Variability in the acid adaptation of ten different O157:H7 and non-O157 Escherichia coli strains in orange juice and the impact on UV radiation resistance.

This study aimed to assess the impact of adaptation of ten strains of O157:H7 and non-O157 Escherichia coli to low pH (acid shock or slow acidification) and the effects of this exposure or not on the resistance of E. coli strains to UV radiation in orange juice (pH 3.5). The acid-shocked cells were obtained through culture in tryptic soy broth (TSB) with a final pH of 4.8, which was adjusted by hydrochloric, lactic, or citric acid and subsequently inoculated in orange juice at 4 °C for 30 days. No significant differences (p > 0.05) in survival in orange juice were observed between the serotypes O157:H7 and non-O157:H7 for acid-shocked experiments. After slow acidification, where the cells were cultured in TSB supplemented with glucose 1% (TSB + G), a significant increase (p < 0.05) in survival was observed for all strains evaluated. The D-values (radiation dose (J/cm2) necessary to decrease the microbial population by 90%) were determined as the inverse of the slopes of the regressions (k) obtained by plotting log (N/N0). The results show that among the strains tested, E. coli O157:H7 (303/00) and O26:H11 were the most resistant and sensitive strains, respectively. According to our results, the method of acid adaptation contributes to increasing the UV resistance for most of the strains tested.

Variations in quality attributes of pulsed light-treated table grape juice during refrigerated storage (4°C) and ambient conditions (25°C).

Pulsed light (PL) pasteurization is being explored as a substitute for the conventional thermal pasteurization of juices in recent times due to better retention of nutrients and overall quality. However, the long-term stability of the PL-pasteurized juice must be investigated to promote its application by the industry. The effect of PL treatment (effective fluence of 1.15 J·cm-2) and thermal treatment (90°C for 60 s) on microbial quality, enzyme activity, bioactive compounds, sensory acceptance, and color profile of table grape juice during storage at 4 and 25°C was investigated in this study. The PL pasteurization enhanced the microbial shelf-life of the juice (<6 log10cfu·mL-1) from 5 to 35 days at 4°C. The PL and thermally-pasteurized juice demonstrated a shelf-life of only 10 days when stored at 25°C. The total soluble solids and titratable acidity did not alter significantly throughout the storage period. The peroxidase, polyphenol oxidase, and pectin methylesterase activities were below 10% for the PL and thermally-treated beverage when stored at 4°C. The sensory acceptability of the PL-pasteurized juice after 35 days of refrigerated storage (6.9 ± 0.3) was close to the untreated juice (7.2 ± 0.3) and greater than thermally-treated juice (6.2 ± 0.2). After the 35th day of storage at 4°C, PL-treated grape juice retained 55%, 12%, and 15.3% more phenolics, flavonoids, and antioxidant capacity, respectively, than the thermally-pasteurized juice. Hence, PL pasteurization can effectively prolong the shelf-life of table grape juice while achieving microbial and enzymatic stability, along with high sensory and nutritional appeal. PRACTICAL APPLICATION: Exploring non-thermal methods like pulsed light (PL) pasteurization as a substitute for conventional thermal methods is gaining recognition for its ability to retain nutrients and improve overall juice quality. However, the industry's adoption depends on understanding the shelf-stability of PL-pasteurized juice. This study specifically investigates the practical applications of PL treatment in comparison with conventional thermal treatment in enhancing microbial safety and enzymatic stability in table grape juice. The findings contribute insights into optimizing the shelf life of table grape juice and preserving its quality, supported by microbial, enzymatic, and sensory evaluations.

Blackberry Juice Fermented with Two Consortia of Lactic Acid Bacteria and Isolated Whey: Physicochemical and Antioxidant Properties during Storage.

Fermenting fruit juices with lactic acid bacteria (LAB) is a sustainable method to enhance fruit harvests and extend shelf life. This study focused on blackberries, rich in antioxidants with proven health benefits. In this research, we examined the effects of fermentation (48 h at 37 °C) at 28 days on whey-supplemented (WH, 1:1) blackberry juice (BJ) inoculated with two LAB mixtures. Consortium 1 (BJWH/C1) included Levilactobacillus brevis, Lactiplantibacillus plantarum, and Pediococcus acidilactici, while consortium 2 (BJWH/C2) comprised Lacticaseibacillus casei and Lacticaseibacillus rhamnosus. All of the strains were previously isolated from aguamiel, pulque, and fermented milk. Throughout fermentation and storage, several parameters were evaluated, including pH, lactic acid production, viscosity, stability, reducing sugars, color, total phenolic content, anthocyanins, and antioxidant capacity. Both consortia showed a significant increase in LAB count (29-38%) after 16 h. Sample BJWH/C2 demonstrated the best kinetic characteristics, with high regression coefficients (R2 = 0.97), indicating a strong relationship between lactic acid, pH, and fermentation/storage time. Despite some fluctuations during storage, the minimum LAB count remained at 9.8 log CFU/mL, and lactic acid content increased by 95%, with good storage stability. Notably, sample BJWH/C2 increased the total phenolic content during storage. These findings suggest that adding whey enhances biomass and preserves physicochemical properties during storage.

Effect of UV LED and Pulsed Light Treatments on Polyphenol Oxidase Activity and Escherichia coli Inactivation in Apple Juice.

Enzymatic browning in fruits and vegetables, driven by polyphenol oxidase (PPO) activity, results in color changes and loss of bioactive compounds. Emerging technologies are being explored to prevent this browning and ensure microbial safety in foods. This study assessed the effectiveness of pulsed light (PL) and ultraviolet light-emitting diodes (UV-LED) in inhibiting PPO and inactivating Escherichia coli ATTC 25922 in fresh apple juice (Malus domestica var. Red Delicious). Both treatments' effects on juice quality, including bioactive compounds, color changes, and microbial inactivation, were examined. At similar doses, PL-treated samples (126 J/cm2) showed higher 2,2- diphenyl-1-picrylhydrazyl inhibition (9.5%) compared to UV-LED-treated samples (132 J/cm2), which showed 1.06%. For microbial inactivation, UV-LED achieved greater E. coli reduction (>3 log cycles) and less ascorbic acid degradation (9.4% ± 0.05) than PL. However, increasing PL doses to 176 J/cm2 resulted in more than 5 log cycles reduction of E. coli, showing a synergistic effect with the final temperature reached (55 °C). The Weibull model analyzed survival curves to evaluate inactivation kinetics. UV-LED was superior in preserving thermosensitive compounds, while PL excelled in deactivating more PPO and achieving maximal microbial inactivation more quickly.

Alicyclobacillus spp. in fruit-based products: Isolation, identification, quantitative assessment (SPME/GC-MS) of spoilage compounds and spore's resistance to thermal shocks.

Alicyclobacillus spp. is the cause of great concern for the food industry due to their spores' resistance (thermal and chemical) and the spoilage potential of some species. Despite this, not all Alicyclobacillus strains can spoil fruit juices. Thus, this study aimed to identify Alicyclobacillus spp. strains isolated from fruit-based products produced in Argentina, Brazil, and Italy by DNA sequencing. All Alicyclobacillus isolates were tested for guaiacol production by the peroxidase method. Positive strains for guaiacol production were individually inoculated at concentration of 103 CFU/mL in 10 mL of orange (pH 3.90) and apple (pH 3.50) juices adjusted to 11°Brix, following incubation at 45 °C for at least 5 days to induce the production of the following spoilage compounds: Guaiacol, 2,6-dichlorophenol (2,6-DCP) and 2,6-dibromophenol (2,6-DBP). The techniques of micro-solid phase extraction by headspace (HS-SPME) and gas-chromatography with mass spectrometry (GC-MS) were used to identify and quantify the spoilage compounds. All GC-MS data was analyzed by principal component analysis (PCA). The effects of different thermal shock conditions on the recovery of Alicyclobacillus spores inoculated in orange and apple juice (11°Brix) were also tested. A total of 484 strains were isolated from 48 brands, and the species A. acidocaldarius and A. acidoterrestris were the most found among all samples analyzed. In some samples from Argentina, the species A. vulcanalis and A. mali were also identified. The incidence of these two main species of Alicyclobacillus in this study was mainly in products from pear (n = 108; 22.3 %), peach (n = 99; 20.5 %), apple (n = 86; 17.8 %), and tomato (n = 63; 13 %). The results indicated that from the total isolates from Argentina (n = 414), Brazil (n = 54) and Italy (n = 16) were able to produce guaiacol: 107 (25.8 %), 33 (61.1 %) and 13 (81.2 %) isolates from each country, respectively. The PCA score plot indicated that the Argentina and Brazil isolates correlate with higher production of guaiacol and 2,6-DCP/2,6-DBP, respectively. Heatmaps of cell survival after heat shock demonstrated that strains with different levels of guaiacol production present different resistances according to spoilage ability. None of the Alicyclobacillus isolates survived heat shocks at 120 °C for 3 min. This work provides insights into the incidence, spoilage potential, and thermal shock resistance of Alicyclobacillus strains isolated from fruit-based products.

Cupuassu juice fermentation by Lactiplantibacillus plantarum Lp62 produces an antioxidant enriched probiotic beverage.

The present work aimed to produce a cupuassu juice (Theobroma grandiflorum) fermented by the probiotic bacterium Lactiplantibacillus plantarum Lp62 and to analyze its antioxidant potential, antimicrobial activity, and resistance to biological barriers. The fermented beverage showed an increase in the content of phenolics, flavonoids, and antioxidant potential. The culture showed antagonistic activity against pathogens, but this result was not observed when the juice was tested. The probiotic strain remained viable under refrigeration, even in an acidified environment, and survived simulated gastrointestinal transit in vitro. L. plantarum Lp62 showed 30% adherence to HT-29 intestinal cells and proved to be safe in terms of antibiotic resistance and production of virulence factors. Fermentation increased the functional characteristics of cupuassu juice. This drink proved to be a good vehicle for the delivery of the probiotic bacteria L. plantarum Lp62.

Development of a pulse-induced electrochemical biosensor based on gluconamide for Gram-negative bacteria detection.

Pathogenic bacteria can cause the outbreaks of disease and threaten human health, which stimulates the development of advanced detection techniques. Herein, a specific and sensitive electrochemical biosensor for Gram-negative bacteria was established based on the conductive polymer with artificial muscle properties.  The effective recognition was achieved through the specific carbohydrate-carbohydrate interaction between gluconamide and lipopolysaccharide.  The application of impulse voltage enhances the efficiency of recognition and shortens the detection time through the temporary deformation of the electrode surface, with a limit of detection (LOD)  of 1 × 100 CFU/mL and a linear range of 1 × 100 - 1 × 106 CFU/mL for Escherichia coli (E. coli). In addition  to the merits of low cost, high efficiency, and rapidity,  the developed label-free electrochemical biosensor can also be applicable for other Gram-negative bacteria, owning promising potential in the application of portable devices and paving a potential way for the construction of electrochemical biosensors.

Fermentation of Jamaican Cherries Juice Using Lactobacillus plantarum Elevates Antioxidant Potential and Inhibitory Activity against Type II Diabetes-Related Enzymes.

Jamaican cherry (Muntinga calabura Linn.) is tropical tree that is known to produce edible fruit with high nutritional and antioxidant properties. However, its use as functional food is still limited. Previous studies suggest that fermentation with probiotic bacteria could enhance the functional properties of non-dairy products, such as juices. In this study, we analyze the metabolite composition and activity of Jamaican cherry juice following fermentation with Lactobacillus plantarum FNCC 0027 in various substrate compositions. The metabolite profile after fermentation was analyzed using UPLC-HRMS-MS and several bioactive compounds were detected in the substrate following fermentation, including gallic acid, dihydrokaempferol, and 5,7-dihydroxyflavone. We also found that total phenolic content, antioxidant activities, and inhibition of diabetic-related enzymes were enhanced after fermentation using L. plantarum. The significance of its elevation depends on the substrate composition. Overall, our findings suggest that fermentation with L. plantarum FNCC 0027 can improve the functional activities of Jamaican cherry juice.

Antibacterial Activity of Caffeic Acid Combined with UV-A Light against Escherichia coli O157:H7, Salmonella enterica Serovar Typhimurium, and Listeria monocytogenes.

The aim of this study was to evaluate the antibacterial activity of caffeic acid (CA), which is a natural polyphenol, combined with UV-A light against the representative foodborne bacteria Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes. Data regarding the inactivation of these bacteria and its dependence on CA concentration, light wavelength, and light dose were obtained. E. coli O157:H7 and Salmonella Typhimurium were reduced to the detection limit when treated with 3 mM CA and UV-A for 3 J/cm2 and 4 J/cm2, respectively, and 5 J/cm2 treatment induced 3.10 log reduction in L. monocytogenes. To investigate the mechanism for inactivation of Salmonella Typhimurium and L. monocytogenes, measurement of polyphenol uptake, membrane damage assessment, enzymatic activity assay, and transmission electron microscopy (TEM) were conducted. It was revealed that CA was significantly (P < 0.05) absorbed by bacterial cells, and UV-A light allowed a higher uptake of CA for both pathogens. Additionally, CA plus UV-A treatment induced significant (P < 0.05) cell membrane damage. In the enzymatic activity assay, the activities of both pathogens were reduced by CA, and a greater reduction occurred by use of CA plus UV-A. Moreover, transmission electron microscopy (TEM) images indicated that CA plus UV-A treatment notably destroyed the intercellular structure. In addition, antibacterial activity was also observed in commercial apple juice, which showed results similar to those obtained from phosphate-buffered saline (PBS), resulting in a significant (P < 0.05) reduction for all three pathogens without any changes in color parameters (L*, a*, and b*), total phenolic compounds, and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity. IMPORTANCE Photodynamic inactivation (PDI), which involves photoactivation of a photosensitizer (PS), is an emerging field of study, as it effectively reduces various kinds of microorganisms. Although there are several PSs that have been used for PDI, there is a need to find naturally occurring PSs for safer application in the food industry. Caffeic acid, a natural polyphenol found in most fruits and vegetables, has recently been studied for its potential to act as a novel photosensitizer. However, no studies have been conducted regarding its antibacterial activity depending on treatment conditions and its antibacterial mechanism. In this study, we closely examined the effectiveness of caffeic acid in combination with UV-A light for inactivating representative foodborne bacteria in liquid medium. Therefore, the results of this research are expected to be utilized as basic data for future application of caffeic acid in PDI, especially when controlling pathogens in liquid food processing.

Production of probiotic wort-based beverages with grapefruit (Citrus paradisi L.) or tangerine (Citrus reticulata L.) zest essential oil addition.

BACKGROUND: In recent years, increasing health awareness in consumers has motivated breweries to expand their beverage ranges with products with increased biological value. The aim of the present research was to develop probiotic wort-based beverages with grapefruit or tangerine zest essential oil addition. METHODS: Wort was produced with 60% Pilsen malt, 20% Vienna malt and 20% Caramel Munich ІІ malt with and without the addition of 0.05% (v/v) grapefruit or tangerine essential oils. It was inoculated with the probiotic yeast strain Saccharomyces cerevisiae var. boulardii Y1. Fermentations were carried out at a constant temperature of 10°C for 5 days. The dynamics of the extract, the alcohol content and the concentration of viable cells were monitored daily. The total phenolic content, phenolic acid and flavonoid phenolic compounds were determined because of their antioxidant activity. The antioxidant activity was determined by radical scavenging assay (DPPH) and ferric reducing antioxidant power (FRAP). A descriptive organoleptic evaluation of the final beverages was performed. RESULTS: The essential oils inhibited yeast growth to some extent at the beginning of the fermentation, even at a concentration of 0.05% (v/v), which resulted in lower alcohol content in the beverages with essential oil addition. Nevertheless, at the end of fermentation the concentration of viable cells was almost equal in all the beverages. Tangerine essential oil addition led to the highest content of phenolics, of which phenolic acids predominated. Therefore, the highest antioxidant activity of the beverage with tangerine essential oil can be ascribed to phenolic acids. The results of the sensorial evaluation also showed that the panel had preference towards the beverage with tangerine essential oil. CONCLUSIONS: The combination of essential oil and the probiotic yeast strain resulted in beverages with higher biological value than the beverages produced with the probiotic strain alone. The results obtained will be used for optimisation of process variables in the production of pilot-scale wort-based probiotic beverages with essential oil addition.

Cloudy Apple Juice Fermented by Lactobacillus Prevents Obesity via Modulating Gut Microbiota and Protecting Intestinal Tract Health.

Obesity and hyperglycemia are two serious chronic diseases that are increasing in incidence worldwide. This research aimed to develop a fermented cloudy apple juice with good hyperglycemia intervention activities. Here, cloudy apple juice (CAJ), cloudy apple juice rich in polyphenols (CAJP) and fermented cloudy apple juice rich in polyphenols (FCAJP) were prepared sequentially, and then the effects of the three apple juices on weight, lipid level, gut microbiota composition and intestinal tract health were evaluated for obese mice induced by a high-fat diet. The research findings revealed that the FCAJP showed potential to inhibit the weight gain of mice, reduce fat accumulation, and regulate the blood lipid levels of obese mice by decreasing the ratio of the Firmicutes/Bacteroidotas, improving the Sobs, Ace, and Chao indexes of the gut microbiota and protecting intestinal tract health. In addition, the FCAJP augmented the abundance of Akkermansia and Bacteroides, which were positively related to SCFAs in cecal contents. This study inferred that FCAJP could be developed as a healthy food for preventing obesity and hyperglycemia.

Fermentation of blueberry and blackberry juices using Lactobacillus plantarum, Streptococcus thermophilus and Bifidobacterium bifidum: Growth of probiotics, metabolism of phenolics, antioxidant capacity in vitro and sensory evaluation.

In this study, three potential probiotic strains were selected to ferment blueberry and blackberry juices. The viable cell counts of selected strains were increased by 0.4-0.7 log CFU/mL in berry juices environments after 48-h fermentation. Meanwhile, the contents of cyanindin-3-glucoside and peonidin-3-glucoside decreased over 30%. Heatmap presented an upgrade trend of syringic acid, ferulic acid, gallic acid and lactic acid during fermentation. However, the contents of p-coumaric acid, protocatechuic acid, chlorogenic acid, critic acid and malic acid showed downgrade trend. The metabolism of phenolics probably contributed to the enhancement of the ABTS radical scavenging activity (40%-60%) in fermented berry juices. Moreover, the three strains presented different capacities on changing the quality of berry juices according to the PCA and LDA analysis. The contents of individual organic acids had positive correlations with sensory quality, especially for sourness. Overall, probiotic fermentation could improve the sensory quality of berry juices.

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.

Control of the growth of Alicyclobacillus acidoterrestris in industrialized orange juice using rosemary essential oil and nisin.

The use of rosemary essential oil (RO) and its combination with nisin (RO+N) in preventing the multiplication of Alicyclobacillus acidoterrestris in orange juice was evaluated. The minimum inhibitory and bactericidal concentrations (MIC and MBC) for RO were both 125 µg ml-1 while RO+N displayed a synergistic effect. The use of RO and RO+N at concentrations of 1, 4 and 8× MIC in orange juice for 96 h was evaluated in terms of their sporicidal effectiveness. With regard to the action against A. acidoterrestris spores, RO at 8× MIC was sporostatic, whereas RO+N at 1× MIC was sporicidal. Morphological changes in the structure of the micro-organism after treatment were also observed by microscopy. Furthermore, flow cytometric analysis showed that most cells were damaged or killed after treatment. In general, the antioxidant activity after addition of RO+N decreased with time. The results demonstrate that using the combination of RO and nisin can prevent the A. acidoterrestris growth in orange juice.

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

The objective of this study was to investigate the effects of four commercial lactic acid bacteria (LAB), namely L. acidophilus, L. casei, L. helveticus and L. plantarum, on the phenolic profiles, antioxidant capacities and flavor profiles of jujube juices prepared from two crop varieties (Ziziphus Jujuba cv. Muzao and Hetian). Results showed that both jujube juices were excellent matrices for LAB growth with more than 11 log CFU/mL of viable counts at the end of fermentation. LAB fermentation dramatically increased total phenolic content, while decreased total flavonoid content of jujube juices. However, antioxidant capacities based on DPPH and FRAP methods were significantly improved by LAB fermentation and positively correlated with caffeic acid and rutin contents. Furthermore, a total of 74 volatile compounds were identified and increased in total content by LAB fermentation, which resulted in 22 and 19 new flavor volatiles formation in Muzao juice and Hetian juice, respectively.

Metabolic extract of the endophytic fungus Flavodon flavus isolated from Justicia brandegeana in the control of Alicyclobacillus acidoterrestris in commercial orange juice.

In this work, the antibacterial activity of a crude extract of the endophytic fungus Flavodon flavus (JB257), isolated from leaves of Justicia brandegeana, was evaluated against both the vegetative and sporulated forms of Alicyclobacillus acidoterrestris. The microdilution technique was performed in order to determine the antibacterial activity of the crude extract alone as well as in combination with the bacteriocin, nisin. The minimum inhibitory concentration (MIC) of the crude extract and nisin alone against A. acidoterrestris vegetative forms were 250 µg/mL and 31.5 µg/mL, respectively, while the minimum bactericidal concentrations (MBC) were 1000 µg/mL and 62.5 µg/mL,respectively. For A. acidoterrestris spores, treatment with the crude extract at a concentration of 500 µg/mL caused a 47% reduction in growth, while nisin at 62.5 µg/mL could reduce 100% of the growth. The in vitro evaluation of the crude extract combined with nisin against A. acidoterrestris by the Checkerboard method showed a synergistic interaction between the two compounds. In addition, greater selectivity towards bacterial cells over host cells, a human hepatocyte cell line, was achieved when the crude extract was combined with nisin, Using scanning electron microscopy, interferences in the cell membrane of A. acidoterrestris could be observed after treatment with the crude extract. The results presented in this study indicate that the crude extract of the endophyte F. flavus has biotechnological potential in the food industry, especially for the treatment of orange juices through the control of A. acidoterrestris.

Sea buckthorn (Hippophae rhamnoides L.) fermentation liquid protects against alcoholic liver disease linked to regulation of liver metabolome and the abundance of gut microbiota.

BACKGROUND: Alcoholic liver disease (ALD) refers to liver damage caused by long-term heavy drinking, which causes oxidative stress and changes in gut microbiota. In this paper, we investigated the hepatoprotective effect of sea buckthorn fermentation liquid on ALD in mice and the interaction between ALD and gut microbiota using animal experiments and gut microbiota measurements. RESULTS: We found that the contents of total flavonoids, total triterpenes and related short-chain fatty acids (SCFAs) in sea buckthorn fermentation liquid (SFL) were significantly greater. Liver index, kidney index, spleen index, serum indexes of liver injury - alanine aminotransferase (ALT) and spartate aminotransferase (AST), inflammatory factors in liver tissues - tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), oxidation indexes - malondialdehyde (MDA) and superoxide dismutase (SOD), and lipid metabolism indexes - high-density liptein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and triglyceride (TG), suggested that SFL significantly ameliorates liver injury caused by alcohol. By measuring gut microbiota in mice feces samples, we found that the high-dose group of SFL reversed the declining trend of the gut microbiota Firmicutes/Bacteroidetes (F/B) ratio caused by alcohol, reducing the number of gram-negative bacteroidetes. Patescibacteria was tightly connected with the indicators of ALD. At the genus level, high-dose SFL significantly downregulated Akkermansia, Turicibacter, Alistipes and Ruminiclostridium, and improved the abundance of beneficial bacteria in Lactobacillus. In addition, Alistipes and Ruminiclostridium was closely connected with the indicators of ALD. CONCLUSION: Sea buckthorn fermentation liquid protected against alcoholic liver disease and modulated the composition of gut microbiota. © 2020 Society of Chemical Industry.

Evaluation of fermentation assisted by Lactobacillus brevis POM, and Lactobacillus plantarum (TR-7, TR-71, TR-14) on antioxidant compounds and organic acids of an orange juice-milk based beverage.

The impact of fermentation assisted by four different lactic acid bacteria (LAB) on polyphenols, carotenoids, organic acids, and antioxidant capacity of orange-juice milk based beverages was evaluated. Lactobacillus brevis POM, and Lactobacillus plantarum (TR-7, TR-71, TR-14) were used to promote the fermentation of the beverages for 72 h at 37 °C. The bacteria population increased with the elapse of fermentation period, except for beverages inoculated with L. plantarum TR-7. After fermentation period, total polyphenols, total carotenoids and total antioxidant capacity were increased compared to the control ones (non-fermented). Two phenolic acids (DL-3-phenylactic acid and 3-4-dihydroxyhydrocinnamic acid) and lactic acid were identified after 72 h fermentation. Overall, it is possible to conclude that orange-juice milk beverages are a good medium for the growth of L. brevis POM, and L. plantarum (TR-71, TR-14), observing higher antioxidant properties in the fermented beverages compared to the control ones.

Inactivation of Listeria monocytogenes and Salmonella Typhimurium in strawberry juice enriched with strawberry polyphenols.

BACKGROUND: Low molecular-weight phenolic fractions (LMPFs) were extracted from Albion (LMPF-A) and Camarosa (LMPF-C) strawberry cultivars. Their antibacterial activity against Listeria monocytogenes and Salmonella Typhimurium cocktails in vitro and in vivo was investigated using strawberry juice as a food model. This study also sought to determine their antibacterial mechanism. RESULTS: Quercetin was identified as a principal compound in both phenolic fractions. The minimum bactericide concentration (MBC) values were 750 and 850 µg mL-1 (LMPF-C) and 800 and 950 µg mL-1 (LMPF-A) against S.Typhimurium and L. monocytogenes, respectively. The possible antibacterial activity of the phenolic extracts could be related to the release of phosphate and potassium ions, the effect of the disruption of membrane integrity on L. monocytogenes, and the effect of the inhibition of dihydronicotinamide adenine dinucleotide (NADH) oxidase activity on S. Typhimurium. Quercetin and kaempferol were the most active compounds in producing bacterial damage. Strawberry juice supplemented with the phenolic fractions and incubated at 37, 20, and 4 °C reduced bacterial viability; moreover, after treatment with the phenolic fraction at the lowest temperature, no viable cells were detected after 7 days' incubation. Salmonella was more sensitive to the supplements than Listeria in strawberry juice. CONCLUSIONS: This study could form the basis for the development of natural antibacterial agents that could be included in natural juice or used by the pharmaceutical industry. © 2020 Society of Chemical Industry.

Modeling the inactivation of Aspergillus fischeri and Paecilomyces niveus ascospores in apple juice by different ultraviolet light irradiances.

The present work aimed to evaluate and to model the influence of UV-C light treatments with different irradiances (6.5, 13, 21, and 36 W/m2) on Aspergillus fischeri and Paecilomyces niveus ascospores inactivation in clarified apple juice. Approximately 5.0 and 6.0 log CFU/mL spores of P. niveus and A. fischeri, respectively, were suspended in 30 mL of clarified apple juice (pH 3.8, 12 ± 0.1°Brix) and exposed to UV-C light at different irradiances (as above) and exposure times (0 to 30 min). The first-order biphasic model was able to describe the experimental data with good statistical indices (RMSE = 0.296 and 0.308, R2 = 0.96 and 0.98, for P. niveus and A. fischeri respectively). At the highest irradiance level tested (36 W/m2), the UV-C light allowed the reduction of 5.7 and 4.2 log-cycles of A. fischeri and P. niveus ascospores, respectively, in approximately 10 min. P. niveus was the most UV-C resistant mould. The results showed that, to a defined UV-C fluence, a change in the level of either time or UV-C irradiance did not affect the effectiveness of UV-C light for A. fischeri and P. niveus inactivation. Thus, the modeling of the inactivation as a function of the UV-C fluence allowed the estimation of the primary model parameters with all experimental data and, consequently, no secondary models were needed. The model parameters were validated with experiments of variable UV-C fluences. Accordingly, experimental results allowed to conclude that UV-C treatment at the irradiances tested is a promising application for preventing A. fischeri and P. niveus spoilage of juices.