جستجوی مقالات مرتبط با کلیدواژه « عصاره آبی » در نشریات گروه « صنایع غذایی »

Prangos ferulacea is a plant that has been used in traditional medicine for its therapeutic properties. The present study was conducted to investigate the antifungal effect of P. ferulacea aqueous extract on Alternaria alternata, Alternaria solani, Saccharomyces cerevisiae, and Fusarium solani. The antifungal methods used were disc diffusion agar, well diffusion agar, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC). The extract concentrations used in the study were 20, 40, 60, and 80 mg/mL. The study found that the antifungal effect was concentration-dependent and increased with concentration. S. cerevisiae was the most sensitive species to the extract while F. solani was the most resistant. At 80 mg/mL, the inhibition zones for S. cerevisiae were found to be 11.90 mm and 13.00 mm in disc diffusion agar and well diffusion agar methods, respectively. The corresponding zones were 9.60 mm and 10.20 mm for F. solani, respectively. In the combined mode (interaction) of P. ferulacea aqueous extract with nystatin antibiotic, synergistic mode was observed for all fungal strains. The MIC and MFC values for S. cerevisiae were 32 and 128 mg/mL, respectively. The MIC and MFC results for F. solani were found to 256 and > 512 mg/mL, respectively. The results of this study showed that P. ferulacea aqueous extract could be used as a natural antifungal agent to inhibit the growth of pathogenic fungi on fresh fruits and vegetables.

The plant Russian knapweed is known as a blood sugar lowering drug, and the antimicrobial properties of its extracts and essential oils have been proven; Therefore, this study was conducted with the aim of extracting the aqueous extract of R. knapweed and investigating its antimicrobial activity. The aqueous extract of R. knapweed was extracted by the maceration method. The antibacterial activity of the extract against Escherichia coli, Salmonella typhi, Listeria monocytogenes, and Bacillus cereus was investigated using disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods. The results of this research showed that the antimicrobial activity of the extract was dependent on the concentration and the highest diameter of the inhibition zone was observed at the concentration of 100 mg/ml of the extract. Based on disk diffusion agar and well diffusion agar tests, Listeria monocytogenes bacteria had the highest and Escherichia coli, Salmonella typhi, and Bacillus cereus had the lowest inhibition zones, respectively. The minimum inhibitory concentration for Escherichia coli, Salmonella typhi, Listeria monocytogenes, and Bacillus cereus bacteria was obtained as 64, 64, 16, and 32 mg/ml, respectively, and the minimum bactericidal concentration values for these bacteria were 512, 512, 256, and 256 mg/ml, respectively. In generally, the Gram-positive bacteria were more sensitive to the extract compared to the Gram-negative types. The growth of pathogenic bacteria and the diseases transmitted by these bacteria can be controlled by using natural antimicrobial compounds such as R. knapweed aqueous extract.

The usage of plant extraction such as tannins, flavonoids & et. as an alternative to fungicidal effects. The aim of this study was to evaluate of  the antifungal effect of Iranian oak Jaft extract after extraction by different methods on Penicillium italicum and (Penicillium digitatum as an indicator of citrus fruit mold spoilage. molds were expossered by different concentrations of oak Jaft extract. The investigated factors including minimum inhibitory concentration (MIC) (mg/ml), minimum lethal concentration (MFC) (mg/ml) and non-growth diameter (mm) were determined by the methods of tube dilution, surface culture and diffusion in agar well (WD). The results showed that different concentrations of aqueous extract had significantly effect (p<0.05) on the non-growth  diameter of molds. The antifungal effect was significantly (p<0.05)increased in concentrations of 40 and 80 mg/ml aqueous extract. In this research, Fludioxionil 25%  poison as a control group showed a significant difference(p<0.05) in molds growth. In general, the extract of Iranian oak Jaft can be used to control the fungal spoilage of citrus fruits.

Nowadays, production and utilization of Nano materials have increased due to their unique and interesting properties. So far, different physical and chemical methods have been used to synthesize silver nanoparticles. Chemical synthesis is not compatible due to the hazardous chemicals residues on the surface of the nanoparticles (NP) as well as production of by products with high impact on the environment. Physical routes for synthesis of NPs have some drawbacks, too. These methods require high energy and space, and are expensive.  Therefore, biological methods for the synthesis of silver nanoparticles are considered emerging technologies as economic choices in the green chemistry field. Among these methods, plant-mediated synthesis of AgNPs is a rapid, simple, non-toxic and eco-friendly technique. Silver nanoparticles exhibit high bactericidal activity at their utilized concentrations with no toxic effect on human cells, and they also strongly enhance the antibacterial activity of conventional antibiotics even against multi-resistant bacteria through their synergistic effects. Callistemon citrinus belongs to the family Myrtaceae and includes more than 30 species. The plant is widespread in wet tropics, notably Australia, South America and tropical Asia, but presently can be found all over the world. Callistemon citrinus is a potential medicinal plant used to treat gastrointestinal distress, pain, and infectious diseases caused by bacteria, fungi, viruses, and parasites. In this study Callistemon citrinus aqueous extract was used to reduce silver ions in silver nitrate solution.  In the following, the antimicrobial activity of nanoparticles synthesized by various qualitative and quantitative methods on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi and Listeria innocua was investigated.  For the synthesis of silver nanoparticles, 25 mL of silver nitrate solution was added to 5 mL of leaf extract with a concentration of 100 mg/mL and maintained for 24 h at 20 °C.  Change the color of the solution to Red represents the production of silver nanoparticles in the solution. To stabilize the presence of silver nanoparticles, the absorption spectrum of silver nanoparticles produced by spectrophotometer was prepared. Antimicrobial activity of silver nanoparticles synthesized using Callistemon citrinus leaf aqueous extract was examined by disc diffusion agar, well diffusion agar, minimum inhibitory concentration (microdilution broth) and minimum bactericidal concentration on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi and Listeria innocua.  The results showed that in disc diffusion agar method, the diameter inhibition zone increased with increasing the concentration of silver nanoparticles. The maximum effect of silver nanoparticles synthesized using Callistemon citrinus leaf aqueous extract at a concentration of 150 mg / ml was observed for Pseudomonas aeruginosa. An inhibition zone was observed for all examined pathogenic microorganisms at all concentrations. The results showed that in the well diffusion agar method, nanosilver particles at a concentration of 18.75 mg/ml did not show any inhibitory effect on all the pathogenic microorganisms. The results of statistical analysis showed that there was no significant difference between all the concentrations of silver nanoparticles synthesized for Escherichia coli, Salmonella typhi and Staphylococcus aureus (P˂ 0.05(. The MIC for Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium and Listeria innocua was 128, 256, 256, 256 and 512 mg/mm, respectively. The MBC for all the pathogenic strains was 512 mg/mm. The results of this study showed that the Callistemon citrinus leaf extract has a good ability to synthesize silver nanoparticles. Nanoparticles synthesized from Callistemon citrinus leaf extract had good antimicrobial activity against examined pathogenic bacteria, especially Gram-negative bacteria. Green-synthesized nanoparticles can be used as antimicrobial agent to fight infectious diseases caused by various microbial strains, although more research is needed in vitro, animal models and in vivo.

The toxic effects of synthetic antimicrobial and antioxidant compounds have led to an increase in the use of natural types, such as plant extracts. In this study, the antimicrobial effect of Lawsonia inermis aqueous extract was investigated against Escherichia coli, Salmonella typhimurium, Staphylococcus epidermidis, and Listeria innocua, by disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods. The higher concentrations of the extract showed higher antimicrobial effects against S. epidermidis and L. innocua compared to E. coli and S. typhimurium. Moreover, the total phenolic and flavonoids contents of the extract were 59.45±1.12 mg gallic acid per gram of extract and 40.35±0.70 mg quercetin per gram of extract, respectively. The antioxidant properties of aqueous extract were measured based on the DPPH and ABTS free radical scavenging activities. It was found that the antioxidant activity increased significantly as a function of L. inermis aqueous extract concentration. The antimicrobial and antioxidant properties of L. inermis leaf aqueous extract could make it a natural bioactive compound to be used as in food and medicinal products.

Green tea leaves is a non-fermented product which contains many phenolic compounds. Green tea polyphenols are natural compound with antioxidants and anti-carcinogenic potential. Polyphenols are sensitive to high temperature and alkaline pH. To improve the stability of polyphenols, green tea extract was microencapsulated by co-crystallization technique. Entrapment yield, loading capacity, antioxidant activity, characteristics of co-crystallized product such as moisture, water activity, bulk and tapped density, solubility and hygroscopicity, morphology as well as flowability properties of powder (carr index, hausner ratio and angle of repose) were characterized. It was revealed that the effect of concentration on total phenolic compounds of co-crystallized products was significant (p<0.05). Encapsulation efficiency was increased by increasing the extract concentration. The 10% concentration of microencapsulated extract showed the highest DPPH scavenging activity, ABTS and hydroxyl radicals inhibition activity, and reducing power (56.90, 69.37, 71.63% & 0.81, respectively). The difference in particle size of co-crystallized product was significantly (p˂0.05) influenced the flow properties. In general, the values of water activity, moisture content and hygroscopicity showed that co-crystallized product was stable and have good characteristics during storage. Therefore, microencapsulation by co-crystallization technique can be used as an efficient method for increasing the stability of green tea extract against the environmental conditions.

This Research was to investigate the antibacterial effects of aqueous and ethanolic extracts of Aloe Vera on pathogenic bacteria such as Staphylococcus aureus (ATCC25923), Escherichia coli (ATCC25922), Listeria monocytogenes (ATCC33090) using disk diffusion and broth Microdilution methods. The results illustrated that gram-positive bacteria are more sensitive to ethanolic extract of Aloe Vera as compared with gram-negatives bacteria. This phenomenon is due to the structure and the strength of cell wall in gram-negative bacteria as well as the nature and active compounds of Aloe Vera. Ethanolic extract of Aloe Vera showed that the maximum antibacterial activity on Staphylococcus aureus and Listeria monocytogenes in whichthe minimum inhibitory concentration (MIC) was 0.132 and 0.625 mg/ml respectively. The maximum inhibition zone was observed on Staphylococcus aureus and Listeria monocytogenes with 12 and 8 mm respectively. On the other hand, aqueous extract of Aloe Vera did not show any antibacterial activity. It is supposed that antibacterial compounds such as Anthraquinone, Hydroxyanthra and Saponin had the most roles for antibacterial activity in ethanolic extract on Aloe Vera.

Microbial growth and lipid peroxidation are primary factors of meat spoilage during refrigerated storage. Rosemary Boiss, locally known as Tashenadri, has been extensively used as a medicinal plant in Iran. In this study, the effects of Rosmarinus officinalis aqueous extract on quality and shelf life of chicken during chilled storage were investigated. Chicken samples were treated with aqueous extract of 1%، 3% and 5% R. officinalis, and then stored at 4 οC for 5 days. The control and the treated chicken samples were analyzed periodically for Microbial (Total count, staph aureus, Coliforms), chemical (pH, PV) and sensory characteristics. The results indicated that incorporation of R. officinalis water extract on chicken fillets caused the delay of lipid peroxidation and microbial spoilage. In this respect, the sample supplemented with 3% aqueous extract was more effective compared with the 1% and 5% in extending the shelf life of chicken fillets (P < 0. 05). It was concluded that the effect of R. officinalis extract on chicken samples kept their good quality characteristics and extended the shelf life during refrigerated storage, which was supported by the results of Microbial, chemical and sensory evaluation analyses.

Plants derived products have been used for medicinal purposes for centuries because of antimicrobial activity. In this investigation Antibacterial effect of Hop (Humulus lupulus)، the pharmaceutical plant which has an important place in traditional medicine of Iran، was evaluated on some of food borne pathogens. This study conducted in order to evaluate antimicrobial effect of Hop water extract compared to Humulune from Hop against Staphylococcus aureus (PTTC1431)، Enterobacter aerogenes (PTCC1221)، Listeria monocytogenes (PTCC1298) and Salmonella enterica (PTCC1709) by agar disk diffusion and broth microdilution methods. The results indicated that gram positive bacteria were more sensitive to the extracts compared to gram negative bacteria. The minimum inhibitory concentration (MIC) of Humulune and water extract of Hop against Staphylococcus aureus were 0. 039 and 0. 625 mg/ml respectively. Findings indicate that Humulune had the most antibacterial activity in both methods. The most inhibitory effect was shown against staphylococcus aureus in disk diffusion method (inhibition zone of 17mm). The effect of Humulune were more than water extract of Hop. Results indicate that Hop extract has antibacterial effect and can be used in combinational therapy or as a food preservative.

In this study، the antibacterial aqueous extract of mountain sagebrush، Artemisia sieberi، Artemisia aucheri and Hyssopus officinalis against the bacteria such as Escherichia coli، Staphylococcus aureus and Listeria monocytogenes were investigated. The extracts were prepared by maceration and then the minimum inhibitory concentration (MIC) using the broth micro-dilution and minimal bactericidal concentration (MBC) was measured. The minimum inhibitory concentration of aqueous Artemisia aucheri and Artemisia sieberi against Escherichia coli، Staphylococcus aureus and Listeria monocytogenes was 160، 80 and 80 mgml-1 respectively. Also، the minimum inhibitory concentration of aqueous extract of hyssop against Escherichia Coli، Staphylococcus aureus and Listeria monocytogenes was 80، 40 and 40 mgml-1 respectively. Based on these results، the aqueous extracts of the three plants have the strong antibacterial effect against gram-positive bacteria. The most sensitive organism regarding extracts experiment was Listeria monocytogenes wheras the most resistant bacteria was Escherichia coli. Among the extracts، the hyssop had the highest antibacterial activity While the antibacterial activity of aqueous extract of Artemisia aucheri and Artemisia sieberi were identical.