Lactic acid fermentation of guava juice: Evaluation of nutritional and bioactive properties, enzyme (α-amylase, α-glucosidase, and angiotensin-converting enzyme) inhibition abilities, and anti-inflammatory activities.

In the present research, the impact of fermentation with two strains of Lactiplantibacillus plantarum subsp. plantarum (PTCC 1896 and PTCC 1745) on physicochemical properties, antioxidant bioactive compounds, and some health-promoting features of guava juice was investigated. Results showed a significant (p < .05) decrease in pH, total soluble solids, glucose and fructose residues, vitamin C, and total carotenoids after 32 h of fermentation. Total phenolic content, free radical scavenging abilities, and ferrous reducing power were markedly enhanced during the fermentation process. Moreover, fermented juice represented good enzyme inhibition abilities (α-amylase and α-glucosidase) and anti-inflammatory activities. The initial amount of angiotensin-converting enzyme inhibitory activity (26.5%) increased to 72.1% and 66.4% in L. plantarum subsp. plantarum 1896 and L. plantarum subsp. plantarum 1745 treatments, respectively. These findings reveal that guava juice fermentation with the studied Lactobacillus strains can be a promising strategy to augment the functional properties of the fruit-based beverage.

Inactivation kinetics of pathogenic bacteria in persimmon using the combination of thermosonication and formic acid.

Four models (Baranyi, modified Gompertz, log-logistic and Weibull models) were applied to examine the performance of thermosonication (TS) and formic acid (FA), individually and in combination, at three temperatures (40, 50, and 60 °C) for the inactivation of pathogens inoculated on persimmon. Results indicated that all nonlinear kinetic models provided a good fit to data; however, the Baranyi showed the best performance in fitting data. The combined treatment of FA and TS had a higher negative impact on the microbial population compared to each treatment alone. The highest lethal impact was observed at 60 °C and in TS-3%FA treatment, which reduced the initial population of Escherichia coli, Salmonella enterica subsp. enterica, and Listeria monocytogenes (8.1 log CFU/mL) to 2.2, 1.6, and 1.3 log CFU/mL, respectively. Hence, the obtained models can be used to predict the inactivation of pathogens in a food model subjected to the combined treatment of thermosonication and FA.

Comparison between response surface methodology and genetic algorithm analysis to optimize lactic acid production by Lactobacillus rhamnosus and Lactobacillus acidophilus under ultrasonic pretreatment.

This work compared response surface methodology (RSM) and genetic algorithm (GA) analysis to optimize the lactic acid content by Lactobacillus rhamnosus PTCC 1637 and Lactobacillus acidophilus PTCC 1643 in a medium based on date syrup. Three parameters including concentrations of sucrose [10 and 20% (w/w)] and yeast extract [1, 2 and 3% (w/w)] along with different amplitudes of ultrasound (30 kHz, 25 and 50%) were investigated in terms of their impacts on both viable cell counts and lactic acid production. Regarding RSM and GA, optimized samples were selected by achieving high lactic acid concentration. The results indicated that an increase in the amounts of sucrose and yeast extract led to increasing the cell growth and lactic acid production. Application of ultrasound at 25% amplitude significantly (P < 0.05) stimulated the fermentation process. However, increasing the amplitude to 50% significantly (P < 0.05) decreased the lactic acid production compared with the control samples. The best treatment was observed at 20% sucrose, 3% yeast extract and 25% ultrasound amplitude. The present results indicate that the best productivity of lactic acid can be achieved at appropriate fermentation conditions, including a suitable amplitude of ultrasound and supplementation of date syrup.

Improving bioactive properties of peach juice using Lactobacillus strains fermentation: Antagonistic and anti-adhesion effects, anti-inflammatory and antioxidant properties, and Maillard reaction inhibition.

The purpose of the current study was to evaluate the antimicrobial activity of Lactobacillus acidophilus PTCC 1643 and Lactobacillus fermentum PTCC 1744 against Shigella flexneri PTCC 1865 in fermented peach juice, as well as the anti-adhesion ability on epithelial Caco-2 cells. Moreover, the biological activities of peach juice were examined. We found that the studied Lactobacillus strains effectively inhibited the growth of S. flexneri during the peach juice fermentation. In addition, L. acidophilus revealed more anti-adhesion ability than L. fermentum. The inhibition of the Maillard reaction increased from 4.10% to 36.70% and 33.00% in L. acidophilus and L. fermentum treatments, respectively. Additionally, the ferrous reducing power, superoxide anion antiradical and anti-inflammatory activities of the beverage augmented during the fermentation period. These findings may be helpful for inhibition of foodborne pathogens by Lactobacillus strains and production of fruit-based fermented beverages with high functional and nutritional value.

Bioactive edible film based on Konjac glucomannan and probiotic Lactobacillus plantarum strains: Physicochemical properties and shelf life of fresh-cut kiwis.

This study investigates the efficacy of Lactobacillus plantarum strains (L. plantarum LP3, L. plantarum AF1, and L. plantarum LU5) incorporated into a Konjac-based edible coating in order to prevent fungi growth and retain physicochemical characteristics of fresh-cut kiwis kept at 4 °C for 5 days. For this purpose, probiotic survivability, fungi counts, decay percentage, color changes, titratable acidity (TA), total soluble solids (TSS), ascorbic acid content, chlorophyll amount, total phenolics, and DPPH radical scavenging of fresh-cut kiwis were evaluated. Results indicated that the population of L. plantarum strains in all treated groups retained at sufficient amounts of probiotic consumption (above 6 and 7 log CFU/g) at the end of the storage period and L. plantarum LP3 had the highest viability in comparison to other strains. The incorporation of L. plantarum in Konjac coatings markedly reduced the amount of decay and color changes and maintained the chlorophyll and ascorbic acid contents of fresh-cut kiwis compared to control samples. After 5 days of storage, total phenol content and the DPPH antiradical activities of coated kiwi slices treated with probiotics were observed about 1.2 and 10.23 g/kg compared to the pure Konjac-coated (0.84 and 7.6 g/kg) and Konjac-uncoated samples (0.44 and 4.1 g/kg), respectively. No significant difference in TSS and TA of various treatments was detected. Coated kiwi slices loaded with probiotics had higher overall acceptability compared to Konjac-coated and control samples. In addition, probiotic treatment significantly reduced mold and yeast counts compared to the control group. PRACTICAL APPLICATIONS: Recently, edible films have received more consideration as a promising method to enhance the shelf life of fresh-cut fruit. The presence of probiotics in edible films reduces the growth of spoilage microorganisms and improves consumer health. Our findings encourage the application of edible coating incorporated with L. plantarum to design multifunctional foods and preserve the qualities of fresh-cut kiwifruit.

The efficacy of edible film from Konjac glucomannan and saffron petal extract to improve shelf life of fresh-cut cucumber.

The efficacy of saffron petal extract (SPE; 1%-4%) incorporated into Konjac glucomannan (KGM) edible films on the quality and shelf life of fresh-cut cucumbers was evaluated. Changes in chemical, physical, and microbial properties, antioxidant activity, and total soluble phenolic contents of sliced cucumbers during storage at 4°C for 5 days were investigated. Results showed that the addition of SPE markedly reduced the water vapor permeability features of produced films, whereas the moisture content and transparency of them increased (p < .05). All the formulated films containing 1%-4% of SPE exhibited significant antimicrobial properties against the examined pathogens (Escherichia coli, Shigella sonnei, Salmonella Typhi, Staphylococcus aureus, and Bacillus cereus) both in vitro and in vivo conditions. KGM films incorporated SPE were successful in reducing mesophilic bacteria and fungi populations so that the microbial load significantly decreased as the concentrations of SPE increased and KGM + 4% of SPE was considered as the most effective treatment in decreasing the microbial content of sliced cucumbers. Total soluble solids of the treated cucumbers were significantly increased at the end of the storage in refrigerator, compared to the control sample. Moreover, antioxidant activity (DPPH assay) and total soluble phenols in treated fruit increased with storage time, while these parameters decreased with increasing concentrations of SPE incorporated into KGM film. So according to the findings, the introduced film with KGM and SPE could be considered as an edible film and be applied to preserve the fruit and vegetables quality and extend the shelf life of sliced cucumbers.

Protective effects of synbiotic diets of Bacillus coagulans, Lactobacillus plantarum and inulin against acute cadmium toxicity in rats.

BACKGROUND: Cadmium is a heavy metal that causes oxidative stress and has toxic effects in humans. The aim of this study was to investigate the influence of two probiotics along with a prebiotic in preventing the toxic effects of cadmium in rats. METHODS: Twenty-four male Wistar rats were randomly divided into four groups namely control, cadmium only, cadmium along with Lactobacillus plantarum (1 × 109 CFU/day) and inulin (5% of feedstuff) and cadmium along with Bacillus coagulans (1 × 109 spore/day) and inulin (5% of feedstuff). Cadmium treated groups received 200 µg/rat/day CdCl2 administered by gavage. During the 42-day experimental period, they were weighed weekly. For evaluation of changes in oxidative stress, the levels of some biochemicals and enzymes of serum including SOD, GPX, MDA, AST, ALT, total bilirubin, BUN and creatinine, and also SOD level of livers were measured at day 21 and 42 of treatment. The cadmium content of kidney and liver was determined by using atomic absorption mass spectrophotometry. Data were analyzed using analysis of variance (ANOVA) followed by Duncan's post hoc test. RESULTS: Treatment of cadmium induced rats with synbiotic diets significantly improved the liver enzymes and biochemical parameters that decreased AST, ALT, total bilirubin, BUN and metal accumulation in the liver and kidney and increased body weight, serum and liver SOD values in comparison with the cadmium-treated group. No significant differences were observed with MDA and GPX values between all groups (p > 0.05). CONCLUSIONS: This study showed that synbiotic diets containing probiotics (L. plantarum and B. coagulans) in combination with the prebiotic (inulin) can reduce the level of cadmium in the liver and kidney, preventing their damage and recover antioxidant enzymes in acute cadmium poisoning in rat.