In vitro metabolism of elderberry juice polyphenols by lactic acid bacteria

Study of Bacillus cereus as an Effective Multi-Type A Trichothecene Inactivator

Type A trichothecenes are common mycotoxins in stored cereal grains, where co-contamination is likely to occur. Seeking new microbiological options capable of inactivating more than one type A trichothecene, this study aimed to analyze facultative anaerobe bacteria isolated from broiler proventriculus. For this purpose, type A trichothecenes were produced in vitro, and a facultative anaerobic bacterial consortium was obtained from a broiler's proventriculus. Then, the most representative bacterial strains were purified, and trichothecene inactivating assays were performed. Finally, the isolate with the greatest capacity to remove all tested mycotoxins was selected for biosorption assays. The results showed that when the consortium was tested, neosolaniol (NEO) was the most degraded mycotoxin (64.55%; p = 0.008), followed by HT-2 toxin (HT-2) (22.96%; p = 0.008), and T-2 toxin (T-2) (20.84%; p = 0.014). All isolates were bacillus-shaped and Gram-positive, belonging to the Bacillus and Lactobacillus genera, of which B. cereus was found to remove T-2 (28.35%), HT-2 (32.84%), and NEO (27.14%), where biosorption accounted for 86.10% in T-2, 35.59% in HT-2, and 68.64% in NEO. This study is the first to prove the capacity of B. cereus as an effective inactivator and binder of multi-type A trichothecenes.

The influence of co-encapsulated L. plantarum and Silybum marianum seed extract on the physicochemical properties of synbiotic cheese during ripening

The effect of Silybum marianum seed extract (SMSE), added freely or in co-encapsulated with L. plantarum (MT, ZH593), on cell survivability, physicochemical and textural parameters in synbiotic cheeses for 60 days at 4 °C were studied. Incorporated cheeses with free, single encapsulated, and co-encapsulated probiotic + SMSE experimented a reduction of 3.19, 1.23, and 0.76 log CFU/mL for the cell survivability and their antioxidant activity reached 15.19, 16.26, and 31.73%, respectively, at the end of the storage. Decrease in hardness, cohesiveness, and springiness of the cheese containing free probiotic + SMSE upon compression during storage revealed proteolysis pattern and pH development being the most effective agents while whey percentage and moisture loss were the most effective agents in the rest of the cheeses. Overall, microcapsules containing L. plantarum and SMSE propose an easy and efficient delivery vehicle for the transition of bio-compounds into cheese as a novel synbiotic food.

Research Progress on Methods for the Deacidification of Small Berry Juice: An Overview

As some of the richest sources of natural antioxidants, small berry fruits have attractive colors and special tastes, with recognized benefits for human health. However, sour tastes in small berry juices result in a poor flavor and low acceptance among consumers, greatly limiting their marketability. Among the most commonly used deacidification methods, chemical deacidification methods can neutralize fruit juice via the addition of a deacidification agent, while physical deacidification methods include freezing deacidification, ion-exchange resin deacidification, electrodialysis deacidification, and chitosan deacidification. All of these methods can markedly improve the pH of fruit juice, but they introduce new substances into the juice that may have an influence on its color, taste, and stability. Biological deacidification can effectively remove malic acid from fruit juice, reducing the content from 15 g/L to 3 g/L; additionally, it maintains the taste and stability of the juice. Therefore, it is widely applied for fruit juice deacidification. On this basis, some compound deacidification technologies have also emerged, but they also present problems such as high costs and complicated working procedures. This review of deacidification methods for small berry juice provides a foundation for the industrial development of such juices.

Apple Blossom Agricultural Residues as a Sustainable Source of Bioactive Peptides through Microbial Fermentation Bioprocessing

This study explored the impact of starter-assisted fermentation on apple blossoms to enhance their potential as a source of antioxidant and antifungal molecules. Fructobacillus fructosus PL22 and Wickerhamomyces anomalus GY1 were chosen as starters owing to their origin and promising ability to modify plant secondary metabolites. An initial assessment through microbiological and physicochemical analyses showed superior outcomes for starter-assisted fermentation compared to the spontaneous process. Enzymatic hydrolysis of proteins, primarily controlled by starters, orchestrated the generation of new low-molecular-weight peptides. W. anomalus GY1 also induced modifications in the phenolic profile, generating a diverse array of bioactive metabolites. These metabolic changes, particularly the release of potentially bioactive peptides, were associated with significant antioxidant activity and marked antifungal efficacy against three common mold species. Our results shed light on the potential of microbial starters to valorize agricultural wastes and convert them into a valuable resource for industry.

Characterization of C-phycocyanin antioxidant, anti-inflammatory, anti-tumour, and anti-HCoV-229E activities and encapsulation for implementation in an innovative functional yogurt

Functional bioactive ingredients isolated from microalgae as sustainable sources have become a new subject of pharmacology and functional foods. Thus, the work aims to produce crude phycocyanin (C-PC), define it, and investigate its pharmacological effects before warping it in a nanophytosome. Subsequently, the physicochemical properties of nanoparticles were evaluated. Both free and nanophytosomes of C-PC were incorporated into cow milk fermented with the probiotic Lactobacillus rhamnosus KU985435 to make functional yoghurt and the stability of C-PC of both phytosomes was assessed. The amino acid content of C-PC revealed the presence of eight of nine essential amino acids and eight of eleven non-essential amino acids. C-PC has a medium molecular weight (82.992 kDa). Some pharmacological effects like reducing inflammation (98.76 % ± 0.065), fighting free radicals (99.12 % ± 0.027), and being able to inhibit the human coronavirus 229 E with a selective index of 27.9 were observed. The maximum viral inhibitory activity was detected during the adsorption stage. Anti-human liver and colon carcinomas that exceeded Doxorubicin with very low cytotoxicity against normal cell lines were detected. C-PC is an unstable protein that could be degraded in the yoghurt during storage. Therefore, phytosome encapsulation can effectively stabilize C-PC (particle size 44.50 ± 12 nm and zeta-potential -32.4 ± 5 mV) and protect it from the acidic environment of the yoghurt. The produced yoghurt showed the desired physicochemical and functional properties and overall acceptance. The results prove that C-PC from spirulina algae is a renewable source of dyes. The encapsulation process using phytosomes gave it high stability against environmental influences, and therefore, it can be applied in the food and pharmaceutical industries in the future.

Elderberry, an Ancient Remedy: A Comprehensive Study of the Bioactive Compounds in Three Sambucus nigra L. Subspecies

Elderberry, the fruit of Sambucus nigra, has become a popular inclusion in foods, beverages, supplements, and more in recent years. Although the European subspecies, S. nigra ssp. nigra, has been widely studied for its composition, particularly for phenolic and volatile profiles, other subspecies, such as the American elderberry S. nigra ssp. canadensis and the blue elderberry S. nigra ssp. cerulea, have also become contenders in the elderberry supply chain. For the first time, the composition (including micronutrients, macronutrients, organic acids, titratable acid, soluble solids, phenolic compounds, and cyanogenic glycosides) of these three subspecies of elderberry is compared, highlighting the unique qualities of each subspecies and identifying gaps in the available data on the three subspecies.

Antioxidant properties and changes in vitro digestion of the fermented kiwifruit extract prepared by lactic acid bacteria and yeasts

The health benefits of fermented fruits have attracted consumers' attention. High levels of antioxidant ability in the fermented kiwifruit extract were found at the early stage of fermentation. The co-fermention with Lactobacillus paracasei LG0260 and Kluyveromyces marxianus J2853 showed the highest ABTS radical scavenging ability (ABTS⋅+-SA) and superoxide dismutase (SOD) activity. Also, the typical antioxidant components of SOD activity, vitamin C concentration and total phenol content were highly correlated with ABTS⋅+-SA. Obviously, polyphenols in the fermented kiwifruit extract evolved into monophenols during fermentation. Compared to undigested samples, the activity of ABTS⋅+-SA and reducing power capacity (RP-CA) after the final intestinal digestion decreased and ranged 387.44-531.89 VCμg/mL, 650.95-981.63 VCμg/mL, respectively (P < 0.05). Meanwhile, SOD activity on the 10th day of fermentation were still remained 222.82 U/mL, 206.98 U/mL and 217.23 U/mL, respectively. These results suggested that the fermented kiwifruit extract could exhibit antioxidant activity through tolerance to the digestive environment.

Role of Phenolic Acid Metabolism in Enhancing Bioactivity of Mentha Extract Fermented with Plant-Derived Lactobacillus plantarum SN13T

Plant-derived lactic acid bacteria are major fermentation organisms that can grow in medicinal herb extracts enriched with phytochemicals like glycosides, phenolic acids, flavonoids, and tannins. Fermentation with strain-specific Lactobacilli harboring metabolic enzymes can increase the bioactivity and bioavailability of medicinal herbs. Fermentation of extracts of Artemisia princeps and Paeonia lactiflora has been previously found to increase their bioactivities. Therefore, this study explores the possibility of increasing the bioactivity of Mentha arvensis (Mentha) extract against lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells by fermenting with plant-derived probiotic strains Lactobacillus (Lact.) plantarum SN13T and Pediococcus (Ped.) pentosaceus LP28. As a result, fermentation with SN13T significantly increased the bioactivity of Mentha extract as compared to unfermented or LP28-fermented extracts. This higher bioactivity was associated with the metabolism of rosmarinic acid (RA) and caffeic acid (CA), the major bioactive phenolic acids reported in Mentha, along with the production of the metabolite dihydrocaffeic acid (DHCA). DHCA was found to be a more potent LPS-induced nitric oxide (NO) inhibitor than its precursor phenolic acids. The metabolism of RA to DHCA via CA could be mediated by the enzymes cinnamoyl ester hydrolase and hydroxycinnamate reductases, encoded by the ceh gene and the hcrRABC gene operon, respectively, which were identified in the complete genome sequence of Lact. plantarum SN13T but were absent in Ped. pentosaceus LP28. The genes hcrA, hcrB, and hcrC were significantly and time-dependently overexpressed in Lact. plantarum SN13T when grown in the Mentha extract, suggesting the role of phenolic acid metabolism in enhancing its bioactivity.

Lactic acid fermented microalgae and cyanobacteria as a new source of lipid reducing compounds: assessment through zebrafish Nile red fat metabolism assay and untargeted metabolomics

Obesity is one of the most important threats to human health. Besides existing pharmacological or clinical interventions, novel effective and largely available solutions are still necessary. Among diverse natural resources, microalgae are well known for their complexity in the production of novel secondary metabolites. At the same time, lactic acid bacteria (LAB) are known for their capacity to metabolize, through fermentation, different matrices, and consequently to modify or produce new compounds with potential bioactivity. This work aimed to study the production of fermented microalgae and cyanobacteria, and to analyse their extracts in the zebrafish Nile red fat metabolism assay. Three microalgal species (Chlorella vulgaris, Chlorococcum sp. and Arthrospira platensis) were fermented with seven strains of LAB from 4 species (Lacticaseibacillus rhamnosus, Lacticaseibacillus casei, Lactobacillus delbrueckii bulgaricus and Lacticaseibacillus paracasei), derived from the UPCCO - University of Parma Culture Collection, Parma, Italy). All the selected strains were able to ferment the selected species of microalgae, and the most suitable substrate for LAB growth was Arthrospira platensis. Extracts from fermented Chlorella vulgaris and Chlorococcum sp. reduced significantly the neutral lipid reservoirs, which was not observed without fermentations. The strongest lipid reducing effect was obtained with Arthrospira platensis fermented with Lactobacillus delbrueckii bulgaricus 1932. Untargeted metabolomics identified some compound families, which could be related to the observed bioactivity, namely fatty acids, fatty amides, triterpene saponins, chlorophyll derivatives and purine nucleotides. This work opens up the possibility of developing novel functional foods or food supplements based on microalgae, since lactic acid fermentation enhanced the production of bioactive compounds with lipid reducing activities.

Fermentation of Inula britannica using Lactobacillus plantarum SY12 increases of epigallocatechin gallate and attenuates toxicity

This study aimed to increase epigallocatechin gallate (EGCG) levels and attenuate the toxicity in Inulabritannica by fermentation using Lactobacillus plantarum SY12. The optimal medium was composed of 10 g of I. britannica, 4 g of xylose, 5 g of soytone, and 5 g of beef extract. The predicted value of EGCG was 237.327 μg/mL. To investigate damage in HepG2 cell lines by I. britannica extracts (IE) or fermented I. britannica extracts (FIE), cell viability, mitochondria membrane potential, the expression of apoptosis and autophagy genes, and chemical composition were measured. FIE increased cell viability, regulation of the gene expression (decreased p53, p62, p-ERK 1/2, and p-p38; increased CDK2 and CDK4) compared with IE. These results were explained by an increase in 1,3-dicaffeoylquinic acid and a decrease in 1-O-caffeoylquinic acid, 1-O-acetylbritannilactone, and ergolide in FIE. In conclusion, these results indicated that fermentation can mitigate the toxicity in I. britannica.

Phenolic Profile and Bioactivity Changes of Lotus Seedpod and Litchi Pericarp Procyanidins: Effect of Probiotic Bacteria Biotransformation

Theoretically, lactic acid bacteria (LABs) could degrade polyphenols into small molecular compounds. In this study, the biotransformation of lotus seedpod and litchi pericarp procyanidins by Lactobacillus plantarum 90 (Lp90), Streptococcus thermophilus 81 (ST81), Lactobacillus rhamnosus HN001 (HN001), and Pediococcus pentosus 06 (PP06) were analysed. The growth curve results indicated that procyanidins did not significantly inhibit the proliferation of LABs. Ultra-high-performance liquid chromatography high-resolution mass spectrometry (UPLC-HRMS) revealed that procyanidin B2 and procyanidin B3 in lotus seedpod decreased by 62.85% and 25.45%, respectively, with ST81 metabolised, while kaempferol and syringetin 3-O-glucoside content increased. Although bioconversion did not increase the inhibitory function of procyanidins against glycosylation end-products in vitro, the 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) free radical scavenging capacity and ferric reducing antioxidant power of litchi pericarp procyanidins increased by 157.34% and 6.8%, respectively, after ST81 biotransformation. These findings may inspire further studies of biological metabolism of other polyphenols and their effects on biological activity.

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).

Impact of Fermentation Pretreatment on Drying Behaviour and Antioxidant Attributes of Broccoli Waste Powdered Ingredients

Valorisation of fruit and vegetable wastes by transforming residues and discards into functional powdered ingredients has gained interest in recent years. Moreover, fermentation has been recalled as an ancient technology available to increase the nutritional value of foods. In the present work, the impact of pretreatments (disruption and fermentation) on drying kinetics and functional properties of powdered broccoli stems was studied. Broccoli stems fermented with Lactiplantibacillus plantarum and non-fermented broccoli stems were freeze-dried and air-dried at different temperatures. Drying kinetics were obtained and fitted to several thin layer mathematical models. Powders were characterized in terms of physicochemical and antioxidant properties, as well as of probiotic potential. Fermentation promoted faster drying rates and increased phenols and flavonoids retention. Increasing drying temperature shortened the process and increased powders' antioxidant activity. Among the models applied, Page resulted in the best fit for all samples. Microbial survival was favoured by lower drying temperatures (air-drying at 50 °C and freeze-drying). Fermentation and drying conditions were proved to determine both drying behaviour and powders' properties.

Fermentation of Betaphycus gelatinum Using Lactobacillus brevis: Growth of Probiotics, Total Polyphenol Content, Polyphenol Profile, and Antioxidant Capacity

Little information is available regarding polyphenol variations in the food processing of edible and medicinal red seaweed, Betaphycus gelatinum. This study investigated the effects of Lactobacillus brevis fermentation on total polyphenol content (TPC), polyphenol profile, and antioxidant activity in Betaphycus gelatinum pretreated by ultrasound-assisted mild acid hydrolysis for the first time. During 60 h of fermentation, the viable colony number significantly increased, pH significantly decreased, and reducing sugar content significantly decreased initially, then significantly increased. Free TPC significantly increased to 865.42 ± 29.29 μg GAE/g DW (163.09% increase) with increasing antioxidant activity, while bound TPC significantly decreased to 1004.90 ± 87.32 μg GAE/g DW (27.69% decrease) with decreasing antioxidant activity. Furthermore, 27 polyphenol compounds were identified by ultra-high-performance liquid chromatography with Xevo triple quadrupole mass spectrometry. In total, 19 and 23 free polyphenols and 24 and 20 bound polyphenols were identified before and after fermentation, respectively. Before fermentation, bound trans-cinnamic acid (56.75%), bound rosmarinic acid (26.62%), and free trans-cinnamic acid (3.85%) were the main components. After fermentation, free rosmarinic acid (43.57%), bound trans-cinnamic acid (15.19%), bound rosmarinic acid (13.33%), and free trans-cinnamic acid (5.99%) were the main components. These results provide information for the food processing of Betaphycus gelatinum.

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.

Spontaneous fermentation improves the physicochemical characteristics, bioactive compounds, and antioxidant activity of acerola (Malpighia emarginata D.C.) and guava (Psidium guajava L.) fruit processing by-products

This study aimed to investigate the effects of spontaneous fermentation on physicochemical characteristics, bioactive compounds, and antioxidant activity of acerola and guava fruit industrial by-products. Viable cell counts of lactic acid bacterial (LAB) in acerola and guava by-products were ≥ 5.0 log CFU/mL from 24 h up to 120 h of fermentation. Fermented acerola and guava by-products had increased luminosity and decreased contrast. Contents of total soluble solids and pH decreased, and titrable acidity increased in acerola and guava by-products during fermentation. Ascorbic acid contents decreased in acerola by-product and increased in guava by-product during fermentation. Different phenolic compounds were found in acerola and guava by-products during fermentation. Fermented acerola and guava by-products had increased contents of total flavonoids, total phenolics, and antioxidant activity. The contents of total flavonoids and total phenolics positively correlated with antioxidant activity in fermented acerola and guava by-products. These results indicate that spontaneous fermentation could be a strategy to improve the contents of bioactive compounds and the antioxidant activity of acerola and guava by-products, adding value and functionalities to these agro-industrial residues.

Valorization of orange peels exploiting fungal solid-state and lacto-fermentation

BACKGROUND

Orange peels can serve as a cost-effective raw material for the production of lactic acid. Indeed, given their high concentration of carbohydrates and low content of lignin, they represent an important source of fermentable sugars, recoverable after a hydrolytic step.

RESULTS

In the present article, the fermented solid, obtained after 5 days of Aspergillus awamori growth, was used as the only source of enzymes, mainly composed of xylanase (40.6 IU g^-1 of dried washed orange peels) and exo-polygalacturonase (16.3 IU g^-1 of dried washed orange peels) activities. After the hydrolysis, the highest concentration of reducing sugars (24.4 g L^-1 ) was achieved with 20% fermented and 80% non-fermented orange peels. The hydrolysate was fermented with three lactic acid bacteria strains (Lacticaseibacillus casei 2246 and 2240 and Lacticaseibacillus rhamnosus 1019) which demonstrated good growth ability. The yeast extract supplementation increased the lactic acid production rate and yield. Overall, L. casei 2246 produced the highest concentration of lactic acid in mono-culture.

CONCLUSION

To the best of our knowledge this is the first study exploiting orange peels as low-cost raw material for the production of lactic acid avoiding the employment of commercial enzymes. The enzymes necessary for the hydrolyses were directly produced during A. awamori fermentation and the reducing sugars obtained were fermented for lactic acid production. Despite this preliminary work carried out to study the feasibility of this approach, the concentrations of reducing sugars and lactic acid produced were encouraging, leaving open the possibility of other studies for the optimization of the strategy proposed here. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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).

Microbial production of lactic acid using organic wastes as low-cost substrates

Lactic acid is a natural organic acid with diverse of applications in food, pharmaceutical, cosmetics, and chemical industry. Recently, the demand of lactic acid has been grown due to its utilization for polylactic acid production. Microbial production of lactic acid production is preferable due to optical purity of product, utilization of low cost substrates, and low energy requirement. Lignocellulosic biomass and other organic wastes are considered potential raw materials for cost-effective production of lactic acid. The raw materials are either hydrolyzed by enzymes or dilute acids to release the reducing sugars that are fermented in to lactic acid. This review has been focussed on microbial production of lactic acid using different organic wastes as low cost substrate.

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.

Optimization of Major Extraction Variables to Improve Recovery of Anthocyanins from Elderberry by Response Surface Methodology

Elderberry, which is well known for its richness in anthocyanin, is attracting attention in the bioindustry as a functional material with high antioxidant capacity. The aim of this study is to optimize extraction conditions to more effectively recover anthocyanins from elderberry. In a fundamental experiment to determine the suitable solvent, various GRAS reagents, such as acetone, ethanol, ethyl acetate, hexane, and isopropyl alcohol, were used, and total phenol and anthocyanin contents were detected as 9.0 mg/g-biomass and 5.1 mg/g-biomass, respectively, only in the extraction using ethanol. Therefore, ethanol was selected as the extraction solvent, and an experimental design was performed to derive a response surface model with temperature, time, and EtOH concentration as the main variables. The optimal conditions for maximal anthocyanin recovery were determined to be 20.0 °C, 15.0 min, and 40.9% ethanol, and the total anthocyanin content was 21.0 mg/g-biomass. In addition, the total phenol and flavonoid contents were detected as 67.4 mg/g-biomass and 43.8 mg/g-biomass, respectively. The very simple and economical extraction conditions suggested in this study contributed to improving the utilization potential of anthocyanin, a useful antioxidant derived from elderberry.

Fermentation of rose residue by Lactiplantibacillus plantarum B7 and Bacillus subtilis natto promotes polyphenol content and beneficial bioactivity

The present study evaluated the effect of fermentation with Lactiplantibacillus plantarum B7 and Bacillus subtilis natto on phenolic compound levels and enzyme activity, as well as antioxidant capacity of the rose residue. Results showed that the polyphenol content of rose residue was significantly increased from 16.37 ± 1.51 mg/100 mL to 41.02 ± 1.68 mg/100 mL by fermentation at 37 °C and 2.0% (v/v) inoculum size for 40 h. The flavone, soluble dietary, and protein contents were also enhanced by almost 1-fold, 3-fold, and 1-fold, respectively. Fifteen phenolic compounds were quantified in the fermented broth, among which the concentration of gallic acid, quercetin, and p-coumaric acid increased by 5-fold, 4-fold, and almost 8-fold, respectively. Chlorogenic acid was a new phenolic compound produced during fermentation. Moreover, the fermented rose residue presented higher superoxide dismutase, α-amylase, and protease activity. ABTS^•+, hydroxylradical, and DPPH^• scavenging activity increased by 60.93%, 57.70%, and 37.00%, respectively. This provides an effective means of transforming rose residue into a highly bioactive value-added substance.

New insights into immunomodulatory properties of lactic acid bacteria fermented herbal medicines

The COVID-19 pandemic has brought more attention to the immune system, the body’s defense against infectious diseases. The immunomodulatory ability of traditional herbal medicine has been confirmed through clinical trial research, and has obvious advantages over prescription drugs due to its high number of potential targets and low toxicity. The active compounds of herbal drugs primarily include polysaccharides, saponins, flavonoids, and phenolics and can be modified to produce new active compounds after lactic acid bacteria (LAB) fermentation. LAB, primary source of probiotics, can produce additional immunomodulatory metabolites such as exopolysaccharides, short-chain fatty acids, and bacteriocins. Moreover, several compounds from herbal medicines can promote the growth and production of LAB-based immune active metabolites. Thus, LAB-mediated fermentation of herbal medicines has become a novel strategy for regulating human immune responses. The current review discusses the immunomodulatory properties and active compounds of LAB fermented herbal drugs, the interaction between LAB and herbal medicines, and changes in immunoregulatory components that occur during fermentation. This study also discusses the mechanisms by which LAB-fermented herbal medicines regulate the immune response, including activation of the innate or adaptive immune system and the maintenance of intestinal immune homeostasis.

Debate: Could the litchi pericarp oligomeric procyanidins bioconverted by Lactobacillus plantarum increase the inhibitory capacity on advanced glycation end products?

Lactic acid bacteria (LAB) have already been used as fermentation strains to enhance the antioxidant capacity of polyphenols. Antioxidant capacity is one of the most important factors to inhibit advanced glycation end product (AGE) formation and could LAB increase the inhibitory capacity of procyanidins on AGEs formation? It was surprising that opposite results were obtained both in simulated food processing and gastrointestinal digestion systems. After incubation with Lactobacillus plantarum (L. plantarum), litchi pericarp oligomeric procyanidins (LPOPCs) were bioconverted to several phenolic acids, which increased the antioxidant activity as expected. However, antiglycation ability and trapping carbonyl compounds capacity both weakened and it might be the primary reason for decreasing the inhibitory effect on AGE formation. Furthermore, it was found that LPOPCs incubated with L. plantarum inhibited the activity of digestive enzymes and thus decreased the digestibility of glycated protein. Our study systematically proposed for the first time that procyanidins bioconversion is an effective means to improve the antioxidant activity but has no remarkable promoting effect on AGEs inhibition.

Study of Fermentation Strategies by Lactobacillus gasseri for the Production of Probiotic Food Using Passion Fruit Juice Combined with Green Tea as Raw Material

Foods fermented by Lactobacillus with probiotic properties convey health benefits to consumers, in addition to fulfilling the basic function of nourishing. This work aimed to evaluate the growth characteristics of L. gasseri in passion fruit juice and passion fruit added with green tea. Fermentation under evaluation of different pH (3.5–7.5), temperature (30–44 °C), and with the addition of green tea (7.5–15%), took place for 48 h. The results showed that a pH of 7.5 and temperature of 44 °C showed higher cell production, and it was also verified that the addition of 15% of green tea induced the growth of L. gasseri in passion fruit juice. The concentrations of probiotic cells observed were above 9 Log CFU.mL⁻¹ and, therefore, they are promising products for consumption as a functional food and application in the food industry with potential health benefits.

LAB Fermentation Improves Production of Bioactive Compounds and Antioxidant Activity of Withania somnifera Extract and Its Metabolic Signatures as Revealed by LC-MS/MS

In this study we investigated the effect of lactic acid bacteria (LAB) fermentation on the ingredients and anti-oxidant activity of Withania somnifera extract. Four strains of LAB could proliferate normally in medium containing W. somnifera extract after the pH reached 3.1~3.5. LAB fermentation increased the content of alcohols and ketones, endowing the extract with the characteristic aroma of fermentation. Compared to the control, the DPPH and ABTS free radical scavenging rates in the fermented samples were significantly improved, ranging from 48.5% to 59.6% and 1.2% to 6.4%. The content of total phenols was significantly increased by 36.1% during the fermentation of mixed bacteria. Moreover, the original composition spectrum of the extract was significantly changed while the differentially accumulated metabolites (DAMs) were closely related to bile secretion, tryptophan metabolism and purine metabolism. Therefore, LAB fermentation can be used as a promising way to improve the flavor and bioactivity of the extracts of W. somnifera, making the ferments more attractive for use as functional food.

(Poly)phenolic composition of tomatoes from different growing locations and their absorption in rats: A comparative study

The aim of this work was to address whether the growing location of tomato could generate a different (poly)phenol profile able to affect both in vivo absorption and (poly)phenol metabolite pattern upon tomato consumption. uHPLC-MSⁿ analyses allowed to obtain a detailed (poly)phenol profile of tomatoes from two locations in Spain, quantifying 57 (poly)phenolic compounds. However, local and non-local tomatoes showed a different concentration of their native (poly)phenols, which could be attributed to diverse cultivation origin. Rat serum was analysed after an acute tomato feeding. Seven phenolic metabolites were quantified through uHPLC-MSⁿ. Pharmacokinetic parameters were further evaluated, revealing different serum concentrations of (poly)phenolic metabolites between tomatoes. The maximum peak serum concentrations, reached mainly after 2 h after ingestion, led to suppose that serum metabolites were mostly derived from absorption in the upper gastrointestinal tract. The growing location of tomatoes affected both the content of native (poly)phenols and their in vivo absorption.

Elderberry (Sambucus nigra L.): Bioactive Compounds, Health Functions, and Applications

Elderberry (Sambucus nigra L.) is rich in many bioactive compounds and exhibits diverse health functions, of which an understanding can be helpful for its better utilization in the food industry. This review mainly summarizes recent studies about the bioactive compounds and health functions of elderberry, highlighting the potential mechanism of action. In addition, the applications of elderberry in foods are also discussed. Elderberry contains diversely bioactive ingredients, such as (poly)phenolic compounds and terpenoid compounds. Recent studies report that some food processing methods can affect the content of bioactive compounds in elderberry. Additionally, elderberry exhibits various health functions in vitro and in vivo, including antioxidant, anti-inflammatory, anticancer, anti-influenza, antimicrobial, antidiabetic, cardiovascular protective, and neuroprotective activities, and their potential molecular mechanisms are associated with regulating some key signaling pathways and molecular targets. Up to now, there have been limited clinical trials supporting the health benefits of elderberry. Overall, elderberry is a promising dietary source of bioactive ingredients and has the potential to be developed into functional foods or nutraceuticals for preventing and treating certain chronic diseases.

Fermentation of kiwifruit juice from two cultivars by probiotic bacteria: Bioactive phenolics, antioxidant activities and flavor volatiles

Three commercial lactic acid bacteria (LAB), namely Lactobacillus acidophilus 85 (La85), Lactobacillus helveticus 76 (Lh76) and Lactobacillus plantarum 90 (Lp90), were employed to investigate the effects on the phenolic compounds, antioxidant capacities and flavor volatiles of kiwifruit juices prepared from two cultivars (Actinidia deliciosa cv. Xuxiang and Actinidia chinensis cv. Hongyang). Results showed that both kiwifruit juices were favorable matrices for LAB growth and the colony counts remained above 9.0 log CFU/mL after fermentation. Total phenolics and flavonoids in Xuxiang and Hongyang juices were increased dramatically by Lh76. Correspondingly, antioxidant capacities based on DPPH, ABTS and FRAP methods were improved significantly and positively correlated with protocatechuic acid and catechin contents (p < 0.05), two newly formed phytochemicals in fermented kiwifruit juices. Furthermore, results of hierarchical cluster analysis revealed that flavor profiles were improved significantly by LAB, and there were noticeable differences between fermented Xuxiang and Hongyang juices.

Fermentation and Storage Characteristics of "Fuji" Apple Juice Using Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus plantarum: Microbial Growth, Metabolism of Bioactives and in vitro Bioactivities

Fruit juices have been widely used as the substrates for probiotic delivery in non-dairy products. In this study, three lactic acid bacteria (LAB) strains, including Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus plantarum, were selected to ferment apple juice. During 72-h of fermentation, these LAB strains grew well in the apple juice with significant increases in viable cell counts (from 7.5 log CFU/mL to 8.3 log CFU/mL) and lactic acid content (from 0 to 4.2 g/L), and a reduction of pH value (from 5.5 to around 3.8). In addition, the antioxidant and antibacterial capacities of fermented apple juice in vitro were significantly improved through the phenolic and organic acid metabolisms. After storage at 4°C for 30 days, the total amino acid content of fermented apple juice was significantly increased, although the viable cell counts and total phenolic content were decreased (p < 0.05). Furthermore, the stored fermented apple juices still possessed antibacterial and in vitro antioxidant activities. Overall, all the selected LAB strains could be suitable for apple juice fermentation and can effectively improve their biological activities.

Fermentation Affects the Antioxidant Activity of Plant-Based Food Material through the Release and Production of Bioactive Components

This review reports on the effects of fermentation on the chemical constituents and antioxidant activity of plant-based food materials. Fermentation involves a series of reactions that modify the chemical components of the substrate. It could be considered a tool to increase the bioactive compounds and functional properties of food plant materials. Oxidative damage is key to the progression of many human diseases, and the production of antioxidant compounds by fermentation will be helpful to reduce the risk of these diseases. Fermentation also can improve antioxidant activity given its association with increased phytochemicals, antioxidant polysaccharides, and antioxidant peptides produced by microbial hydrolysis or biotransformation. Additionally, fermentation can encourage the breakdown of plant cell walls, which helps to liberate or produce various antioxidant compounds. Overall, results indicated that fermentation in many cases contributed to enhancing antioxidants' content and antioxidant capacity, supporting the fermentation use in the production of value-added functional food. This review provides an overview of the factors that impact the effects of fermentation on bioactive compound composition and antioxidant activity. The impacts of fermentation are summarized as a reference to its effects on food plant material.

Biotransformation of Polyphenols in Apple Pomace Fermented by β-Glucosidase-Producing Lactobacillus rhamnosus L08

Apple pomace, the main by-product in apple processing, is a cheap source of bioactive compounds that could be used in the food industry. However, the value of this by-product is still far from being fully realized. In this study, 11 strains of Lactobacillus strains were assayed for β-glucosidase activity, and only Lactobacillus rhamnosus L08 (L. rhamnosus L08) showed high cell-membrane associated β-glucosidase activity. We then evaluated the effects of fermentation of apple pomace using the selected strain, focusing on the biotransformation of polyphenols and antioxidant capacity. We found that L. rhamnosus L08 fermentation significantly reduced the contents of quercitrin and phlorizin in apple pomace, while increasing the contents of quercetin and phloretin. The contents of gallic acid, epicatechin acid, caffeic acid, and ferulic acid were also increased in apple pomace after fermentation. In addition, the antioxidant activities of apple pomace were enhanced during fermentation, based on the bioconversion of phenolic profiles. Our results demonstrate that lactic acid bacteria fermentation is a promising approach to enhance the bioactivity of phenolic compounds in apple pomace. Moreover, this study demonstrates that, as a valuable processing by-product with bioactive components, apple pomace can be used in the food industry to provide economic benefits.

Antimicrobial Activity of Fermented Vegetable Byproduct Extracts for Food Applications

To prevent foodborne diseases and extend shelf-life, antimicrobial agents may be used in food to inhibit the growth of undesired microorganisms. In addition to the prevention of foodborne diseases, another huge concern of our time is the recovery of agri-food byproducts. In compliance with these challenges, the aim of this work was to more deeply investigate the antimicrobial activity of extracts derived from fermented tomato, melon, and carrot byproducts, previously studied. All the fermented extracts had antimicrobial activity both in vitro and in foodstuff, showing even higher activity than commercial preservatives, tested for comparison against spoilage microorganisms and foodborne pathogens such as Salmonella spp., L. monocytogenes, and B. cereus. These promising results highlight an unstudied aspect for the production of innovative natural preservatives, exploitable to improve the safety and shelf-life of various categories of foodstuff.

Fermentation as a tool for increasing food security and nutritional quality of indigenous African leafy vegetables: the case of Cucurbita sp

Sub-Saharan region is often characterized by food and nutrition insecurity especially "hidden hunger" which results from inadequate micronutrients in diets. African indigenous leafy vegetables (AILVs) can represent a valid food source of micronutrients, but they often go to waste resulting in post-harvest losses. In an attempt to prolong AILVs shelf-life while enhancing their nutritional quality, fermentation was studied from a microbiological and nutritional point of view. Pumpkin leaves (Cucurbita sp.) were spontaneously fermented using the submerged method with 3% NaCl and 3% sucrose. Controls were set up, consisting of leaves with no additions. During fermentation, samples of both treatments were taken at 0, 24, 48, 72 and 168 h to monitor pH and characterize the microbial population through culture-based and molecular-based analyses. Variations between fresh and treated leaves in B-group vitamins, carotenoids, polyphenols, and phytic acid were evaluated. Data revealed that the treatment with addition of NaCl and sucrose hindered the growth of undesired microorganisms; in controls, unwanted microorganisms dominated the bacterial community until 168 h, while in treated samples Lactobacillaceae predominated. Furthermore, the content in folate, β-carotene and lutein increased in treated leaves compared to the fresh ones, while phytic acid diminished indicating an amelioration in the nutritional value of the final product. Thus, fermentation could help in preserving Cucurbita sp. leaves, avoiding contamination of spoilage microorganisms and enhancing the nutritional values.

Exploitation of Sea Buckthorn Fruit for Novel Fermented Foods Production: A Review

Sea buckthorn fruit is abundant with essential nutrients and bioactive substances, yet it remains less sought after. Therefore, it is valuable to explore new ways of sea buckthorn fruit processing, which can boost consumer acceptance of sea buckthorn fruit and also lead to formulation of new functional foods. In the presented review, we summarize studies focused on development of foods utilizing sea buckthorn fruit or its components and bacterial food cultures. Firstly, we discuss the impact of malolactic fermentation on content and profile of organic acids and polyphenols of sea buckthorn fruit juice. During this process, changes in antioxidant and sensory properties are considerable. Secondly, we address the role of sea buckthorn fruit and its components in formulating novel probiotic dairy and non-dairy products. In this regard, a synergic effect of prebiotic material and probiotic bacteria against pathogens is distinguished. Overall, the potential of sea buckthorn fruit as a botanical ingredient for application in novel foods is highlighted.

Effect of fermentation with single and co-culture of lactic acid bacteria on okara: evaluation of bioactive compounds and volatile profiles

Okara is the main soybean by-product resulting from the processing of soy milk and tofu. Despite being a product with a lot of potential and rich in many bioactive compounds such as polyphenols, it presents an unpleasant, rancid aroma. For this reason its use in the food industry is limited. In this study, we have reported the integral use of okara in a solid state fermentation process, conducted with wild strains of lactic acid bacteria, to evaluate the effect of bacterial metabolism on the volatile and polyphenolic profiles. Strains belonging to Lactobacillus acidophilus, Lacticaseibacillus rhamnosus and Pediococcus acidilactici species were used in monoculture and, for the first time, in co-culture. The results showed an improvement in the aromatic fraction showing a decrease in hexanal, responsible for off-flavour, and an increase in ketones with fruity and buttery notes in fermented okara. Polyphenols were also affected, and, in particular, a bioconversion of glucoside isoflavones to the aglycone forms was highlighted in all fermented substrates. In addition, the appearance of both phenyllactic and p-hydroxyphenyllactic acids as well as the increase in indole-3-lactic acid was observed for the first time upon okara fermentation. Overall, the co-culture appears to be the most promising for biovalorization of okara, thereby opening the possibility of its use in the development of functional ingredients.

L-Lactic acid production from fructose by chitosan film-coated sodium alginate-polyvinyl alcohol immobilized Lactobacillus pentosus cells and its kinetic analysis

Under the optimal conditions of immobilization and fermentation, the highest LA yield of 0.966 ± 0.006 g/g fructose and production rate of 2.426 ± 0.018 g/(L × h) with an error of -0.5% and -0.2% to the predicted results were obtained from batch fermentation by the CS film-coated SA-PVA immobilized L. pentosus cells. The LA yield and production rate of these immobilized cells were 2.7% and 10.1% higher than that of normal SA-PVA immobilized cells respectively, and they were 5.7% and 48.4% higher than that of free cells, respectively. The effect of temperature on different types of immobilized cells and free cells was significantly different, but the effect of pH on different types of cells was not much different. The kinetic models could effectively describe the different fermentation performances of three types of cells. The immobilized cells have excellent reusability to conduct 9 runs of repeated batch fermentation.

Catabolism of hydroxycinnamic acids in contact with probiotic Lactobacillus

AIMS

The catabolism products of the fermentation process of selected hydroxycinnamic acids initiated by different species of Lactobacillus strains were identified.

METHODS AND RESULTS

Three dietary supplements (Sanprobi IBS^® , BioGaia ProTectis Baby^® and Dicoflor 60^® ) were used to isolate the Lactobacillus strains. The overnight bacterial cultures (18 h) were diluted and grown in a microaerophilic atmosphere at 37°C. Then, each phenolic acid was added to bacterial cultures and incubated for 24 h at 37°C. Samples were collected at specific intervals for a further 24 h of incubation. LC-MS/MS was used for the identification of metabolism products of selected phenolic acids.

CONCLUSIONS

The phenolic acids were resistant to the Lactobacillus rhamnosus GG. Lactobacillus plantarum 299v caused degradation of caffeic and ferulic acids. The former was degraded either to dihydrocaffeic acid or to 4-vinylcatechol and 4-ethylcatechol. Ferulic acid was degraded only to dihydroferulic acid. Lactobacillus reuteri DSM 17938 caused only the degradation of chlorogenic acid (5-caffeoylquinic acid, referred to IUPAC nomenclature) to caffeic acid.

SIGNIFICANCE AND IMPACT OF THE STUDY

Using of Lactobacilli as food additive should be taken into account that phenolic acids metabolism rate depends on not only the specific bacterial strain but also the structural properties of the acid.

An overview of the perception and mitigation of astringency associated with phenolic compounds

Astringency, as a kind of puckering, drying, or rough sensation, is widely perceived from natural foods, especially plants rich in phenolic compounds. Although the interaction and precipitation of salivary proteins by phenolic compounds was often believed as the major mechanism of astringency, a definitive theory about astringency is still lacking due to the complex oral sensations. The interaction with oral epithelial cells and the activation of trigeminal chemoreceptors and mechanoreceptors also shed light on some of the phenolic astringency mechanisms, which complement the insufficient mechanism of interaction with salivary proteins. Since phenolic compounds with different types and structures show different astringency thresholds in a certain regularity, there might be some relationships between the phenolic structures and perceived astringency. On the other hand, novel approaches to reducing the unfavorable perception of phenolic astringency have been increasingly emerging; however, the according summary is still sparse. Therefore, this review aims to: (a) illustrate the possible mechanisms of astringency elicited by phenolic compounds, (b) reveal the possible relationships between phenolic structures and perception of astringency, and (c) summarize the emerging mitigation approaches to astringency triggered by phenolic compounds. This comprehensive review would be of great value to both the understanding of phenolic astringency and the finding of appropriate mitigation approaches to phenolic astringency in future research.