Screening of a Novel Lactiplantibacillus plantarum MMB-05 and Lacticaseibacillus casei Fermented Sandwich Seaweed Scraps: Chemical Composition, In Vitro Antioxidant, and Volatile Compounds Analysis by GC-IMS

Impact of Monascus purpureus combined with Lactobacillus plantarum and Saccharomyces cerevisiae fermentation on nutritional and flavor characteristics of Pyropia yezoensis

Fermentation can promote various properties of food. This study investigated the impact of fermentation by Monascus purpureus combined with Lactobacillus plantarum and Saccharomyces cerevisiae on the physicochemical and flavor characteristics of Pyropia yezoensis. Results indicate that the protein and free amino acid content increased threefold. A total of 62 volatile flavor compounds were identified by GC-IMS. Alcohols, ketones and esters were enhanced with 2- to 6-fold, while aldehydes were reduced by 76.56 %, contributing to the enhancement of pleasant fragrances and the reduction of fishy and seawater odors. As for the non-volatile properties, the content of organic acids and free amino acids increased from 2.18 mg/g and 0.19 mg/g to 46.03 mg/g and 4.93 mg/g, respectively, as assessed by HPLC and amino acid analyzer. The metabolic pathways of non-volatile substances were speculated upon. This work provides a basic theory and a practical reference for fermentation food processing of P. yezoensis.

Integrated metagenomics and metatranscriptomics analyses reveal the impacts of different Lactiplantibacillus plantarum strains on microbial communities and metabolic profiles in pickled bamboo shoots

Effects of two different Lactobacillus plantarum fermentation processes on microbial communities and metabolic functions were evaluated using metagenomics and metatranscriptomics. Dominant species in Lactobacillus plantarum DACN4208 (LPIF8) and DACN4120 (LPIF10) were Lactobacillus pentosus and Lactobacillus plantarum, with Lactiplantibacillus comprised 75.31 % of the microbial community in LPIF10. Metatranscriptomic revealed that LPIF8 had more genes associated with carbohydrate-binding modules and auxiliary activities, totaling 7500 and 4000 genes, respectively. Metabolic reconstruction further showed that LPIF8 had the most genes involved in pyruvate and lactose metabolism, with 633 and 389 genes, respectively. In contrast, LPIF10 fewer genes related to the biosynthesis and metabolism of phenylalanine, tyrosine, and tryptophan. These results indicate that LPIF8 could efficiently improve fermentation efficiency and increase metabolic activity, while LPIF10 exhibited a more moderate and controlled metabolic process. These provide valuable insights into how different starter cultures influence the structure and metabolic functions of microbial communities in pickled bamboo shoots.

Screening approaches and potential of isolated lactic acid bacteria for improving fermentation of Saccharina latissima

BACKGROUND

With the growing interest in applying fermentation to seaweed biomasses, there is a need for fast and efficient selection of microbial strains that have the ability to 1) acidify quickly, 2) utilize seaweed constituents and c) exhibit some proteolytic activity. The present study aims to provide a fast methodology to screen large bacterial collections for potential applications in optimized seaweed fermentations, as well as investigate and assess the performance of a selected bacterial collection of the National Food Institute Culture Collection (NFICC) in seaweed fermentation. This approach is directed toward high-throughput (HT) methodologies, employing microwell assays for different phenotypical characteristics of lactic acid bacteria isolated from different sources. The overarching aim is the deeper understanding of the selection criteria when designing starter cultures for seaweed fermentation.

RESULTS

By employing high-throughput analytical workflows, the screening processing time is minimized, and among the different strains from a well-characterized strain collection, it was possible to distinguish between strong acidifiers and to replicate similar results when the volumes were scaled from 96-well plates to lab-scale fermentations (40 mL) of whole seaweed. Lactiplantibacillus plantarum, Lacticaseibacillus paracasei and, to a lesser extent, Lacticaseibacillus rhamnosus were among the fastest strains to reach the lowest endpoint pH values (< 4.5) in less than 48 h. Although the results regarding proteolytic capacity were not sufficient to prove that the candidates can also provide some flavor generation by the cleavage of proteins, NFICC1746 and NFICC2041 exhibited potential in releasing free alanine, glutamate and asparate as free amino acids.

CONCLUSIONS

With the described methodology, a large number of terrestrial lactic acid bacteria (LAB) isolates were screened for their performance and possible application for fermentation of brown sewaeeds. With a a fast conversion of sugars to organic acids, three potential new plant-isolated strains from NFICC, specifically Lactiplantibacillus plantarum ssp. argentoratensis (NFICC983), Lacticaseibacillus paracasei (NFICC1746) and Lacticaseibacillus rhamnosus (NFICC2041), were identified as promising candidates for future synthetic consortia aimed at application in bioprocessed seaweed. The combination of such strains will be the future focus to further optimize robust seaweed fermentations.

Peptidomics- inspired discovery and activity evaluation of antioxidant peptides in multiple strains mixed fermentation of Porphyra yezoensis

This study investigated the production of antioxidant peptides from Porphyra yezoensis through fermentation with three strains of microorganisms: Lactiplantibacillus plantarum L13, Bacillus amyloliquefaciens MMB-02, and Saccharomyces cerevisiae A8. The crude peptides were extracted by aqueous acid precipitation and purified by Sephadex G-25 gel column to produce highly active antioxidant components with molecular weight of <4000 Da. The LC-MS/MS result revealed that the fermentation group contained more hydrophobic amino acids and oligopeptides, which were mainly originated from phycobiliproteins and algal blue proteins. Finally, the antioxidant activity of Porphyra yezoensis was determined with DPPH· and ABTS· scavenging rates of 54.87% and 57.39%, respectively. The ferric ion-reducing power (FRAP) and enzyme activities of SOD and CAT were significantly higher than those of the control group. This study provides a scientific foundation for the deep processing of striped seaweed and contributes to the theoretical understanding of synthetic antioxidant substitutes.

Fermentation of Pyropia spp. seaweed: a comprehensive review on processing conditions, biological activities and potential applications in the food industry

Pyropia spp. seaweeds are delicious and nutritious red algae widely consumed for a long history. However, due to the non-digestibility of cell wall components by the human intestinal tract, the bioaccessibility of the intracellular bioactive compounds is low. The current industrial processing of Pyropia spp. food by drying and roasting cannot break down the cell wall; however, studies indicate that fermentation of Pyropia spp. by food-derived microorganisms is an efficient processing method to solve this problem. This paper reviews research on the fermentation of Pyropia spp., including the manufacturing process, alterations in chemical composition, flavor properties, bioactivities, and mechanisms. Furthermore, the limitations and opportunities for developing Pyropia spp. fermentation food are explored. Studies demonstrated that key metabolites of fermented Pyropia spp. were degraded polysaccharides, released phenolic compounds and flavonoids, and formed amino acids, which possessed bioactivities such as antioxidant, anti-glycation, anti-diabetic, lipid metabolism regulation beneficial to human health. The increased bioactivities implied the promoted bioaccessibility of intracellular components. Notably, fermentation positively contributed to the safety of Pyropia spp. food. In conclusion, benefits in nutrition, flavor, bioactivity, and safety suggest that fermentation technology has a promising future for application in Pyropia spp. food industry.

The Impact of Fermentation on the Antioxidant Activity of Food Products

From ancient times to the present day, fermentation has been utilized not only for food preservation but also for enhancing the nutritional and functional properties of foods. This process is influenced by numerous factors, including the type of microorganisms used, substrate composition, pH, time, and temperature, all of which can significantly alter the characteristics of the final product. Depending on the parameters, fermentation enhances the bioactive content of the products and imparts the necessary properties, such as antioxidant characteristics, for the products to be considered functional. The enhancement of these properties, particularly antioxidant activity, enriches foods with bioactive compounds and functional attributes, contributing to improved health benefits. Through a review of recent research, this study elucidates how different fermentation processes can enhance the bioavailability and efficacy of antioxidants, thereby improving the nutritional and functional qualities of foods. This study investigated the multifaceted effects of fermentation on antioxidant properties by exploring various types and conditions of fermentation. It highlights specific examples from dairy products and other food categories as well as the valorization of food waste and byproducts. The findings underscore the potential of fermentation as a sustainable method to produce health-promoting foods with elevated antioxidant activities, offering new perspectives for food science and technology.

Changes in Flavor-Related Biomarkers in Pacific Oysters (Crassostrea gigas) Following Microplastic Exposure

Microplastics have been an emerging threat to filtering species and the ingestion and impacts of microplastics on oysters are a cause for concern. However, much remains unknown about the effects of microplastics on flavor-related biomarkers in oysters. Herein, a laboratory microplastic exposure with concentrations of 1, 10, and 100 mg/L for 15 days was performed to investigate the impacts of microplastics on the flavor parameters of oysters. Exposure to microplastics changed the odor characteristics of oysters. Microplastic exposure had minor effects on the fatty acid composition; however, significant alterations in free amino acids and nucleotides were observed under the 1 and 10 mg/L exposure groups, respectively. The overall results indicated 10 mg/L of microplastic exposure significantly increased the equivalent umami value of oysters. These findings stressed the effects of microplastics on oysters and would be an important reference for the assessment of the potential risks associated with microplastics in marine edible species.

Ultrasound-assisted fermentation of Porphyra yezoensis sauce at different growth stages using Lactiplantibacillus plantarum: Metabolic response and biological activity

This study first employed ultrasonic-assisted fermentation of seaweed foot material with Lactiplantibacillus plantarum to produce Porphyra yezoensis sauce. The aim was to examine L. plantarum's growth and metabolism of nutritional components at different growth stages under low- (133.99 W/L) and high-ultrasonic power densities (169.17 W/L). After 24-h fermentation, L. plantarum exhibited a 21.32 % increase in the sonicated P. yezoensis sauce at 133.99 W/L and the logarithmic growth phase compared to that at 169.17 W/L. In addition, compared to the non-sonicated sauce, total phenolic and flavonoid contents increased by around 58 % and 27 % in sonicated sauce at 133.99 W/L, reaching 92.38 mg GEA/g DW and 111.08 mg RE/g DW, respectively. Principal Component Analysis (PCA) of the evaluation criteria for different fermentation stages under 133.99 W/L power ultrasonication revealed that the P. yezoensis sauce generated more phenolic compounds and exhibited stronger antioxidant capabilities in the sonicated sample at the logarithmic phase of L. plantarum. Compared to the traditional treated P. yezoensis sauce, the content of free amino acids was significantly increased in sonicated sauce, especially for logarithmic phase. Finally, GC-IMS analysis demonstrated that the ultrasonication at logarithmic phase released more volatile compounds compared to the non-sonicated sauce. This led to a reduction in the fishy odour of the Porphyra yezoensis sauce and an improved release of favourable flavour compounds.

Effect of Capsaicin Stress on Aroma-Producing Properties of Lactobacillus plantarum CL-01 Based on E-Nose and GC-IMS

Capsaicin stress, along with salt stress, could be considered the main stressors for lactic acid bacteria in traditional fermented pepper products. Until now, insufficient attention has been paid to salt stress, while the effect of capsaicin on the aroma-producing properties of Lactobacillus plantarum (L. plantarum) is unclear. The present study attempted to illustrate the effect of capsaicin stress on the aroma-producing properties of L. plantarum CL-01 isolated from traditionally fermented peppers based on E-nose and GC-IMS. The results showed that E-nose could clearly distinguish the overall flavor differences of L. plantarum CL-01 under capsaicin stress. A total of 48 volatile compounds (VOCs) were characterized by means of GC-IMS, and the main VOCs belonged to acids and alcohols. Capsaicin stress significantly promoted L. plantarum CL-01 to produce alpha-pinene, ethyl crotonate, isobutyric acid, trans-2-pentenal, 2-methyl-1-butanol, 3-methyl-3-buten-1-ol, 1-penten-3-one, 2-pentanone, 3-methyl-1-butanol-D, and 2-heptanone (p < 0.05). In addition, under capsaicin stress, the contents of 1-penten-3-one, 3-methyl-3-buten-1-ol, 5-methylfurfuryl alcohol, isobutanol, 2-furanmethanethiol, 2,2,4,6,6-pentamethylheptane, 1-propanethiol, diethyl malonate, acetic acid, beta-myrcene, 2-pentanone, ethyl acetate, trans-2-pentenal, 2-methylbutyl acetate, and 2-heptanone produced by L. plantarum CL-01 were significantly increased along with the fermentation time (p < 0.05). Furthermore, some significant correlations were observed between the response values of specific E-nose sensors and effective VOCs.