From probiotic fermentation to functional drinks: a review on fruit juices with lactic acid bacteria and prebiotics

In recent years, the demand for probiotic beverages has surged, with dairy products traditionally serving as the primary sources of probiotics. However, many consumers face health issues such as lactose intolerance, milk allergies, and high cholesterol, which prevent them from consuming dairy products. This has led to the exploration of nondairy alternatives, particularly fruit juices, as carriers for probiotics. Lactic acid bacteria (LAB) have been identified as beneficial probiotics that can be incorporated into these beverages. The inclusion of prebiotics, such as inulin and galacto-oligosaccharides (GOS), in fruit juices has shown promise in enhancing the growth and activity of LAB, thereby creating functional beverages that support digestive health. Despite numerous studies on fruit juice fermentation, there is limited data on the optimal pairing of probiotics and prebiotics to develop stable, nondairy functional drinks. This review underscores the potential of lactic acid fermentation and the integration of prebiotics and probiotics in fruit juices, highlighting the necessity for further research to optimize these combinations for enhanced health benefits and improved beverage stability.

Different Combinations of Nitrogen and Carbon Sources Influence the Growth and Postbiotic Metabolite Characteristics of Lactiplantibacillus plantarum Strains Isolated from Malaysian Foods

Postbiotic metabolites produced by Lactiplantibacillus plantarum strains isolated from Malaysian food have been extensively reported for their positive effects on health. Understanding the effects of different combinations of carbon and nitrogen sources on the growth and corresponding characteristics of postbiotic metabolites produced by different strains of L. plantarum is important for various applications. Hence, the effects of different combinations of carbon (glucose, lactose, sucrose and dextrose) and nitrogen (X-SEED Kat, X-SEED Peptone, X-SEED Nucleo Advanced, Nucel875 MG, FM888 and FM902) sources on the growth of six strains of L. plantarum (RG11, RG14, RI11, RS5, TL1 and UL4) and the functional characteristics (bacteriocin inhibitory activity, antioxidant activity and lactic acid concentration) of their respective postbiotic metabolites were investigated in this study. UL4 produced the highest viable cell population with sucrose and Nucel875 nitrogen source. The UL4 strain also produced the strongest bacteriocin inhibitory activity with dextrose and FM888 nitrogen source. In comparison, the RI11 strain produced the highest lactic acid concentration with dextrose and Nucel875 nitrogen source and the highest reducing power of RS5 and TL1 postbiotic metabolites was achieved with MRS medium. In the combination of sucrose and X-Seed KAT nitrogen source, RG14 produce the highest hydroxyl radical scavenging activity. The effects of different combinations of carbon and nitrogen sources on the viable cell population of L. plantarum strains and the respective functional characteristics of postbiotic metabolites were strain dependent. The current study also revealed that fermentation media were an important factor that greatly impacted the functionalities of postbiotic metabolites due to the presence of various bioactive compounds that contributed to high antioxidant and antimicrobial properties. The results of this study will facilitate the subsequent medium design and optimisation for the development and production of specific postbiotic metabolites produced by the respective L. plantarum strain for their applications in various industries.

Fermentation of Polygonati Rhizoma aqueous extract using Lactiplantibacillus plantarum under the condition of eutrophication

In this experiment, the eutrophication system was established by adding sucrose and yeast powder, and the pH and dissolved oxygen were measured in a bioreactor in real time to study the effect of aerobic environment on the fermentation process of Polygonati Rhizoma extract by Lactiplantibacillus plantarum. To further analyze metabolic changes, UPLC-Q-Exactive MS was used for metabolomic analysis and metabolic profiling. Multivariate analysis was performed using principal component analysis and Orthogonal projections to latent structures discriminant analysis. Finally, 313 differential metabolites were selected, 196 of which were annotated through database matching. After fermentation, the content of short-chain fatty acids, lactic acid, and their derivatives increased significantly, and there were 13 kinds and 4 kinds, respectively. Both compounds and their derivatives are beneficial to the intestinal flora. Consequently, incorporating L. plantarum into the aerobic fermentation process of Polygonati Rhizoma extract within the eutrophic system is potentially advantageous in enhancing the impact of its fermentation solution on the gut microbiota and its effects on human health. Our findings for this kind of edible and medicinal material research and development offer useful insights.

Production of red beetroot juice by different methods: Kinetics of microbial growth, sugar consumption, and acid production

As a fermentation method, the utilisation of starter culture is a common practice in industrial manufacturing, although spontaneous methods have been employed since ancient times. The objective of this study was to investigate the effect of different production methods on red beetroot juice (RBJ). For this purpose, as a starter culture, the probiotic Lactibasillus paracasei (Lc. paracasei) was inoculated into the RBJ samples after pasteurization. Also, the growth of cells, acid production, and substrate utilisation were monitored throughout the fermentation process of RBJ under two different methods of fermentation. The samples produced by the addition of Lc. paracasei demonstrated a slightly lower decrease in pH values in comparison to the samples obtained by the spontaneous method. The concentration of lactic acid (LA) and acetic acid (AA) at the end of fermentation reveals that Lc. paracasei exhibits a greater capacity for both LA and AA generation compared to the spontaneous method. The ratios of LA and AA molar concentrations of RBJ were determined to be 1.7 and 3.6 for the samples produced by adding Lc. paracasei and the spontaneous method, respectively. The samples produced by adding Lc. paracasei exhibited a greater consumption of sucrose. Both fermentation methods provide LAB counts exceeding 8 log CFU/mL at the end of fermentation. Time demonstrated a significant correlation with LA and AA in the method by adding Lc. paracasei (r = 0.942 and 0.745), respectively (p < 0.01). In both methods, it was demonstrated that while sucrose content decreased during the fermentation period, fructose and glucose content remained constant (p < 0.05).

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

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

Fermentation improves antioxidant capacity and γ-aminobutyric acid content of Ganmai Dazao Decoction by lactic acid bacteria

Introduction

Ganmai Dazao Decoction is a traditional Chinese recipe, and is composed of licorice, floating wheat, and jujube.

Methods

Effects of lactic acid bacteria fermentation on the physicochemical properties, antioxidant activity, and γ-aminobutyric acid of Ganmai Dazao Decoction were studied. The changes of small and medium molecules in Ganmai Dazao Decoction before and after fermentation were determined by LC-MS non-targeted metabolomics.

Results

The results showed that the contents of lactic acid, citric acid, acetic acid, and total phenol content increased significantly, DPPH free radical clearance and hydroxyl free radical clearance were significantly increased. γ-aminobutyric acid content was 12.06% higher after fermentation than before fermentation. A total of 553 differential metabolites were detected and identified from the Ganmai Dazao Decoction before and after fermentation by partial least squares discrimination and VIP analysis.

Discussion

Among the top 30 differential metabolites with VIP values, the content of five functional substances increased significantly. Our results showed that lactic acid bacteria fermentation of Ganmai Dazao Decoction improves its antioxidant effects and that fermentation of Ganmai Dazao Decoction with lactic acid bacteria is an innovative approach that improves the health-promoting ingredients of Ganmai Dazao Decoction.

Lactobacillus co-fermentation of Cerasus humilis juice alters chemical properties, enhances antioxidant activity, and improves gut microbiota

Fermentation with Lactobacillus has been shown to improve the nutritional value of juice. In this study, Cerasus humilis juice was fermented using two commercial probiotics, namely, Lactobacillus acidophilus and Lactobacillus plantarum. The total antioxidant capacity (TAOC), viable count, chemical properties, antioxidant activity after in vitro digestion, and alterations in the gut microbiota composition of the fermented juice were investigated. After fermentation, the TAOC increased from 107.66 U mL-1 to 126.72 U mL-1; viable count increased from 5.85 lg (CFU mL-1) to 8.17 lg (CFU mL-1); and the contents of total phenols, total flavonoids, proanthocyanins, four organic acids, and 29 amino acids had changed. Overall, 47 compounds were identified in the juice, 20 of which were enriched after fermentation. Furthermore, Lactobacillus co-fermentation improved the antioxidant properties of the juice after in vitro digestion and increased the abundance of probiotics to regulate the gut microbiota. These findings illustrate the potential use of Lactobacillus acidophilus and Lactobacillus plantarum in the co-fermentation of C. humilis juice to enhance its nutritional and functional properties.

Optimization of Fermentation Conditions and Metabolite Profiling of Grape Juice Fermented with Lactic Acid Bacteria for Improved Flavor and Bioactivity

To enrich the flavor compounds and retain the content of polyphenolics in grape juice (GJ) under long-term storage, Lactiplantibacillus plantarum, Lactobacillus acidophilus, Lacticaseibacillus casei, and Lacticaseibacillus paracasei, were screened and the optimal fermentation conditions were determined as fermentation temperature of 41.2 °C for 24 h with an initial LAB density of 8.5 × 10⁶ CFU/mL. Surprisingly, the retention rates of TPC still remained at 50% after storage for 45 days at 4 °C. Moreover, 251 different metabolites were identified, include 23 polyphenolics, 11 saccharides, and 9 organic acids. Most importantly, the total content of polyphenolics reserved was 92.65% at the end of fermentation. Among them, ephedrannin A content significantly decreased; however, 2',6'-Di-O-acetylononin gradually increased with the fermentation time, which resulted in FGJ maintaining excellent bioactivity. Meanwhile, organic acid content (palmitoylethanolamide, tetraacetylethylenediamine) increased with saccharides (linamarin) decreasing, which leads to FGJ having a unique taste. Furthermore, a total of 85 Volatile organic compounds (VOCs) were identified, mainly including esters, aldehydes, and alcohols. Interestingly, key VOCs could be formed by carboxylic acids and derivatives, and fatty acyls via complex metabolic pathways.

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

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

Valorisation of Wasted Immature Tomato to Innovative Fermented Functional Foods

In this study, the lactic fermentation of immature tomatoes as a tool for food ingredient production was evaluated as a circular economy-oriented alternative for valorising industrial tomatoes that are unsuitable for processing and which have wasted away in large quantities in the field. Two lactic acid bacteria (LAB) were assessed as starter cultures in an immature tomato pulp fermentation to produce functional food ingredients with probiotic potential. The first trial evaluated the probiotic character of Lactiplantibacillus plantarum (LAB97, isolated from immature tomato microbiota) and Weissella paramesenteroides (C1090, from the INIAV collection) through in vitro gastrointestinal digestion simulation. The results showed that LAB97 and C1090 met the probiotic potential viability criterion by maintaining 6 log10 CFU/mL counts after in vitro simulation. The second trial assessed the LAB starters’ fermentative ability. Partially decontaminated (110 °C/2 min) immature tomato pulp was used to prepare the individually inoculated samples (Id: LAB97 and C1090). Non-inoculated samples, both with and without thermal treatment (Id: CTR-TT and CTR-NTT, respectively), were prepared as the controls. Fermentation was undertaken (25 °C, 100 rpm) for 14 days. Throughout storage (0, 24, 48, 72 h, 7, and 14 days), all the samples were tested for LAB and Y&M counts, titratable acidity (TA), solid soluble content (SSC), total phenolic content (TPC), antioxidant capacity (AOx), as well as for organic acids and phenolic profiles, and CIELab colour and sensory evaluation (14th day). The LAB growth reached ca. 9 log10 CFU/mL for all samples after 72 h. The LAB97 samples had an earlier and higher acidification rate than the remaining ones, and they were highly correlated to lactic acid increments. The inoculated samples showed a faster and higher decrease rate in their SSC levels when compared to the controls. A nearly two-fold increase (p < 0.05) during the fermentation, over time, was observed in all samples’ AOx and TPC (p < 0.05, r = 0.93; similar pattern). The LAB97 samples obtained the best sensory acceptance for flavour and overall appreciation scores when compared to the others. In conclusion, the L. plantarum LAB97 starter culture was selected as a novel probiotic candidate to obtain a potential probiotic ingredient from immature tomato fruits.

Flavour Volatiles of Fermented Vegetable and Fruit Substrates: A Review

Health, environmental and ethical concerns have resulted in a dramatic increase in demand for plant-based dairy analogues. While the volatile organic compounds (VOCs) responsible for the characteristic flavours of dairy-based products have been extensively studied, little is known about how to reproduce such flavours using only plant-based substrates. As a first step in their development, this review provides an overview of the VOCs associated with fermented (bacteria and/or fungi/yeast) vegetable and fruit substrates. Following PRISMA guidelines and using two English databases (Web of Science and Scopus), thirty-five suitable research papers were identified. The number of fermentation-derived VOCs detected ranged from 32 to 118 (across 30 papers), while 5 papers detected fewer (10 to 25). Bacteria, including lactic acid bacteria (LAB), fungi, and yeast were the micro-organisms used, with LAB being the most commonly reported. Ten studies used a single species, 21 studies used a single type (bacteria, fungi or yeast) of micro-organisms and four studies used mixed fermentation. The nature of the fermentation-derived VOCs detected (alcohols, aldehydes, esters, ketones, acids, terpenes and norisoprenoids, phenols, furans, sulphur compounds, alkenes, alkanes, and benzene derivatives) was dependent on the composition of the vegetable/fruit matrix, the micro-organisms involved, and the fermentation conditions.

The anti-inflammatory activity of GABA-enriched Moringa oleifera leaves produced by fermentation with Lactobacillus plantarum LK-1

Introduction

Gamma-aminobutyric acid (GABA), one of the main active components in Moringa oleifera leaves, can be widely used to treat multiple diseases including inflammation.

Methods

In this study, the anti-inflammatory activity and the underlying anti-inflammatory mechanism of the GABA-enriched Moringa oleifera leaves fermentation broth (MLFB) were investigated on lipopolysaccharide (LPS)-induced RAW 264.7 cells model. The key active components changes like total flavonoids, total polyphenols and organic acid in the fermentation broth after fermentation was also analyzed.

Results

ELISA, RT-qPCR and Western blot results indicated that MLFB could dose-dependently inhibit the secretions and intracellular expression levels of pro-inflammatory cytokines like 1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α). Furthermore, MLFB also suppressed the expressions of prostaglandin E2 (PGE2) and inducible nitric oxide synthase (iNOS). Moreover, the mRNA expressions of the key molecules like Toll-like receptor 4 (TLR-4) and nuclear factor (NF)-κB in the NF-κB signaling pathway were also restrained by MLFB in a dose-dependent manner. Besides, the key active components analysis result showed that the GABA, total polyphenols, and most organic acids like pyruvic acid, lactic acid as well as acetic acid were increased obviously after fermentation. The total flavonoids content in MLFB was still remained to be 32 mg/L though a downtrend was presented after fermentation.

Discussion

Our results indicated that the MLFB could effectively alleviate LPS-induced inflammatory response by inhibiting the secretions of pro-inflammatory cytokines and its underlying mechanism might be associated with the inhibition of TLR-4/NF-κB inflammatory signaling pathway activation. The anti-inflammatory activity of MLFB might related to the relative high contents of GABA as well as other active constituents such as flavonoids, phenolics and organic acids in MLFB. Our study provides the theoretical basis for applying GABA-enriched Moringa oleifera leaves as a functional food ingredient in the precaution and treatment of chronic inflammatory diseases.

Antioxidant capacity, flavor and physicochemical properties of FH06 functional beverage fermented by lactic acid bacteria: a promising method to improve antioxidant activity and flavor of plant functional beverage

The ability of natural plants to treat chronic diseases is closely related to their antioxidant function. Lactic acid bacteria (LAB) fermentation is an effective way to improve the nutritional value, biological activity and flavor of food. This study investigated the pH, titratable acidity, total polysaccharide, total flavone, total saponin, total polyphenol, and antioxidant activity of the FH06 beverage before and after probiotic fermentation. Results: After fermentation, FH06 had lower contents of total polysaccharides, total flavonoids, total saponins and total polyphenols but higher titratable acidity. The antioxidant activity was tested by total antioxidant capacity (FRAP method) and DPPH· scavenging ability. The FRAP value significantly increased after fermentation (P < 0.05), and the maximum increase was observed for Lactobacillus fermentum grx08 at 25.87%. For DPPH· scavenging ability, the value of all fermentations decreased, and L. fermentum grx08 had the smallest reduction at 2.21% (P < 0.05). The results of GC-MS and sensory analysis showed that fermentation eliminated bad flavors, such as grass, cassia and bitterness, and highlighted the fruit aroma and soft sour taste. Conclusion: The FRAP value and sensory flavor of FH06 fermentation by L. fermentum grx08 were significantly improved, indicating its great potential as a functional food with both strong antioxidant activity and good flavor.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s13765-022-00762-2.

Evaluating the effect of lactic acid bacteria fermentation on quality, aroma, and metabolites of chickpea milk

Legumes are an attractive choice for developing new products since their health benefits. Fermentation can effectively improve the quality of soymilk. This study evaluated the impact of Lactobacillus plantarum fermentation on the physicochemical parameters, vitamins, organic acids, aroma substances, and metabolites of chickpea milk. The lactic acid bacteria (LAB) fermentation improved the color, antioxidant properties, total phenolic content, total flavonoid content, lactic acid content, and vitamin B6 content of raw juice. In total, 77 aroma substances were identified in chickpea milk by headspace solid-phase microextraction with gas chromatography/mass spectrometry (HS-SPME-GC-MS); 43 of the 77 aroma substances increased after the LAB fermentation with a significant decrease in beany flavor content (p < 0.05), improving the flavor of the soymilk product. Also, a total of 218 metabolites were determined in chickpea milk using non-targeted metabolomics techniques, including 51 differentially metabolites (28 up-regulated and 23 down-regulated; p < 0.05). These metabolites participated in multiple metabolic pathways during the LAB fermentation, ultimately improving the functional and antioxidant properties of fermented soymilk. Overall, LAB fermentation can improve the flavor, nutritional, and functional value of chickpea milk accelerating its consumer acceptance and development as an animal milk alternative.

Flavor and Functional Analysis of Lactobacillus plantarum Fermented Apricot Juice

The small white apricot is a juicy, delicious fruit with a short shelf life. Slight fermentation can significantly promote the flavors and nutrient value of apricot juice. This study used high-performance liquid chromatography (HPLC) and headspace solid-phase microextraction combined with gas chromatography–mass spectrometry (HS-SPME-GC-MS) to examine the physicochemical properties, nutritive value and flavor substances of apricot juice fermented by Lactobacillus plantarum LP56. Fermentation significantly increased lactic acid bacteria (LAB) and their product lactic acid, adding probiotic benefits to fermented apricot juice. In addition, the total phenolic compounds and antioxidant capacity increased, while the levels of soluble solids and organic acids decreased. Gallic acid, 3-caffeoylquinic acid and rutin mainly contributed to the antioxidant activity of fermented apricot juice. Alcohols, aldehyde, acid, ester, etc., were the main volatile compounds. Among the flavors, 12 substances with high odor activity values (OAV > 1) were the key aroma-producing compounds with fruit, pine and citrus flavors. In conclusion, this study shows that L. plantarum LP56 fermentation can improve the nutritional value and aroma characteristics of apricot juice.

The Mechanisms of the Potential Probiotic Lactiplantibacillus plantarum against Cardiovascular Disease and the Recent Developments in its Fermented Foods

Cardiovascular disease (CVD) has become the leading cause of death worldwide. Many recent studies have pointed out that Lactiplantibacillus plantarum (Lb. plantarum) has great potential in reducing the risk of CVD. Lb. plantarum is a kind of lactic acid bacteria (LAB) widely distributed in fermented food and the human intestinal tract, some strains of which have important effects on human health and the potential to be developed into probiotics. In this review, we summarize the mechanism of potential probiotic strains of Lb. plantarum against CVD. It could regulate the body’s metabolism at the molecular, cellular, and population levels, thereby lowering blood glucose and blood lipids, regulating blood pressure, and ultimately reducing the incidence of CVD. Furthermore, since Lb. plantarum is widely utilized in food industry, we highlight some of the most important new developments in fermented food for combating CVD; providing an insight into these fermented foods can assist scientists in improving the quality of these foods as well as alleviating patients’ CVD symptoms. We hope that in the future functional foods fermented by Lb. plantarum can be developed and incorporated into the daily diet to assist medication in alleviating CVD to some extent, and maintaining good health.

Effects of acidified blanching water and pectinase enzyme pretreatments on physicochemical properties and antioxidant capacity of Carica papaya juice

The high pectin content in papaya (Carica papaya) causes the juice extraction to be difficult and results in a low yield. This study aims to determine the effect of acidified blanching water and pectinase enzyme pretreatments on the yield, physicochemical properties, and antioxidant activities of the papaya juice. For acidified blanching treatment, papaya cubes (3 cm³ ) were blanched in water containing 0%, 0.5%, 1.5%, and 2.5% w/v citric acid at 95℃ for 2 min. For enzyme treatment, a pectinase enzyme (10, 20, and 30 ppm) was added to the homogenous papaya puree and incubated at 45℃ (200 rpm) for 60 min. The enzyme reaction was stopped by pasteurization at 74℃ for 2 min. The puree was filtered, and the juice was pasteurized at 74℃ for 7 min. All pretreated papaya juice were analyzed for physicochemical properties (color, clarity, viscosity, pH, total soluble solids [TSSs], total carotenoid content, total phenolic content [TPC], and total flavonoid content [TFC]), and antioxidant activities (2,2-diphenyl-1-picrylhydrazyl [DPPH] and ferric reducing antioxidant power [FRAP] assay). Both pretreatments improved the clarity of papaya juice, and was significantly greater after pretreatment with pectinase enzyme. The TPC and antioxidant activities of papaya juice were conserved and maintained by acidified blanching at 1.5% (w/v) citric acid. Increased concentrations of pectinase enzyme significantly reduced the TPC and total carotenoid content. Pretreatment with pectinase enzyme up to 20 ppm does not significantly reduce the TFC and antioxidant activities. Acidified blanching and pectinase enzyme pretreatments have an impact on extraction of papaya fruit juice while retaining the nutritional composition of the juice. PRACTICAL APPLICATION: Papaya (Carica papaya) is a fruit with great nutritional values but is highly perishable and prone to postharvest loss. Juice has become a more cost-effective and convenient option for preserving the fruit. However, since papaya is a pectin-rich fruit, the extraction of juice using mechanical pressing is difficult due to the bonding of juice to the pulp in the form of a jellied mass, which results in juice with low yield. Using acidified blanching and pectinase enzyme to clarify the juice not only increases the yield but also retains the nutrient composition of the juice.

An agar-based bioassay for accurate screening of the total antioxidant capacity of lactic acid bacteria cell-free supernatants

This study aims to develop a new, simple, and efficient method for estimating the total antioxidant capacity of lactic acid bacteria-free supernatant. The bioassay is based on diffusion and reduction of permanganate in agar medium under acidic conditions where the Mn7+ ions are quantitatively oxidized to Mn2+ and shift from an intense purple color to colorless. Hence, the reaction enables fast detection of the bleaching diameter during diffusion of the sample in permanganate agar. This bleaching diameter is correlated to the reducing power of the substance tested. The method was tested and validated to quantify the total antioxidant capacity of culture supernatants of probiotic strains (Lacticaseibacillus rhamnosus LGG and Lactiplantibacillus plantarum 299v) and 25 lactic acid bacteria isolated from a human intestinal origin and compared to the PRAC and DPPH methods. The results were treated statistically by analysis of variance. This method proved to be linear (R² in the linear experiment of ascorbic acid was 0,99), precise with repeatability intraday RSD of 2.07 to 5.5% and intermediate precision RSD of 2.95 to 5.53%, and accurate (100.29 to 108.58%) at 30 min, 1 h, and 4 h in the selected range of 1.5-5.5 mM of ascorbic acid. The developed permanganate agar reduction bioassay is a fast, reliable, and cost-effective technique for the prescreening and detecting the total antioxidant capacity of supernatants of lactic acid bacteria and possibly other sources of natural antioxidants.

Changes in Organic Acids, Phenolic Compounds, and Antioxidant Activities of Lemon Juice Fermented by Issatchenkia terricola

High content of citric acid in lemon juice leads to poor sensory experience. The study aimed to investigate the dynamics changes in organic acids, phenolic compounds, and antioxidant activities of lemon juice fermented with Issatchenkia terricola WJL-G4. The sensory evaluation of fermented lemon juice was conducted as well. Issatchenkia terricola WJL-G4 exhibited a potent capability of reducing the contents of citric acid (from 51.46 ± 0.11 g/L to 8.09 ± 0.05 g/L within 60 h fermentation) and increasing total phenolic level, flavonoid contents, and antioxidant activities compared to those of unfermented lemon juice. A total of 20 bioactive substances, including 10 phenolic acids and 10 flavonoid compounds, were detected both in fermented and unfermented lemon juice. The lemon juice fermented for 48 h had better sensory characteristics. Our findings demonstrated that lemon juice fermented with Issatchenkia terricola exhibited reduced citric acid contents, increased levels of health-promoting phenolic compounds, and enhanced antioxidant activities.

Strategies to Improve the Potential Functionality of Fruit-Based Fermented Beverages

It is only recently that fermentation has been facing a dynamic revival in the food industry. Fermented fruit-based beverages are among the most ancient products consumed worldwide, while in recent years special research attention has been granted to assess their functionality. This review highlights the functional potential of alcoholic and non-alcoholic fermented fruit beverages in terms of chemical and nutritional profiles that impact on human health, considering the natural occurrence and enrichment of fermented fruit-based beverages in phenolic compounds, vitamins and minerals, and pro/prebiotics. The health benefits of fruit-based beverages that resulted from lactic, acetic, alcoholic, or symbiotic fermentation and specific daily recommended doses of each claimed bioactive compound were also highlighted. The latest trends on pre-fermentative methods used to optimize the extraction of bioactive compounds (maceration, decoction, and extraction assisted by supercritical fluids, microwave, ultrasound, pulsed electric fields, high pressure homogenization, or enzymes) are critically assessed. As such, optimized fermentation processes and post-fermentative operations, reviewed in an industrial scale-up, can prolong the shelf life and the quality of fermented fruit beverages.

Probiotics-fermented blueberry juices as potential antidiabetic product: antioxidant, antimicrobial and antidiabetic potentials

BACKGROUND

Fermentation is a traditional food-preserving technique. It is an effective process, widely used to enrich the nutrients diversity and bioactivity of the fermented foods since ancient times. This study aimed at investigating the effects of various fermentation starters on the physicochemical, antioxidant, antimicrobial, and antidiabetic properties of blueberry juices. The blueberry juices were fermented by natural fermentation (NFBJ), self-made starters fermentation (SFBJ), and commercial starters fermentation (CFBJ); fresh blueberry juice (BBJ) was processed without fermentation for comparison.

RESULTS

Probiotics-fermented blueberry juices (SFBJ and CFBJ) showed less total and reducing sugars, higher titratable acidity, and a wider variety and higher amounts of organic acids than non-fermented blueberry juice (BBJ) did. All the fermented blueberry juices (NFBJ, SFBJ, and CFBJ) showed significantly (P < 0.05) higher antioxidant potentials than that of BBJ measured by 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid, cupric-reducing antioxidant capacity, and ferric-reducing ability power assays. The SFBJ exhibited the highest antibacterial activities against Escherichia coli, Staphylococcus aureus, and Salmonella Typhimurium, with inhibition zone diameters of 38.84 ± 1.74 mm, 34.91 ± 1.53 mm, and 36.18 ± 3.16 mm respectively. Compared with BBJ, the α-glucosidase inhibitory activity of the SFBJ and CFBJ increased by two-to threefold. The α-amylase inhibitory activity of the SFBJ and CFBJ increased by 600%, whereas the spontaneous fermentation showed no improvement. The SFBJ and CFBJ promoted glucose consumption of HepG2 cell lines, indicating the promising potential for a higher glucose bio-utilization.

CONCLUSIONS

The SFBJ and CFBJ showed remarkable improvements in the antioxidant, antimicrobial, and antidiabetic activities compared with non-fermented and spontaneous fermented juices, indicating their promising potentials as an antihyperglycemic agent. © 2021 Society of Chemical Industry.

Possibility of Reinforcement the Functional Potential of Vegetable Juices with the use of Novel Strain Lactiplantibacillus Plantarum EK11 Isolated from an Unconventional Fermented Food Matrix

The study investigated the suitability of a novel strain Lactiplantibacillus plantarum EK11 for obtaining fermented tomato and beetroot juices with improved functional potential. EK11 had the capability of dynamic acidification of pasteurized vegetable beverages. The lowest values of pH were noted in juices after 48 h of fermentation with the probiotic L. plantarum 299v (pH=3.72±0.01 in beet juice and pH=3.43±.0.01 in tomato juice). The fermentation increased the lycopene content in tomato juices from 27.90±0.31µg mL−1 (after 24-h fermentation by strain EK11) to 116.86 ±0.19 µg mL−1 (final products obtained using strain 299v after 7-day cold storage). The process contributed to changes in the betanin and vulgaxanthin-I concentration in beetroot beverages. All fermented products exhibited antioxidative activity, i.e. 50% inhibition of 1,1-diphenyl-2-picrylhydrazyl free radicals. Moreover, three genes involved in the biosynthesis of bacteriocins were detected in the novel strain EK11, which exhibits functional and technological potential for the production of fermented foods.

Physicochemical Parameters and Bioaccessibility of Lactic Acid Bacteria Fermented Chayote Leaf (Sechium edule) and Pineapple (Ananas comosus) Smoothies

In this study, popularly consumed traditional chayote leaves and locally produced pineapple fruit were used to develop a fermented smoothie using lactic acid bacteria (LAB) strains: Lactobacillus plantarum (L75), Weissella cibaria (W64), and their combination (LW64 + 75). The physicochemical parameters [pH, total soluble solids (TSS), and color], total phenols, and carotenoid contents of the smoothies fermented for 48 h and stored for 7 days at 4°C were compared with the unfermented (control) smoothies. Results indicated that LAB fermentation reduced the pH from 3.56 to 2.50 after 48 h (day 2) compared with the non-fermented smoothie at day 2 (pH 3.37). LAB strain L75 significantly reduced the TSS content of the smoothies to 13.06°Bx after 2 days of fermentation. Smoothies fermented by L75 showed overall acceptability after 7 days of storage compared with the non-fermented puree on day 0. The LW64 + 75 significantly reduced the color change (ΔE), which was similar to the control. L75 increased the phenolic content, and W64 enhanced the total carotenoid content of the smoothies after 2 days of fermentation compared with other treatments. The use of an in vitro model simulating gastrointestinal (GI) digestion showed that fermentation with L75 improved the total phenol recovery by 65.96% during the intestinal phase compared with the control. The dialysis phase mimicked an epithelial barrier, and 53.58% of the recovered free soluble are bioavailable from the L75 fermented smoothies compared with the control. The antioxidant capacity of dialyzable fraction of the L75 fermented smoothie was significantly higher than that of the control and smoothies fermented with W64 or LW64 + 75.

Comparative Studies of Inhibitory and Antioxidant Activities, and Organic Acids Compositions of Postbiotics Produced by Probiotic Lactiplantibacillus plantarum Strains Isolated From Malaysian Foods

Despite inflammation being a protective natural defense against imbalance stressors in the body, chronic inflammation could lead to the deterioration of immune response, low production, and poor performance in livestock as well as severe economic losses to the farmers. Postbiotics produced by Lactiplantibacillus plantarum has been reported recently to be a natural source of antioxidant, promoting growth performance, anti-inflammation, and immune responses. However, the effects of fermentation media on the compositions of L. plantarum postbiotic have not been reported elsewhere. Hence, a comparative study was conducted to compare the volatile compounds, organic acid composition, and antioxidant and antimicrobial activities of postbiotics produced by six strains of L. plantarum cultivated by using formulated media and the commercial de Man, Rogosa, and Sharpe (MRS) medium as a control. Postbiotics RG14, RI11, and UL4 produced by using formulated media exhibited higher inhibitory activity against Pediococcus acidilactici 446, Escherichia coli E-30, Salmonella enterica CS3, and vancomycin-resistant Enterococci except for Listeria monocytogenes LS55. As for the antioxidant activity, hydroxyl radical scavenging activity was enhanced in formulated media, whereas reducing power activity was the highest in postbiotic RI11. Three organic acids, namely, acetic acid, caproic acid, and lactic acid, were detected in the postbiotic produced by various L. plantarum strains. The concentration of acetic acid was influenced by the fermentation media, whereas caproic acid was detected as the highest in postbiotic RG11. Lactic acid was the predominant compound detected in all the postbiotics and had the significantly highest concentration in postbiotic RS5 when produced by using the MRS medium. Intermediary and pyrrole compounds were the other main compounds that were detected by using GC-MS. Positive correlations were found between organic acid production and inhibitory activity, as well as antioxidant activity exhibited by postbiotics. In conclusion, the compositions and functional characteristics of postbiotics produced by the six strains of L. plantarum were strain-dependent and affected greatly by the fermentation medium. The effects of postbiotic composition on the functional characteristics of postbiotics were elucidated in this study to warrant their applications as a promising beneficial natural growth promoter for the livestock industry.

Improving Kefir Bioactive Properties by Functional Enrichment with Plant and Agro-Food Waste Extracts

An increase in the number of novel fortified kefir-based beverages was observed in the last decades. Vegetables were often proposed as convenient resources of bioactive molecules able to improve nutraceutical benefits of these drinks and/or to confer them new significant features. These findings have been well accepted by the consumers, which generally reserve an important role to the quality of the assumed food and beverages. Specifically, functional fermented milk-based drinks enriched with vegetable extracts display significant biological properties, due to the presence of bioactive compounds exhibiting antimicrobial and antioxidant features. In addition, agro-industrial wastes have been also proposed as innovative resources of secondary metabolites to enrich kefir-based products. Eco-friendly extraction techniques were generally exploited to achieve the isolation of biomolecules and reducing, at the same time, economic and environmental loads. To this regard, this review deeply investigates the main findings to improve kefir bioactive properties by functional enrichment with plant and agro-food waste extracts. The nutraceutical characteristics related to the consumers’ health benefits, as well as their effects on the sensorial, chemical, and microbiological properties of the products were evaluated.

Ready to Use Therapeutical Beverages: Focus on Functional Beverages Containing Probiotics, Prebiotics and Synbiotics

The growing global interest in functional foods containing nutrients capable of adding possible beneficial health effects is rapidly increasing both interest and consumer demand. In particular, functionalized beverages for their potential positive effect on health e.g., decreasing cholesterol level, lowering sugar, high fiber content, ability to enhance the immune system, and help digestion, have recently received special attention. Among the different beverages available on the market, probiotic dairy and non-dairy products have attracted much attention because of their affordable cost and their numerous therapeutic activities. Fermented milk and yogurt are currently worth €46 billion, with 77% of the market reported in Europe, North America, and Asia. Consumption of dairy beverages has some limitations due for example to lactose intolerance and allergy to milk proteins, thereby leading consumers to use non-dairy beverages such as fruit, grains, and vegetable juices to add probiotics to diet as well as driving the manufacturers to food matrices-based beverages containing probiotic cultures. The purpose of this review article is to evaluate the therapeutic performance and properties of dairy and non-dairy beverages in terms of probiotic, prebiotic, and synbiotic activities.

Microbiological, Biochemical, and Functional Aspects of Fermented Vegetable and Fruit Beverages

In recent years, the request for the functional beverages that promote health and wellness has increased. In fact, fermented juices are an excellent delivering means for bioactive components. Their production is of crucial importance to supply probiotics, in particular, for people with particulars needs like dairy-product allergic consumers and vegetarians. This review focuses on recent findings regarding the microbial composition and the health benefits of fermented fruit and vegetable beverages by lactic acid bacteria, kefir grains, and SCOBY as well as discussing the metabolites resulting from these fermentations process. Moreover, limits that could restrain their production at the industrial level and solutions that have been proposed to overcome these constraints are also reviewed.

Shelf life enhancement and associated quality and sensory changes on refrigerated storage of tender coconut water subjected to non-thermal microfiltration and treated with additives

Evaluation of tender coconut water was done that was subjected to a nonthermal two stage microfiltration process that involved filtration through 0.8 µm and 0.45 µm pore size filters followed by addition of 200 mg/L citric acid, 180 mg/L ascorbic acid, orange honey at 5% (w/v) followed by packaging in glass bottles with headspace flushed with nitrogen. The effect of storage under refrigeration was studied. Microfiltration reduced the total simple sugars, protein and reducing sugars respectively by 13.4, 13.0 and 21.5% without significantly affecting the overall acceptability. Microfiltered samples did not show any signs of haemolytic activity. Addition of citric acid, ascorbic acid and honey was able to reduce activity of polyphenol oxidase and peroxidase and maintain product stability. Even though microfiltered samples were sterile for 190 days, the samples were acceptable for sensory attributes till day 90 of storage. Microfiltration and use of additives were thus found to increase the shelf life of tender coconut water.

Exploring the microbiota and metabolites of traditional rice beer varieties of Assam and their functionalities

Rice beer is traditionally prepared and consumed by various ethnic populations in the Southeast Asian countries. To understand the probable effects of rice beer on human health, present research was aimed to study biochemical parameters, microbial diversity and metabolites of major rice beer varieties of Assam, namely Apong (Poro and Nogin), Xaaj and Joubishi. Alcoholic content of rice beer varieties varied from 9.41 to 19.33% (v/v). Free radical scavenging activity against DPPH· and ABTS⁺ were 1.94-4.14 and 1.69-3.91 mg of ascorbic acid/ml of rice beer, respectively. In relation to antioxidant activities, phenolic content varied from 2.07 to 5.40 mg gallic acid/ml of rice beer. Next-generation sequencing of 16S rDNA showed that 18 genera of bacteria were present irrespective of rice beer varieties in which lactic acid bacteria were the dominant group (90% abundance). Functional predictions based on the bacterial profiles indicated pathways, such as metabolisms of carbohydrate, amino acid, vitamins and cofactors, and xenobiotic biodegradation, to be active in the rice beer varieties. Out of 18 core bacterial genera, 7 had correlations with the predicted functions. Gas chromatography and mass spectroscopy-based metabolite analysis revealed that the metabolite profiles of the rice beer varieties consisted of 18 saccharides, 18 organic acids, 11 sugar alcohols, 8 amino acids, 1 vitamin and nutraceutical compounds thiocoumarine, carotene, oxazolidine-2-one and acetyl tyrosine. Due to the presence of potent prebiotics, probiotics and nutraceuticals, rice beer may have health benefits which need to be studied further.

Volatile compounds associated with growth of Asaia bogorensis and Asaia lannensis-unusual spoilage bacteria of functional beverages

Acetic acid bacteria of the genus Asaia are recognized as common bacterial spoilage in the beverage industry. Their growth in contaminated soft drinks can be visible in the form of flocs, turbidity and flavor changes. Volatile profiles associated with the growth and metabolic activities of Asaia lannensis and As. bogorensis strains were evaluated using comprehensive gas chromatography-time of flight mass spectrometry (GC × GC-ToF MS). Based on obtained results, 33 main compounds were identified. The greatest variety of volatile metabolites was noted for As. lannensis strain W4. 2-Phenylethanol, 3-pentanone, 2-nonanol, 2-hydroxy-3-pentanone, and 2-nitro-1-butanol were detected as dominant volatile compounds. Additionally, As. lannensis strains formed 2-propenoic acid ethyl ester. As. bogorensis ISD1 was distinguished by the higher concentration of 2-hydroxy-3-pentanone and 3-methyl-1-butene but the lowest concentration of 2-phenylethanol. Based on these results, it was found that volatile profiles of Asaia spp. are unique among acetic acid bacteria. Moreover, obtained profiles depended not only on bacterial species and strains but also on the composition of culture media.

Comparative Evaluation of the Antioxidant Capacities and Organic Acid and Volatile Contents of Mango Slurries Fermented with Six Different Probiotic Microorganisms

Mango slurries were fermented with 6 different probiotic microorganisms (Lactobacillus plantarum, Streptococcus thermophilus, Lactobacillus casei, Saccharomyces cerevisiae D254, S. cerevisiae DV10, and S. cerevisiae R2) to develop products with higher bioactivity. Changes in pH, reducing sugars, organic acids, and volatile compounds were determined. In addition, total phenolics and antioxidant capacity during fermentation were monitored. Among the strains used, S. cerevisiae D254 exhibited the fastest utilization of sugar in a mango slurry. Different volatile compounds were produced, mainly consisting of fatty acids, alcohols, and esters. S. cerevisiae DV10 produced higher amounts of esters and alcohols. The antioxidant capacity of the mango slurries improved by different degrees after fermentation with the six probiotic microorganisms. Fermentation with L. plantarum obtained the most organic acids as well as total phenolics and exhibited the highest FRAP and CUPRAC values. The results of this study indicated that fermentation with probiotic microorganisms can enhance the health benefits obtained from mango slurries. PRACTICAL APPLICATION: Probiotic-fermented mango slurry is a fermentation product that combines the nutritional value of mango with the health benefits of probiotics. Probiotic fermentation improves the flavor of a mango slurry and increases the availability and variety of mango products that can be appreciated by consumers.