Influence of Fermentation with Different Lactic Acid Bacteria and in Vitro Digestion on the Biotransformation of Phenolic Compounds in Fermented Pomegranate Juices

Changes in the structural, physicochemical and functional properties and in vitro fecal fermentation characteristics of barley dietary fiber fermented by Lactiplantibacillus plantarum dy-1

Fermentation is an effective method for improving the nutritional quality and functional characteristics of grains. This study investigated changes in the structural, physicochemical, and functional properties of fermented barley dietary fiber (FBDF) exerted by Lactiplantibacillus plantarum dy-1 (Lp. plantarum dy-1) as well as its in vitro fecal fermentation characteristics. Lp. plantarum dy-1 fermentation remarkably changed the structure of FBDF, including the microstructure and monosaccharide components, correlating with improved water or oil retaining and cholesterol adsorption capacities. Additionally, Lp. plantarum dy-1 fermentation significantly (p < 0.05) promoted the release of bound phenolics from 6.24 mg g-1 to 6.93 mg g-1 during in vitro digestion, contributing to the higher antioxidant capacity and inhibitory activity of α-amylase and pancreatic lipase compared with those of raw barley dietary fiber (RBDF). A total of 14 phenolic compounds were detected in the supernatants of digestion and fermentation samples. During colonic fermentation, FBDF significantly increased the production of acetate, propionate, and butyrate (p < 0.05), inhibited the growth of Escherichia-Shigella, and promoted the abundance of SCFA-producing microbiota such as Faecalibacterium and Prevotella_9. In conclusion, Lp. plantarum dy-1 fermentation enhanced the physicochemical properties and in vitro fermentation characteristics of barley dietary fiber, representing a promising bioprocessing technology for modifying barley bran.

Effects of fermentation with Lactiplantibacillus plantarum NCU116 on the antihypertensive activity and protein structure of black sesame seed

Effects of fermentation by Lactobacillus Plantarum NCU116 on the antihypertensive potential of black sesame seed (BSS) and structure characteristics of fermented black sesame seed protein (FBSSP) were investigated. Angiotensin-I-converting enzyme (ACE) inhibition and zinc chelating ability of fermented black sesame seed hydrolysate (FBSSH) reached the highest of 60.78 ± 3.67 % and 2.93 ± 0.04 mg/mL at 48 h and 60 h of fermentation, respectively. Additionally, the antioxidant activities of FBSSH and surface hydrophobicity of FBSSP were increased noticeably by fermentation. The α-helix and β-rotation of FBSSP tended to decrease and increase, respectively, during fermentation. Correlation analysis indicated strong positive relationships between β-turn and ACE inhibition activity as well as zinc chelating ability with correlation coefficients r of 0.8976 and 0.8932. Importantly, novel ACE inhibitory peptides LLLPYY (IC50 = 12.20 μM) and ALIPSF (IC50 = 558.99 μM) were screened from FBSSH at 48 h using in silico method. Both peptides showed high antioxidant activities in vitro. Molecular docking analysis demonstrated that the hydrogen bond connected with zinc ions of ACE mainly attributed to the potent ACE inhibitory activity of LLLPYY. The findings indicated that fermentation by Lactobacillus Plantarum NCU116 is an effective method to enhance the antihypertensive potential of BSS.

Characterization of fermented pomegranate juice: ACE inhibitory activity under in vitro digestion, antioxidant capacity, phenolics composition, chemical properties and sensory evaluation

Consuming pomegranate juice (PJ) is beneficial for hypertensive regulation because of the phenolic compounds in PJ and their inhibitory activity on angiotensin-I-converting enzyme (ACE). To better utilize bioactive function of food, microorganism fermentation has been adopted to alter phenolic metabolism. This study confirms that even under in vitro digestion, fermented PJ (FPJ) maintains higher ACE inhibitory activity than that of PJ. The main phenolic compounds in PJ were compared either under fermentation or in vitro digestion. This study finds that fermentation promotes antioxidant capacity of PJ. The chemical properties of FPJ are evaluated and the corresponding relationship with bioactivities is analyzed. A sensory evaluation comparison is conducted between FPJ and PJ, furnishing interesting information for consumers. This study highlights the relationship between ACE inhibitory activity of PJ and phenolic composition under fermentation and in vitro digestion, providing novel insights for diet regulation of phenolic-rich FPJ in ACE inhibition therapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01388-w.

The improvement of Hovenia acerba-sorghum co-fermentation in terms of microbial diversity, functional ingredients, and volatile flavor components during Baijiu fermentation

The quality of Baijiu was largely affected by raw materials, which determine the flavor and taste. In the present study, organic acids, polyphenols, volatile flavor components and microbial community in Hovenia acerba-sorghum co-fermented Baijiu (JP1) and pure sorghum-fermented Baijiu (JP2) were comprehensively analyzed. Organic acids, polyphenols and volatile flavor components in JP1 were more abundant than JP2. The abundance and diversity of bacteria and fungi in JP1 was higher than that in JP2 in the early stage of fermentation, but presented opposite trend in the middle and late stages. Leuconostoc, Lentilactobacillus and Issatchenkia were dominant genera in JP1. Whereas, Cronobacter, Pediococcus and Saccharomyces occupied the main position in JP2. Lentilactobacillus and Issatchenkia were positively related to most of organic acids and polyphenols. Pseudomonas, Rhodococcus, Cronobacter, Pediococcus, Brucella, Lentilactobacillus, Lactobacillus, Saccharomycopsis, Wickerhamomyces, Aspergillus, Thermomyces and unclassified_f-Dipodascaccae were associated with the main volatile flavor components. The main metabolic pathways in two JPs exhibited the variation trend of first decreasing and then increasing, and the metabolism activity in JP1 were higher than that in JP2. The results demonstrated the introduction of Hovenia acerba improved the functional ingredients and volatile flavor components, which is helpful for the quality promotion of Baijiu. This study identified the key microorganisms and discussed their effect on organic acids, polyphenols and volatile flavor components during the fermentation of Baijiu with different raw materials, providing a scientific basis for the development and production of high-quality Baijiu.

Influence of spontaneous and inoculated fermentation of açai on simulated digestion, antioxidant capacity and cytotoxic activity

This work describes the kinetic study of different types (spontaneous, lactic and alcoholic) of açai fermentation in terms of total phenolics and total anthocyanins, as well as antioxidant capacity, before and after simulated digestion (SD). Cytotoxicity (A549, HCT8 and IMR90 cells) and formation of reactive oxygen species (A549 cells) were also evaluated. The results revealed that spontaneous fermentation (SF) for 24 h, followed by SD, generated a product with greater bioaccessibility of phenolics (52.68%) and cyanidin-3-glucoside (27.01%) than unfermented açai. Likewise, lactic fermentation (LF) for 72 h improved the bioavailability of phenolics (64.49%) and cyanidin-3-rutinoside (20.00%). On the other hand, alcoholic fermentation (AF) decreased the bioaccessibility of phenolic compounds and anthocyanins after SD. The SF 24 h (10.16 ± 1.25 μmol Trolox /g) and LF 72 h (15.90 ± 0.51 μmol Trolox /g) significantly increased the antioxidant capacity after SD, when compared to unfermented açai (SF 0 h, 4.00 ± 0.09 μmol Trolox /g; LF 0 h, 10.57 ± 0.91 μmol Trolox /g). It was concluded that the samples did not show cytotoxicity in the cell lines tested and, in addition, AF 24 h showed antioxidant and antimutagenic effects in vitro, reducing about 40% of chromosomal aberrations. The results obtained provide important information that can be used to produce foods with greater bioaccessibility of bioactive compounds.

Phytochemical Properties and Antioxidant Capacities of Apple Juice Fermented by Probiotics During Refrigerated Storage and Simulated Gastrointestinal Digestion

The phytochemical characteristics and antioxidant capacities of fermented apple juice (FAJ) by Lactobacillus plantarum 90 (Lp90) and Lactobacillus acidophilus 85 (La85) during refrigerated storage and simulated gastrointestinal digestion (SGD) were investigated. Viable counts of Lp90 and La85 were decreased, while phenolic content and antioxidant capacities were improved during refrigerated storage, especially for the increased chlorogenic acid content. Ester content was decreased slightly after refrigeration, while the primary esters including ethyl acetate, amyl acetate, and ethyl 2-methylbutyrate were significantly increased (p < 0.05). Furthermore, ketone content was increased significantly after refrigeration (p < 0.05). In addition, viable counts of Lp90 and La85 remained higher than 6 log CFU/mL after SGD. The presence of probiotics delayed the decrease of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability and increased ferric reducing antioxidant power (FRAP) of FAJ. The contents of gallic acid, chlorogenic acid, epicatechin, ferulic acid, and phlorizin were decreased, while ellagic acid and rutin contents in FAJ were significantly increased after SGD (p < 0.05).

Aronia in the Type 2 Diabetes Treatment Regimen

Aronia melanocarpa berries are rich in antioxidants and possess a high antioxidant capacity. Aronia berries have shown potential in type 2 diabetes mellitus (T2DM) treatment, and previous studies indicate improvements in glycemia after supplementation. Unfortunately, the effectiveness of aronia berries is limited by the low bioavailability of aronia, which fermentation could potentially overcome. The objective of this study was to compare the effects of fermented or non-fermented aronia pulp with placebo in subjects with T2DM. This study was a triple-blinded, triple-crossover study with eight-week intervention periods with fermented aronia extract (FAE), non-fermented aronia extract (AE), and placebo. Extracts were incorporated in snack bars with 37% aronia (FAE or AE) or wheat bran (placebo) and 63% raisins and coconut oil. Pre- and post-treatment period, we did fasting blood samples, including hemoglobin A1c, fructosamine, insulin, glucose, glucagon-like peptide-1, glucose-dependent insulinotropic peptide (GIP) and glucagon, oral glucose tolerance tests, and anthropometric measurements. Of 36 randomized participants, 23 completed the trial. Aside from a higher increase in GIP after FAE supplementation compared to after placebo supplementation, aronia extracts had no effect. The increase in GIP levels after FAE supplementation may hold potential benefits, but the overall clinical impact remains unclear.

Effects of Fermentation on Bioactivity and the Composition of Polyphenols Contained in Polyphenol-Rich Foods: A Review

Polyphenols, as common components with various functional activities in plants, have become a research hotspot. However, researchers have found that the bioavailability and bioactivity of plant polyphenols is generally low because they are usually in the form of tannins, anthocyanins and glycosides. Polyphenol-rich fermented foods (PFFs) are reported to have better bioavailability and bioactivity than polyphenol-rich foods, because polyphenols are used as substrates during food fermentation and are hydrolyzed into smaller phenolic compounds (such as quercetin, kaempferol, gallic acid, ellagic acid, etc.) with higher bioactivity and bioavailability by polyphenol-associated enzymes (PAEs, e.g., tannases, esterases, phenolic acid decarboxylases and glycosidases). Biotransformation pathways of different polyphenols by PAEs secreted by different microorganisms are different. Meanwhile, polyphenols could also promote the growth of beneficial bacteria during the fermentation process while inhibiting the growth of pathogenic bacteria. Therefore, during the fermentation of PFFs, there must be an interactive relationship between polyphenols and microorganisms. The present study is an integration and analysis of the interaction mechanism between PFFs and microorganisms and is systematically elaborated. The present study will provide some new insights to explore the bioavailability and bioactivity of polyphenol-rich foods and greater exploitation of the availability of functional components (such as polyphenols) in plant-derived foods.

Viability of Probiotic Microorganisms and the Effect of Their Addition to Fruit and Vegetable Juices

Consumers' recent interest in healthier diets has increased the demand for food products with functional properties, such as probiotics. However, most probiotic food types available on the market are of dairy origin, which limits their consumption by individuals with food intolerances and by those who adhere to strict vegan and vegetarian diets. The aim of the current review is to assess both the limitations and impacts of the addition of probiotic microorganisms to fruit, vegetable, and/or mixed juices. Thus, an integrative literature review was herein carried out. A bibliographic survey was carried out in the following databases: Lilacs, Medline, Web of Science, Scopus, and Scielo. In addition, searches for studies published in English from 2010 to 2021 were carried out, based on the following meshes: "fruit", ''vegetable", ''juice", and "probiotics", which were used both in combination with each other and with Boolean operators such as "AND" and "OR". Although 254 articles were initially found in the literature search, only 21 of them were selected to compose the final sample. The included studies mainly addressed microorganism viability and physicochemical analyses. Overall, fruit and/or vegetable juices can be suitable matrices used to help the development of probiotic food types. However, the microorganisms added to these products must be capable of adapting to and surviving in them to enable a product's success. Therefore, factors such as pH, fiber content, amino acids, and phenolic compounds play an essential role in the survival of probiotic microorganisms. Given the wide variety of analyses, a comparison between parameters was the major limitation of the present study. Future studies should focus on filling the gaps persisting in the development of probiotic fruit and/or vegetable juices as well as mixed juices.

Fermented Whey Ewe's Milk-Based Fruit Smoothies: Bio-Recycling and Enrichment of Phenolic Compounds and Improvement of Protein Digestibility and Antioxidant Activity

This study aimed to recycle whey milk by-products (protein source) in fruit smoothies (phenolic compounds source) through started-assisted fermentation and delivering sustainable and healthy food formulations capable of providing nutrients that are unavailable due to an unbalanced diet or incorrect eating habits. Five lactic acid bacteria strains were selected as best starters for smoothie production based on the complementarity of pro-technological (kinetics of growth and acidification) traits, exopolysaccharides and phenolics release, and antioxidant activity enhancement. Compared to raw whey milk-based fruit smoothies (Raw_WFS), fermentation led to distinct profiles of sugars (glucose, fructose, mannitol, and sucrose), organic acids (lactic acid and acetic acid), ascorbic acid, phenolic compounds (gallic acid, 3-hydroxybenzoic acid, chlorogenic acid, hydrocaffeic acid, quercetin, epicatechin, procyanidin B2, and ellagic acid) and especially anthocyanins (cyanidin, delphinidin, malvidin, peonidin, petunidin 3-glucoside). Protein and phenolics interaction enhanced the release of anthocyanins, notably under the action of Lactiplantibacillus plantarum. The same bacterial strains outperformed other species in terms of protein digestibility and quality. With variations among starters culture, bio-converted metabolites were most likely responsible for the increase antioxidant scavenging capacity (DPPH, ABTS, and lipid peroxidation) and the modifications in organoleptic properties (aroma and flavor).

Characterization of Physicochemical, Biological, and Chemical Changes Associated with Coconut Milk Fermentation and Correlation Revealed by 1H NMR-Based Metabolomics

Fermentation of milk enhances its nutritional and biological activity through the improvement of the bioavailability of nutrients and the production of bioactive compounds. Coconut milk was fermented with Lactiplantibacillus plantarum ngue16. The aim of this study was to evaluate the effect of fermentation and cold storage for 28 days on physicochemical characteristics, shelf life, and antioxidant and antibacterial activities of coconut milk as well as its proximate and chemical compositions. The pH of fermented milk decreased from 4.26 to 3.92 on the 28^th day during cold storage. The viable cell count of lactic acid bacteria (LAB) in fermented coconut milk was significantly increased during fermentation and cold storage period (1 to 14 days), reaching 6.4 × 10⁸ CFU/mL, and then decreased significantly after 14 days to 1.6 × 10⁸ CFU/mL at 28 days. Yeast and molds in fermented coconut milk were only detected on the 21^st and 28^th days of cold storage, which ranged from 1.7 × 10² to 1.2 × 10⁴ CFU/mL, respectively. However, the growth of coliforms and E. coli was observed on the 14^th until the 28^th day of cold storage. The fermented coconut milk demonstrated strong antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Cronobacter sakazakii, Bacillus cereus, and Salmonella typhimurium compared to fresh coconut milk. Fermented coconut milk had the greatest 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values, with 67.1% and 61.961 mmol/g at day 14 of cold storage, respectively. Forty metabolites were detected in fermented and pasteurized coconut milk by proton nuclear magnetic resonance (¹H NMR) metabolomics. The principal component analysis (PCA) showed clear difference between the fermented and pasteurized coconut milk as well as the studied cold storage days. The metabolites responsible for this variation were ethanol, valine, GABA, arginine, lactic acid, acetoin, alanine, phenylalanine, acetic acid, methionine, acetone, pyruvate, succinic acid, malic acid, tryptophan, uridine, uracil, and cytosin, which were higher in fermented coconut milk. However, sugars and other identified compounds were higher in fresh coconut milk. The findings of this study show that fermentation of coconut milk with L. plantarum ngue16 had high potential benefits to extending its shelf life and improved biological activities as well as other beneficial nutrients.

Influence of Fermentation on Functional Properties and Bioactivities of Different Cowpea Leaf Smoothies during In Vitro Digestion

This study investigated the effects of Lactiplantibacillus plantarum 75 (LAB 75) fermentation at 37 °C for 48 h on the pH, total soluble solids (TSS), colour, total titratable acidity (TTA), carotenoids, and bioactivities of cowpea leaf smoothies from three cultivars (VOP 1, VOP 3, and VOP 4). Fermentation reduced the pH from 6.57 to 5.05 after 48 h. The TTA increased with the fermentation period, whilst the TSS reduced. Fermentation of the smoothies resulted in the least colour changes (∆E) in VOP 1 after 48 h. Fermentation of cowpea smoothies (VOP 1, VOP 3, and VOP 4) improved the antioxidant capacity (FRAP, DPPH, and ABTS), which was attributed to the increase in total phenolic compounds and carotenoid constituents in all of the fermented cowpea smoothies. VOP 1 was further selected for analysis due to its high phenolic content and antioxidant activity. The VOP 1 smoothie fermented for 24 h showed the lowest reduction in TPC (11%) and had the highest antioxidant (FRAP, DPPH, and ABTS) activity. Ltp. plantarum 75 was viable and survived the harsh conditions of the gastrointestinal tract, and, hence, could be used as a probiotic. VOP 1 intestinal digesta showed significantly higher glucose uptake relative to the undigested and the gastric digesta, while the gastric phase had higher levels of α-amylase and α-glucosidase compared to the undigested samples.

Changes of Bioactive Components and Antioxidant Capacity of Pear Ferment in Simulated Gastrointestinal Digestion In Vitro

Fruit ferment is rich in polyphenols, organic acids, enzymes, and other bioactive components, which contribute to their antioxidant ability. In this study, we investigated the effect of the simulated gastric and intestinal digestion in vitro on the total phenolic content (TPC), total flavonoid content (TFC), phenolic components content, organic acid content, protease activity, superoxide dismutase (SOD) activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (DPPH-RSA), hydroxyl (·OH) radical scavenging activity (·OH-RSA), and total reducing capacity in ‘Xuehua’ pear (Pyrus bretschneideri Rehd) ferment. The result showed that the TPC, TFC, protease activity, and phenolic components such as arbutin, protocatechuic acid, malic acid, and acetic acid showed a rising trend during the simulated gastric digestion in ‘Xuehua’ pear ferment, and these components might contribute to the increasing of ·OH-RSA and total reducing capacity. The SOD activity and epicatechin content showed an increasing trend at first and then a decreasing trend, which was likely associated with DPPH-RSA. During in vitro-simulated intestinal digestion, the majority of evaluated items reduced, except for protease activity, quercetin, and tartaric acid. The reason for the decreasing of bio-accessibility resulted from the inhibition of the digestive environment, and the transformation between substances, such as the conversion of hyperoside to quercetin. The correlation analysis indicated that the antioxidant capacity of ‘Xuehua’ pear ferment was mainly affected by its bioactive compounds and enzymes activity as well as the food matrices and digestive environment. The comparison between the digestive group with and without enzymes suggested that the simulated gastrointestinal digestion could boost the release and delay the degradation of phenolic components, flavonoids, and organic acid, protect protease and SOD activity, and stabilize DPPH-RSA, ·OH-RSA, and total reducing capacity in ‘Xuehua’ pear ferment; thus, the ‘Xuehua’ pear ferment could be considered as an easily digestible food.

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.

Biodegradation of Punicalagin into Ellagic Acid by Selected Probiotic Bacteria: A Study of the Underlying Mechanisms by MS-Based Proteomics

Pomegranate (Punica granatum L.) is a well-known source of bioactive phenolic compounds such as ellagitannins, anthocyanins, and flavanols. Punicalagin, one of the main constituents of pomegranate, needs to be biodegraded by bacteria to yield metabolites of medicinal interest. In this work, we tested 30 lactic acid bacteria (LAB) and their capacity to transform punicalagin from a punicalagin-rich pomegranate extract into smaller bioactive molecules, namely, ellagic acid and urolithins. These were identified and quantified by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS²). Further, we evaluated the molecular mechanism governing this transformation through label-free comparative MS-based proteomics. All tested LAB strains were capable of transforming punicalagin into ellagic acid, while the biosynthesis of urolithins was not observed. Proteomic analysis revealed an increase of generic transglycosylases that might have a hydrolytic role in the target phenolic molecule, coupled with an increase in the quantity of ATP-binding cassette (ABC) transporters, which might play a relevant role in transporting the resulting byproducts in and out of the cell.

Effect of Gastrointestinal Digestion on the Bioaccessibility of Phenolic Compounds and Antioxidant Activity of Fermented Aloe vera Juices

Plant-based beverages are enriched by the fermentation process. However, their biocompounds are transformed during gastrointestinal digestion, improving their bioaccessibility, which is of primary importance when considering the associated health benefits. This study aimed to evaluate the effect of in vitro gastrointestinal digestion on phenolic compound bioaccessibility and antioxidant activity of novel Aloe vera juices fermented by probiotic Enterococcus faecium and Lactococcus lactis. Aloe vera juices were digested using the standardized static INFOGEST protocol. During digestion, phenolic compounds and antioxidant activity (DPPH, ABTS, and FRAP) were accessed. The digestion process was seen to significantly increase the total phenolic content of the fermented Aloe vera juices. The fermentation of Aloe vera increased the bioaccessibility of juice biocompounds, particularly for kaempferol, ellagic acid, resveratrol, hesperidin, ferulic acid, and aloin. The phenolics released during digestion were able to reduce the oxidative radicals assessed by ABTS and FRAP tests, increasing the antioxidant action in the intestine, where they are absorbed. The fermentation of Aloe vera by probiotics is an excellent process to increase the bioavailability of beverages, resulting in natural added-value functional products.

The promotion mechanism of prebiotics for probiotics: A review

Prebiotics and probiotics play a positive role in promoting human nutrition and health. Prebiotics are compounds that cannot be digested by the host, but can be used and fermented by probiotics, so as to promote the reproduction and metabolism of intestinal probiotics for the health of body. It has been confirmed that probiotics have clinical or health care functions in preventing or controlling intestinal, respiratory, and urogenital infections, allergic reaction, inflammatory bowel disease, irritable bowel syndrome and other aspects. However, there are few systematic summaries of these types, mechanisms of action and the promotion relationship between prebiotics and probiotic. Therefore, we summarized the various types of prebiotics and probiotics, their individual action mechanisms, and the mechanism of prebiotics promoting probiotics in the intestinal tract. It is hoped this review can provide new ideas for the application of prebiotics and probiotics in the future.

Probiotic fermentation of polyphenols: potential sources of novel functional foods

Fermented functional food products are among the major segments of food processing industry. Fermentation imparts several characteristic effects on foods including the enhancement of organoleptic characteristics, increased shelf-life, and production of novel health beneficial compounds. However, in addition to macronutrients present in the food, secondary metabolites such as polyphenols are also emerging as suitable fermentable substrates. Despite the traditional antimicrobial view of polyphenols, accumulating research shows that polyphenols exert differential effects on bacterial communities by suppressing the growth of pathogenic microbes while concomitantly promoting the proliferation and survival of probiotic bacteria. Conversely, probiotic bacteria not only survive among polyphenols but also induce their fermentation which often leads to improved bioavailability of polyphenols, production of novel metabolic intermediates, increased polyphenolic content, and thus enhanced functional capacity of the fermented food. In addition, selective fermentation of combinations of polyphenol-rich foods or fortification with polyphenols can result in novel functional foods. The present narrative review specifically explores the potential of polyphenols as fermentable substrates in functional foods. We discuss the emerging bidirectional relationship between polyphenols and probiotic bacteria with an aim at promoting the development of novel functional foods based on the amalgamation of probiotic bacteria and polyphenols.

Graphical abstract

The Bioaccessibility and Antioxidant Activities of Fermented Mango Cultivar Juices after Simulated In Vitro Digestion

The purpose of this study was to investigate the bioaccessibilities of total phenolic compounds, carotenoid profile, antioxidant activity, and Lactic acid bacteria (LAB) survival in fermented mango juice (MJs) obtained from three mango cultivars after exposure to an in vitro gastrointestinal digestion model. The MJs from three cultivars ('Sabre', 'Peach', and 'Tommy Atkins') were fermented using Lactiplantibacillus plantarum 75 (L75), Leuconostoc pseudomesenteroides 56 (L56), and their combination (L56 + 75). Fermented MJs were digested and fractions: gastric (GF), intestinal (IF), and dialysis (DF) were analyzed for total polyphenolic content (TPC), antioxidant activity (FRAP), 1-diphenyl-2-picrylhydrazyl (DPPH), and 2.2-azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS). In addition, the carotenoid content and the LAB population were determined from the GF and IF. After digestion, TPC decreased while fermentation improved its bioaccessibility. L75-fermented 'Sabre' MJs had the highest bioaccessible TPC in the GF (75.65%), IF (50.10%), and DF (32.52%) while L56 'Peach' MJs increased the β-carotene bioaccessibility by 1.32-fold at GF and IF (1.21-fold). When compared to the other two juices, 'Sabre' and 'Peach' MJs fermented with L75 showed the highest IC₅₀ values for DPPH and ABTS. Generally, L75-fermented 'Sabre' MJs had the highest LAB survival at both GF (7.57 Log CFU/mL) and IF (7.45 Log CFU/mL) and hold potential as probiotic juices. L56-fermented 'Sabre' MJs would ensure the delivery of four times the carotenoid recommended dietary allowance (RDA) to a target site in the body while L75-fermented 'Peach' MJs could be used to effectively counteract oxidants in the body system.

Valorization of Lactic Acid Fermentation of Pomegranate Juice by an Acid Tolerant and Potentially Probiotic LAB Isolated from Kefir Grains

The present study describes the application of an acid tolerant and potentially probiotic L. paracasei SP3 strain, recently isolated from kefir grains, in the production of a novel functional beverage based on the fermentation of pomegranate juice. The fermentation ability of the novel strain was assessed during pomegranate juice fermentations at 30 °C for 24 h and storage at 4 °C for 4 weeks. Various parameters were assessed such as residual sugar, organic acid and alcohol levels, total phenolics content, antioxidant activity, astringency, cell viability, and consumer acceptance. Residual sugar was decreased by approximately 25%, while respectable amounts of lactic acid were determined (4.8 g/L) on the 28th day of storage, proving that the novel strain was effective at lactic acid fermentation. The concentration of ethanol was maintained at low levels (0.3–0.4 % v/v) and low levels of acetic acid were detected (0.6 g/L). The viability of L. paracasei SP3 cells retained high levels (>7 log cfu/mL), even by the 4th week. The total phenolic content (123.7–201.1 mg GAE/100 mL) and antioxidant activity (124.5–148.5 mgTE/100 mL) of fermented pomegranate juice were recorded at higher levels for all of the studied time periods compared to the non-fermented juice. The employment of the novel strain led to a significant reduction in the levels of hydrolysable tannins (42%) in the juice, reducing its astringency. The latter was further proven through sensorial tests, which reflected the amelioration of the sensorial features of the final product. It should be underlined that fruit juices as well as pomegranate juice comprised a very harsh food matrix for microorganisms to survive and ferment. Likewise, the L. paracasei SP3 strain showed a significant potential, because it was applied as a free culture, without the application of microencapsulation methods that are usually employed in these fermentations, leading to a product with possible functional properties and a high nutritive value.

Growth Promoting Activity of Annona muricata L. Leaf Extracts on Lactobacillus casei

Soursop leaves are a source of phytochemical compounds, such as phenolic acids, flavonoids, hydrolyzable tannins, and acetogenins. These compounds can have several types of biological activities. Lactic acid bacteria can uptake phenolic compounds present in plants or fruits. The aim of the present work was to investigate the in vitro effect of hexane, acetone, methanolic, and aqueous extracts of soursop leaves (Annona muricata L.) on the growth, motility, and biofilm formation of Lactobacillus casei, and to determine compounds related to growth. The minimum concentration promoting growth, motility (swimming, swarming, and twitching), and biofilm-forming capacity (crystal violet) were evaluated. The results showed the growth-promoting capacity of acetone and aqueous extracts at low doses 25-50 mg/L, and an inhibition in the four extracts at higher doses of 100 mg/L. The L. casei growth is related to ellagic acid, quercetin rhamnoside, kaempferol dihexoside, quercetin hexoside, secoisolariciresinol, and kaempferol hexoside-rhamnoside. Hexane extract increased the three types of motility, while aqueous maintained swimming and twitching motility similar to control. The four extracts inhibited the biofilm formation capacity.

Microorganisms in Whole Botanical Fermented Foods Survive Processing and Simulated Digestion to Affect Gut Microbiota Composition

Botanical fermented foods have been shown to improve human health, based on the activity of potentially beneficial lactic acid bacteria (LAB) and yeasts and their metabolic outputs. However, few studies have explored the effects of prolonged storage and functional spices on microbial viability of whole fermented foods from fermentation to digestion. Even fewer have assessed their impact on the gut microbiota. Our study investigated the effects of production processes on LAB and yeast microbial viability and gut microbiota composition. We achieved this by using physicochemical assessments and an in vitro gastrointestinal and a porcine gut microbiota model. In low-salt sauerkraut, we assessed the effects of salt concentration, starter cultures, and prolonged storage, and in tibicos, prolonged storage and the addition of spices cayenne, ginger, and turmeric. In both food matrices, LAB counts significantly increased (p<0.05), reaching a peak of 7–8 log cfu/g, declining to 6–6.5 log cfu/g by day 96. Yeast viability remained at 5–6 log cfu/g in tibicos. Ginger tibicos had significantly increased LAB and yeast viability during fermentation and storage (p<0.05). For maximum microbial consumption, tibicos should be consumed within 28days, and sauerkraut, 7weeks. Simulated upper GI digestion of both products resulted in high microbial survival rates of 70–80%. The 82% microbial survival rate of cayenne tibicos was significantly higher than other treatments (p<0.05). 16S rRNA sequencing of simulated porcine colonic microbiota showed that both spontaneously fermented sauerkraut and tibicos increase the relative abundance of Megasphaera 85-fold. These findings will inform researchers, producers, and consumers about the factors that affect the microbial content of fermented foods, and their potential effects on the gut.

Effect of Lactobacillus acidophilus fermentation on the composition of chlorogenic acids and anti-hyperuricemia activity of Artemisia selengensis Turcz

FASTE can relieve hyperuricemia by inhibiting the production of uric acid, alleviating oxidative stress damage and inflammation, promoting uric acid excretion and improving the abundance of intestinal flora.

Advancements in the Use of Fermented Fruit Juices by Lactic Acid Bacteria as Functional Foods: Prospects and Challenges of Lactiplantibacillus (Lpb.) plantarum subsp. plantarum Application

Lactic acid fermentation of fresh fruit juices is a low-cost and sustainable process, that aims to preserve and even enhance the organoleptic and nutritional features of the raw matrices and extend their shelf life. Selected Lactic Acid Bacteria (LAB) were evaluated in the fermentation of various fruit juices, leading in some cases to fruit beverages, with enhanced nutritional and sensorial characteristics. Among LAB, Lactiplantibacillus (Lpb.) plantarum subsp. plantarum strains are quite interesting, regarding their application in the fermentation of a broad range of plant-derived substrates, such as vegetables and fruit juices, since they have genome plasticity and high versatility and flexibility. L. plantarum exhibits a remarkable portfolio of enzymes that make it very important and multi-functional in fruit juice fermentations. Therefore, L. plantarum has the potential for the production of various bioactive compounds, which enhance the nutritional value and the shelf life of the final product. In addition, L. plantarum can positively modify the flavor of fruit juices, leading to higher content of desirable volatile compounds. All these features are sought in the frame of this review, aiming at the potential and challenges of L. plantarum applications in the fermentation of fruit juices.

Anti-aging effects of the fermented anthocyanin extracts of purple sweet potato on Caenorhabditis elegans

Anthocyanins have anti-inflammatory, anticarcinogenic and antioxidant properties and anti-aging effects as well as potential application as pigments. The metabolism of anthocyanins in fermented food has attracted increasing attention. However, the effect of lactic acid bacteria (LAB) fermentation on its anti-aging activity remains mostly unknown. The current study aimed to investigate the compositions, antioxidant activities and anti-aging effect of fermented purple sweet potato anthocyanins (FSPA) on aging Caenorhabditis elegans compared to raw purple sweet potato anthocyanins (PSPA). Results showed that anthocyanins were degraded into more bioavailable phenolic acids by Weissella confusa fermentation. PSPA and FSPA can extend the lifespan of C. elegans by 26.7% and 37.5%, respectively, through improving the activity of antioxidant enzymes as well as decreasing MDA content, ROS levels and lipofuscin accumulation. Pretreatment of the worms with PSPA and FSPA induced their potential to resist to thermal tolerance and oxidative stress, and FSPA exerted a higher anti-stress effect than PSPA. Moreover, FSPA supplementation upregulated the mRNA expressions of genes daf-16, hsp-16.2, sir-2.1, skn-1 and sod-3 and downregulated the expression of daf-2 in the nematodes, whereas PSPA only induced the increase in the expressions of sir-2.1, skn-1 and sod-3. Overall, FSPA can improve stress resistance and extend the lifespan of C. elegans by both insulin/IGF-1 signaling pathway and dietary restriction pathway, providing a theoretical basis for the application of PSPA in fermented food as functional pigments.

Tracking the dynamic changes of a flavor, phenolic profile, and antioxidant properties of Lactiplantibacillus plantarum- and Saccharomyces cerevisiae-fermented mulberry wine

The process of fermentation renders the superior quality of mulberry wine based on the microorganisms utilized. The present study aimed at investigating the changes and correlation between phenols and product quality of mulberry wine fermented with Lactiplantibacillus plantarum and Saccharomyces cerevisiae combinatorially. Total anthocyanins concentration (TAC), polyphenols concentration (TPC), flavonoids concentration (TFC), and antioxidant capacity decreased significantly with high correlation in the fermentation process. TAC gradually reduced with a loss rate of 47.98% from 0 to third day of fermentation. Fermented mulberry wine obtained indicated a dynamic balance due to the presence of p-hydroxybenzoic acids as compared to the primary phenolic constituent. Chlorogenic acid usually presents in mulberry juice. The relative intensity of sourness was the most prominent and reached the maximum (10.93) on day 2 of fermentation. A total of 21 volatile esters were quantified (6621.59 μg/L), which contributed significantly to the aroma of mulberry wine. The enhanced quality of fermented mulberry wine showed contraindications with decreased constituents and escalated wine quality. Rather than usual single inoculum, fermentation combination of LAB and yeast holistically influenced the color, taste, fragrance, phenolic profiles, and antioxidant properties in mulberry wine, ensuring palatability and fit for commercialization prospects.

Role of non-thermal treatments and fermentation with probiotic Lactobacillus plantarum on in vitro bioaccessibility of bioactives from vegetable juice

BACKGROUND

Lactic acid fermentation is a natural way to increase the bioactive and functional properties of fruit and vegetable juices. In this study, the in vitro gastrointestional digestion of phenolics, flavonoids, anthocyanins, and antioxidant activity of mixed vegetable juice was investigated as affected by fermentation with probiotic Lactobacillus plantarum and non-thermal treatments (ultraviolet (UV) and/or ultrasonic (US) treatment). For this purpose heat, US, UV or US/UV treated vegetable juice samples were fermented by probiotic L. plantarum and percentage recovery of bioactive (total phenolic (TPC), total flavonoid (TFC) and total anthocyanin contents (TAC) and antioxidant (DPPH [1,1-diphenyl-2-picrylhydrazyl] and CUPRAC [CUPric Reducing Antioxidant Capacity]) properties was evaluated during simulated gastrointestinal digestion.

RESULTS

Total mesophilic aerobic bacteria (TMAB) and total yeast-mold (TYM) counts were significantly decreased by thermal and non-thermal processes and coliforms were fully eliminated. The bioaccessibility of total phenolics, anthocyanins, and flavonoids decreased after in vitro digestion. In general, recovery (5.78-34.71%) and serum availability of the bioactives was positively influenced by the fermentation and non-thermal treatments. Phenolics and anthocyanins exhibited the highest and the lowest recovery, respectively, while post-digestion recovery of antioxidant was between that of the phenolics and anthocyanins.

CONCLUSIONS

This study confirmed that US and UV treatment could be advantageous alternatives to heat treatment for ensuring the microbial safety of vegetable juices with increased in vitro bioaccessibility of bioactive compounds while probiotic fermentation with L. plantarum contributed to the improvement of the bioactive profile. © 2021 Society of Chemical Industry.

Fermented pomegranate extracts protect against oxidative stress and aging of skin

BACKGROUND

Punica granatum (pomegranate) potentially ameliorates skin inflammation and pain, including herpetic stromal keratitis. Fermentation is a biotechnological technique that may naturally induce health benefits by producing antioxidants. However, the anti-aging effect of fermented pomegranate extracts (FPE) on the skin is still unclear.

AIM

This investigation evaluates the effects of fermented pomegranate as a functional supplement (FPE drink, FPE-D) and a cosmetic ingredient (FPE serum, FPE-S) in vitro and in vivo.

PATIENTS/METHODS

The effects of FPE products for anti-oxidation, anti-tyrosinase, anti-inflammation, and anti-aging were examined. Forty subjects were randomly allocated to FPE-D or placebo drink groups (50 ml of a FPE-D /placebo drink daily for 8 weeks for each subject), and another 40 subjects were recruited to FPE-S or placebo serum groups (about 3 ml of a FPE-S /placebo serum daily and nightly/daily for 4 weeks for each subject) in a double-blind study.

RESULTS

The effects of FPE products on the DPPH, ABTS⁺ , and NO· free radical scavenging activities, their inhibiting of tyrosinase activity and their enhancement of the skin health of healthy subjects, were investigated. FPE-D improved the moisture, brightness, elasticity, and collagen density of the skin of most subjects at 8 weeks relative to the baseline without treatment (p < 0.05). After 4 weeks of FPE-S serum consumption, the moisture, brightness, elasticity, spots, UV spots, and collagen density of skin were slightly better than those at week 0 (p < 0.05).

CONCLUSIONS

The daily consumption of fermented pomegranate extracts can protect the skin against oxidative stress and slow skin aging.

Rice Bran Fermented with Kimchi-Derived Lactic Acid Bacteria Prevents Metabolic Complications in Mice on a High-Fat and -Cholesterol Diet

This aim of this study was to investigate the potential beneficial effects of rice bran powder, fermented by Weissella koreensis DB1 isolated from kimchi, to protect against obesity and dyslipidemia induced by a high-fat and high-cholesterol diet, in a mouse model. Male mice were fed a modified AIN-93M diet containing high fat/high-cholesterol (HFCD), or same diet supplemented with non-fermented rice bran powder (HFCD-RB) or fermented rice bran powder (HFCD-FRB) for 10 weeks. In the HFCD-FRB group, body weight, liver and white fat pads weights, triglyceride (TG), total cholesterol (TC), non-high-density lipopreotein cholesterol (non-HDL-C), insulin, glucose and leptine levels in serum, TG levels and the ratio of fat droplets in the liver, TG levels and fat cell size in adipose tissue were decreased, and (high-density lipopreotein cholesterol) HDL-C and adiponectin levels in serum were increased, compared with the HFCD group. The HFCD-FRB group had significantly lower CCAAT-enhancer-binding potein α (C/EBPα), sterol regulatory element-binding transcription protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl CoA carboxylase (ACC) gene expression when compared to the HFCD group. The anti-obesity and hypolipidemic effects were marginally greater in the HFCD-FRB group than in the HFCD-RB group. These results suggest that fermented rice bran powder by Weissella koreensis DB1 may have potential beneficial effects on the obesity-related abnormalities and the dysfunction of lipid metabolism.

Biotransformation of the Brazilian Caatinga fruit-derived phenolics by Lactobacillus acidophilus La-5 and Lacticaseibacillus casei 01 impacts bioaccessibility and antioxidant activity

This study aims to evaluate the effect of fermentation of fruit purees (seriguela, mangaba, mango, and acerola) with Lacticaseibacillus casei 01 and/or Lactobacillus acidophilus LA-05 on the profile and bioaccessibility of phenolics and antioxidant activity. The physicochemical parameters and sugar and organic acid contents were also measured for evaluating the fermentation system. Fruit purees were adequate substrates for the growth of probiotic cultures, presenting high viability in the product and after simulated gastrointestinal conditions (≥7 log CFU/g). The fermentation with probiotic cultures increased the lactic acid (8.45-15.44 mg/mL), acetic acid (0.05-1.05 mg/mL), and phenolic contents and bioaccessibility, while the pH values and glucose and fructose contents were decreased (p < 0.05). L. acidophilus was found in higher counts in seriguela puree (8.00 ± 0.03), resulting in a higher consumption of maltose, fructose, and glucose, increased phenolic compounds content and bioacessibility and higher antioxidant activity (p < 0.05). The co-cultivation of both probiotic strains showed promising results for mango, mangaba and seriguela purees, resulting in an increased content and bioaccessibility of phenolics and higher antioxidant activity (p < 0.05). Our findings demonstrate for the first time that the Brazilian Caatinga fruit-derived phenolics can be biotransformed by Lactobacillus and amended genera probiotics to bioaccesible phenolics with antioxidant activity. The knowledge obtained from this study will provide fundamental concepts of the use of synergistic probiotics for future fermentation of other fruit purees to increase the bioaccesibility and antioxidant activity of biotransformed phenolic compounds.

Probiotic red quinoa drinks for celiacs and lactose intolerant people: study of functional, physicochemical and probiotic properties during fermentation and gastrointestinal digestion

The consumption of probiotic foods is rather limited for many sectors of the population (vegans, lactose intolerant and celiacs). Therefore, it is necessary to offer functional alternatives for these sectors. Different red quinoa drinks were fermented with L. plantarum (QLPBB) and B. longum (QBLBB) at different times. Results showed that microbial concentration reached high levels (6-8 Log CFU/mL) after 6 h and probiotic viability was very high (6 Log CFU/mL) after gastrointestinal digestion (GD). However, QBLBB reached the best probiotic concentration at 24 h. From 6 h of fermentation, probiotic resistance to some antibiotics, especially B. longum, could have a great potential to restore the intestinal microbiota during and after treatment with certain antibiotics. QLPBB showed the highest levels of total polyphenols and antioxidant capacity (AOC) after GD. Therefore, these red quinoa drinks have potential as functional probiotic beverages for vegans, celiacs and allergic to milk protein and lactose-intolerant people.

Influence of Fermentation of Pasteurised Papaya Puree with Different Lactic Acid Bacterial Strains on Quality and Bioaccessibility of Phenolic Compounds during In Vitro Digestion

This study describes the impact of utilising different strains of lactic acid bacteria (LAB) for the fermentation of papaya puree and their effect on the quality parameters and bioaccessibility of phenolic compounds during simulated in vitro gastrointestinal digestion. Papaya was processed into puree; pasteurised and fermented at 37 °C for 2 days; and stored for 7 days at 4 °C using LAB strains Lactiplantibacillus plantarum 75 (L75*D2; L75*D7), Weissella cibaria64 (W64*D2; W64*D7) and Leuconostoc pseudomesenteroides 56 (L56*D2; L56*D7), respectively. Non-fermented samples at 0 (PPD0), 2 (PPD2) and 7 days (PPD7) served as controls. pH was reduced with fermentation and was lowest in L56*D2 (3.03) and L75*D2 (3.16) after storage. The colour change (ΔE) increased with the fermentation and storage of purees; L75*D7 showed the highest ΔE (13.8), and its sourness reduced with storage. The fermentation by W64*D7 and L75*D7 increased the % recovery of chlorogenic, vanillic, syringic, ellagic, ferulic acids, catechin, epicatechin and quercetin in the intestinal fraction compared to the L56*D7 and PPD7. Fermentation by W64*D7 and L75*D7 significantly improved the antioxidant capacity of the dialysed fraction compared to the L56*D7 or PPD7. L56*D7-fermented papaya puree showed the highest inhibitory effect of α-glucosidase activity followed by L75*D7. L75*D7 had a significantly higher survival rate. LAB fermentation affected the bioacessibilities of phenolics and was strain dependent. This study recommends the use of Lpb. plantarum 75 for fermenting papaya puree.

Evaluation of Growth, Viability, Lactic Acid Production and Anti-Infective Effects of Lacticaseibacillus rhamnosus ATCC 9595 in Bacuri Juice (Platonia insignis)

Fruit juices have been emerging as excellent vehicles for development of probiotic products due to their nutritional properties and presence of bioactive compounds. This work evaluated the growth and viability of Limosilactobacillus fermentum ATCC 23271 and Lacticaseibacillus rhamnosus ATCC 9595 in bacuri juice (Platonia insignis Mart., Clusiaceae). Both strains were able to grow in bacuri juice, without any supplementation. Viability was kept after 28 days of storage; however, growth was significantly higher for L. rhamnosus ATCC 9595 (7.40 ± 0.04 Log CFU/mL). Following this, the effects of bacterial inoculum and pulp concentration on growth and lactic acid production by L. rhamnosus ATCC 9595 were investigated using a central composite rotational design. The inoculum concentration was the main factor for obtaining the most favorable relation between growth and organic acid production (G/pH ratio). Among the tested conditions, those used in assay 6 allowed the best G/pH ratio (2.13) and higher lactic acid production (4.14 g/L). In these conditions, L. rhamnosus ATCC 9595 grown in bacuri juice showed the same resistance towards acidification or addition of lysozyme than when cultivated in MRS. Finally, the anti-infective effects of fermented and non-fermented juices were analyzed using Tenebrio molitor larvae infected by enteroaggregative Escherichia coli 042. The pre-treatment with supernatants of both fermented and non-fermented juices significantly increased the survival of E. coli-infected larvae. However, only the L. rhamnosus-fermented juice had protective effects when inoculated 2 h after infection. Collectively, the results obtained in this research allowed the basis for the development of a non-dairy probiotic product from bacuri juice.

Effect of in vitro digestion on phenolics and antioxidant activity of red and yellow colored pea hulls

To explore the effect of digestion on pea hull phenolics, an in vitro model consisting sequential oral, gastric, small and large intestinal digestions was applied to pea hulls. The phenolic content and antioxidant activity of the samples collected from these digestion steps were determined. The phenolics in these samples generally decreased in the order of sequential digestions in both red and yellow hull series, and no significant increase of total phenolic content (TPC), total flavonoid content (TFC) and individual phenolics were found in most digested groups compared with the corresponding control groups. The antioxidant activity of the samples generally changed according to their TPC and strong correlations (r > 0.92, p < 0.001) existed between them in red hull series. The present study implies that phenolics are released gradually from pea hulls during in vitro digestion and their release was mainly due to the pH of the digestion.