Antimicrobial effects of Kelussia odoratissima extracts against food borne and food spoilage bacteria "in vitro"

The aim of this paper was to investigate the antibacterial potential of Kelussia odoratissima Mozff extract against Gram-negative and Gram-positive bacteria. Karafs-eKoohi with the scientific name of Kelussia odoratissima is an Iranian endemic edible plant in the middle region of Iran with enormous use as food, spice and medicinal herb. The antibacterial effect of the extracts was investigated using pour plate and disk diffusion methods. Minimum Inhibitory Concentration (MIC( and Minimum Bactericidal Concentration (MBC) were also studied using the dilution method. Repeated measure ANOVA was used for data analysis. The results showed that in disk diffusion method all concentrations of ethanolic extract had inhibitory effect against Bacillus subtilis and Staphylococcus aureus. Minimum Inhibitory Concentration (MIC( of Kelussia odoratissima leaves of aqueous and ethanolic extracts for Bacillus subtilis and Staphylococcus aureus were 16 and 8 mg/ml, and for Enterobacter aerogenes were 32 and 16 mg/ml, respectively. Minimum Bactericidal Concentration (MBC) of Kelussia odoratissima leaves of aqueous and ethanolic extracts for Bacillus subtilis and Staphylococcus aureus were 32 and 16 mg/ml, and for Enterobacter aerogenes were 64 and 32mg/ml, respectively. The results showed that the extract of Kelussia odoratissima had a satisfactory antimicrobial activity and the ethanolic extract of Kelussia odoratissima leaves had greater inhibitory effects on the strains studied compared to aqueous extract in vitro. A significant correlation was also observed between zone of inhibition and concentration of extracts

Antifungal potential of mangrove extracts against Aspergillus flavus and Penicillium italicum

      The interest in plants antimicrobial properties has been revived because of the current problems associated with the use of antibiotics. Nowadays, the fact that microorganisms tend to develop drug resistance, besides the side effects of certain antibiotics has offered considerable potentials for the development of new effective antifungal and antioxidant agents; medicinal plants are prolific sources. Avicennia marina, commonly known as grey mangrove, is a species of mangrove tree classified in the plant family Acanthaceae. The aim of this experimental study is determination of antifungal effect of the aqueous and ethanolic extracts of Avicennia marina on Aspergillus flavus and Penicillium italicum ”in vitro”. In this study, quantitative bioassay was done using disc diffusion method, Minimum Inhibition Concentration (MIC) and Minimum Fungicidal Concentration (MFC) was carried out using broth dilution methods. The results showed that the ethanol extract of Avicennia marina leaves with “antimicrobial activity method” in 2000 μg/ml, were inhibited the growth of Aspergillus flavus and Penicillium italicum. In “disk agar diffusion test” the mentioned   extract were shown inhibiti on effect on pathogenic molds growth (p<0.05). The result showed that MIC of ethanolic extract of Avicenna marina leaves for Aspergillus flavus and Penicillium italicum was 16 and 8 mg/ml respectively. The results showed that MFC of ethanolic extract of Avicenna marina for Aspergillus flavus was 32 mg/ml, and for Penicillium italicum was 16 mg/ml. Ethanolic extract compared to the aqueous extract was more effective and has a greater inhibition effect. This study showed that the extract of Avicennia marina had antifungal effects that justify their traditional use as medicinal plants. Finally, the data suggested that Avicennia marina extracts could have notable antifungal effects

Analysis of different signal peptides for the secretory production of Ama r 2 in gram-positive systems (Lactococcus lactis)

Prokaryotic systems have been considered the most affordable and simplest hosts which are being employed to express recombinant proteins such as allergens; nevertheless, without appropriate signal peptide (SP), these systems cannot be used for secretory proteins. Recently, a lot of effort has been put into assessing the potential of gram-positive strains such as lactic acid bacteria for new applications in the production of heterologous proteins. Ama r 2 is a respiratory allergen from Amaranthus retroflexus, whose recombinant production in the probiotic host could be introduced as a specific and effective way to rapid diagnosis and immunotherapy of this allergy. Consequently, the production of this recombinant protein using the prokaryotic system, requires a suitable SP to protect disulfide bonds and to prevent misfolding. This study was designed to predict the best SPs for the expression of Ama r 2 protein in Lactococcus lactis as the host. In this study, 42 signal sequences were selected from SP databases and the most important features of them were evaluated. First, n, h and c regions of the SPs and their probabilities were investigated by signalP software version 4.1. Then, their physicochemical properties were evaluated by Portparam and SOLpro. Moreover, the secretion sorting and sub-cellular localization sites were evaluated by PRED-TAT and ProtcompB software programs. The results revealed that yjgB, entC2 (Entrotoxine type C-2), ent B (Entrotoxine type), blaZ (Beta lactamase), dex (number 21), blm (Beta lactamase 2), dex (Dextranase; number 20) and number 26 were introduced theatrically as the best SPs to express Ama r 2 in Lactococcus lactis

Evaluation and measurement of bioethanol extraction from melon waste (Qassari cultivar)

As the world progresses, more energy is required to get along with everyday changes. Using bio-ethanol as one of the most important bio-fuels is an appropriate response to those changes. Much agricultural waste is being produced in Iran and the combination of such waste can turn it into a good source for the production of bio-ethanol. Thus, in this study, the amount of bioethanol extracted from melon waste was measured and evaluated. To do so, considering the 15 kg capacity of the device's fermenter, 12 kg of refined melon sugar syrup and three kilograms of water (with the standard ratio of 4 to 1), i.e. a total of 15 kg of substrate with the brix degree of 20, as well as 75 gr of saccharomyces cervisiae yeast, cultured in standard conditions (5 grams of yeast for each kilogram of substrate) were transferred into the fermenter. The tests were conducted in 35 hours with three replications and at three different rotation speeds of the fermenter's mixer. Sampling took place every five hours. Fermentation temperature was set as 30 degrees centigrade and distillation temperature was set to be 75 degrees centigrade which is the standard temperature of bioethanol's boiling point. The results showed that about 60.5 grams of bioethanol was obtained from each kilogram of melon. In addition, considering the alcohol produced and in order to optimize energy consumption, it was observed that the best speed for the mixer in the device's fermenter was 120 rpm.

Effects of Mung Bean (<i>Vigna radiata</i>) Protein Isolate on Rheological, Textural, and Structural Properties of Native Corn Starch

It is critical to understand the starch–protein interactions in food systems to obtain products with desired functional properties. This study aimed to investigate the influence of mung bean protein isolate (MBPI) on the rheological, textural, and structural properties of native corn starch (NCS) and their possible interactions during gelatinization. The dynamic rheological measurements showed a decrease in the storage modulus (G’) and loss modulus (G”) and an increase in the loss factor (tan δ), by adding MBPI to NCS gels. In addition, the textural properties represented a reduction in firmness after the addition of MBPI. The Scanning electron microscope (SEM) images of the freeze-dried NCS/MBPI gels confirmed that the NCS gel became softer by incorporating the MBPI. Moreover, X-ray diffraction (XRD) patterns showed a peak at 17.4°, and the relative crystallinity decreased with increasing MBPI concentrations. The turbidity determination after 120 h refrigerated storage showed that the addition of MBPI could reduce the retrogradation of NCS gels by interacting with leached amylose. Additionally, the syneresis of NCS/MBPI gels decreased at 14 days of refrigerated storage from 60.53 to 47.87%

Evaluation of the bioprotectivity of Lactobacillus binary/ternary cultures in yogurt

The attempts toward addition of biocontrol agents in dairy products have gained popularity. Here, we worked on analysing the antifungal activity of binary and ternary combinations of three Lactic Acid Bacteria (LAB) against five spoilage yeasts in yogurt. The yogurt samples were characterized in terms of pH, acidity, WHC, textural parameters, viscosity, survivability and antifungal activity of LAB and sensorial properties during cold storage. The results showed that the inoculation of LAB in yogurt gave rise in significant reduction of pH throughout cold storage while titrable acidity and WHC decreased (p &lt; .05). Inoculation of LAB resulted in significant increase in hardness and adhesiveness while springiness remained constant. On the other hand, apparent viscosity of all samples experienced a profound increase up to the 10th day of storage followed by a reduction trend for the rest of storage period. Analysis of inhibitory activity of LAB showed an efficient barrier against all five yeasts, in which the most activity was recorded for Lactobacillus reuteri followed by Lactobacillus acidophilus. On the other hand, the most resistance yeast was Kluyveromyces marxianus followed by Rhodotorula mucilaginosa. Sensorial analysis revealed that addition of LAB in yogurt brought about a profound improvement in textural quality of samples. Inoculation of LAB cultures in yogurt at 5% (v/v) not only could improve the physicochemical and sensorial properties of yogurt, but also could introduce a strategy toward substituting of chemical preservatives with biocontrol agents

Physicochemical, Pasting, and Thermal Properties of Native Corn Starch&ndash;Mung Bean Protein Isolate Composites

Starch is widely used in food and non-food industries because of its unique characteristics. However, native starch shows some weaknesses that restrict its applications. Recently, some studies have demonstrated the benefits of using protein to overcome these limitations. Therefore, the aim of the present study was to investigate the effect of mung bean protein isolate (MBPI) (2%, 4%, 6%, and 8%) on the physicochemical, pasting, and thermal properties of native corn starch (NCS), as a novel starch&ndash;protein composite. Higher swelling power (SP), water absorbance capacity (WAC), and solubility values of NCS were observed with increasing MBPI concentration. Additionally, by the addition of MBPI, the rapid visco analyzer (RVA) showed a reduction in pasting temperature (77.98 to 76.53 &deg;C), final viscosity (5762 to 4875 cP), and setback (3063 to 2400 cP), while the peak viscosity (4691 to 5648 cP) and breakdown (1992 to 3173 cP) increased. The thermal properties of NCS/MBPI gels investigated by differential scanning calorimetry (DSC) showed higher onset, peak, and conclusion temperatures (69.69 to 72.21 &deg;C, 73.45 to 76.72 &deg;C, and 77.75 to 82.26 &deg;C, respectively), but lower gelatinization enthalpy (10.85 to 8.79 J/g) by increasing MBPI concentration. Fourier transform infrared spectroscopy (FT-IR) indicated that the addition of MBPI decreased the amount of hydrogen bonds within starch. Furthermore, after three cycles of freeze-thaw shocks, the syneresis of NCS-MBPI composites decreased from 38.18 to 22.01%. These results indicated that the MBPI could improve the physicochemical properties of NCS, especially its syneresis and retrogradation characteristics

Investigating the Probiotic Properties and Antimicrobial Activity of Lactic Acid Bacteria Isolated from an Iranian Fermented Dairy Product, Kashk

In the present study, kashk samples were collected from two regions of Iran, the Fars (Abadeh) and Razavi Khorasan (Kalat) provinces. Fifteen bacteria were isolated and physiological and biochemical assays were performed. After identification to the genus level, eight isolates were identified as lactic acid bacteria (LAB) and subjected to molecular identification and probiotic properties assays. The results revealed that the isolates were Enterococcus faecium KKP 3772 (KF1), Enterococcus faecium C1 (KF2), Pediococcus pentosaceus H11 (KF3), Pediococcus pentosaceus VNK-1 (KK4), Lactococcus lactis RSg (KK1), Enterococcus faecalis P190052 (KK2), Enterococcus mundtii CECT972T (KK3), and Lactiplantibacillus plantarum PM411 (KK5). Only the numbers of L. lactis RSg (KK1) and Lpb. Plantarum PM411 (KK5) decreased to below 9 Log CFU/mL after acidic conditions (pH = 3) and showed weak antibacterial activity. Enterococcus mundtii CECT972T (KK3) and E. faecium C1(KF2) were highly susceptible to bile salts, while P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) showed the highest resistance. All of the isolates were resistant to tetracycline and sensitive to chloramphenicol and gentamicin. The antimicrobial activity of P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) was higher than other isolates and consequently, their inhibition zones were larger. The adhesion capabilities of LAB isolates to intestinal epithelial cells were evaluated by examining the auto-aggregation factor and cell surface hydrophobicity. The highest and lowest cell surface hydrophobicity and auto-aggregation were obtained from P. pentosaceus VNK-1 (KK4) and E. mundtii CECT972T (KK3), respectively. In general, P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) have shown better probiotic properties as compared to other isolates

Investigation of antibacterial activity of Lactic Acid Bacteria isolated from traditional kordish cheese in comparison with commercial strains

Background and Aim: The health benefits of lactic acid bacteria in human, especially their anti-pathogenic properties has been the focus of recent interests. The objective of this study was to investigate the antibacterial activity of lactic acid bacteria (LAB) isolated from traditional Kurdish cheese against a few bacterial pathogens. Materials and Methods: The cell free culture supernatant of LAB isolated from Kurdish cheese which was treated with heat and NaOH were tested for their antibacterial activity by Agar Disk Diffusion method. Moreover, Minimum Inhibition Concentration and Co-aggregation of LAB against pathogens were determined. Each test was repeated for three times. Results: The LAB isolates, in comparison with commercial lactic acid bacteria, showed suitable antibacterial activity. Heating the bacterial supernatant eliminated its anti-bacterial property; however, alkali treatment did not have any effect. The Minimum Inhibition Concentration did not show significant differences between native and commercial lactic acid bacteria; however, the native LAB showed suitable co-aggregation with pathogens. Conclusion: Traditional lactic acid bacteria and their metabolites can inhibit growth of pathogens. This shows the positive role of LAB in human health which necessitates their increase usage as natural antimicrobial agent