Effect of Lactobacillus plantarum-fermented mulberry pomace on antioxidant properties and fecal microbial community

Combination of fermentation and enzymolysis enhances bioactive components and function of de-oiled rice bran

BACKGROUND

De-oiled rice bran (DORB), a substantial yet underutilized byproduct of rice processing, boasts a rich composition of active ingredients but suffers from limited application. Previous studies have indicated that enzymatic or fermentation treatments enhanced these active components. In this study, lactobacilli and complex enzymes were employed to co-treat DORB, involving the determination of the changes in active components and functionalities of DORB extract (DORBE) before and after this treatment.

RESULTS

Following fermentation-enzymolysis, the total phenol and total flavonoid contents in DORBE were significantly increased by 43.59% and 55.10%, reaching 19.66 and 34.34 g kg-1, respectively. Antioxidant tests in vitro demonstrated that the co-treatment enhanced the scavenging activities of DPPH, hydroxyl and ABTS radicals. Porcine intestinal epithelial cell experiments revealed that, compared to DORBE, the fermentation and enzymolysis DORBE (FDORBE) exhibited significantly improved cell viability and catalase activity as well as scavenging capacity for reactive oxygen species and malondialdehyde after induction by H2O2. Furthermore, FDORBE restored the decreased mRNA expression levels of Nrf2, HO-1 and NQO1 in the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway stimulated by H2O2.

CONCLUSION

Fermentation-enzymolysis co-treatment increases the contents of bioactive components of DORBE and enhances its antioxidant capacity, leading to a better protection against intestinal disorders induced by oxidative stress, suggesting that this co-treatment is a rational and effective strategy to increase the value of grains and promotes the use of DORB as a functional feed in animal production. © 2024 Society of Chemical Industry.

Transformation of mulberry polyphenols by Lactobacillus plantarum SC-5: Increasing phenolic acids and enhancement of anti-aging effect

Fermentation can transform bioactive compounds in food and improve their biological activity. This study aims to explore the transformation of polyphenols in mulberry juice and the improvement of its anti-aging effect. The results demonstrated that Lactobacillus plantarum SC-5 transformed anthocyanin in mulberry juice into more phenolic acids, especially improved 2-hydroxy-3-(4-hydroxyphenyl) propanoic acid from 4.16 ± 0.06 to 10.07 ± 0.03. In the D-gal-induced mouse model, fermented mulberry juice significantly raised the abundance of Bifidobacteriaceae (303.7 %) and Lactobacillaceae (237.2 %) and Short-chain fatty acids (SCFAs) in intestine, further reducing the level of oxidative stress (12.3 %). Meanwhile, the expression of Sirtuin 1 (SIRT1) and Brain-derived neurotrophic factor (BDNF) increased, which protected the integrity of hippocampal tissue. Morris water maze results approved that fermented mulberry juice improved cognitive ability in aging mice (30.3 %). This study provides theoretical support for the view that fermentation is an effective means of developing functional foods.

Blackberry Juice Fermented with Two Consortia of Lactic Acid Bacteria and Isolated Whey: Physicochemical and Antioxidant Properties during Storage

Fermenting fruit juices with lactic acid bacteria (LAB) is a sustainable method to enhance fruit harvests and extend shelf life. This study focused on blackberries, rich in antioxidants with proven health benefits. In this research, we examined the effects of fermentation (48 h at 37 °C) at 28 days on whey-supplemented (WH, 1:1) blackberry juice (BJ) inoculated with two LAB mixtures. Consortium 1 (BJWH/C1) included Levilactobacillus brevis, Lactiplantibacillus plantarum, and Pediococcus acidilactici, while consortium 2 (BJWH/C2) comprised Lacticaseibacillus casei and Lacticaseibacillus rhamnosus. All of the strains were previously isolated from aguamiel, pulque, and fermented milk. Throughout fermentation and storage, several parameters were evaluated, including pH, lactic acid production, viscosity, stability, reducing sugars, color, total phenolic content, anthocyanins, and antioxidant capacity. Both consortia showed a significant increase in LAB count (29-38%) after 16 h. Sample BJWH/C2 demonstrated the best kinetic characteristics, with high regression coefficients (R2 = 0.97), indicating a strong relationship between lactic acid, pH, and fermentation/storage time. Despite some fluctuations during storage, the minimum LAB count remained at 9.8 log CFU/mL, and lactic acid content increased by 95%, with good storage stability. Notably, sample BJWH/C2 increased the total phenolic content during storage. These findings suggest that adding whey enhances biomass and preserves physicochemical properties during storage.

Probiotic-fermented edible herbs as functional foods: A review of current status, challenges, and strategies

Recently, consumers have become increasingly interested in natural, health-promoting, and chronic disease-preventing medicine and food homology (MFH). There has been accumulating evidence that many herbal medicines, including MFH, are biologically active due to their biotransformation through the intestinal microbiota. The emphasis of scientific investigation has moved from the functionally active role of MFH to the more subtle role of biotransformation of the active ingredients in probiotic-fermented MFH and their health benefits. This review provides an overview of the current status of research on probiotic-fermented MFH. Probiotics degrade toxins and anti-nutritional factors in MFH, improve the flavor of MFH, and increase its bioactive components through their transformative effects. Moreover, MFH can provide a material base for the growth of probiotics and promote the production of their metabolites. In addition, the health benefits of probiotic-fermented MFH in recent years, including antimicrobial, antioxidant, anti-inflammatory, anti-neurodegenerative, skin-protective, and gut microbiome-modulating effects, are summarized, and the health risks associated with them are also described. Finally, the future development of probiotic-fermented MFH is prospected in combination with modern development technologies, such as high-throughput screening technology, synthetic biology technology, and database construction technology. Overall, probiotic-fermented MFH has the potential to be used in functional food for preventing and improving people's health. In the future, personalized functional foods can be expected based on synthetic biology technology and a database on the functional role of probiotic-fermented MFH.

In vitro digestion and colonic fermentation of phenolic compounds and their antioxidant potential in Australian beach-cast seaweeds

Beach-cast seaweed has recently garnered attention for its nutrient-rich composition, including proteins, carbohydrates, vitamins, minerals, and phytochemicals. This study focuses on the phenolic content and antioxidant potential of five Australian beach-cast seaweed species during in vitro digestion and colonic fermentation. The bioaccessibility of the selected phenolic compounds was estimated and short chain fatty acids (SCFAs) production was determined. Cystophora sp., showed a notable increase in phenolic content (23.1 mg GAE/g) and antioxidant capacity (0.42 mg CE/g) during the intestinal and gastric phases of in vitro digestion. Durvillaea sp. demonstrated a significant release of flavonoids (0.35 mg QE/g), while Phyllosphora comosa released high levels of tannins (0.72 mg CE/g) during the intestinal phase. During colonic fermentation, P. comosa released the highest levels of phenolic compounds (4.3 mg GAE/g) after 2 h, followed by an increase in flavonoids (0.15 mg QE/g), tannins (0.07 mg CE/g), and antioxidant activity (DPPH: 0.12 mg CE/g; FRAP: 0.61 mg CE/g) after 4 h. Moreover, P. comosa released a considerable amount of phenolic compounds during both in vitro digestion and colonic fermentation. All species consistently released phenolic compounds throughout the study. Phloroglucinol, gallic acid, and protocatechuic acid were identified as the most bioaccessible phenolic compounds in all five Australian beach-cast seaweeds in the in vitro digestion. Nevertheless, compound levels declined during the colonic fermentation phase due to decomposition and fermentation by gut microbiota. With regard to SCFAs, P. comosa displayed elevated levels of acetic (0.51 mmol/L) and propionic acid (0.36 mmol/L) at 2 h, while Durvillaea sp. showed increased butyric (0.42 mmol/L) and valeric (0.26 mmol/L) production acid after 8 h. These findings suggest that seaweed such as Cystophora sp., Durvillaea sp., and P. comosa are promising candidates for food fortification or nutraceutical applications, given their rich phenolic content and antioxidant properties that potentially offer gut health benefits.

Identification of the chemical composition of distiller's grain polyphenols and their effects on the fecal microbial community structure

Distiller grains are the main by-products of Baijiu production and are usually discarded, ignoring their abundant functional phytochemicals. The free and bound polyphenols from distiller grains were extracted and their potential effect on modulating fecal microbiota was investigated using in vitro fecal fermentation. The results showed that 34 polyphenols were quantified from distiller grains. The antioxidant activity was positively correlated with quercetin, myricetin, epicatechin, and naringenin. The abundance of Bifidobacterium, Ruminobacterium, Lactobacillus, Akkermansia, and butyrate-producing bacteria was enhanced by distiller's grain polyphenols by approximately 10.66-, 6.39-, 7.83-, 2.59-, and 7.74-fold, respectively. Moreover, the production of short-chain fatty acids (SCFAs), especially acetic, butyric, and propionic acid, was promoted (increased 1.99-, 1.71-, and 1.34-fold, respectively). Correlated analysis revealed quercetin, daidzein, and kaempferol as the key polyphenols by analyzing the effects on gut microbiota and SCFAs. This study could provide a reference for converting distiller grains into high-nutrient functional food ingredients and feeds.

Unlocking Flavor Potential Using Microbial β-Glucosidases in Food Processing

Aroma is among of the most important criteria that indicate the quality of food and beverage products. Aroma compounds can be found as free molecules or glycosides. Notably, a significant portion of aroma precursors accumulates in numerous food products as nonvolatile and flavorless glycoconjugates, termed glycosidic aroma precursors. When subjected to enzymatic hydrolysis, these seemingly inert, nonvolatile glycosides undergo transformation into fragrant volatiles or volatiles that can generate odor-active compounds during food processing. In this context, microbial β-glucosidases play a pivotal role in enhancing or compromising the development of flavors during food and beverage processing. β-glucosidases derived from bacteria and yeast can be utilized to modulate the concentration of particular aroma and taste compounds, such as bitterness, which can be decreased through hydrolysis by glycosidases. Furthermore, oral microbiota can influence flavor perception by releasing volatile compounds that can enhance or alter the perception of food products. In this review, considering the glycosidic flavor precursors present in diverse food and beverage products, we underscore the significance of glycosidases with various origins. Subsequently, we delve into emerging insights regarding the release of aroma within the human oral cavity due to the activity of oral microbial glycosidases.

Plant-Based Nutraceutical Formulation Modulates the Human Gut Microbiota and Ferulic Acid Esterase Activity During In Vitro Fermentation

Oxidative stress is an imbalance between free reactive oxygen species and antioxidant defences leading to neurological and other chronic disorders. The interaction between food and gut microbiota and their metabolites significantly reduces oxidative stress and influences host physiology and metabolism. This process mainly involves enzymes that hydrolyse complex polysaccharides and produce metabolites. Ferulic acid esterases (FAE) one of the most important enzymes of the gut microbiome, release ferulic acid from feruloylated sugar ester conjugates, that occur naturally in grains, fruits, and vegetables. FA is crucial in combating oxidative stress resulted from free radical formation. This study investigated the effect of two plant-based nutraceutical formulations, cereal-millet-based (PC1) and fruit-vegetable-based (PC2), on gut microbiota and the production of FAE, short chain fatty acids (SCFA) and other small metabolites in in vitro fermentation using human faecal samples. After in vitro fermentation, both nutraceutical formulations increased the abundance of Bifidobacterium, Lactobacillus, Prevotella, Feacalibacteria, and Clostridium leptum. Furthermore, they induced the production of FAE, xylanase and pectinase enzymes, SCFA and other small metabolites, resulting in increased antioxidation activity of the fermentate. PC1 stimulated FAE and xylanase production more effectively. These results demonstrated a positive correlation between the feruloylated nutraceutical formulation and the production of FAE and other accessory enzymes, suggesting that PC1 and PC2 stimulate the proliferation of the FAE-producing microbial consortium of the gut microbiome and therefore, increase FA and SCFA concentration. From this study it is evident that FA-rich plant-based formulation can be used as a prophylactic nutraceutical supplement to alleviate oxidative stress by modulating the gut microbiota.

Sustainable extraction of bioactive compound from apple pomace through lactic acid bacteria (LAB) fermentation

Apple pomace (AP), a by-product of the juice industry, is a rich and inexpensive source of natural bioactive substances, including phenolic compounds, that exhibit health-promoting effects. The recovery of these compounds from plant material using only classical extraction techniques and environmentally friendly solvents is often ineffective due to the entrapment of some compounds in the complex structures of plant cell walls. Lactic Acid Bacteria (LAB) fermentation can be a simple technology to increase the content of phenolic compounds, as well as the antioxidant activity of plant material. In this study, pomace from conventionally grown apples (Malus Domestica) of the Ligol cultivar were fermented with selected LAB strains (Lpb. plantarum KKP 3182, Lpb. plantarum KKP 1527, Lpb. plantarum ZFB 200), commercial starter cultures of Lpb. plantarum, and spontaneously. The fermented material was then subjected to ultrasound-assisted extraction, and the resulting extracts were analysed for their composition (phenolic compounds, triterpenoids, simple organic acids), and antioxidant activity. We found that: (1) the total phenolic content of AP extracts fermented with Lpb. plantarum KKP 1527 was about 30% higher than that of non-fermented AP extracts, (2) extracts of AP fermented with Lpb. plantarum KKP 1527 characterized a higher value of the antioxidant activity, (3) an increase in gallic acid procyanidin A2, protocatechuic acid, and procyanidin B2, while a decrease in rutin and quercetin was observed. The results indicated that AP fermented with Lpb. plantarum KKP 1527 may be a powerful and low-cost source of natural antioxidants which have applications in many industries.

Hypoglycemic effect of Lactobacillus plantarum-fermented mulberry pomace extract in vitro and in Caenorhabditis elegans

Mulberry pomace is rich in phytochemicals, but there are few studies on its utilization as a by-product. Natural foods containing phytochemicals can alleviate the toxic effects of excessive glucose intake. In this study, we investigated the protective effect of Lactobacillus plantarum-fermented mulberry pomace extract (FMPE) under hyperglycemic conditions. The phenolic compounds and α-glucosidase inhibition of FMPE were determined using UPLC-MS and chemical models. Furthermore, Caenorhabditis elegans was a model system to study the hypoglycemic effects. The results showed that the polyphenolics and α-glucosidase inhibition were improved during fermentation. Three phenolic components (cyanidin, 2,4,6-trihydroxybenzaldehyde, and taxifolin) were important variables for α-glucosidase inhibition. FMPE and the three key compound treatments reduced the glucose content and reactive oxygen species (ROS) level in Caenorhabditis elegans. The protective mechanism occurred by activating DAF-16/FOXO and SKN-1/Nrf2. This study suggests that Lactobacillus plantarum-fermentation was a potential way to utilize mulberry pomace polyphenols as hypoglycemic food ingredients.

Fermentation of Persimmon Leaves Extract by Lactiplantibacillus plantarum and Saccharomyces cerevisiae

Persimmon leaves usually as agricultural and forestry waste were fermented by Lactiplantibacillus plantarum and Saccharomyces cerevisiae. Growth and metabolic performances of L. plantarum and S. cerevisiae, as well as the effect of fermentation on the antioxidant abilities of the extract was investigated, including the content of flavonoids, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical clearance rates. Growth of L. plantarum was limited, even though the acid production was sustainable, while S. cerevisiae was more suitable to inhabit in the persimmon leaves extract. A symbiotic relationship was observed between the two microbes, reflected in aspects of growth of S. cerevisiae, pH reduction, and ethanol production. The DPPH radical clearance rates of all groups decreased at the early period, and increased later. The co-culture group reached the second highest value of DPPH radical clearance rate only next to the single group of L. plantarum at 9 h. All groups showed an overall downward trend of the hydroxyl radical clearance rates during the 9 h-fermentation. These findings highlight the promising industrial application of fermentation of the plant-based materials with Lactiplantibacillus and Saccharomyces species to improve the biological properties.

Conversion of (poly)phenolic compounds in food fermentations by lactic acid bacteria: Novel insights into metabolic pathways and functional metabolites

Lactobacillaceae are among the major fermentation organisms in most food fermentations but the metabolic pathways for conversion of (poly)phenolic compounds by lactobacilli have been elucidated only in the past two decades. Hydroxycinnamic and hydroxybenzoic acids are metabolized by separate enzymes which include multiple esterases, decarboxylases and hydroxycinnamic acid reductases. Glycosides of phenolic compounds including flavonoids are metabolized by glycosidases, some of which are dedicated to glycosides of plant phytochemicals rather than oligosaccharides. Metabolism of phenolic compounds in food fermentations often differs from metabolism in vitro, likely reflecting the diversity of phenolic compounds and the unknown stimuli that induce expression of metabolic genes. Current knowledge will facilitate fermentation strategies to achieve improved food quality by targeted conversion of phenolic compounds.

The Sustainability of Sweet Potato Residues from Starch Processing By-Products: Preparation with Lacticaseibacillus rhamnosus and Pediococcus pentosaceus, Characterization, and Application

The effects of Lacticaseibacillus rhamnosus and Pediococcus pentosaceus on the nutritional-functional composition, structure, in vitro saliva-gastrointestinal digestion, and colonic fermentation behaviors of fermented sweet potato residues (FSPR) were investigated. The FSPR was obtained under the condition of a solid-to-liquid ratio of 1/10, inoculation quantity of 1.5%, mixed bacteria ratio 1:1, fermentation time of 48 h, and fermentation temperature of 37 °C. The FSPR showed higher contents of soluble dietary fiber (15.02 g/100 g), total polyphenols content (95.74 mg/100 g), lactic acid (58.01 mg/g), acetic acid (1.66 mg/g), volatile acids (34.26%), and antioxidant activities. As exhibited by FTIR and SEM, the higher peak intensity at 1741 cm^-1 and looser structure were observed in FSPR. Further, the FSPR group at colonic fermentation time of 48 h showed higher content of acetic acid (1366.88 µg/mL), propionic acid (40.98 µg/mL), and butyric acid (22.71 µg/mL), which were the metabolites produced by gut microbiota using dietary fiber. Meanwhile, the abundance of Bifidobacterium and Lacticaseibacillus in the FSPR group was also improved. These results indicated that FSPR potentially developed functional foods that contributed to colonic health.

Development of Probiotic-Fermented Black Mulberry (Morus nigra L.) Juice and Its Antioxidant Activity in C2C12 Cells

Black mulberry (Morus nigra L.) is considered a medicinal and food-homologous plant in China. An obstacle to its widespread use is that its annual season and shelf life are extremely short. In this paper, fermented black mulberry juice (FBMJ) was prepared with various probiotic strains, and response surface methodology was used to determine the optimum production conditions for achieving the maximum active substance content in the resulting product. The fermentation process increased levels of biological enzymes and total phenols in the resulting juice. When the ratios of the Lactobacillus inocula to the total inoculum were 27.96% for L. paracasei, 15.37% for L. casei, 16.64% for L. plantarum, and 5.12% for L. delbrueckii, the B. animalis subsp. lactis content reached 15.83%, the L. fermentum content reached 19.08%, and the superoxide dismutase (SOD) activity reached 310 U/g. To study the antioxidant characteristics of the juice, C2C12 cells were treated with H2O2 to induce oxidative stress and the cytoprotective activity of FBMJ was subsequently evaluated. After treatment with FBMJ for 24 h, cell viability was found to be protected under H2O2 exposure, while SOD and glutathione peroxidase (GSH-Px) levels were increased. The reactive oxygen species level and malondialdehyde content were also decreased. These results provide molecular evidence for the antioxidant effect of FBMJ and demonstrate that lactic acid bacteria fermentation has a positive effect on black mulberry juice (BMJ).

Characterization, High-Density Fermentation, and the Production of a Directed Vat Set Starter of Lactobacilli Used in the Food Industry: A Review

Lactobacilli have been widely concerned for decades. Bacteria of the genus Lactobacillus have been commonly employed in fermented food to improve the appearance, smell, and taste of food or prolong its shelf-life. They comprise 261 species (by March 2020) that are highly diverse at the phenotypic, ecological, and genotypic levels. Some Lactobacilli strains have been documented to be essential probiotics, which are defined as a group of living microorganisms that are beneficial to the health of the host when ingested in sufficiency. However, the characterization, high-density fermentation, and the production of a directed vat set (DVS) starter of Lactobacilli strains used in the food industry have not been systematically reported. This paper mainly focuses on reviewing Lactobacilli as functional starter cultures in the food industry, including different molecular techniques for identification at the species and strain levels, methods for evaluating Lactobacilli properties, enhancing their performance and improving the cell density of Lactobacilli, and the production techniques of DVS starter of Lactobacilli strains. Moreover, this review further discussed the existing problems and future development prospects of Lactobacilli in the food industry. The viability and stability of Lactobacilli in the food industry and gastrointestinal environment are critical challenges at the industrial scale. The new production equipment and technology of DVS starter of Lactobacilli strains will have the potential for large-scale application, for example, developing low-temperature spray drying, freezing granulation drying, and spray freeze-drying.

Fermented natural product targeting gut microbiota regulate immunity and anti-inflammatory activity: A possible way to prevent COVID-19 in daily diet

Low immune function makes the body vulnerable to being invaded by external bacteria or viruses, causing influenza and inflammation of various organs, and this trend is shifting to the young and middle-aged group. It has been pointed out that natural products fermented by probiotic have benign changes about their active ingredients in some studies, and it have shown strong nutritional value in anti-oxidation, anti-aging, regulating lipid metabolism, anti-inflammatory and improving immunity. In recent years, the gut microbiota plays a key role and has been extensively studied in improving immunity and anti-inflammation activity. By linking the relationship between natural products fermented by probiotic, gut microbiota, immunity, and inflammation, this review presents the modulating effects of probiotics and their fermented natural products on the body, including immunity-enhancing and anti-inflammatory activities by modulating gut microbiota, and it is discussed that the current understanding of its molecular mechanisms. It may become a possible way to prevent COVID-19 through consuming natural products fermented by probiotic in our daily diet.

Assessments of Probiotic Potentials of Lactiplantibacillus plantarum Strains Isolated From Chinese Traditional Fermented Food: Phenotypic and Genomic Analysis

The lack of rapid and effective approaches to determine the health benefits of strains is one of the main challenges affecting the selection of probiotics from large numbers of candidates. In this study, the probiotic potential of 44 Lactiplantibacillus plantarum strains isolated from different Chinese traditional fermented foods was evaluated, including acid and bile salt resistance, adhesion ability, survival in simulated human gastrointestinal transit, antioxidant activity, bile salt hydrolase (BSH) activity, and antibacterial activity. All tested L. plantarum strains showed high antioxidant capacity, BSH activity, and antibacterial activity. Among the strains, B652, C232, D444, and E932 were identified as the best comprehensive performed strains, which were selected for whole-genome sequencing, in order to provide clear information and identify key genes responsible for functional characteristics in vitro. It demonstrated that the antioxidant activity, adhesion activity, and ability to survive in the simulated gastric environment were found to be closely correlated with antioxidant enzyme encoding genes, cell-surface protein-encoding genes, and stress response genes, respectively. The numbers of functional genes present in strains might decide their performance in probiotic profile evaluation. The outcome of the study could support the development of a novel approach for the screening and identification of probiotics.

Lactobacillus plantarum DP189 Reduces α-SYN Aggravation in MPTP-Induced Parkinson's Disease Mice via Regulating Oxidative Damage, Inflammation, and Gut Microbiota Disorder

This study aimed to evaluate the attenuating effect of Lactobacillus plantarum DP189 on α-synuclein (α-SYN) aggregates in the substantia nigra (SN) of Parkinson's disease (PD) mice via 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced. Our results indicated that L. plantarum DP189 increased the levels of superoxide dismutase (SOD), glutathione peroxide (GSH-Px), and interleukin-10 (IL-10) and decreased the levels of malondialdehyde (MDA), reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β). Moreover, L. plantarum DP189 reduced the α-SYN accumulation in SN. Mechanistically, L. plantarum DP189 activated the expression of nuclear factor erythroid 2-related factor (Nrf2)/ARE and PGC-1α pathways and suppressed the NLRP3 inflammasome. Furthermore, fecal analysis showed that L. plantarum DP189 reshaped the gut microbiota in PD mice by reducing the number of pathogenic bacteria (Proteobacteria and Actinobacteria) and increased the abundance of probiotics (Lactobacillus and Prevotella). Our results suggested that L. plantarum DP189 could delay the neurodegeneration caused by the accumulation of α-SYN in the SN of PD mice via suppressing oxidative stress, repressing proinflammatory response, and modulating gut microbiota.

Modulation of Gut Microbiota by Lactobacillus casei Fermented Raspberry Juice In Vitro and In Vivo

The aim of this study was to investigate the modulation of gut microbiota by fermented raspberry juice (FRJ) both in vitro and in vivo. Results showed that total phenolic content and antioxidant activities of FRJ reached the highest after fermentation for 42 h. Seventeen phenolic compounds were contained in FRJ, mainly including ellagic acid (496.64 ± 2.91 μg/g) and anthocyanins (total concentration: 387.93 μg/g). FRJ modulated the gut microbiota into a healthy in vitro status, with increase of valeric and isovaleric acids production. In healthy mice, all FRJ treatments improved the production of acetic, butyric and isovaleric acids as well as the gene expression of ZO-1, Claudin-1, Claudin-4, Ocdudin, E-cadherin and Muc-2. Moreover, variable gut microbial compositions were found among the groups fed diet-supplemented the different doses of FRJ, within low and median doses of FRJ may regulate the microbiota to a healthier state compared to the high dose supplementation. This study indicated that fermentation is a potential way to produce plant-based juices, which could reshape the gut microbiota and improve the host health.

Influence of Drying Type of Selected Fermented Vegetables Pomace on the Natural Colorants and Concentration of Lactic Acid Bacteria

Nowadays, foods with probiotic bacteria are valuable and desired, because of their influence on human gut and health. Currently, in the era of zero waste, the food industry is interested in managing its waste. Therefore, the aim of the study was to determine the influence of drying process on the physicochemical properties of fermented vegetable pomace. The work included examining the influence of the lactic acid bacteria (Levilactobacillus brevis, Lactiplantibacillus plantarum, Limosilactobacillus fermentum and its mixture in the ratio 1:1:1) used for vegetable fermentation (beetroot, red pepper, carrot), obtaining pomace from fermented vegetables, and then selection of drying technique using the following methods: convection drying (CD) or freeze-drying (FD) on the physical and chemical properties of pomace. In the obtained pomace and its dried form, dry substance, water activity, color, and active substances such as betalains and carotenoids by spectrophotometric method and also bacteria concentration were evaluated. After fermentation of pomace from the same vegetable, a similar concentration of lactic acid bacteria was found as well as dry substances, color and colorants. Results of physico-chemical properties were related to the used vegetable type. After drying of pomace, it could be seen a high decrease in bacteria and colorant concentration (betalains, carotenoids) independently from drying and vegetable type as well as used starter cultures. The smallest change was observed for spontaneously fermented vegetables compared to those in which the starter culture was used.

Structural and compositional changes of whey protein and blueberry juice fermented using Lactobacillus plantarum or Lactobacillus casei during fermentation

This study aimed to improve the stability of the anthocyanins and phenolic acids of blueberry by forming hydrogen bonds or hydrophobic interactions with whey protein using lactic acid fermentation. The effects of the initial pH on the characteristics of the whey protein and blueberry juice system fermented using Lactobacillus plantarum and Lactobacillus casei were investigated. The color and total phenol and anthocyanin contents of the blueberry juice and whey protein system became stable after fermentation using Lactobacillus plantarum and Lactobacillus casei. Fluorescence measurements and Fourier transform infrared spectroscopy (FTIR) analysis reveal that the characteristics of whey protein and blueberry juice changed significantly after fermentation using Lactobacillus plantarum and Lactobacillus casei indicating the binding of anthocyanins or phenolic hydroxyl groups of blueberry to N-H, C-N and C[double bond, length as m-dash]O groups of whey protein. The α-helix content of whey protein and blueberry fermented using Lactobacillus plantarum alone decreased by 18% and β-sheet content increased by approximately 27% compared to whey protein fermented using Lactobacillus plantarum.