Effect of the apple cultivar on cloudy apple juice fermented by a mixture of Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus fermentum

Evaluation of sapodilla pulp as a matrix for probiotic fermentation: Physicochemical changes, antioxidant potential, and in vitro digestibility during storage

This study investigated the influence of three probiotic strains (Lacticaseibacillus paracasei subsp. paracasei, Bifidobacterium animalis subsp. lactis, and Lacticaseibacillus rhamnosus) on the fermentation of sapodilla pulp, assessing its bioactive and antioxidant potential, in vitro digestibility, and stability during 28 days of storage. The sapodilla pulp, with high moisture (72.13 %), fiber (6.27 %), and sugars (14.70 % total, 8.96 % reducing), provided a protective matrix for probiotics. Fermentation at 35 °C for 24 h resulted in significant microbial growth, with L. rhamnosus exhibiting the highest viable cell count (8.90 log CFU/g), followed by B. animalis (8.70 log CFU/g) and L. paracasei (8.49 log CFU/g). HPLC analysis revealed substantial glucose and fructose depletion, particularly in L. rhamnosus-fermented samples. Throughout storage, pH (5.10-5.90) and total soluble solids (19.60-19.9°Brix) decreased, while cell viability remained stable (8-9 CFU/g). Fermentation enhanced bioactive compounds, with increased total phenolic content (TPC), β-carotene, and lycopene, the latter peaking at 14 days in B. animalis (45.72 μg/100 g). Antioxidant capacity improved across assays (ABTS, FRAP, and DPPH), with DPPH showing the highest values (2.19-2.85 μM TE/g). Simulated digestion revealed viability loss in oral and gastric phases but a marked recovery in the intestinal phase, where L. rhamnosus demonstrated superior resistance and regrowth. These findings emphasize the role of sapodilla pulp in enhancing probiotic stability and functionality, positioning it as a promising matrix for functional food development with potential health and economic benefits.

Effect of mixed fermentation of compound grapes on organic acids and volatiles in mulberry wine

The main objective of this study was to investigate the effect of mixed fermentation of blended grapes on the organic acid and volatile content of mulberry fruit wines before and after fermentation. Rose-scented grapes and blackberry grapes were chosen to produce fruit wines through mixed fermentation with mulberries, respectively. HPLC was employed for the content of organic acids, whereas the concentrations of volatile compounds in the mulberry wines were determined using HS-SPME-GC-MS. The results showed that yeast fermentation could effectively reduce the content of malic acid and citric acid while generating rich aroma substances. During compound grape blend fermentation, the organic acid content decreases, and more volatile compounds are produced. Among them, mulberry rosé grapefruit wine exhibits a more complex array of volatile compounds, including phenylethanol, ethyl caprylate, and ethyl caprate, alongside recently discovered compounds like isobutanol, (+)-3-methyl-2-butanol, and α-pinitol. These compounds contribute to the enhanced flavor of mulberry wine.

The potential of red-fleshed apples for cider production

Cider quality is influenced by numerous factors relating to the apples used during production. While extensive research has been done to explore the phenolic content, sensory quality, and storage stability of various apple products, the domain of fermented apple products, such as ciders, remains underrepresented. Red-fleshed apples (RFAs) have naturally high concentrations of phenolic compounds, which indicate their potential in the production of novel cider products. However, a knowledge gap remains regarding the application of RFAs in cider production and how their physicochemical and sensory properties are changed during processing. This review is the first to comprehensively investigate whether and to what extent apple categories (dessert, cider, and RFAs) differ regarding their physicochemical and sensory properties from harvest throughout cider processing. Furthermore, it highlights the importance of a holistic understanding of apple characteristics, encompassing both traditional and RFA varieties in the context of cider production. The findings offer valuable insights for stakeholders aiming to enhance product quality, providing a foundation for future studies on optimizing processing methods for a diverse and appealing range of ciders.

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.

Sensory improvement of fermented apple juice diluted from concentrate by lactic acid bacteria

To evaluate the fermentation potential of diluted concentrated apple juice (CAJ) and identify suitable strains, seven lactic acid bacteria (LAB) strains, including Lactiplantibacillus plantarum (TM3-23), Pediococcus acidilactici (G1-14), Lacticaseibacillus paracasei (TH4-4), Limosilactobacillus fermentum (LX4-19), Lactobacillus acidophilus (G3-2), Lactobacillus helveticus (G3-4), and Lactobacillus delbrueckii (SJ2-10), were employed for diluted CAJ fermentation. The identification of volatile compounds was conducted using gas chromatography-mass spectrometry (GC-MS), while sensory quality of fermented products was evaluated using electronic tongue analysis and sensory evaluation. Results indicated that TM3-23, TH4-4, G1-14, and G3-4 adapted well to diluted CAJ and demonstrated a robust ability to metabolize malic acid, with TM3-23 achieving 8.27 Log CFU/mL. TM3-23 and LX4-19 enhanced the diversity of phenolic compounds. LAB fermentation enhanced the aroma by reducing aldehyde content and increasing the diversity of alcohols and other volatile compounds. Fermentation increased L* values and reduced a* values significantly (p < 0.05). CAJ fermented by TM3-23 received the highest sensory scores for taste (22.67) and flavor (22.48). G1-14 demonstrated significant DPPH radical scavenging activity and FRAP (p < 0.05). A comparison of the physicochemical properties of fresh squeezed apple juice and diluted CAJ after fermentation revealed that diluted CAJ serves as a suitable substrate for LAB fermentation, with Lactiplantibacillus plantarum TM3-23 being the dominant strain for the development of fermented apple juice. This study demonstrates the feasibility of using diluted CAJ for fermentation, supporting its high-value application in the food industry.

Immunomodulatory Potential of 6-Gingerol and 6-Shogaol in Lactobacillus plantarum-Fermented Zingiber officinale Extract on Murine Macrophages

In this study, we aimed to investigate whether the physiological activity of ethanol extracts of Zingiber officinale was improved after fermentation with Lactobacillus plantarum strains KCTC 3108 (FLP8) and KCL005 (FLP9). Total polyphenol and flavonoid content was substantially increased after fermentation with FLP8 and FLP9 for 48 h and 24 h, respectively, compared with the unfermented control. The 6-gingerol content was significantly increased in FLP9 after 24 h of fermentation, whereas in FLP8, it remained comparable to pre-fermentation levels. The 6-shogaol content significantly increased in FLP8 and FLP9 at 48 h and 24 h, respectively, compared with the pre-fermentation levels. The anti-inflammatory effects were evaluated using RAW 264.7 cells stimulated with lipopolysaccharides. The fermented product of FLP8 at 48 h and FLP9 at 24 h maintained over 80% cell viability at a concentration of 200 µg/mL and significantly reduced nitric oxide production compared to the lipopolysaccharide-stimulated control. Moreover, each extract downregulated pro-inflammatory gene expression. Furthermore, the purified 6-gingerol and 6-shogaol, which were purchased as reference compounds, were included in the fermentation extracts of FLP8 at 48 h and FLP9 at 24 h, and both inhibited cell migration in a dose-dependent manner without any cytotoxicity. In conclusion, the fermentation of Z. officinale with these L. plantarum strains enhanced its antioxidant and anti-inflammatory activities, with significant increases in bioactive compound content.

Lactic acid bacteria sequential fermentation improves viable counts and quality of fermented apple juice via generating two logarithmic phases

This study investigated the impact of lactic acid bacteria (LAB) sequential fermentation on viable counts and apple juice quality. The optimal fermentation conditions were obtained by a step-by-step optimization process, including pH 4.5, temperature 37 °C, the second inoculation time 16 h, total fermentation time 40 h and fermentation sequence (first 21,805 + 21,828, second 20,241). Under the optimal conditions, sequential fermentation allowed LAB to experience two logarithmic phases, increasing viable counts to 1.38 × 108 CFU/mL, exceeding simultaneous fermentation for 24 h and 40 h by 4.10 × 107 CFU/mL and 5.40 × 107 CFU/mL, respectively. This process enhanced sugar utilization, yielding more lactic acid and polyphenols. Furthermore, sequential fermentation improved DPPH (71.71 %) and ABTS (84.79 %) scavenging rates, and enriched volatile compounds, particularly beta-Damascenone, potentially contributing to floral and richer apple flavor. Sequential fermentation also achieved optimal sensory acceptability. This study proposes a novel strategy for high-density LAB fermentation to produce high-quality apple juice.

Inactivation activity and mechanism of high-voltage pulsed electric fields combined with antibacterial agents against Alicyclobacillus spp. in apple juice

Alicyclobacillus spp. are crucial factors affecting the quality of fruit juice, so it is very important to control their contamination. In this study, the inactivation activity and mechanism of high-voltage pulsed electric fields (HVPEF) combined with antibacterial agents against Alicyclobacillus spp. in apple juice were investigated. It was found that under the optimal conditions of electric field strength 9.6 kV/cm, treatment time 20 min, frequency 1000 Hz, and duty ratio 50 %, HVPEF treatment could reduce bacteria by 1.89-4.76 log CFU/mL. Moreover, the inactivation activities of six antibacterial agents (propyl paraben, glycerol monocaprate, octyl gallate, heptyl paraben, nisin, carvacrol) alone and their combination with HVPEF were further investigated. The results showed that with the combined treatment, the minimum bactericidal concentrations of carvacrol, nisin, and heptyl paraben were reduced by >50 % to 1 mg/mL, 10 IU/mL, and 0.02 mg/mL, respectively. Based on this, the most resistant strain of A. acidoterrestris (DSM 3922) was identified to elucidate the inactivation mechanism. It was demonstrated that the antibacterial process could alter the permeability and fatty acid composition of the cell membrane, causing the cells to deform and shrink, leading to leakage of intracellular proteins, and also affect the synthesis of ROS and ATP, ultimately resulting in bacterial death. In addition, the various treatments had no significant effect on the soluble solids content, titratable acid, soluble sugar content, organic acids and aroma components of apple juice. The combination of HVPEF treatment and antibacterial agents could effectively maintain the quality of apple juice.

Innovative enhancement of flavor profiles and functional metabolites composition in Pandanus amaryllifolius through lactic acid bacteria fermentation

Pandanus amaryllifolius, known as Pandan, serves as a coloring agent and spice in food. The effects of lactic acid bacteria (LAB) on Pandan are underexplored. This study aimed to investigate changes in physicochemical properties, antioxidant activity, volatile compounds and metabolites of Pandan fermented with Lactobacillus acidophilus, Levilactobacillus brevis and Lacticaseibacillus rhamnosus. Fermented Pandan showed increased total phenol (13 %-21 %) and flavonoid (33 %-53 %) content. Pandan fermented with L. rhamnosus exhibited significantly higher antioxidant activity, followed by those fermented with L. brevis and L. acidophilus. Key components like naringenin and volatile compounds such as α-ionone significantly increased after fermentation, with the production of new compounds, including damascenone and linalool. These compounds enhance the flavor and functional properties of fermented Pandan. This research lays a foundation for developing novel LAB-fermented Pandan products.

Effect of Organic Acid Addition Before Fermentation on the Physicochemical and Sensory Properties of Cherry Wine

Lack of acidity is the main reason for the spoilage of cherry wine, and for insufficient aroma and mouthfeel. In this study, the initial acidity of cherry purees was adjusted to 3.50, 4.15, 4.80 and 5.45 g/kg by using malic acid, lactic acid and a mixture of the two before fermentation. And the effects of different organic acid additions on the physicochemical profiles and sensory properties of cherry wines were investigated. Our findings suggest that organic acid addition can inhibit the formation of volatile acid and enhance ethanol production, while having a negative effect on their polyphenol contents. These additions can be utilized as carbon sources during cherry wine fermentation and affect its metabolism. Among them, the application of malic acid with lactic acid was shown to have more metabolically active effects on non-volatile compounds, and enhanced the total volatile organic compounds by 14.04%-66.92%. MC-4.80 and MLC-4.80 had the highest total VOC content and odor score in the sensory evaluation. However, the addition of large amounts of acids reduced the acidity score and overall acceptability of cherry wine. In conclusion, adjusting the initial acid content to 4.15 g/kg before fermentation significantly improved the quality of cherry wines, and the combination of malic acid and lactic acid was more effective for cherry winemaking. This finding evidenced that organic acid addition could be an effective strategy for improving the quality of cherry wines.

Effect of bacterial diversity on the quality of fermented apple juice during natural fermentation of Hanfu apples

The fermented cloudy apple juice (FCAJ) bacterial phase was analyzed by 16S rRNA gene-based sequencing. During fermentation, the bacterial phase transition promoted quality changes, such as carbohydrate, organic acid, total phenol, taste and volatiles of FCAJ. Citrobacter and Lactobacillus were the dominant bacterial genera of Hanfu apple juice by natural fermentation, and lactic acid was the most abundant organic acid in FCAJ. Citrobacter showed a continuous increase trend along with fermentation time, while Lactobacillus showed a slight decrease during the later period of fermentation. The contents of total phenolic and flavonoid both showed a trend of rising first and then decreasing in FCAJ during fermentation. Alcohols and esters, the main aromatic volatiles in FCAJ, showed significant increases, especially for ethanol, 3-methyl-1-butanol and ethyl acetate. Citrobacter presented a higher correlation than Lactobacillus with some volatile flavor.

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.

Impact of Thermophysical and Biological Pretreatments on Antioxidant Properties and Phenolic Profile of Broccoli Stem Products

Fruit and vegetable industrialisation is a major contributor to food waste; thus, its integral transformation into functional powders has gained attention. Pretreatments can be incorporated into valorisation processes to generate structural or biochemical changes that improve powders' characteristics. This study deepens into the impact of biological (fermentation, FERM) and thermophysical (autoclaving, AUTO; microwaves, MW; ultrasound, US; and pasteurisation, PAST) pretreatments, combined with dehydration (hot air-drying, HAD; or freeze-drying, FD) on the characteristics of powdered products obtained from broccoli stems. The impact of pretreatments on physicochemical (moisture, water activity, total soluble solids) and antioxidant properties (phenols, flavonoids, antioxidant capacity by ABTS and DPPH) on residue and powdered products was studied, together with their impact on plant tissue structure (Cryo-SEM) and the powders' phenolic profile (HPLC). Probiotic viability was also determined on the fermented samples. The pretreatments applied, particularly the ultrasound, improved the antioxidant properties of the broccoli stems compared to the unpretreated samples, in line with microscopic observations. Dehydration did also improve the antioxidant attributes of the broccoli wastes, especially drying at 60 °C. However, pretreatments combined with dehydration did not generally lead to an improvement in the antioxidant properties of the powders. Probiotic properties were preserved in the freeze-dried products (>107 CFU/g). In conclusion, pretreatments may be applied to enhance the antioxidant attributes of broccoli wastes, but not necessarily that of dried powdered products.

Effect of microwave-puffed on Auricularia auricula polysaccharide and probiotic fermentation on its biotransformation and quality characteristics during storage period

In this study, probiotics with superior fermentation performance were screened, and the mixed-bacteria fermentation was carried out with Auricularia auricula treated with microwave-puffed process as fermentation substrate, and the changes in nutritional quality under different storage conditions were investigated. The results showed that the acid and bile salt resistance of Lactiplantibacillus plantarum 21,801 and 21,805 reached 95 % and 75 % respectively, and the intestinal adhesion was superior; microwave puffing treatment had the highest retention rate of A. auricula polysaccharides and the lowest loss of polyphenols, and no effect on soluble protein. Mixed bacterial fermentation significantly increased the total polyphenols and total flavonoids of A. auricula (p < 0.05), and the DPPH and ABTS radical scavenging reached 48.31 % and 73.21 % respectively. Furthermore, the viable counts, DPPH radical scavenging, color, and sensory quality of fermented A. auricula remained stable when stored at 4 °C. In contrast, when stored at 25 °C for 7 days, the taste was unfavorable, undesirable odor and spoilage occurred; by 21 days, DPPH clearance rate dropped below 40 % and color changed significantly (△E > 2). In conclusion, the probiotic mixed fermentation and storage conditions had a significant effect on the biometabolic transformation of macromolecules and other substances in A. auricula.

Transcriptomic analysis of the antibacterial mechanism of ε-polylysine-functionalized magnetic composites against Alicyclobacillus acidoterrestris and its application in apple juice

BACKGROUND

Alicyclobacillus acidoterrestris is a common microorganism in fruit juice. It can produce off-odor metabolites and has been considered to be an important factor in juice contamination. Thus, the development of new strategy for the control of A. acidoterrestris has important practical significance. The primary objective of this work was to assess the antibacterial performance of ε-polylysine-functionalized magnetic composites (Fe3O4@MoS2@PAA-EPL) in apple juice and its effect on juice quality. Moreover, the molecular mechanism of Fe3O4@MoS2@PAA-EPL against A. acidoterrestris was explored by RNA sequencing (RNA-Seq).

RESULTS

Experimental results indicated that the synthesized composites possessed the ability to inhibit the viability of A. acidoterrestris vegetative cells and spores. Besides, investigation on the quality of apple juice incubated with Fe3O4@MoS2@PAA-EPL implied that the fabricated composites displayed negligible adverse effects on juice quality. In addition, the results of RNA-Seq demonstrated that 833 differentially expressed genes (DEGs) were identified in Fe3O4@MoS2@PAA-EPL-treated A. acidoterrestris, which were associated with translation, energy metabolism, amino acid metabolism, membrane transport and cell integrity.

CONCLUSION

These results suggested that the treatment of Fe3O4@MoS2@PAA-EPL disrupted energy metabolism, repressed cell wall synthesis and caused membrane transport disorder of bacterial cells. This work provides novel insights into the molecular antibacterial mechanism for ε-polylysine-functionalized magnetic composites against A. acidoterrestris. © 2024 Society of Chemical Industry.

Lactiplantibacillus plantarum exerts strain-specific effects on malolactic fermentation, antioxidant activity, and aroma profile of apple cider

This study aimed to investigate the impact of different strains of Lactiplantibacillus plantarum on malolactic fermentation (MLF), antioxidant activity, and aroma of ciders. A commercial strain of Saccharomyces cerevisiae and six indigenous L. plantarum strains were co-inoculated into apple juice to induce simultaneous alcoholic fermentation (AF) and MLF. The findings indicated that despite belonging to the same species, the different L. plantarum strains significantly differed (p < 0.05) in terms of antioxidant activity and aroma compounds in the ciders. MLF induced by L. plantarum resulted in the substantial consumption of malic acid and increased levels of lactic acid in the ciders, with strain-specific effects observed, particularly with L. plantarum SCFF284. In addition, ciders produced from mixed fermentations exhibited higher levels of antioxidant activity than those from pure S. cerevisiae fermentation (p < 0.05), especially for LAM284. Furthermore, ciders produced from mixed fermentations exhibited higher levels of aroma compounds, such as ethyl acetate and isoamyl alcohol, and also received higher sensory scores compared to ciders produced through pure S. cerevisiae fermentation (p < 0.05). These results highlight the effectiveness of MLF induced by L. plantarum in enhancing the antioxidant activity and aroma profile of ciders.

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.

Organic acids drove the microbiota succession and consequently altered the flavor quality of Laotan Suancai across fermentation rounds: Insights from the microbiome and metabolome

Laotan Suancai, a popular traditional Chinese fermented vegetable, is manufactured in the industry via four fermentation rounds. However, the differences in flavor quality of Laotan Suancai from the four fermentation rounds and the causes of this variation remain unclear. Metabolome analysis indicated that the different content of five taste compounds and 31 aroma compounds caused the differences in flavor quality among the variated fermentation rounds of Laotan Suancai. Amplicon sequencing indicated that the microbial succession exhibited a certain pattern during four fermentation rounds and further analysis unveiled that organic acids drove the microbiota shift to more acid-resistant populations. Spearman correlation analysis highlighted that seven core microbes may be involved in the formation of differential flavor and the corresponding metabolic pathways were reconstructed by function prediction. Our findings offer a novel perspective on comprehending the deterioration of flavor quality across the fermentation rounds of Laotan Suancai.

Physicochemical, microbiological, and sensory properties of healthy juices containing aloe vera gel and probiotics and their antidiabetic effects on albino rats

The consumption of fruit and vegetable juices is widely recognized as a healthy choice across all age groups. Orange, carrot, and aloe vera are renowned for their functional properties and health benefits. In this study, we investigated the potential incorporation of aloe vera gel into blended orange and carrot juices. We also evaluated the resulting mixed probiotic juices (chemical, microbiological, and sensory aspects) during a 14-day storage period at refrigerator temperature. The chemical composition and phytochemical structure of aloe vera gel were examined, followed by an assessment of the biological effects of these healthy juices on diabetic albino rats. The results indicated improvements in total soluble solids, reducing sugars, and total sugars with increasing storage duration. Furthermore, the study demonstrated that incorporating aloe vera into the natural mixed juices enhanced their phytochemical quality. The treatment supplemented with aloe vera gel gave the highest total content of phenolic and flavonoid substances, which were 310 mg of GAE/100 g and 175 mg of quercetin/100 g, respectively. Probiotic strains (Bifidobacterium animalis subsp lactis Bb12, Lactiplantibacillus plantarum 299V, and Lactobacillus acidophilus L10) exhibited good viable cell counts in orange and mixed orange and carrot probiotics juices with viable counts of 7.42-8.07 log CFU/mL. Regarding sensory attributes, the study found that increasing the ratio of orange juice improved the taste while increasing the ratio of carrot juice enhanced the color in juice mixtures. Incorporation of aloe vera into mixed natural juices also enhanced the reduction of blood glucose, triglyceride, cholesterol, LDL, creatinine, ALT, AST, and urea levels while increasing total protein and HDL levels in diabetic rats. Based on these findings, oranges, carrots, and aloe vera offer the potential to produce new, flavorful, nutritious, and appealing juices. Moreover, this study determined that a functional juice with favorable sensory properties can be created by blending 75% orange juice, 20% carrot juice, and 5% aloe vera gel. Additionally, aloe vera demonstrated greater efficacy as an antidiabetic agent in rats. Further research is suggested to explore the potential advantages of aloe vera gel and probiotic juices in mitigating diabetes and other metabolic syndromes.

Reusable thiol-modification Lactobacillus plantarum embedded in cellulose nanocrystals composite aerogel for efficient removal of Ochratoxin A in grape juice

Ochratoxin A (OTA) contamination in grape juice has attracted widespread concern as OTA can lead to kidney disease and cause adverse neurological effects. An effective method to remove OTA is to make use of highly adsorbent materials that are able to remove the toxic contaminant. Recently, inactivated Lactobacillus plantarum-based biosorbents have shown to be an efficient, cost-effective and environmentally friendly bioremediation method in removing toxic pollutants such as OTA. We used five chemical thiol-modification methods to improve the adsorption efficiency of OTA in grape juice. The esterification of Lactobacillus plantarum (L-Es) significantly increased the sulfhydryl contents (-SH) by 251.33 μmol/g and >90% of OTA was removed. However, the inactivated microbial adsorbent was difficult to separate after adsorption and therefore, the prepared L-Es were embedded into the cellulose nanocrystals (L-Es@CNCs). Moreover, L-Es@CNCs significantly increased the adsorption rate of OTA in grape juice samples by 88.28% with negligible effects on juice quality due to the properties of easy re-use and excellent biodegradability. This showcases its potential application for OTA removal in the grape juice industry.

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 function and application of edible fungal polysaccharides

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Development of a polyphenol-enriched whole kiwifruit dietary supplement and its potential in ameliorating hyperlipidemia

BACKGROUND

Kiwifruit pomace, which contains abundant phenolic compounds, is typically discarded during the juicing process, leading to wastage of valuable resources. To address this issue, various indicators (including total acidity, sugar/acid ratio, vitamin C, total polyphenols, polyphenol monomers, and soluble solids content) of 15 kiwifruit cultivars were evaluated and juiced. Then, a polyphenol-concentrated solution from kiwifruit pomace was backfilled into kiwi juice to prepare whole nutritious compound kiwi juice, and its anti-hyperlipidemic activity on obese model mice was then investigated.

RESULTS

Through grey relational analysis and the technique for order preference by similarity to an ideal solution (TOPSIS), Kuimi and Huayou were identified as the predominant varieties for juicing, with weighted relevance scores of 0.695 and 0.871 respectively and TOPSIS scores of 0.6509 and 0.8220 respectively. The polyphenol content of Cuixiang pomace was 43.97 mg g-1 , making it the most suitable choice for polyphenol extraction. By backfilling a polyphenol-concentrated solution derived from Cuixiang pomace into compound kiwi juice of Huayou and Kuimi, the whole nutritious compound kiwi juice with polyphenols was produced and exhibited superior bioactivities, including enhanced hepatic oxidative stress defense, and alleviated serum lipid abnormalities. Furthermore, whole nutritious compound kiwi juice with polyphenols ameliorated host intestinal microbiota dysbiosis by increasing the relative abundance of the phyla Bacteroidota and Verrucomicrobiota.

CONCLUSION

A hypolipidemic dietary supplement based on kiwifruit pomace polyphenols has been successfully developed, providing an effective solution for hyperlipidemia intervention. © 2023 Society of Chemical Industry.

Inactivation activity and mechanism of pulsed light against Alicyclobacillus acidoterrestris vegetative cells and spores in concentrated apple juice

Alicyclobacillus acidoterrestris has received much attention due to its unique thermo-acidophilic property and implication in the spoilage of pasteurized juices. The objective of this study was to evaluate the sterilization characteristics and mechanisms of pulsed light (PL) against A. acidoterrestris vegetative cells and spores in apple juice. The results indicated that bacteria cells in apple juice (8-20°Brix) can be completely inactivated within the fluence range of 20.25-47.25 J/cm2, which mainly depended on the soluble solids content (SSC) of juice, and the spores in apple juice (12°Brix) can be completely inactivated by PL with the fluence of 54.00 J/cm2. The PL treatment can significantly increase the leakage of reactive oxygen species (ROS) and proteins from cells and spores. Fluorescence studies of bacterial adenosine triphosphate (ATP) indicated that the loss of ATP was evident. Scanning electron microscopy and confocal laser scanning microscope presented that PL-treated cells or spores had serious morphological damage, which reduced the integrity of cell membrane and led to intracellular electrolyte leakage. In addition, there were no significant negative effects on total sugars, total acids, total phenols, pH value, SSC and soluble sugars, and organic acid content decreased slightly during the PL treatment. The contents of esters and acids in aroma components had a certain loss, while that of alcohols, aldehydes and ketones were increased. These results demonstrated that PL treatment can effectively inactivate the bacteria cells and spores in apple juice with little effect on its quality. This study provides an efficient method for the inactivation of A. acidoterrestris in fruit juice.

Polyphenolic profile, processing impact, and bioaccessibility of apple fermented products

Health-promoting foods have become increasingly popular due to intensified consumer interest and awareness of illnesses. There is a global market for apple fruits, which are affordable, nutritious, tasty, and produced in large quantities for direct consumption as well as food processing to make derived products. The food matrix of apples is suitable for fermentation, besides containing a high amount of phenolics and polyphenols. Fermentation of apples is one of the most common methods of preserving apple fruit and its byproducts. With different fermentation techniques, apple fruit can be used to make a wide range of products, such as fermented apple juice, cider, liqueurs, apple cider, apple vinegar and fermented apple solids, because it is not only a low-cost and simple method of processing the fruit, but it can also sometimes increase the bioavailability of nutrients and the levels of components that can improve health and sensory quality. To understand the health benefits of food products and how the fermentation process impacts polyphenols, it is also crucial to observe the effects of digestion on polyphenol bioaccessibility. Polyphenolic profile changes can be observed via both in vitro and in vivo digestion methods; however, in vitro digestion methods have the advantage of observing every step of gastrointestinal track effects and have less cost as well. In this review, the polyphenolic profile, processing impact, and bioaccessibility of apple-fermented products is assessed, with most available studies showing polyphenol profiles and bioaccessibility in apple varieties and fermented apple products.

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.

Comprehensive Evaluation of Ten Actinidia arguta Wines Based on Color, Organic Acids, Volatile Compounds, and Quantitative Descriptive Analysis

Actinidia arguta wine is a low-alcoholic beverage brewed from A. arguta with a unique flavor and sweet taste. In this study, the basic physicochemical indicators, color, organic acid, and volatile aroma components of wines made from the A. arguta varieties 'Kuilv', 'Fenglv', 'Jialv', 'Wanlv', 'Xinlv', 'Pinglv', 'Lvbao', 'Cuiyu', 'Tianxinbao', and 'Longcheng No.2' were determined, and a sensory evaluation was performed. The findings show that 'Tianxinbao' produced the driest extract (49.59 g/L), 'Kuilv' produced the most Vitamin C (913.46 mg/L) and total phenols (816.10 mg/L), 'Jialv' produced the most total flavonoids (477.12 mg/L), and 'Cuiyu' produced the most tannins (4.63 g/L). We analyzed the color of the A. arguta wines based on CIEL*a*b* parameters and found that the 'Kuilv' and 'Longcheng No.2' wines had the largest L* value (31.65), the 'Pinglv' wines had the greatest a* value (2.88), and the 'Kuilv' wines had the largest b* value (5.08) and C*ab value (5.66) of the ten samples. A total of eight organic acids were tested in ten samples via high-performance liquid chromatography (HPLC), and we found that there were marked differences in the organic acid contents in different samples (p < 0.05). The main organic acids were citric acid, quinic acid, and malic acid. The aroma description of a wine is one of the keys to its quality. A total of 51 volatile compounds were identified and characterized in ten samples with headspace gas chromatography-ion mobility spectrometry, including 24 esters, 12 alcohols, 9 aldehydes, 3 aldehydes, 2 terpenes, and 1 acid, with the highest total volatile compound content in 'Fenglv'. There were no significant differences in the types of volatile compounds, but there were significant differences in the contents (p < 0.05). An orthogonal partial least squares discriminant analysis (OPLS-DA) based on the odor activity value (OAV) showed that ethyl butanoate, ethyl pentanoate, ethyl crotonate, ethyl isobutyrate, butyl butanoate, 2-methylbutanal, ethyl isovalerate, and ethyl hexanoate were the main odorant markers responsible for flavor differences between all the A. arguta wines. Sensory evaluation is the most subjective and effective way for consumers to judge A. arguta wine quality. A quantitative descriptive analysis (QDA) of the aroma profiles of ten grapes revealed that the 'fruity' and 'floral' descriptors are the main and most essential parts of the overall flavor of A. arguta wines. 'Tianxinbao' had the highest total aroma score. The flavor and quality of A. arguta wines greatly depend on the type and quality of the A. arguta raw material. Therefore, high-quality raw materials can improve the quality of A. arguta wines. The results of the study provide a theoretical basis for improving the quality of A. arguta wines and demonstrate the application prospects of HS-GC-IMS in detecting A. arguta wine flavors.

Innovative beverage creation through symbiotic microbial communities inspired by traditional fermented beverages: current status, challenges and future directions

Fermented beverages (FBs) are facing challenges in functional performance and flavor complexity, necessitating the development of new multi-functional options. Traditional fermented beverages (TFBs), both alcoholic and nonalcoholic, have gained increased attention for their health-promoting effects during the COVID-19 pandemic. This review summarized the primary commercially available probiotics of FBs, along with the limitations of single and mixed probiotic FBs. It also examined the recent research progress on TFBs, emphasizing the typical microbial communities (MC) of TFBs, and TFBs made from crops (grains, vegetables, fruits, etc.) worldwide and their associated functions and health benefits. Furthermore, the construction, technical bottlenecks of the synthetic MC involved in developing innovative FBs were presented, and the promising perspective of FBs was described. Drawing inspiration from the MC of TFBs, developing of stable and multifunctional FBs using synthetic MC holds great promise for beverage industry. However, synthetic MC suffers from structural instability and poorly acknowledged interaction mechanisms, resulting in disappointing results in FBs. Future researches should prioritize creating synthetic MC fermentation that closely resemble natural fermentation, tailored to meet the needs of different consumers. Creating personalized FBs with high-tech intelligence is vital in attracting potential consumers and developing novel beverages for the future.

Impact of Fermentation Conditions on Physicochemical Properties, Antioxidant Activity, and Sensory Properties of Apple-Tomato Pulp

The aim of the study was to optimize the conditions [inoculum size (4, 6, and 8%), fermentation temperature (31, 34, and 37 °C), and apple: tomato ratio (2:1, 1:1, and 1:2)] on the viable cell count and sensory evaluation in apple-tomato pulp by response surface methodology (RSM), and determine the physicochemical properties, antioxidant activity, and sensory properties during fermentation. The optimal treatment parameters obtained were an inoculum size of 6.5%, a temperature of 34.5 °C, and an apple: tomato ratio of 1:1. After fermentation, the viable cell count reached 9.02 lg(CFU/mL), and the sensory evaluation score was 32.50. During the fermentation period, the pH value, total sugar, and reducing sugar decreased by 16.67%, 17.15%, and 36.05%, respectively. However, the total titratable acid (TTA), viable cell count, total phenol content (TPC), and total flavone content (TFC) increased significantly by 13.64%, 9.04%, 21.28%, and 22.22%, respectively. The antioxidant activity [2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging ability, 2,2'-azino-di(2-ethyl-benzthiazoline-sulfonic acid-6) ammonium salt (ABTS) free-radical scavenging ability, and ferric-reducing antioxidant capacity power (FRAP)] also increased by 40.91%, 22.60%, and 3.65%, respectively, during fermentation. A total of 55 volatile flavour compounds were detected using HS-SPME-GC-MS among the uninoculated samples and fermented samples before and after fermentation. The results showed that fermentation increased the types and total amount of volatile components in apple-tomato pulp, and eight new alcohols and seven new esters were formed. Alcohols, esters, and acids were the main volatile components in apple-tomato pulp, accounting for 57.39%, 10.27%, and 7.40% of the total volatile substances, respectively.

Potentially Synbiotic Yellow Mombin Beverages: Stability during Refrigerated Storage, Physicochemical Characteristics, and Sensory Properties

This study aimed to develop potentially synbiotic yellow mombin (Spondias mombin L.) beverages added with fructooligosaccharides and Lactiplantibacillus plantarum NRRL B-4496. Six formulations of yellow mombin beverages were prepared to measure the influence of fermentation and pH, which was adjustment to 4.5 for stability and quality parameters. Formulations were evaluated for probiotic survival, pH, titratable acidity, total phenolic compounds (TPC), and antioxidant activity for 28 days at 4 °C. Additionally, the proximate composition, color, sensory aspects, and survival to simulated gastrointestinal conditions were studied. At 21 days of storage, the viability of L. plantarum was 9 CFU/mL for the fermented symbiotic (SYNf) and non-fermented symbiotic with adjusted pH (SYNa) formulations. In addition, the fermented synbiotic with an adjusted pH beverage (SYNfA) showed a count of 8.2 log CFU/mL at 28 days. The formulations showed a high TPC (234-431 mg GAE/L), antioxidant activity (48-75 µM trolox), and a potential use as low-calorie beverages. The SYNf formulation showed an acceptability index higher than 70% and a high purchase intent. The SYNf and SYNa formulations maintained suitable probiotic counts after exposure to the simulated gastrointestinal digestion. Therefore, it was possible to develop a new potentially synbiotic yellow mombin beverage with a high sensory acceptance, supplying the market with a new functional food alternative.

Non-gene-editing microbiome engineering of spontaneous food fermentation microbiota-Limitation control, design control, and integration

Non-gene-editing microbiome engineering (NgeME) is the rational design and control of natural microbial consortia to perform desired functions. Traditional NgeME approaches use selected environmental variables to force natural microbial consortia to perform the desired functions. Spontaneous food fermentation, the oldest kind of traditional NgeME, transforms foods into various fermented products using natural microbial networks. In traditional NgeME, spontaneous food fermentation microbiotas (SFFMs) are typically formed and controlled manually by the establishment of limiting factors in small batches with little mechanization. However, limitation control generally leads to trade-offs between efficiency and the quality of fermentation. Modern NgeME approaches based on synthetic microbial ecology have been developed using designed microbial communities to explore assembly mechanisms and target functional enhancement of SFFMs. This has greatly improved our understanding of microbiota control, but such approaches still have shortcomings compared to traditional NgeME. Here, we comprehensively describe research on mechanisms and control strategies for SFFMs based on traditional and modern NgeME. We discuss the ecological and engineering principles of the two approaches to enhance the understanding of how best to control SFFM. We also review recent applied and theoretical research on modern NgeME and propose an integrated in vitro synthetic microbiota model to bridge gaps between limitation control and design control for SFFM.

Antimicrobial activity and mechanism of preservatives against Alicyclobacillus acidoterrestris and its application in apple juice

Alicyclobacillus acidoterrestris has great influence on the quality of apple juice products. In this study, the antibacterial activity of five preservatives (ε-polylysine, propylparaben, monocaprin, octyl gallate and heptylparaben) against A. acidoterrestris and its underlying mechanism were investigated. Results showed that these five preservatives all exerted antibacterial activity through a multiple bactericidal mechanism, and monocaprin and octyl gallate had the highest antibacterial activity, with the minimum inhibitory concentration (MIC) values of 22.5 and 6.25 mg/L, respectively. Five preservatives all changed the permeability of the cell membrane and destroyed the complete cell morphology, with the leakages of the intracellular electrolytes. Moreover, the treatment of ε-polylysine, propylparaben and monocaprin increased the leakage of intracellular protein; propylparaben and octyl gallate reduced the levels of cellular adenosine triphosphate. Also, monocaprin and octyl gallate may stimulate bacteria to release a large amount of reactive oxygen species, so that certain oxidative damage can kill the bacteria. Furthermore, monocaprin and octyl gallate could effectively inactivate the contamination of A. acidoterrestris in apple juices, with the slightly decrease of soluble sugars and organic acids, without significant adverse effects on total sugars and titratable acids. This research highlights the great promise of using monocaprin and octyl gallate as the safe multi-functionalized food additives for food preservations.

Aroma profiles of sweet cherry juice fermented by different lactic acid bacteria determined through integrated analysis of electronic nose and gas chromatography-ion mobility spectrometry

Sweet cherries are popular among consumers, with a recent explosion in sweet cherry production in China. However, the fragility of these fruits poses a challenge for expanding production and transport. With the aim of expanding the product categories of sweet cherries that can bypass these challenges, in this study, we prepared sweet cherry juice fermented by three different lactic acid bacteria (LAB; Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus rhamnosus GG), and evaluated the growth, physiochemical, and aroma characteristics. All three strains exhibited excellent growth potential in the sweet cherry juice; however, Lactobacillus acidophilus and Lactobacillus plantarum demonstrated more robust acid production capacity and higher microbial viability than Lactobacillus rhamnosus GG. Lactic acid was the primary fermentation product, and malic acid was significantly metabolized by LAB, indicating a transition in microbial metabolism from using carbohydrates to organic acids. The aroma profile was identified through integrated analysis of electronic nose (E-nose) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) data. A total of 50 volatile compounds characterized the aromatic profiles of the fermented juices by HS-GC-IMS. The flavor of sweet cherry juice changed after LAB fermentation and the fruity odor decreased overall. Lactobacillus acidophilus and Lactobacillus plantarum significantly increased 2-heptanone, ethyl acetate, and acetone contents, bringing about a creamy and rummy-like favor, whereas Lactobacillus rhamnosus GG significantly increased 2-heptanone, 3-hydroxybutan-2-one, and 2-pentanone contents, generating cheesy and buttery-like odors. Principal component analysis of GC-IMS data and linear discriminant analysis of E-nose results could effectively differentiate non-fermented sweet cherry juice and the sweet cherry juice separately inoculated with different LAB strains. Furthermore, there was a high correlation between the E-nose and GC-IMS results, providing a theoretical basis to identify different sweet cherry juice formulations and appropriate starter culture selection for fermentation. This study enables more extensive utilization of sweet cherry in the food industry and helps to improve the flavor of sweet cherry products.

Changes of Volatile Flavor Compounds in Sea Buckthorn Juice during Fermentation Based on Gas Chromatography-Ion Mobility Spectrometry

Sea buckthorn is rich in polyphenolic compounds with antioxidant activities. However, it is very sour, and its odor is slightly unpleasant, so it requires flavor improvement. Fermentation is one potential method. Sea buckthorn juice was fermented at 37 °C for 72 h and then post-fermented at 4 °C for 10 days. The flavor-related properties of the sea buckthorn juice were evaluated during fermentation, including the pH, total soluble solids (TSS), color, sensory evaluation, and volatile flavors. The sea buckthorn fermented juice had a low pH. The total soluble solids decreased from 10.60 ± 0.10% to 5.60 ± 0.12%. The total color change was not more than 20%. Fermentation increased the sweet odor of the sea buckthorn juice, but the fruity flavor decreased and the bitter flavor increased. A total of 33 volatile flavors were identified by headspace gas chromatography-ion mobility spectrometry (GC-IMS), including 24 esters, 4 alcohols, 4 terpenes, and 1 ketone. Their total relative contents were 79.63-81.67%, 10.04-11.76%, 1.56-1.22%, and 0.25-0.55%, respectively. The differences in the characteristic volatile molecular species of the sea buckthorn juice at different fermentation stages could be visually discerned using fingerprint maps. Through principal component analysis (PCA), the total flavor difference of the sea buckthorn juice at different fermentation stages could be effectively distinguished into three groups: the samples fermented for 0 h and 12 h were in one group, the samples fermented for 36 h, 48 h, 60 h, and 72 h were in another group, and the samples fermented for 24 h were in another group. It is suggested that sea buckthorn juice be fermented for 36 h to improve its flavor. GC-IMS and PCA are effective methods of identifying and distinguishing the flavor characteristics of sea buckthorn juice. The above results can provide a theoretical basis for studying the changes in sea buckthorn's characteristics as a result of fermentation, particularly with regard to its flavor.

Probiotic fermentation of polyphenols: potential sources of novel functional foods

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

Graphical abstract

Enhancement of nutritional, sensory and storage stability by lactic fermentation of Auricularia auricula

BACKGROUND

Auricularia auricula is of important nutritional value, although its utilization or consumption are mainly under the original form with no further processing. Indeed, its liquid or other fermented products contribute to improved digestion and absorption of nutrients.

RESULTS

The present study used Lactiplantibacillus plantarum to ferment A. auricula juice after an initial processing comprising superfine grinding and high-pressure homogenization. The content of probiotic bacteria in the juice of A. auricula reached 8.48 log colony-forming units mL^-1 after 24 h of fermentation under 37 °C, with the addition of 3% carbon and 0.3% nitrogen source. Meanwhile, the antioxidant activity was increased approximately two-fold, as well as the enriched volatile flavors, both effectively cover up the unwelcoming earthy smell of A. auricula. Furthermore, the storage stability was also strengthened up to 28 days.

CONCLUSION

In summary, the introduced fermentation process not only realized the purpose of improving the nutritional value of A. auricula, but also effectively upgraded the sensory evaluation of A. auricula products. © 2022 Society of Chemical Industry.

Effect of Six Lactic Acid Bacteria Strains on Physicochemical Characteristics, Antioxidant Activities and Sensory Properties of Fermented Orange Juices

Six lactic acid bacteria strains were used to study the effects on physicochemical characteristics, antioxidant activities and sensory properties of fermented orange juices. All strains exhibited good growth in orange juice. Of these fermentations, some bioactive compositions (e.g., vitamin C, shikimic acid) and aroma-active compounds (e.g., linalool, 3-carene, ethyl 3-hydroxyhexanoate, etc.) significantly increased in Lactiplantibacillus plantarum and Lactobacillus acidophilus samples. DPPH free radical scavenging rates in L. plantarum and Lacticaseibacillus paracasei samples increased to 80.25% and 77.83%, respectively. Forty-three volatile profiles were identified, including 28 aroma-active compounds. 7 key factors significantly influencing sensory flavors of the juices were revealed, including D-limonene, linalool, ethyl butyrate, ethanol, β-caryophyllene, organic acids and SSC/TA ratio. The orange juice fermented by L. paracasei, with more optimization aroma-active compounds such as D-limonene, β-caryophyllene, terpinolene and β-myrcene, exhibited more desirable aroma flavors such as orange-like, green, woody and lilac incense, and gained the highest sensory score. Generally, L. paracasei fermentation presented better aroma flavors and overall acceptability, meanwhile enhancing antioxidant activities.

Production and Shelf-Life Study of Probiotic Caja (Spondias mombin L.) Pulp Using Bifidobacterium animalis ssp. Lactis B94

The highly nutritional caja fruit (Spondias mombin L.) is an accessible source of vitamins and antioxidants that are indispensable for the human diet. The objective of the present work was to study the production of a probiotic caja pulp using Bifidobacterium animalis ssp. lactis B94. Firstly, a kinetic study was performed on the fermentation of the caja pulp with Bifidobacterium animalis ssp. lactis B94 to determine the optimum conditions of the process. Growth kinetics revealed that the ideal time for ending the fermentation would be at 22 h because it corresponds to the end of the exponential phase. Both the whole pulp and the probiotic pulp were characterized for pH, acidity, total soluble solids, water content, phenolic content, reducing carbohydrates, ascorbic acid, and total carotenoids. Physicochemical characterization revealed similar results between the whole and the probiotic pulp. The stability test demonstrated that the probiotic pulp is stable and preserved the probiotic attributes of the final product. In conclusion, our results reveal that caja pulp can be considered a favorable medium for the Bifidobacterium animalis ssp. lactis B94 growth and consequently can be explored biotechnologically for new food products.

Effects of fermentation with Lactobacillus fermentum 21828 on the nutritional characteristics and antioxidant activity of Lentinus edodes liquid

BACKGROUND

Few studies to date have evaluated the use of Lactobacillus and Bifidobacterium in edible fungus fermentation. To obtain a fermented Lentinus edodes liquid product with good taste and effects, a strain with good fermentation performance from nine strains tested was selected, and the physicochemical properties and antioxidant capacity of the resulting product were evaluated.

RESULTS

Lactobacillus fermentum 21828 exhibited adhesion, tolerance to low pH and bile salts, and good fermentation performance. The number of viable bacteria was 1.05 × 10⁸  CFU mL^-1 , and the extraction rate of crude polysaccharide from L. edodes was 2.79% after fermentation. The effects of fermentation on the contents and composition of nutrients in L. edodes liquid were marked, with changes in total soluble protein, total soluble sugar, total acid, and total phenol levels. The 2,2-diphenyl-1-picrylhydrazyl radical-scavenging rate in the fermentation liquid was 93.01%, which was significantly higher than that in non-fermented liquid (80.33%). Furthermore, analysis of volatile and 5'-nucleotide contents showed that fermentation altered the flavor of the product, whereas sensory evaluation showed that the fermented product was preferred.

CONCLUSION

Our study demonstrated that the fermented L. edodes liquid exhibited better nutritional and functional properties, as well as sensory characteristics, compared with unfermented liquid. © 2021 Society of Chemical Industry.