietary supplement offering enhanced quality and more beneficial effects on people's health.

Black Goji Berry (Lycium ruthenicum) Juice Fermented with Lactobacillus rhamnosus GG Enhances Inhibitory Activity against Dipeptidyl Peptidase-IV and Key Steps of Lipid Digestion and Absorption

With the global increase in hyperglycemia and hyperlipidemia, there is an urgent need to explore dietary interventions targeting the inhibition of dipeptidyl peptidase-IV (DPP-IV) and lipid digestion and absorption. This study investigated how Lactobacillus rhamnosus GG (LGG) affects various aspects of black goji berry (BGB) (Lycium ruthenicum Murr.) juice, including changes in physicochemical and functional properties, as well as microbiological and sensory attributes. Throughout the fermentation process with 2.5-10% (w/v) BGB, significantly improved probiotic viability, lactic acid production, and decreased sugar content. While total flavonoids increase, anthocyanins decrease, with no discernible change in antioxidant activities. Metabolite profiling reveals elevated phenolic compounds post-fermentation. Regarding the inhibition of lipid digestion and absorption, fermented BGB exhibits improved bile acid binding, and disrupted cholesterol micellization by approximately threefold compared to non-fermented BGB, while also increasing pancreatic lipase inhibitory activity. Furthermore, a decrease in cholesterol uptake was observed in Caco-2 cells treated with fermented BGB (0.5 mg/mL), with a maximum reduction of 16.94%. Fermented BGB also shows more potent DPP-IV inhibition. Sensory attributes are significantly improved in fermented BGB samples. These findings highlight the potential of BGB as a bioactive resource and a promising non-dairy carrier for LGG, enhancing its anti-hyperglycemic and anti-hyperlipidemic properties.

Waste to Wealth: Dynamics and metabolic profiles of the conversion of jackfruit flake into value-added products by different fermentation methods

Thus far, little is known about whether jackfruit flake, a byproduct of jackfruit, can be used as a fermentation substrate to obtain value-added products through microbial fermentation. Here, jackfruit flake puree was fermented by three different ways: spontaneous fermentation (JF), inoculated with LAB (JFL), inoculated co-fermentation with LAB and yeast (JFC). In contrast to JF, the total polyphenol and flavonoid content and syndrome-associated enzyme inhibition are significantly increased in JFC at the end of fermentation. Electronic tongue analysis revealed that the JFC was significantly lower in astringency and higher in bitterness. 41 volatile compounds were identified during fermentation by HS-SPME-GC-MS, and JFC was richer in honey, rose, and fruity flavors. A total of 290 compounds were screened for discriminative pre- and post-fermentation differential metabolites by non-target metabolomics analysis. These results provide a potential reference for the conversion of jackfruit waste into functional products using fermentation.

Preparation of sea buckthorn (Hippophae rhamnoides L.) seed meal peptide by mixed fermentation and its effect on volatile compounds and hypoglycemia

This study employed mixed bacterial strains to ferment seabuckthorn seed meal into peptides, and conducted a comprehensive evaluation of the growth adaptive conditions, molecular weight distribution, volatile compounds, and in vitro hypoglycemic activity required for fermentation. Results showed that when the amount of maltose was 1.1% and MgSO4·7H2O was added at 0.15 g/L, the peptide yield reached 43.85% with a mixed fermentation of Lactobacillus fermentum, Bacillus subtilis, Lactobacillus casei, Lactobacillus rhamnosus, and Lactobacillus acidophilus. Components with a molecular weight below 1 kDa were found to be more effective in inhibiting the activity of α-amylase and α-glucosidase, with the identified sequence being FYLPKM. Finally, SPME/GC-MS results showed that 86 volatile components were detected during the fermentation of seabuckthorn seed meal, including 22 alcohols, 9 acids, 7 ketones, 14 alkanes, 20 esters, and 14 other compounds. With prolonged fermentation time, the content of acids and esters increased significantly.