Biotransformation of phenolic profiles and improvement of antioxidant capacities in jujube juice by select lactic acid bacteria

Impact of ripeness stages on the chemical and sensory profiles of jujube wine: An analysis of physicochemical parameters, antioxidant activity, and volatile compounds

This study demonstrates that the jujube maturity significantly affects the physicochemical properties, antioxidant capacities, and volatile profiles of jujube wine. The semi-red jujube wine exhibited the highest concentrations of total phenolics (1069.73 mg GAE/L) and flavonoids (629.82 mg RE/L), underscoring potential health benefits. These levels decreased with fruit maturation, with notable decreases in catechin, chlorogenic acid, and eugenol concentrations, especially evident between the semi-red and full-red stages. Amino acid concentrations, particularly proline, increased significantly with ripeness, from 5.93 mg/L in semi-red stage to 775.91 mg/L in sweetheart stage, enhancing the wine's flavor complexity. Volatile analysis showed significant changes in the aromatic profile at the sweetheart stage, enriching the wine with fruity and floral esters. These results emphasize that the selection of optimal ripeness depends on balancing the chemical, nutritional, and sensory qualities most desired in jujube wine, providing practical guidelines for wine producers.

Co-cultivation effects of Lactobacillus plantarum and Pichia pastoris on the key aroma components and non-volatile metabolites in fermented jujube juice

Fermented jujube products are gradually becoming popular. However, few studies have focused on the relationship between the metabolites and aroma compounds in jujube during the fermentation process. Hence, in this study, jujube was fermented with the co-culture of Lactobacillus plantarum and Pichia pastoris, and the key volatile organic components (VOCs) and non-volatile organic components (nVOCs) in the fermented jujube juice (FJJ) were studied to determine the possible aromatic production pathway during microbial metabolism and propose the possibility of regulating flavor during fermentation. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was employed to analyze and compare the VOCs in the jujube juice before and after fermentation, which showed that the fermented aroma had increased floral, winy and sour notes. Specifically, 13 key aroma compounds were found using the aroma extract dilution analysis (AEDA) and aroma recombination/omission model. Additionally, 32 differential nVOC metabolites, mainly involved in amino acid and nucleotide metabolism pathways, were screened in FJJ using liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with multivariate statistical analysis. After correlation analysis, 14 nVOCs were significantly correlated with 8 key aroma compounds. This study indicates that the combination of Lactobacillus plantarum and Pichia pastoris may supply a new mixed fermentation agent towards fermented jujube products and provides reference values for flavor regulation in the co-fermentation of jujube juice.

Enhancing the Physicochemical Properties, Bioactivity, and Functional Applications of Fresh Jujube Juice Using Media Milling

This study systematically evaluated the effects of media milling on the physicochemical properties, bioactive compound content, and functional applications of fresh jujube (Ziziphus jujuba Mill.) juice. Optimization experiments identified ideal conditions for nanoparticle production, including 5% solid content and a 180 min milling duration, resulting in significantly reduced particle sizes-volume-weighted average diameter (from 229.0 ± 1.0 to 25.0 ± 0.2 μm) and number-weighted average diameter (from 7.2 ± 0.0 to 0.1 ± 0.0 μm)-and improved dispersion stability. Media milling enhanced key physicochemical properties such as zeta potential, viscosity, and suspension stability, while also modifying color and pH. The process notably increased the content of bioactive compounds, including total flavonoids (from 2.9 ± 0.1 to 3.8 ± 0.0 mg catechin equivalent (CE)/g dry weight (DW)) and triterpenoids (from 15.4 ± 1.2 to 28.0 ± 4.9 mg oleanolic acid equivalent (OAE)/g DW). The antioxidant activity before and after media milling, assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, remained comparable. Fermentation with Lactiplantibacillus plantarum demonstrated that both blended and media-milled jujube juice can serve as effective substrates for substrate utilization and lactic acid production. Anti-inflammatory assays using RAW 264.7 macrophages revealed reduced nitric oxide production and lower levels of pro-inflammatory cytokines such as IL-1β, showcasing the juice's potential to modulate inflammation. In a dextran sodium sulfate (DSS)-induced colitis mouse model, media-milled jujube juice demonstrated safety, though it did not show significant protective effects. These findings position media-milled jujube juice as a promising functional food ingredient with potential applications in health promotion and disease management.

Effects of different lactic acid bacteria on the physicochemical properties, functional characteristics and metabolic characteristics of fermented hawthorn juice

Lactic acid bacteria (LAB) fermentation enhances the flavour and functionality of juice substrates; however, research on hawthorn juice is limited. We hypothesize that due to strain specificity, the changes in hawthorn juice after fermentation with different LAB may vary. After selecting LAB strains based on pH and sensory evaluation, the physicochemical properties and anti-inflammatory potential in a lipopolysaccharide-induced RAW 264.7 macrophage model were analysed in vitro. Non-targeted metabolomics revealed fermentation-driven metabolic changes. All strains exhibited increased total acidity and decreased reducing sugar and flavonoid contents. In particular, the Lactobacillus plantarum SC-1.3 and FWDG (strain preservation number) strains suppressed the pro-inflammatory cytokines interleukin-6 and tumour necrosis factor-α, with FWDG exhibiting the strongest effect. Moreover, fermentation resulted in the enrichment of bioactive metabolites, including prunetin and glycitein, which are unique to FWDG. The results provided a basis for the industrialization of hawthorn juice as a dietary product.

Addition of Lactobacillus fermentum to Fermented Sea Buckthorn (Hippophae rhamnoides L.) Fruit Vinegar Significantly Improves Its Sour Taste

Fruit vinegar is typically produced through a two-stage deep liquid fermentation involving alcohol fermentation (Saccharomyces cerevisiae) and acetic acid fermentation (Acetobacter pasteurianus). In order to enhance the flavor and texture of sea buckthorn fruit vinegar, Lactobacillus fermentum was introduced into the alcoholic fermentation stage. At the end of fermentation, the total acid and acetic acid of sea buckthorn (Hippophae rhamnoides L.) fruit vinegar were both enhanced compared with sea buckthorn vinegar brewed through the traditional liquid fermentation method, and in terms of the main active ingredients, the total flavonoid content was slightly enhanced. Non-targeted metabolomics (LC-MS) was used to characterize the characteristic metabolite profiles during the fermentation process. A total of 55 differential metabolites, including organic acids, flavonoids, and amino acids, were identified, and the contents of citric acid, malic acid, and manganic acid, which are the sources of the irritating taste of sea buckthorn berry vinegar, were significantly reduced. In addition, the co-fermentation of Lactobacillus fermentum promoted both glycolysis and the TCA cycle and also led to a significant up-regulation of aromatic metabolites, such as ethyl acetate, ethyl lactate, and ethyl caproate. These results will provide new information on the dynamics of the characterized metabolites during the fermentation of sea buckthorn fruit vinegar.

Lactic Acid Bacterial Culture Selection for Orange Pomace Fermentation and Its Potential Use in Functional Orange Juice

The main goal of this study is to improve the bioactivity of citrus pomace by subjecting it to solid-state fermentation by Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus plantarum over varying periods of time. The viability of Lactobacillus, as well as the total phenolic content (TPC) and total antioxidant capacity (TAC) values of orange pomace (OP), varied depending on the Lactobacillus species and fermentation period. The incorporation of pomace into orange juice samples at a ratio of 5% considerably enhanced the viability of probiotics. The TPC and TAC of orange juice samples were reduced after fermentation. The addition of orange pomace to orange juice significantly increased prostaglandin H2 and improved antioxidant capacity with more pronounced effects at increased pomace concentrations. After postfermentation with L. plantarum, key bioactive compounds such as corynoxeine and phenolics were upregulated, while picroside III and allocryptopine levels were decreased. On the other hand, metabolomics analysis revealed significant changes after fermentation in amino acid, sphingolipid, and fatty acid metabolism and the synthesis of secondary metabolites improving the nutritional profile and bioactivity of fermented orange juice. These findings highlight the potential of pomace addition and fermentation to improve the health benefits and quality of orange juice products. Therefore, the combined use of fermentation and fortification with OP could be a promising approach to creating new functional foods and promoting the use of edible food waste and byproducts.

Synergistic enhancement of bio-yogurt properties by Lactiplantibacillus plantarum NUC08 and mulberry fruit extract

Lactiplantibacillus plantarum NUC08, a novel probiotic strain, has demonstrated potential for synergistic fermentation with starter cultures. This study investigates its functional properties in fermented milk and examines how mulberry fruit extract (MFE), rich in bioactive compounds, may influence its fermentation performance. MFE significantly boosted LAB growth, improved texture and rheological properties, and enhanced antioxidant capacity in the probiotic yogurt. GC-MS analysis revealed that MFE enriched the flavor profile by increasing key flavor-related metabolites, contributing to superior sensory qualities. Furthermore, the combination of L. plantarum NUC08 and MFE led to distinct shifts in metabolic pathways, as shown by LC-MS analysis, amplifying the regulatory effects on antioxidant activity. These findings demonstrate the synergy between MFE and L. plantarum NUC08, where MFE enhances the growth and functionality of L. plantarum NUC08, improving the yogurt's physicochemical properties, antioxidant capacity, and flavor, with potential for functional dairy product development.

Calcium-ion-driving assembly of polysaccharide deriving from Zizyphus jujuba to hemostatic hydrogel for treating diabetic wound

Due to good biocompatibility and biodegradable, natural polysaccharide-based hydrogels have received worldwide attentions, where polysaccharide polymers were usually chemically modified to meet the specific elastic requirements. However, it remained highly challenging to develop polysaccharide-based hydrogels with desired mechanical properties and biological functions devoid of any structural modifications. Herein, with the coordination of Ca2+ (15.0 mM), the jujuba polysaccharide (JPS, 1 %) was facilely fabricated to a hydrogel (JPS-gel) within 1 min at pH 10, where the residual proteins also played crucial roles on the assembly. The JPS-gel showed outstanding stability and mechanical properties, which were tunable by adjusting the content of Ca2+/JPS. The JPS-gel also revealed excellent biocompatibility, and could expedite the migration and proliferation of healing-related cells, angiogenesis and alleviate inflammation response. More interestingly, the JPS-gel had hemostatic capacity, where the hemostatic time and blood loss in liver incision model were 13 ± 3 s and 6.3 ± 1.6 mg after 120 s treatment with JPS-gel, respectively. All these superiorities endowed JPS-gel high performance healing in diabetic wounds (10 days). Specially, the expressions of inflammation-related genes were downregulated, but gene expressions associated with cell migration and proliferation, and angiogenesis were upregulated, thus uncovering the action mechanism of JPS-gel on accelerating wound contraction.

Magnetic Janus SiO2 nanoparticles immobilized protease mutant T70I as a novel clarification agent for juice processing

The juice processing industry offers several benefits, including promoting health and wellness through the delivery of beverages rich in nutrients. Nonetheless, the industry encounters significant challenges regarding new technologies for processing and preservation given that they can be costly and labor-intensive. In this study, magnetic Janus silica (SiO2) nanoparticle which offers multifunctionality and high stability was synthesized and subsequently immobilized with a protease mutant T70I (T70I@MSNs) to serve as a clarifying agent in juice. The optimal conditions for the protease immobilized with SiO2 nanoparticles showed superior tolerance and stability at pH 5 and 65 °C. Box-Behnken Design revealed optimizing conditions of 60 min, 50 °C and 0.2 % enzyme concentration which significantly influenced the clarification of the juice samples. Immobilized T70I@MSNs decreased >70 % of juice turbidity while maintaining about 78 % of enzyme activity after 7 consecutive cycles of reuse. Notably, T70I@MSN treatment enhanced certain volatile components by increasing alcohol and ester production, while changes in surface microstructure and functional groups were observed. This study highlights the significant improvement of magnetic Janus SiO2 nanoparticles immobilized proteases in the clarification of juice against haze and undesirable properties, thereby offering a notable contribution to the juice processing industry.

Four distinct pathways involved in a "tug-of-war" lead to the non-linear nature of phenolic chemistry during lactic acid fermentation of fruits and vegetables

Introduction Lactic acid fermentation of fruits and vegetables (F&V) is endowed with new nutrients and flavors. "Phenolics" is a hot spot in this area, which evolve irregularly during fermentation. However, the mechanism about this non-linear phenomenon has been poorly understood.Objectives This paper was aimed at decoding the mechanism about the non-linear nature of phenolic chemistry during lactic acid fermentation of F&V.Methods Mango and cress slurries were fermented by Lactiplantibacillus plantarum. Different fractions of the slurry samples were analyzed comprehensively. Four pathways relating to phenolic changes were extracted, including adsorption of free phenolics by F&V cell wall materials, microbial adsorption and biotransformation of free phenolics, destabilization of covalent bond between bound phenolics and F&V cell walls. The in-depth features of each pathway during fermentation were explored by multidisciplinary methodologies.Results Throughout both fermentation of mango and cress slurries, free phenolics and the F&V cell wall components undergo dynamic changes. Due to the reduction of pectin fraction in the F&V cell walls during fermentation, the adsorption of free phenolics by F&V cell wall materials through surface diffusion was improved. Also, microbial cells, especially in the latter stages of fermentation, were capable of adsorbing free phenolics through surface diffusion. Moreover, the padC and bglB genes encoding phenolic acid decarboxylase and β-glucosidase were expressed during fermentation, contributing to the conversion of free phenolics. Besides, bound phenolics were not released during fermentation, although its covalent was weakened. The features of the above pathways vary with the fermentation stages and the composition of F&V components, resulting in non-linear changes of free phenolics during F&V fermentation. Conclusion F&V cell wall adsorption, microbial adsorption, microbial biotransformation, and destabilization of the covalent bond of bound phenolics compete in a dynamic "tug-of-war", leading to non-linear nature of phenolic chemistry during F&V fermentation.

Lacticaseibacillus rhamnosus Fermentation Ameliorates Physicochemical Properties, Physiological Activity, and Volatile and Non-Volatile Compounds of Mango Juice: Preliminary Results at Laboratory Scale

Lacticaseibacillus rhamnosus is a strain predominantly used for juice production because of its excellent fermentation characteristics and strong acid production capacity. However, the influence of L. rhamnosus on the quality of mango juice has not yet been determined. Therefore, the effects of L. rhamnosus FJG1530 on the physicochemical properties, physiological activity, and volatile and non-volatile compounds of mango juice were extensively examined in this study. The data showed that L. rhamnosus FJG1530 possessed strong adaptability to mango juice, reducing its total sugar and increasing its total flavonoids. L. rhamnosus FJG1530 fermentation enhanced the ability of mango juice to clear the free radicals ABTS and DPPH, as well as improving the inhibition of lipase and α-glucosidase. In addition, L. rhamnosus FJG1530 treatment improved the volatile compounds in mango juice, especially promoting the formation of acids and alcohols. Simultaneously, metabolomic analysis revealed that 592 non-volatile compounds in mango juice were significantly changed by L. rhamnosus FJG1530 fermentation, with 413 dramatically increased and 179 significantly decreased metabolites. This study demonstrates that the fermentation process using L. rhamnosus FJG1530 was beneficial for ameliorating the quality of mango juice.

Metabolic and Transcriptomic-Based Characterization of Streptococcus salivarius ssp. thermophilus Snew Fermentation in Milk

Fermented milk has a long history. It is fermented by lactic acid bacteria and is rich in protein, minerals, vitamins, and other nutrients. As people's pursuit of quality of life improves, consumers are paying increasing attention to fermented milk. Streptococcus salivarius ssp. thermophilus is commonly used to make fermented milk. This study investigated the fermentation characteristics and physicochemical properties of Streptococcus salivarius ssp. thermophilus Snew-fermented milk, as well as transcriptomic and metabolomic analyses of different fermentation stages. Streptococcus salivarius ssp. thermophilus Snew can be used as a fermenter strain, as evaluated from the point of view of fermentation time, titratable acidity, post-acidification, viable bacteria count, water holding capacity, and viscosity. The flavor and odor of Snew-fermented milk varied across fermentation stages. The analysis of the detected volatiles revealed that ketones and esters were the main substances responsible for the flavor of Snew-fermented milk. The differentially expressed genes and differential metabolites screened from several categories, such as carbohydrates, proteins, amino acids, fats, and fatty acids, varied at different fermentation stages, while differentially expressed genes and differential metabolites were also threaded together for joint analysis in this study. This study provides theoretical guidance for the practical production application of Streptococcus salivarius ssp. thermophilus in cow's milk fermentation.

Regulation of the phenolic release and conversion in oats (Avena sativa L.) by co-microbiological fermentation with Monascus anka, Saccharomyces cerevisiae and Bacillus subtilis

Microbial fermentation is an effective method to improve the functional activity of oats (Avena sativa L.), while there are some limitations to the advantages of single microbial fermentation. In this study, a microbial co-culture fermentation system with Monascus anka, Saccharomyces cerevisiae and Bacillus subtilis to release and conversion oat phenolics was established. Results showed that the optimal microbial co-fermentation system was obtained by adding Saccharomyces cerevisiae on the fourth day and Bacillus subtilis on the eighth day during Monascus anka fermentation (MF + 4S + 8B). The phenolic content was reached 26.93 mg GAE/g DW, which increased 41.08 times compared to un-fermented oats (UF). In the process of co-fermentation systems, cellulase and β-glucosidase (r2 = 0.97, p < 0.01) had a positive correlation with the release of phenolics. SEM combined with HPLC showed that the complex enzyme system produced by microbial co-fermentation enhanced the disruption of oat cell structure, as well as altered the phenolics fractions and facilitated the conversion of bound phenolics to free phenolics, especially the content of chlorogenic acid and vanillic acid in the free forms was increased 31.42 and 14.15 times, respectively. Additionally, the phenolic contents were increased and the components were changed with the microbial co-fermentation of crude enzyme solution further added, which validated the positive influence of complex enzyme system of MF + 4S + 8B in the phenolic release and transformation of oats. Therefore, this study systematically investigated the phenolic mobilization in oats during the co-fermentation period, which provides a viable option for improving the functional properties of cereal products, as well as the application of microbial cell factories.

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

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

Investigating the triple-frequency ultrasound-assisted fermented rice lees: Impact on physicochemical, structural, morphological, and metabolic properties

This study examined the effect of triple-frequency ultrasound treatment (TFUT)-assisted lactic acid bacteria (LAB-L. plantarum and L. helveticus fermentation for 24-h and 48-h) on the chemical, structural, morphological, metabolic, and sensory properties of rice lees (RL). Ultrasonicated-assisted RL fermented with L. helveticus (URLH-48) had the greatest total phenolic contents (TPC) (112.1 mg GAE/m), total flavonoid contents (TFC) (163.62 mg RE/mL), and proanthocyanidin contents (PAC) (728.34 mg/mL) compared to RL (control) and other treatments. Furthermore, URLH-48 demonstrated an increase in the concentrations of quinic acid (486.96 mg/L) and gallic acid (201.42 mg/L), as determined by HPLC-UV analysis. Additionally, FTIR spectral analyses demonstrated that TFUT-assisted fermented RL exhibited a greater degree of flexibility and mobility in its secondary structures compared to RL (control). The amino acid's profile of RL was significantly increased as LAB degraded the RL proteins, and the function of TFUT facilitates bacterial activity. Moreover, SEM observation provides convincing evidence that TFUT improves and speeds up the breakdown of proteins' structures, resulting in irregular and dense structures. Correlation and molecular docking research suggest that TFUT has different impacts on specific RL and fermented RL characteristics. The analyses conducted using GC-MS and E-nose indicated the generation of highly volatile flavor compounds through fermentation. The sensory evaluation results show an increase in liking following fermentation and TFUT-assisted fermentation, which is attributed to the production of flavor compounds. Consequently, the combined use of TFUT-assisted fermentation markedly improves the polyphenolic composition, antioxidant capacity, flavor profile, micromorphology, and overall quality of RL, which may enhance their functionality and broaden their applications in the food industry.

Changes in Human Colonic Microbiota Promoted by Synbiotic Açai Juice Composed of Gluco-Oligosaccharides, Dextran, and Bifidobacterium breve NRRL B-41408

The present study evaluates the effects of açai juice containing gluco-oligosaccharides and dextran, fermented by Bifidobacterium breve NRRL B-41408 (synbiotic juice), on the human fecal microbiota. The juice is subjected to simulated digestion and fecal fermentation after production and 42 days of refrigerated storage. High throughput 16S rRNA sequencing and HPLC are used to identify the bacterial cells and metabolites. The results show that the viability of B. breve is stable during the refrigerated storage, indicating that the metabolism is maintained even under low temperatures and pH. Furthermore, gluco-oligosaccharides and dextran prove to be resistant to gastrointestinal conditions and are quickly consumed during fecal fermentation. The synbiotic açai juice enhances the microbial diversity and stimulates the production of short-chain fatty acids (SCFA), including acetate, propionate, and isobutyrate. Elevated propionate levels are directly associated with an increased abundance of Bacteroides thetaiotaomicron, Bacteroides uniformis, Bacteroides xylanisolvens, Bacteroides dorei, Bacteroides stercoris, and Bacteroides massiliensis after 48 h of fermentation. This highlights the potential of synbiotic açai juice as a functional beverage, supported by the significant increase in microbial diversity reflected in the Shannon and Simpson's diversity indexes (Shannon = 116.6%, 117.2%, 125.15%, and 116.02%; Simpson's = 151.86%, 177.22%, 152.5%, and 163.73%).

Improvement of antioxidant capacity, aroma quality, and antifungal ability of cherry by phenyllactic acid treatment during low temperature storage

Introduction

Sweet cherries (Prunus avium L.) are highly valued for their taste and nutrients but are prone to decay due to their delicate skin and high respiration rate. Traditional chemical preservatives have drawbacks like residues and resistance, prompting the search for natural alternatives. Phenylactic acid (PLA) has shown promise due to its antibacterial and antioxidant properties, making it a potential natural preservative to extend cherry shelf life.

Methods

'Stella' sweet cherries were treated with varying concentrations of PLA (0, 2, 4, 8, 16 mmol·L-1) and stored at 4°C. Key quality indicators, including firmness, total acidity, total soluble solids, weight loss, decay index, and antioxidant activity, were assessed over time. Additionally, HPLC, GC-MS, GC-IMS, colony counts, in vivo inhibition analyses were conducted to evaluate phenolic content, aroma compounds and antifungal ability.

Results and Discussion

PLA at 8 mmol·L-1 effectively maintained cherry quality by reducing weight loss and decay of cherries, delaying the decline of firmness, while enhancing antioxidant capacity, flavor stability, and antifungal ability. Higher concentrations (16 mmol·L-1) provided stronger antimicrobial effects but caused slight surface wrinkling. Thus, 8 mmol·L-1 was optimal, balancing preservation and appearance, making it a promising natural preservative for extending cherry shelf life.

Effects of Lactic Acid Bacteria Fermentation and In Vitro Simulated Digestion on the Bioactivities of Purple Sweet Potato Juice

The effects of lactic acid bacteria fermentation and in vitro simulated digestion on phenolic bioavailability, phenolic bioavailability, and antioxidant activity of purple sweet potato juice (PSPJ) were investigated. The PSPJ was fermented by Lactobacillus rhamnosus and Streptococcus thermophilus. The viable bacterial count, phenolic components, antioxidant activity, phenolic bioaccessibility, and phenolic bioavailability of PSPJ were analyzed during the simulated digestion process in vitro. The data displayed that lactic acid bacteria fermentation increased total α-glucosidase inhibition, total flavonoid content, and ratephenolic content. The antioxidant activities were improved after in vitro simulated digestion due to the biotransformation of phenolic substances by lactic acid bacteria fermentation. The bioaccessibility and bioavailability of phenols in PSPJ were improved with fermentation of lactic acid bacteria. Furthermore, the viable bacteria count of the two strains was significantly improved (>7 log CFU/mL) after simulated digestion in vitro.

A Novel Non-Alcoholic Einkorn-Based Beverage Produced by Lactic Acid Fermentation: Microbiological, Chemical, and Sensory Assessment

Einkorn (Triticum monococcum L. ssp. monococcum) is gaining renewed interest for its high nutritional value and digestibility. Lactic acid fermentation could enhance these properties by improving micronutrient bioavailability, sensory properties, and shelf life. This study aimed to develop a novel non-alcoholic einkorn-based beverage through lactic acid fermentation. A multiple-strain starter was selected based on acidifying properties and inoculated into an einkorn-based substrate to produce a yogurt-like beverage. Prototypes were evaluated through physico-chemical, chemical, and microbiological analyses and compared to uninoculated controls. A sensory analysis was also performed to assess flavor attributes before and after lactic acid fermentation. The inoculated starter culture reached a load of approximately 9 Log CFU g⁻¹ and remained viable throughout storage, leading to an increase in lactic acid concentration and high titratable acidity, corresponding to low pH values. Total polyphenol content increased during fermentation and remained stable during storage, whereas antioxidant activity did not show significant differences over time. An increase in monosaccharides, acids, and ketones was observed during fermentation and storage. The prototypes exhibited a distinctive proximate composition, along with yogurt and fruity aroma notes. These results suggest the feasibility of producing a safe and stable non-alcoholic einkorn-based fermented beverage with appealing sensory characteristics.

Widely targeted metabolomics and flavoromics reveal the effect of Wickerhamomyces anomalus fermentation on the volatile and nonvolatile metabolites of black garlic juice

Black garlic has a variety of biological activities, but many consumers cannot accept it because of the garlic odor and the bitter taste. In this study, fermentation with yeast Wickerhamomyces anomalus was adopted to improve the flavor of black garlic juice. Although fermentation reduced antioxidant activities, the garlicky odor and bitter taste were weakened. Metabolomic analysis revealed 141 metabolites were significantly differentially regulated. The upregulated metabolites were mainly related to nucleotides, organic acids and their derivatives, while the downregulated metabolites were mainly related to amino acids, lipids and their derivatives. Flavoromics analysis revealed that 137 metabolites were significantly differentially regulated, particularly garlicky and pungent volatiles were significantly downregulated. Correlation analysis indicated that esters are most closely related to nonvolatile metabolites, and lipids degradation was significantly correlated with volatiles. The results indicated that W. anomalus fermentation is an effective strategy to improve the flavor of black garlic juice.

Nutrients, Phytochemicals, and Antioxidant Capacity of Red Raspberry Nectar Fermented with Lacticaseibacillus paracasei

Fresh raspberries are highly perishable, but lactic acid bacteria fermentation offers a favourable method for developing healthy products. This study investigated the effects of Lacticaseibacillus paracasei fermentation on the nutrients and phytochemicals of red raspberry nectar using widely targeted metabolomics, as well as its antioxidant activity. The fermentation notably disrupted the raspberry tissue structure, reshaped its non-volatile composition, and increased its DPPH and hydroxyl free radical scavenging abilities. A total of 261 compounds showed significant differences, with 198 upregulated and 63 downregulated. Among these, certain flavonoid glucosides (e.g., pelargonid-in-3-O-rutinoside, delphinidin-3-O-rutinoside-7-O-glucoside, and kaempferol-3-O-glucoside) were significantly downregulated, while some bioactive phenolic acids (e.g., 3-(4-Hydroxyphenyl)-propionic acid and DL-3-phenyllactic acid), alkaloids (e.g., deoxymutaaspergillic acid and indole-3-lactic acid), amino acids (e.g., L-phenylalanine and L-glutamine), and B vitamins (e.g., VB6, VB7, and VB3) were substantially upregulated. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation and enrichment analysis revealed that metabolic pathways and the biosynthesis of secondary metabolites contributed significantly to the new profile of fermented red raspberry nectar. These findings provide valuable insights for developing fermented raspberry products using Lacticaseibacillus paracasei, which can help minimise fresh raspberry loss and enhance their valorisation.

A new plant-based probiotic from juá: Source of phenolics, fibers and antioxidant properties

The objective of this study was to evaluate the viability of juá pulp for fermentation by monoculture L. casei (Lc - 01) and L. acidophilus (La - 05) and co-culture (25 and 37 °C) for 72 h. Viable strain values (> 7 log CFU/g), pH reduction (below 3.7), fructose and glucose and increased of lactic acid showed that the pulp of juá served as a good matrix for fermentation. Catechin, epicatechin, epigallocatechin procyanidin B1, and gallic acid were the main phenolics that contributed to antioxidant activity. Fermentation by mono or co-culture increased or reduced the content of phenolics and antioxidant activity. Results showed that culture, time and temperature have effects in the fermentation of juá pulp. The co-cultivation of La - 05 + Lc - 01 contributed to improving the bioaccessibility of gallic acid (72.9%) of the jua pulp. Finding indicate juá pulp as a promising substrate to obtaining a new probiotic plant-based fermented beverage.

Unveiling the aromatic diversity of Fermented mango juices through 40 plant-derived Lactiplantibacillus plantarum

Two varieties of mango juices (MJs) were separately fermented with 40 strains Lactiplantibacillus plantarum. The volatile compounds and sensory characteristics of the fermented mango juices (FMJs) were analyzed by HS-SPME-GC-MS and Napping method. The results demonstrated well growth among all strains except for LC25. Strains SS6 and B15 demonstrated the strongest acid production capacity in ReNong and Ketti MJs. Seventy-five volatile compounds were identified, showcasing strain-specific differences. Fermentation significantly enhanced the complexity and intensity of aroma compounds, especially terpenes, esters and alcohols. Sensory evaluation categorized FMJs into six aroma profiles, with strains C10 and LA100 exhibiting pleasant 'mango' flavor in ReNong and Ketti MJs. Multivariate factor analysis revealed that esters potentially play a key role in enhancing the 'mango' and 'floral' aroma of the FMJs. This study serves as a valuable resource for Lp. plantarum strain selection and quality control in FMJ development by analyzing the acid and aroma diversity.

Co-fermentation of Lactiplantibacillus and Streptococcusccus enriches the key-contribution volatile and non-volatile components of jujube juice

Lactic acid bacteria (LAB) fermentation can enhance the quality and flavor characteristics of fruit juice. Herein, the impact of individual Lactiplantibacillus plantarum subsp. plantarum (L. plantarum) or Streptococcus thermophilus (S. thermophilus) and co-fermentation of them on jujube juice was compared, and their quality characteristics, volatile and non-volatile compounds were investigated. The results showed that the co-fermentation of selected LAB strains effectively improved the quality of fermented jujube juice (FJJ) as expected, and the types and content of volatile organic compounds (VOCs) increased in FJJs. Among them, the co-fermented sample posed relatively high content of aroma-active compounds with OAV ≥1 (nonanal, decanal, etc), benzaldehyde and acids compared with others, contributing to a more attractive and pleasant flavor. Moreover, non-targeted metabolomic analysis identified 114 and 79 differential metabolites (DMs) between co-fermented and L. plantarum fermented or S. thermophilus fermented samples, respectively. Notably, carboxylic acids and their derivative metabolites as well as organic acids were the crucial components affecting the quality of FJJ. Furthermore, metabolic pathways of DMs of different samples were predominantly enriched in "biosynthesis" and "metabolism", such as aline, leucine, and isoleucine biosynthesis pathway. Therefore, co-fermentation could enrich the acids, essential amino acid, and VOCs, thereby improving its quality and flavor characteristics. The correlation analysis revealed that most of key VOCs were positively or negatively correlated with D-galacturonate, indicating the importance of D-galactose pathway. Thus, this study provided a theoretical foundation for enhancing the quality and flavor of jujube juice through LAB co-fermentation, offering valuable insights for improving the juice processing.

From flavor to function: A review of fermented fruit drinks, their microbial profiles and health benefits

Fermented fruit drinks (FFDs) are gaining popularity among consumers for their unique flavors and potential health benefits. This review provides a systematic assessment of the flavor components in FFDs and explores the metabolic pathways for their formation. We examine the interactions between the structure of microbial communities and the development of these flavor components, highlighting the role of microorganisms in shaping the unique taste of FFDs. Additionally, we discuss the potential health benefits associated with FFDs, focusing on their relationship with microbial communities as supported by existing literature. The review also addresses future prospects and challenges in the field. Our findings indicate key fermenting microorganisms, such as lactic acid bacteria, yeast and acetic acid bacteria, are responsible for producing the distinctive flavor components in FFDs, including alcohols, ketones, aldehydes, esters, and fatty acids. These microorganisms also generate organic acids, amino acids, and carbohydrates, contributing to the drink's complex taste. Furthermore, this fermentation process enhances the bioactivity of FFDs, offering potential health benefits like antioxidant, anti-obesity, anti-diabetic, and anti-cancer properties. These insights are crucial for advancing fermentation technology and developing guidelines for producing nutrient-rich, flavorful FFDs.

Three-Stage Solid-State Fermentation Technology for Distillers’ Grain Feed Protein Based on Different Microorganisms Considering Oxygen Requirements

The shortage of feed protein has plagued the development of the animal husbandry industry in China. In this study, a new three-stage fermentation technology for producing distillers’ grain feed protein was developed by introducing Aspergillus niger, yeast, and lactic acid bacteria. During the aerobic stage, there was a negative correlation between the reducing sugar content in the distillers’ grains and the amount of Aspergillus niger. The maximum reducing sugar concentration (36.89 mg g−1) was obtained when the oxygen supply was 30 mL min−1 and the fermentation time was two days. During the microaerophilic stage, the natural exchange of oxygen achieved optimal true protein enhancement (from 10.8% to 16.4%) among the three oxygen supply modes (natural exchange, forced ventilation, and filling supplement). During the anaerobic stage, lactic acid bacteria were inoculated for feed protein preservation and flavor enhancement. Our results provided insight and practical guidance for the high-value use of distillers’ grains.

Introducing Bacillus natto and Propionibacterium shermanii into soymilk fermentation: A promising strategy for quality improvement and bioactive peptide production during in vitro digestion

Herein, the texture properties, polyphenol contents, and in vitro protein digestion characteristics of soymilk single- or co-fermented by non-typical milk fermenter Bacillus natto (B. natto), Propionibacterium freudenreichii subsp. shermanii (P. shermanii), and traditional milk fermenter were evaluated. Co-fermenting procedure containing B. natto or P. shermanii could raise the amounts of gallic acid, caffeic acid, and GABA when compared to the unfermented soymilk. Co-fermented soymilk has higher in vitro protein digestibility and nutritional protein quality. Through peptidomic analysis, the co-work of P. shermanii and Lactobacillus plantarum (L. plantarum) may release the highest relative percentage of bioactive peptides, while the intervention of B. natto and Streptococcus thermophilus (S. thermophilus) resulted in more differentiated peptides. The multi-functional bioactive peptides were mainly released from glycine-rich protein, β-conglycinin alpha subunit 1, and ACB domain-containing protein. These findings indicated the potential usage of B. natto/S. thermophilus or P. shermanii/L. plantarum in bio-enhanced soymilk fermentation.

Effects of cholesterol-lowering probiotic fermentation on the active components and in vitro hypolipidemic activity of sea buckthorn juice

Sea buckthorn has lipid-lowering properties and is widely used in the development of functional foods. In this study, a probiotic (Lactobacillus plantarum, Lp10211) with cholesterol-lowering potential and acid and bile salt resistant was screened for the fermentation of sea buckthorn juice. Changes in the active ingredients, such as sugars and phenolics, before and after fermentation, as well as their in vitro lipid-lowering activities, were compared. The contents of reducing and total sugars decreased substantially after fermentation. Lp10211 primarily utilized fructose for growth and reproduction, with a utilization rate of 76.9%. The phenolic compound content of sea buckthorn juice increased by 37.06% after fermentation and protected the phenolic components from degradation (protocatechuic and p-coumaric acids) and produced new polyphenol (shikimic acid). Enhanced inhibition of pancreatic lipase activity (95.42%) and cholesterol micellar solubility (59.15%) was evident. The antioxidant properties of the fermentation broth were improved. Notably, Lp10211 preserved the color and reversed browning in sea buckthorn juice. The collective findings indicate that fermentation of sea buckthorn juice by Lp10211 may enhance the functional components and lipid-lowering activity of sea buckthorn, which may provide a new approach for the development of lipid-lowering foods.

Effects of different lactic acid bacteria on phenolic profiles, antioxidant capacities, and volatile compounds in purple sweet potato juice

The effects of three strains of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus rhamnosus, and Streptococcus thermophilus) on viable counts, physicochemical indicators, phenolic profiles, antioxidant capacities, and volatile compounds in purple sweet potato juice were investigated during fermentation. The results showed the viable count of three bacteria increased and exceeded 11 log CFU/mL after fermentation. At the end of fermentation, the purple sweet potato juice exhibited an increase in total phenolic and flavonoid content. In addition, lactic acid bacteria fermentation changed the phenolic profiles and enhanced antioxidant capacities. Moreover, Pearson's correlation analysis showed that DPPH, ABTS, and hydroxyl radical scavenging capacities were positively correlated with caffeic acid and vanillic acid content (p < 0.05). Furthermore, lactic acid bacteria fermentation improved the aroma complexity and sensory quality of purple sweet potato juice. In conclusion, this study provided useful information for the development of purple sweet potato juice fermented by lactic acid bacteria.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05959-5.

Impact of Different Carbon Sources on Volatile Organic Compounds (VOCs) Produced during Fermentation by Levilactobacillus brevis WLP672 Measured Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS)

Bacterial fermentation is considered to be a cost-effective means of generating desired flavour compounds from plant-based substrates. However, the wide range of substrates present in plants makes it challenging to understand how individual components impact on flavour volatile organic compound (VOC) production. To simplify this, a defined medium can be used to better understand VOCs production with regard to individual compounds. In the current study, the VOCs produced by the lactic acid bacterium, Levilactobacillus brevis WLP672, growing in a defined medium containing different carbon sources (either glucose (DM), fructose (DMFr) or citrate (DMCi)) under a range of fermentation conditions (time: 0, 7, and 14 days; and temperature: 25 and 35 °C) were assessed using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Among the detected mass peaks (m/z), after 7 days of fermentation, the concentrations of m/z 45.033 (t.i. acetaldehyde), m/z 49.011 (t.i. methanethiol), and m/z 89.060 (t.i. ethyl acetate) were significantly (p < 0.05) higher in DM at 35 °C than all other treatments at either temperature. The knowledge obtained will help to produce desirable LAB fermentation flavour VOCs or VOC mixtures that could be used in developing plant-based analogues with acceptable sensory properties.

Effect of jujube pulp on acid- and rennet-induced coagulation properties of milk

Milk coagulation is an important step in the production of fermented dairy products such as yogurt and cheese. Jujube is gaining popularity and acceptance as a food ingredient. In China, jujube yogurt is popular among consumers. However, there is limited information on the effect of jujube on acid- and rennet-induced coagulation properties of milk. The objective of this study was to evaluate the effects of jujube pulp at different concentrations on acid- and rennet-induced coagulation kinetics of milk and the microstructure of acid- and rennet-induced gels. During acid-induced coagulation, with increasing jujube pulp concentration, the initial pH value decreased; however, the final pH value increased. The initial elasticity index (EI) value increased, and the time point at which the mean square displacement curves lost the linear trend advanced. The sample with 10% jujube pulp had the densest structure and highest EI value. During rennet-induced coagulation, with increasing jujube pulp concentration, the production rate and amount of caseinomacropeptide decreased, and the final EI value increased. Protein aggregates in rennet-induced gels became rough, and the sample with 20% jujube pulp had the highest EI value. This study provides a new perspective and understanding of the application of jujube in fermented dairy products.

Mangaba pulp fermented with Lacticaseibacillus casei 01 has improved chemical, technological, and sensory properties and positively impacts the colonic microbiota of vegan adults

This study aimed to evaluate the functional, technological, and sensory aspects of mangaba (Hancornia speciosa Gomes) fruit pulp fermented with the probiotic Lacticaseibacillus casei 01 (LC1) during refrigerated storage (7 °C, 28 days). The effects of the fermented mangaba pulp on the modulation of the intestinal microbiota of healthy vegan adults were also assessed. Mangaba pulp allowed high viability of LC1 during storage and after simulated gastrointestinal conditions (≥7 log CFU/g). The fermented mangaba pulp showed lower pH and total soluble solids, and higher titratable acidity, and concentrations of lactic, acetic, citric, and propionic acids during storage compared to non-fermented pulp. Also, it presented a higher concentration of bioaccessible phenolics and volatiles, and improved sensory properties (yellow color, brightness, fresh appearance, and typical aroma and flavor). Fermented mangaba pulp added to in vitro cultured colonic microbiota of vegan adults decreased the pH values and concentrations of maltose, glucose, and citric acid while increasing rhamnose and phenolic contents. Fermented mangaba pulp promoted increases in the abundance of Dorea, Romboutsia, Faecalibacterium, Lachnospira, and Lachnospiraceae ND3007 genera and positively impacted the microbial diversity. Findings indicate that mangaba pulp fermented with LC1 has improved chemical composition and functionality, inducing changes in the colonic microbiota of vegan adults associated with potential benefits for human health.

Developement of lactic acid fermentation of jackfruit (Artocarpus heterophyllus) seed drink and its physicochemical and sensory properties

The objective of this study was to create a plant-based drink from jackfruit seed. Firstly, jackfruit seed powder was hydrolyzed step by step with 0.2% α-amylase for 60 min and 0.3% glucoamylase for 90 min. The sample then was fermented with Lactiplantibacillus plantarum (L. plantarum) at 37 °C for 15 h. The findings indicated that hydrolysis and lactic acid fermentation enhanced the polyphenol, flavonoid, and antioxidant activity of jackfruit seed drink. Jackfruit seed drink was a favorable matrix for L. plantarum delivery. Moreover, the product underwent fermentation and reached the viability density of L. plantarum of 8.15 Log CFU/mL. The overall sensory liking score was rated between 5 and 5.5/7 points. Throughout the 35 days of storage period at 4-6 °C, the number of L. plantarum uncharged, whereas the bioactive compound and antioxidant activity of the product diminished by nearly 20-50% compared to the sample before storage. Overall, this research highlights the potential of the the fermented jackfruit seed drink as a probiotic plant-based drink with massive biological function and sensory appeal.

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.

Potential neuroprotective benefits of plant-based fermented foods in Alzheimer's disease: an update on preclinical evidence

Alzheimer's disease (AD) currently lacks effective treatments, making its prevention a critical focus. While accumulating evidence supports that plant-based fermented foods may contribute to AD prevention, the neuroprotective effect of plant-based fermented foods on AD has not been comprehensively reviewed. In this study, we conducted a systematic review of preclinical studies on the efficacy of plant-based fermented foods in AD. The literature search was based on databases including PubMed, Embase, Web of Science, and Scopus. The PICO approach was employed for report inclusion, and each report was assessed for risk of bias using the SYRCLE's RoB tool. From the analysis of 25 retrieved reports, we extracted essential details, including bibliographic information, animal models and characteristics, sources of plant-based fermented foods, dosages, administration routes, durations, and outcome measures. Our findings indicate that plant-based fermented foods may positively impact acute and long-term cognitive function, as well as beta-amyloid-mediated neurodegeneration. This review sheds light on the potential neuroprotective benefits of plant-based fermented foods for various AD-related aspects, including oxidative stress, synaptotoxicity, neuroinflammation, tau hyperphosphorylation, dysfunctional amyloidogenic pathways, and cognitive deficits, as observed in rodent models of AD. However, the small number of studies obtained from our literature search and the finding that many of them were of moderate methodological quality suggest the need for further investigation to substantiate the beneficial potential of this class of functional food for the management of AD.

Effects of Torulaspora delbrueckii and Saccharomyces cerevisiae Co-Fermentation on the Physicochemical and Flavor Compounds of Huaniu Apple Cider

The effects of different fermentation methods utilizing Torulaspora delbrueckii 1004 and Saccharomyces cerevisiae 32169 on the physicochemical properties, organic acid content, polyphenol and flavonoid concentrations, antioxidant activity, and volatile aroma compounds of Huaniu apple cider were investigated in this study. Employing methods of single inoculation, co-inoculation, and sequential inoculation, it was found that sequential fermentation exhibited strong fermentative power in the initial stages, effectively reducing the content of soluble solids and achieving a balanced composition of malic, succinic, and citric acids while maintaining a lower titratable acidity. Sequential inoculation was observed to significantly enhance the total polyphenols and flavonoids, as well as the antioxidant capacity (p < 0.05). Specifically, in the synthesis of volatile aroma compounds, sequential inoculation significantly enhanced the richness and diversity of the Huaniu apple cider's aromas, particularly in terms of the concentration of ester compounds (p < 0.05). Principal component analysis further confirmed the superiority of sequential inoculation in terms of aroma component diversity and richness. The findings of this study suggest that sequential inoculation of fermentation with non-Saccharomyces and S. cerevisiae is an effective strategy for optimizing the flavor characteristics of Huaniu apple cider, offering valuable theoretical support and practical guidance for enhancing cider quality and fostering the development of new products.

Recent progress in promoting the bioavailability of polyphenols in plant-based foods

Polyphenols are important constituents of plant-based foods, exhibiting a range of beneficial effects. However, many phenolic compounds have low bioavailability because of their low water solubility, chemical instability, food matrix effects, and interactions with other nutrients. This article reviews various methods of improving the bioavailability of polyphenols in plant-based foods, including fermentation, natural deep eutectic solvents, encapsulation technologies, co-crystallization and amorphous solid dispersion systems, and exosome complexes. Several innovative technologies have recently been deployed to improve the bioavailability of phenolic compounds. These technologies may be utilized to increase the healthiness of plant-based foods. Further research is required to better understand the mechanisms of action of these novel approaches and their potential to be used in food production.

Chemical Profile Characterization of Fruit and Vegetable Juices after Fermentation with Probiotic Strains

Lactic acid bacteria (LAB) are widely applied for fermentation purposes in dairy and non-dairy food matrices with beneficial technological and health-promoting properties. This study describes the effect of two lactic acid bacteria, namely, Lactiplantibacillus paracasei SP5 and Pediococcus pentosaceus SP2, on the phenolic profiles, antioxidant activities, total phenolic content (TPC), carotenoid content, and sensorial profile of two different mixed fruit juices. After 48 h of fermentation, both LABs retained viability over 9 Log CFU/mL in both juices. The TPC, zeaxanthin + lutein, β-carotene content, and antioxidant activity (AA) were elevated for both LABs and mixed juices after 48 h of fermentation compared to control samples. Regarding the phenolic profile, both juices exhibited a significant decrease in chlorogenic acid levels, while quinic acid and tyrosol concentrations showed notable increases.

Effect of mixed fermentation of Lactiplantibacillus plantarum and Lactiplantibacillus pentosus on phytochemical and flavor characteristics of Wallace melon juice

BACKGROUND

Melons (Cucumis melo L.) are among the most commonly consumed fruits but they are highly susceptible to mechanical damage and rot during storage and transportation. New processed products are needed to avoid postharvest fruit loss and to increase health benefits. Fermentation is an effective means of utilizing the nutrients and improving flavor.

RESULTS

Fermented melon juice (MJ) was prepared using three potential probiotics Lactiplantibacillus plantarum CICC21824 (LP), Lactiplantibacillus plantarum GB3-2 (LG), and Lactiplantibacillus pentosus XZ-34 (LX). The nutrition, flavor characteristics, and digestive properties of different fermented MJs were compared. The results demonstrated that, in comparison with mono-fermentation, mixed fermentation by LG and LX could increase the level of organic acids and phenolic acids. Correspondingly, antioxidant capacity was improved significantly and positively correlated with p-coumaric acid and cinnamic acid content. The production of alcohols and acids was more strongly enhanced by mixed culture fermentation, whereas mono-fermentation reduced the content of esters, especially ethyl acetate and isopropyl acetate. Aldehydes and ketones increased significantly in fermented MJ, and damascenone and heptanal could be the characteristic aroma compounds.

CONCLUSION

Mixed fermented MJ provides more beneficial phytochemicals, better flavor, and stronger antioxidant properties than mono-fermentation. © 2024 Society of Chemical Industry.

Investigation of volatile compounds during fermentation of Elaeagnus moorcroftii Wall.ex schlecht. juice by Bifidobacterium animalis subsp. lactis HN-3 and Lacticaseibacillus paracasei YL-29

The influence on and biotransformation of volatile compounds (VOCs) during fermentation of Elaeagnus moorcroftii Wall.ex Schlecht. juice (EWSJ) through single inoculation and co-inoculation of Bifidobacterium animalis subsp. lactis HN-3 (B.an3) and Lacticaseibacillus paracasei YL-29 (L.cp29) were analyzed through headspace-solid phase microextraction-gas chromatography-mass spectrometry. Compared with the B.an3- and L.cp29-fermented EWSJ, the B.an3 + L.cp29-fermented EWSJ had more increased 9 desirable flavor compositions and less decreased in or even elimination of 12 undesirable flavor compositions, and 3 new characteristic VOCs, formed through the interaction between B.an3 and L.cp29 were detected. In addition, biotransformations that led to an increase and a decrease in VOCs mainly involved 3 oxidation, 3 reduction, 1 hydrolysis, and 1 isomerization reactions. This study offers a theoretical basis for investigating the interaction effect of Lactobacillus and Bifidobacterium species on VOCs and developing lactic acid bacteria-fermented plant-based juices with lower sugar content and better flavor.

Non-volatile and volatile compound changes in blueberry juice inoculated with different lactic acid bacteria strains

BACKGROUND

Lactic acid bacteria (LABs) are widely present in foods and affect the flavour of fermented cultures. This study investigates the effects of fermentation with Lactobacillus acidophilus JYLA-16 (La), Lactobacillus plantarum JYLP-375 (Lp), and Lactobacillus rhamnosus JYLR-005 (Lr) on the flavour profile of blueberry juice.

RESULTS

This study showed that all LABs strains preferentially used glucose rather than fructose as the carbon source during fermentation. Lactic acid was the main fermentation product, reaching 7.76 g L-1 in La-fermented blueberry juice, 5.86 g L-1 in Lp-fermented blueberry juice, and 6.41 g L-1 in Lr-fermented blueberry juice. These strains extensively metabolized quinic acid, whereas oxalic acid metabolism was almost unaffected. Sixty-four volatile compounds were identified using gas chromatography-ion mobility spectrometry (GC-IMS). All fermented blueberry juices exhibited decreased aldehyde levels. Furthermore, fermentation with La was dominated by alcohols, Lp was dominated by esters, and Lr was dominated by ketones. Linear discriminant analysis of the electronic nose and principal component analysis of the GC-IMS data effectively differentiated between unfermented and fermented blueberry juices.

CONCLUSION

This study informs LABs selection for producing desirable flavours in fermented blueberry juice and provides a theoretical framework for flavour detection. © 2023 Society of Chemical Industry.

The effect of adding pomace on the bioactive composition and flavor volatiles in fermented orange juice with Lactobacillus

BACKGROUND

The consumption of oranges generates huge amounts of pomaces, which are the potential raw materials to increase the nutritional value of the products.

RESULTS

In this study, the bioactive composition and flavor volatiles in Lactobacillus fermented orange juice with added pomaces were researched. Results showed that the orange juices blended with pomaces were favorable substrates for Lactobacillus growth and the colony counts reached above 9.0 log CFU mL-1 , total phenolics, total flavonoids, and the antioxidant activity in orange juices were increased significantly after adding pomaces. Some amino acids, such as threonine (P < 0.0001), isoleucine (P < 0.01), and glycine (P < 0.01) were markedly higher in fermented orange juices with pomaces. The flavonoid diversity was more abundant by adding pomace fermentation and most flavonoids showed higher levels in fermented juices with the pomace, Lactobacillus fermentum 252 may transform some flavonoids through deglycosylation and reduction reaction. Furthermore, orange pomace mainly improved the flavor volatiles by increasing terpenoids and alcohol, such as d-limonene and benzyl alcohol, and decreasing volatile acids.

CONCLUSION

This study presented a novelty in elevating the nutritional value of juice by the utilization of pomaces, its findings can provide a new way to mine the bioactive ingredient from Citrus by Lactobacillus, and can be used as a guide for the development of new Citrus processing technologies and functional foods. © 2023 Society of Chemical Industry.

Fermentation of Rubus dolichocarpus juice using Lactobacillus gasseri and Lacticaseibacillus casei and protecting phenolic compounds by Stevia extract during cold storage

This study aimed to investigate the biological activities of Lactobacillus gasseri SM 05 (L. gasseri) and Lacticaseibacillus casei subsp. casei PTCC 1608 (L. casei) in the black raspberry (Rubus dolichocarpus) juice (BRJ) environment, and also the anti-adhesion activity against Salmonella typhimurium (S. typhimurium) in fermented black raspberry juice (FBRJ). Results showed significant anti-adhesion activity in Caco-2 epithelial cells. In the anti-adhesion process, lactic acid bacteria (LAB) improve intestinal health by preventing the adhesion of pathogens. Adding LAB to BRJ produces metabolites with bacteriocin properties. Major findings of this research include improved intestinal health, improved antidiabetic properties, inhibition of degradation of amino acids, and increase in the nutritional value of foods that have been subjected to heat processing by preventing Maillard inhibition, and inhibition of oxidation of foodstuff by increased antioxidant activity of BRJ. Both species of Lactobacillus effectively controlled the growth of S. typhimurium during BRJ fermentation. Moreover, in all tests, as well as Maillard's and α-amylase inhibition, L. gasseri was more effective than L. casei. The phenolic and flavonoid compounds increased significantly after fermentation by both LAB (p < 0.05). Adding Stevia extract to FBRJ and performing the HHP process showed convenient protection of phenolic compounds compared to heat processing.

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

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

Volatile Organic Compounds (VOCs) Produced by Levilactobacillus brevis WLP672 Fermentation in Defined Media Supplemented with Different Amino Acids

Fermentation by lactic acid bacteria (LAB) is a promising approach to meet the increasing demand for meat or dairy plant-based analogues with realistic flavours. However, a detailed understanding of the impact of the substrate, fermentation conditions, and bacterial strains on the volatile organic compounds (VOCs) produced during fermentation is lacking. As a first step, the current study used a defined medium (DM) supplemented with the amino acids L-leucine (Leu), L-isoleucine (Ile), L-phenylalanine (Phe), L-threonine (Thr), L-methionine (Met), or L-glutamic acid (Glu) separately or combined to determine their impact on the VOCs produced by Levilactobacillus brevis WLP672 (LB672). VOCs were measured using headspace solid-phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS). VOCs associated with the specific amino acids added included: benzaldehyde, phenylethyl alcohol, and benzyl alcohol with added Phe; methanethiol, methional, and dimethyl disulphide with added Met; 3-methyl butanol with added Leu; and 2-methyl butanol with added Ile. This research demonstrated that fermentation by LB672 of a DM supplemented with different amino acids separately or combined resulted in the formation of a range of dairy- and meat-related VOCs and provides information on how plant-based fermentations could be manipulated to generate desirable flavours.

Lactobacillus acidophilus-Fermented Jujube Juice Ameliorates Chronic Liver Injury in Mice via Inhibiting Apoptosis and Improving the Intestinal Microecology

SCOPE

Chronic liver diseases are clinically silent and responsible for significant morbidity and mortality worldwide. Jujube has displayed various biological activities. Here, the therapeutic effect of Lactobacillus acidophilus (L. acidophilus)-fermented jujube juice (FJJ) and the possible mechanism against chronic liver injury (CLI) in mice are further studied.

METHODS AND RESULTS

After the CCl4 -induced CLI mice are separately treated with L. acidophilus (LA), unfermented jujube juice (UFJJ), and FJJ, FJJ but not LA or UFJJ suppresses the liver index. By using H&E staining, immunofluorescence staining, RT-PCR, and western blotting, it is shown that LA, UFJJ, and FJJ intervention ameliorate hepatocyte necrosis, inhibit the mRNA levels of pro-inflammatory (NLRP3, Caspase-1, IL-1β, and TNF-α) and fibrosis-associated factors (TGF-β1, LXRα, and MMP2). Also, FJJ displays significant protection against mucosal barrier damage in CLI mice. Among the three interventions, FJJ exhibits the best therapeutic effect, followed by UFJJ and LA. Furthermore, FJJ improves dysbiosis in CLI mice.

CONCLUSIONS

This study suggests that FJJ exhibits a protective effect against CCl4 -induced CLI mice by inhibiting apoptosis and oxidative stress, regulating liver lipid metabolism, and improving gut microecology. Jujube juice fermentation with L. acidophilus can be a food-grade supplement in treating CLI and related liver diseases.

Synergistic effects of lactobacillus strains and Acetobacter pasteurianus on jujube puree's product functionality and quality

Commercial lactic acid bacteria strains and indigenous Chinese acetic acid bacterium were co-cultivated bi- and tri-culturally in Junzao jujube puree for the first time to investigate their effects on physicochemical properties and quality attributes. Lactic-acetic acid bacteria co-fermentation was performed at 37 °C for 48 h during the anaerobic fermentation phase and at 30 °C for 144 h during aerobic fermentation. FTIR results showed that predominant wave numbers at 1716-1724 cm-1 and 2922-3307 cm-1 exhibited discernible alterations in the lactic-acetic acid co-fermented jujube purees compared to the control sample. Pearson correlation analysis showed that the flavonoid and flavonol contents were responsible for the enhanced 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl scavenging activities of the fermented jujube purees. Consequently, fermented jujube puree from tricultures of Lactobacillus casei, Lactobacillus plantarum, and Acetobacter pasteurianus gave the best results, with the highest phenolics, flavonoid, and flavonol contents and the most improved antioxidative properties and color. Overall, lactic-acetic acid bacteria co-culture holds significant promise in valorizing Junzao jujube purees for functional ingredient development, paving the way for further research into similar interactions with different food matrices or microbial strains.

Effect of lactic acid bacteria co-fermentation on antioxidant activity and metabolomic profiles of a juice made from wolfberry and longan

Lactic acid bacteria (LAB) fermentation is frequently employed to improve the nutritional, functional, and sensory characteristics of foods. Our study explored the effects of co-fermentation with Lacticaseibacillus paracasei ZH8 and Lactococcus lactis subsp. lactis YM313 on the physicochemical properties, antioxidant activity, and metabolomic profiles of wolfberry-longan juice (WLJ). Fermentation was carried out at 35 °C for 15 h. The results suggest that WLJ is a favorable substrate for LAB growth, reaching a total viable count exceeding 8 log CFU/mL after fermentation. LAB fermentation increased acidity, reduced the sugar content, and significantly impacted the juice color. The total phenolic and flavonoid contents of the WLJ and the antioxidant capacities based on 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS radical scavenging abilities and FRAP were significantly improved by LAB fermentation. Nontargeted metabolomics analysis suggested that the contents of small molecule substances in WLJ were considerably affected by LAB fermentation. A total of 374 differential metabolites were identified in the juice before and after fermentation, with 193 significantly upregulated metabolites and 181 siginificantly downregulated metabolites. The regulation of metabolites is important for improving the flavor and functions of juices, such as L-eucylproline, Isovitexin, Netivudine, 3-Phenyllactic acid, vanillin, and ethyl maltol, ect. This study provides a theoretical foundation for developing plant-based foods fermented with LAB.

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

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