Understanding starch gelatinization and rheology modeling of tapioca starch- NaCl/CaCl2 blends: Thermodynamic properties and gelatinization reaction kinetics during pre- and post-ultrasonication.

The presence of salt can impact the fluid phase and gelatinization process of starch granules. The variation in viscosity and rheology models including the Herschel-Bulkley, the Casson model, and the power law, were determined by adding salts before and after starch ultrasonication. Non-isothermal kinetics can be utilized for the mathematical modeling of the gelatinization process and the evolution of the reaction. Unlike Na+ ions, Ca+2 ions notably elevate viscosity. The Casson model accurately predicts viscosity data. Results indicate that the addition of Na+ ions decreases yield stress by up to 60.4 %, while Ca+2 ions increase by up to 100.8 %. Adding Na+ ions decreases the required thermal energy by as much as 49.6 %, while the presence of Ca+2 ions can lead to a substantial increase of up to 337.1 % compared to control samples. The positive ∆G indicates a non-spontaneous gelatinization process. The addition of NaCl promotes a spontaneous reaction, while the addition of CaCl2 increases the Gibbs energy. The changes in entropy are minimal, implying minimal changes in starches' disorder structure.

Effect of ultrasound geometry on the production efficiency of damaged starch: Determining rheology parameters, and non-isothermal reaction kinetics.

Present study investigates the effects of probe size geometry on thermodynamic kinetics, rheology, and microstructure of wheat and tapioca starch. Ultrasound treatment using different probe diameters (20 mm and 100 mm) significantly influenced the gelatinization process. Results showed reduced enthalpy (ΔH) and Gibbs energy (ΔG), indicating enhanced gelatinization efficiency. According to the results, using a 20 mm and 100 mm probe leads to a reduction of 52.7 % and 68.6 % in reaction enthalpy for wheat starch compared to native starch, respectively. Microstructure analysis revealed structural changes, with ultrasound treatment leading to granular fractures and a sheet-like structure with air bubbles. The rheological behavior of the starches is found to exhibit shear thinning behavior, with the Casson model providing the best fit for the experimental data. Moreover, rheology modeling using Herschel-Bulkley and power law models showed increased viscosity and shear stress in larger probes. Numerical simulation data demonstrated that probe size influenced ultrasonic pressure, sound pressure level, and thermal power dissipation density, affecting fluid motion and velocity field components. Moreover, the maximum dissipated power decreases from 8.43 to 0.655 mW/m3 with an increase in probe diameter from 20 to 100 mm. The average yield shear stress values are calculated as 3.36 and 3.14 for wheat and tapioca starches, respectively. The larger probe diameter leads to greater entropy increases, with tapioca starch showing a 4.72 % increase and wheat starch a 4.97 % increase, compared to 2.56 % and 3.11 %, respectively, with the smaller probe. Additionally, the Keller-Miksis model provided insights into bubble dynamics, revealing increased pressure and temperature with higher pressure amplitudes.

Thermodynamics, kinetics, and computational fluid dynamics modeling of Escherichia coli and Salmonella Typhi inactivation during the thermosonication process of celery juice.

In this study, thermosonication (37 KHz, 300 W; 50, 60, and 70 °C) of celery juice was performed to inactivate Escherichia coli and Salmonella Typhi in 6 min. The inactivation of pathogens and the process were modeled using mathematical, thermodynamic, and computational fluid dynamics models. The findings indicated that the distribution of power dissipation density was not uniform across the entire domain, including the beaker area, with a maximum value of 27.8 × 103 W/m3. At lower temperatures, E. coli showed a 9.4 % higher resistance to sonication, while at higher temperatures, S. Typhi had a 5.4 % higher durability than E. coli. Increasing the temperature decreased the maximum inactivation rate of both S. Typhi and E. coli by 15.5 % and 20.5 % respectively, while increasing the thermal level by 20 °C reduced the log time to achieve the maximum inactivation rate by 20.3 % and 34.9 % for S. Typhi and E. coli respectively, highlighting the stronger effect of sonication at higher temperatures. According to the results, the positive magnitudes of ΔG were observed in both E. coli and S. Typhi, indicating a similar range of variations. Additionally, the magnitude of ΔG increased by approximately 5.2 to 5.5 % for both microorganisms which suggested the inactivation process was not spontaneous.

Investigation of ultrasound-assisted starch acetylation by single- and dual- frequency ultrasound based on rheology modelling, non-isothermal reaction kinetics, and flow/acoustic simulation.

To achieve wheat starch acetylation (AC) with a high degree of substitution (DS), the acetylation process was carried out using various ultrasonication frequencies, including 25 kHz, 40 kHz, and 25 + 40 kHz. In the second step, wheat starch's ultrasound-assisted acetylation (UAA) is simulated using various approaches including the rheology models, non-isothermal reaction kinetics, and flow/acoustic modelling. The computational fluid dynamics (CFD) simulation solves the non-linear acoustic governing equation to determine the flow field and the amount of delivered ultrasound energy. The acetylated starch increased peak and final viscosity, with the highest values observed for the 25 + 40 kHz frequency than other single frequencies (25 kHz and 40 kHz). The viscosity of the starch is specified based on the experimental data using Herschel-Bulkley, power law, and Casson rheology models. According to differential scanning calorimetry (DSC) analysis, the gelatinization parameters and enthalpy of gelatinization (ΔHgel), were found to be lower in acetylated starches at the frequency of 25 + 40 kHz compared to those at frequencies of 25 kHz and 40 kHz, as well as native starches (NS). Moreover, the gelatinization process is examined by implementing the non-isothermal reaction kinetics to obtain the activation energy and reaction order. Based on the results obtained, implementing sonication at 25 kHz reduces the activation energy by 70.3 % compared to native starch. However, the same parameter is obtained to be 69.9 % and 67.1 % for the application of 40 and 25 + 40 kHz transducers, respectively. Additionally, during the sonication treatment, the yield shear stress increases between 24.1 and 31.8 %, based on the applied frequency. Morphology analysis determined by scanning electron microscopy (SEM) revealed that the surfaces and small granules underwent more damage in acetylated starches at frequencies of 25 kHz and 40 kHz. However, in acetylated starches at 25 + 40 kHz, the larger granules were more affected than the smaller ones.

Impact of ultrasonicated Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactiplantibacillus plantarum AF1 on the safety and bioactive properties of stirred yoghurt during storage.

In this study, the effects of ultrasonicated Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactiplantibacillus plantarum AF1 (100 W, 30 kHz, 3 min) on the safety and bioactive properties of stirred yoghurt during storage (4 °C for 21 days) were investigated. The results showed that sonicated cultures were more effective in reducing pathogens than untreated ones. The highest antioxidant activity (DPPH and ABTS), α-glucosidase and α-amylase inhibition capacity were found in yoghurt containing sonicated probiotic + sonicated yoghurt starter cultures (P + Y + ). The highest amount of peptides (12.4 mg/g) was found in P + Y + yoghurts at the end of the storage time. There were not significant differences between the exopolysaccharide content of P + Y+ (17.30 mg/L) and P + Y- (17.20 mg/L) yoghurts, although it was significantly (P ≤ 0.05) higher than the other samples. The use of ultrasonicated cultures could enhance the safety of stirred yoghurt and improve its functional and bioactive properties.

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.

Gliadin and glutenin genomes and their effects on the technological aspect of wheat-based products.

Wheat is the most important crops worldwide, providing about one-fifth of the daily protein and calories for human consumption. The quality of cereal-based products is principally governed by the genetic basis of gluten (glutenin and gliadin proteins), which exists in a wide range of variable alleles and is controlled by clusters of genes. There are certain limitations associated with gluten characteristics, which can be genetically manipulated. The present review aimed to investigate the correlation between the genetic characteristics of gluten protein components and wheat-based product's quality. According to various references, Glu-B1d (6 + 8), Glu-B1h (14 + 15) and Glu-B1b (7 + 8) are related to higher gluten strength and pasta quality, while, subunits Dx2 + Dy12 and Dx5 + Dy10, are usually present at the Glu-D1 locus in bread wheat, resulted in lower cooked firmness in pasta. Moreover, introducing Gli-D1/Glu-D3 and Glu-D1 loci into durum wheat genomes, causing to provide the maximum values of gluten index in pasta products. 1Dx5 + 1Dy10 alleles determine the level of increase in dough's consistency, elasticity, viscosity, and extensibility quality of baking and appropriate bread loaf volume, while 1Dx2 + 1Dy12 as the alleles associated with poor baking quality, being more suitable for soft wheat/pastry end uses. Bx7, Bx7OE, 1Bx17 + 1By18, 1Bx13 + 1By16, Bx7 + By9 and 1Bx7 + 1By8 at Glu-B1alleles and 1Ax2* found on Glu-A1, augmented dough strength and has positive effects on consistency, extensibility, viscosity, and elasticity of bread dough. Breeding programs by genome editing have made gluten a promoting component for improving cereal-based products.

Inactivation of Foodborne Pathogens by Lactiplantibacillus Strains during Meat Fermentation: Kinetics and Mathematical Modelling.

This study examined the effect of beef fermentation with Lactiplantibacillus paraplantarum (L) PTCC 1965, Lactiplantibacillus (L) plantarum subsp. plantarum PTCC 1745, and Lactiplantibacillus (L) pentosus PTCC 1872 bacteria on the growth of pathogenic bacteria, including Salmonella (S) Typhi PTCC 1609 and Staphylococcus (S) aureus PTCC 1826. The growth of lactic acid bacteria (LAB) and the effect of fermentation on pathogenic bacteria were studied using Weibull: biphasic linear and competitive models. The results showed that the rate of pH reduction was lower in the early stages and increased as the microbial population grew. The α parameter was lower for L. plantarum subsp. plantarum compared to L. paraplantarum and L. pentosus. The comparison of the α parameter for bacterial growth and pH data showed that the time interval required to initiate the rapid growth phase of the bacteria was much shorter than that for the rapid pH reduction phase. The pH value had a 50% greater effect on the inactivation of S. Typhi when compared to the samples containing L. plantarum subsp. plantarum and L. pentosus. The same parameter was reported to be 72% for the inactivation of St. aureus. In general, during the fermentation process, LAB strains caused a decrease in pH, and as a result, reduced the growth of pathogens, which improves consumer health and increases the food safety of fermented meat.

Polysaccharide-Based Edible Films/Coatings for the Preservation of Meat and Fish Products: Emphasis on Incorporation of Lipid-Based Nanosystems Loaded with Bioactive Compounds.

The high water and nutritional contents of meat and fish products make them susceptible to spoilage. Thus, one of the most important challenges faced by the meat industry is extending the shelf life of meat and fish products. In recent years, increasing concerns associated with synthetic compounds on health have limited their application in food formulations. Thus, there is a great need for natural bioactive compounds. Direct use of these compounds in the food industry has faced different obstacles due to their hydrophobic nature, high volatility, and sensitivity to processing and environmental conditions. Nanotechnology is a promising method for overcoming these challenges. Thus, this article aims to review the recent knowledge about the effect of biopolymer-based edible films or coatings on the shelf life of meat and fish products. This study begins by discussing the effect of biopolymer (pectin, alginate, and chitosan) based edible films or coatings on the oxidation stability and microbial growth of meat products. This is followed by an overview of the nano-encapsulation systems (nano-emulsions and nanoliposomes) and the effect of edible films or coatings incorporated with nanosystems on the shelf life of meat and fish products.

Rosmarinus officinalis L. Essential Oils Impact on the Microbiological and Oxidative Stability of Sarshir (Kaymak).

This study investigated the effect of Rosmarinus officinalis L. essential oil, REO (one, two and three percent) on the microbiological and oxidative stability of Sarshir during 20 days of refrigerated storage (4 °C). Initially, the chemical composition (gas chromatography/mass spectrometry, GC/MS), antimicrobial (paper disc diffusion) and antioxidant (DPPH) properties of REO were evaluated. Then, the microbial safety, oxidative stability (peroxide and anisidine values) and overall acceptability of the product after addition of REO to Sarshir and the subsequent storage period were determined. According to GC/MS analysis, the major components of REO were α-pinene (24.6%), 1,8-cineole (14.1%), camphor (13.5%), camphene (8.1%) and limonene (6.1%), respectively. Moreover, it was also found that Limosilactobacillus fermentum (inhibition zone (IZ) of 23.5 mm) and Salmonella Typhi (IZ of 16.4 mm) were the most sensitive and resistant spoilage and pathogenic bacteria against REO, respectively. In addition, the half-maximal inhibitory concentration (IC50) of the REO was measured at 24.8 mg/mL, while the IC50 value of butylated hydroxytoluene (BHT) was 16.6 mg/mL. The highest and lowest bacterial populations were detected in the control and the sample containing 3% REO, respectively. The control had the highest extent of lipid oxidation, while the lowest peroxide and anisidine values were measured in Sarshir containing 3% REO.

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.

Sonication treatment of pomegranate juice containing Saccharomyces cerevisiae and Byssochlamys fulva: Thermodynamic and predictive modeling after treatment and during shelf life.

The effect of ultrasound treatment (100 W, 30 kHz; 50 and 100% amplitudes) on inactivation of Saccharomyces cerevisiae and Byssochlamys fulva in pomegranate juice and shelf life of the juice during storage at different temperatures (5, 15 and 30 °C) for 30 days was modeled using predictive and thermodynamics models. The Baranyi and square root type models were implemented to determine the growth rate of microorganisms. It was predicted that the minimum growth temperature (Tmin) of B. fulva increased by increasing sonication amplitude, however, the Tmin of S. cerevisiae was not function of sonication amplitude. The predicted shelf life was shown to be in good agreement with the measured sensorial shelf life. Increasing the temperature from 5 to 35 °C, reduced the shelf life from 17.5 to 3.5 days for B. fulva and from 15 to 5 days for S. cerevisiae. Moreover, for B. fulva, the activation energy (Ea) decreased from 43.4 to 27.5 kJ/mol by increasing the amplitude, while no significant change was observed for S. cerevisiae. Besides, thermodynamics properties of the shelf life such as enthalpy (ΔH++), entropy (ΔS++) and Gibbs free energy (ΔG++)  were proven to be suitable measures to determine the microbial spoilage reaction.

A kinetic analysis of the aflatoxin detoxification potential of lactic acid bacteria in Terxine (a cereal-based food).

Aflatoxin B1 (AFB1) is a hazardous component that can seriously threaten the public health. Terxine is a component used in traditional soup and found in the western mountainous regions of Iran. Several microorganisms have been reported to bind or degrade aflatoxins (AFs) in foods and feeds. This research aimed to investigate the effect of Terxine fermentation by Lactobacillus plantarum strains AF1 and LU5 on AFB1. Fermentation was carried out, and pH, lactic acid and AFB1 amount and microbial count were further determined. In addition, the kinetic experimental data of AFB1 by L. plantarum AF1 and LU5 (obtained at 37°C) were fitted to the zero-order, first-order and parabolic diffusion models. According to the coefficient of determination (R2) and root mean square of errors (RMSE), the zero-order model best described AF degradation. The growth of Lactobacillus strains was increased by the rise in the fermentation time; in this regard, the number of L. plantarum AF1 increased from 4.2 to 5.1 log cfu/g and that of L. plantarum LU5 increased from 4.1 to 5.2 log cfu/g in the first 8 h, reaching 7.2 and 7.4 log cfu/g in the next 8 h, respectively. The results also showed that the amount of lactic acid increased whereas the pH value decreased during the 24 h fermentation. Both microorganisms reduced the amount of AFB1 while L. plantarum AF1 was more effective. Therefore, L. plantarum strains AF1 and LU5 can be effectively used to reduce AFB1 in fermented foods.

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.

Chemical composition, antimicrobial, antioxidant and cytotoxic activity of the essential oil from the leaves of Stachys pilifera Benth.

Stachys pilifera Benth is an endemic species of Stachys family found in Iran with a wide application as an herbal tea. The objective of this research was to evaluate the antimicrobial, antioxidant and cytotoxic activity of the essential oil from the aerial parts of S. pilifera. Essential oil (EO) composition analysis showed that cis-Chrysanthenyl acetate (24.9%), viridiflorol (18.3%), trans-Caryophyllene (9.8%), caryophyllene oxide (4.6%), α-terpineol (3.3%) and linalool (3.1%) were the most abundant components. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the EO showed a higher antimicrobial activity against Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) than Gram-negative organisms (Escherichia coli, Shigella sonnei, Pseudomonas aeruginosa and Salmonella enterica subsp. Enterica). The antioxidant activity of EO was studied using DPPH, FRAP and ß-carotene/linoleic acid assays. IC50 for the DPPH, FRAP and ß-carotene/linoleic acid tests were 23.2, 28.7 and 16.1 µg/mL, respectively, that it was higher than the results for BHT (P ≤ 0.05). The cytotoxic activity of the EO was evaluated using HT29 and HUVEC cells and it was observed that by increasing in EO concentration from 0.026 to 19.4 ug/mL, the viability of the cells for HT29 and HUVEC reduced to 6.8 and 7.1%, respectively. The results from this study suggest the possibility to use the essential oils from S. pilifera Benth as a natural preservative in processed or packaged food due to its high antibacterial, antioxidant and cytotoxic activities.

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.

Antimicrobial activity of Satureja Khuzestanica Jamzad and Satureja bachtiarica Bunge essential oils against Shigella flexneri and Escherichia coli in table cream containing Lactobacillus plantarum LU5.

The essential oils (EOs) from Marzeh khuzestani (Satureja Khuzestanica Jamzad) and Marzeh bakhtiari (Satureja bachtiarica Bunge) were analyzed and their antibacterial activities on Shigella flexneri and Escherichia coli in probiotic table cream containing Lactobacillus plantarum LU5 were evaluated. Carvacrol (86.5%) was the main component of Marzeh khuzestani, but thymol (33.5%), carvacrol (14.2%), borneol (13.4%), and linalool (11.5%) were the major constituents of Marzeh Bakhtiari EOs. Marzeh khuzestani exhibited the highest antibacterial/bactericidal activity on the tested bacteria. EOs combination showed no interaction on the L. plantarum but a synergism effect to inhibit the pathogen strains observed. Agar diffusion assay showed the highest inhibitory effect on S. flexneri (32.7 mm), E. coli (28.4 mm), and L. plantarum (24.7 mm) for the combination 2:1 Marzeh khuzestani:Marzeh Bakhtiari (p ≤ .05). The antibacterial activity of mixture of EOs in creams was evaluated and the sample contained of 1%k + 1%b showed the highest antibacterial activity after day 10 of storage (by lowering the number of E. coli, S. flexneri, and L. plantarum to 2.3, 1.9, and 1.4 log CFU/g compared to control sample). Overall acceptability of creams slightly decreased by the increase in EOs addition and the highest acceptability score of 7.9 observed for the sample contained 0.5%k + 0.5%b EOs. However, all treatments exhibited a high acceptance level that it confirms that the addition of EOs mixture had no effect on the sensorial attributes of the creams. The combination of tested EOs can be used as an antimicrobial agent in probiotic food products containing L. plantarum.

Lactic acid production - producing microorganisms and substrates sources-state of art.

Lactic acid is an organic compound produced via fermentation by different microorganisms that are able to use different carbohydrate sources. Lactic acid bacteria are the main bacteria used to produce lactic acid and among these, Lactobacillus spp. have been showing interesting fermentation capacities. The use of Bacillus spp. revealed good possibilities to reduce the fermentative costs. Interestingly, lactic acid high productivity was achieved by Corynebacterium glutamicum and E. coli, mainly after engineering genetic modification. Fungi, like Rhizopus spp. can metabolize different renewable carbon resources, with advantageously amylolytic properties to produce lactic acid. Additionally, yeasts can tolerate environmental restrictions (for example acidic conditions), being the wild-type low lactic acid producers that have been improved by genetic manipulation. Microalgae and cyanobacteria, as photosynthetic microorganisms can be an alternative lactic acid producer without carbohydrate feed costs. For lactic acid production, it is necessary to have substrates in the fermentation medium. Different carbohydrate sources can be used, from plant waste as molasses, starchy, lignocellulosic materials as agricultural and forestry residues. Dairy waste also can be used by the addition of supplementary components with a nitrogen source.

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.