Food Biotechnology
Ehsan Safari; Hassan Barzegar; Hossein Jooyandeh; Behrooz Alizadeh Behbahani; Mohammad Noshad
Abstract
Introduction The addition of chemical preservatives increases the shelf life of food products, but prolonged and indiscriminate use of chemical preservatives increases the resistance of microorganisms and the health risks associated with theiruptake. Medicinal plants have a wide variety in the world ...
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Introduction The addition of chemical preservatives increases the shelf life of food products, but prolonged and indiscriminate use of chemical preservatives increases the resistance of microorganisms and the health risks associated with theiruptake. Medicinal plants have a wide variety in the world as well as in Iran. In recent years, the use of natural preservatives such as plant extracts and essential oils, due to their importance and role in controlling the growth of pathogenic microorganisms, has been proposed as an alternative to chemical preservatives. Black pepper is an aromatic medicinal plant. The specific properties of black pepper essential oil, such as its antimicrobial and antioxidant activity, have also been confirmed. Amphotericin B is one of the effective antibiotics for treating infections caused by pathogenic fungi. The mechanism of action of amphotericin B is to destroy fungal cells in such a way that by binding to ergosterol in the cell membrane of fungi, it creates pores and eventually destroys them. One of the most important and common antibiotics used in the treatment of infections caused by pathogenic bacteria is chloramphenicol. This antibiotic is effective against gram-positive and gram-negative bacteria due to its broad spectrum. The aim of this study was to identify bioactive functional groups, antioxidant potential, phenol and total flavonoid compounds and to evaluate the antimicrobial activity of black pepper extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger.Materials and Methods In this study, the antimicrobial effect of black pepper aqueous extract was investigated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger by disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods. Total phenol and flavonoid contents of the species were determined by Folin-Ciocalteu and AlCl3 assays, respectively. Three biochemical assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis 3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) free radical scavenging and β- caroten/linoleic acid activity systems, were used to evaluate antioxidant activity. Identification of functional groups as well as the structure of organic compounds in black pepper extract was also performed by Fourier transform infrared spectroscopy (FTIR). To evaluate the synergistic effect of black pepper extract in combination with amphotericin B and chloramphenicol antibiotics, Sub-MIC was used. Results and Discussion The peaks observed in aqueous black pepper extract confirmed the presence of O-H (3000-3500 cm-1), C-H (2800-3000 cm-1), C=O (1613.62-1633.52 cm-1) and C-O (100.57-1038.82 cm-1) functional groups of bioactive compounds. The total phenol and flavonoids content of the extract were 45.12 mg GAE/g extract and its flavonoid content was 29.66 mg QUE/g extract which had an important role in its antioxidant activity. The aqueous black pepper extract had remarkable DPPH free radical scavenging activity (IC50=32.37 μg/ml), ABTS free radical scavenging activity (IC50=28.45 μg/ml) and beta-carotene bleaching inhibitory effect (46.45%), revealing the electron/hydrogen donating ability of the essential oil. The results of measuring the antimicrobial activity of extract by disk diffusion and agar well showed that black pepper extract showed more antimicrobial effect on gram-positive bacteria Staphylococcus aureus and Bacillus coagulans than gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. This could be due to the difference in their cell wall structure. Aspergillus niger is the most sensitive species to aqueous black pepper extract. The minimum inhibitory concentrations of extract for Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger were equal to 32, 16, 4, 8 and 4 mg/ml, respectively. The minimum bactericidal concentration of black pepper extract for two bacterial species, Escherichia coli and Pseudomonas aeruginosa was more than 512 mg/ml. Also, the minimum bactericidal concentration for Staphylococcus aureus and Bacillus coagulans was 128 and 256 mg/ml, respectively, and 128 mg/ml for Aspergillus niger. The results of interaction of black pepper extract with chloramphenicol antibiotic showed that the Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were synergistic, but antagonism was observed for the gram-positive Bacillus coagulans.
Food Biotechnology
Sahar Roshanak; Behrooz Alizadeh Behbahani; Fakhri Shahidi; Farideh Tabatabaei Yazdi; Alireza Vasiee; Neda Hashemi
Abstract
Usage of natural products like herbals, provide unlimited opportunities for novel and suitable additives. Mocheh can be used in fresh form or as an ingredient in soup and salad. This study was aimed to determine the antimicrobial and antioxidant activities of Mocheh (Lepidium draba) extract. The antimicrobial ...
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Usage of natural products like herbals, provide unlimited opportunities for novel and suitable additives. Mocheh can be used in fresh form or as an ingredient in soup and salad. This study was aimed to determine the antimicrobial and antioxidant activities of Mocheh (Lepidium draba) extract. The antimicrobial activity of Mocheh extract was tested against Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus and Aspergillus niger. The extract showed a strong antimicrobial activity with a concentration dependence and a broad antimicrobial spectrum for all tested microorganism species. The results showed that MIC of leaf extract of Lepidium draba on Aspergillus niger, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus was 128, 128, 128 and 128 mg/mL respectively. The results showed that MBC/MFC of leaf extract of Mocheh on the examined microorganisms was 256, 256, 256 and 256 mg/mL respectively. The values obtained for total flavonoid content and total phenolic contents were 22.13 µg/mL and 18.88 mg/mL, respectively. Measured value in the radical scavenging activity was IC50= 168/21 µL/mL. The results showed that Mocheh leaf aqueous extract is a novel source of natural antimicrobial and antioxidant agents for the food and pharmaceutical industries.
Hajar Shahsavar; Marzieh Bolandi; Homa Baghaei
Abstract
Introduction: Plant extracts have antimicrobial properties and can be substituted as chemical flavorings in food. Preservatives are compounds that are used to inhibit the growth or to eliminate harmful microorganisms to increase the shelf life of foods. Nowadays, the use of natural preservatives derived ...
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Introduction: Plant extracts have antimicrobial properties and can be substituted as chemical flavorings in food. Preservatives are compounds that are used to inhibit the growth or to eliminate harmful microorganisms to increase the shelf life of foods. Nowadays, the use of natural preservatives derived from medicinal plants is increasing due to their greater compatibility and the presence of volatile compounds (Celiktas et al., 2007). The antimicrobial properties, antioxidant and anticancer effects of these natural additives have been proven (Tajkarimi et al., 2010). In this study, the antimicrobial activity enhancement effect of the combination of hydroalcoholic extracts of basil, cinnamon and salvia on Escherichia coli, Staphylococcus aureus and Saccharomyces cerevisiae yeast in Iranian yoghurt drink (doogh) was investigated for 4 weeks at ambient temperature. Materials and Methods: The milk was boiled in hygienic conditions at 95 ° C for 5 min. After cooling to 45 ° C, they were inoculated. The aerial parts of the studied plants were milled and powdered. Cinnamon, basil and salvia extracts were then soaked. The food strains of Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 700728 and Saccharomyces cerevisiae PTCC 5193 were prepared as lyophilized ampoules. The microdilution broth method was used to determine the minimum inhibitory concentration. The minimum bactericidal concentration (MBC) was determined in accordance with the minimum inhibitory concentration (MIC) results. To determine the antimicrobial effect of the extracts on the yoghurt drink, 9 ml of the prepared yoghurt drink was poured into each test tube. Then 1 cc of each extract and 1 cc of microbial suspension (1.5 × 108 CFU / ml) were added. One tube was considered as positive control (bacteria + yoghurt drink), one negative control tube (extract + yoghurt drink) and one control tube (yoghurt drink only) and the tubes were placed at ambient temperature. Then, on day 7, 14, 21 and 30 during storage, 20 µl of each tube, were cultured on Muller Hinton agar medium and the same amount of yeast was cultured on blood agar medium. After incubation for 24 h at 37 ° C, the colonies were counted. The interaction of antimicrobial activity of the combination of basil, cinnamon and sage extracts was evaluated on the basis of differential inhibitory concentration index (FIC). Results and discussion: The results showed that the minimum inhibitory concentration of the combined basil, cinnamon and sage extracts against Staphylococcus aureus and Saccharomyces cerevisiae and Escherichia coli were 0.4, 0.4 and 3.12 mg / ml, respectively. Also, Staphylococcus aureus was more susceptible to the extracts, which were used alone, and was inhibited by a lower concentration of used extract (Ahmadi et al., 2018). However, due to the maximum minimum inhibitory concentration (MIC), Escherichia coli was less sensitive to the extracts which was used alone. The combined usage of all three extracts significantly reduced the maximum minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC), indicating that their antimicrobial activity was more effective against the studied microorganisms than each of the extracts which was used alone. The results of this study showed that synergistic effect against Staphylococcus aureus and Saccharomyces cerevisiae was more effective with the combination of the aforementioned extracts (p <0.05). The results of the Escherichia coli population counting during storage indicated that most of the extracts had a good effect on preventing the growth of Escherichia coli in the doogh environment compared to the control sample (p <0.05). Addition of the extract significantly prevented pH reduction over time (p <0.05), so that the control sample had the highest and the sample containing all three extracts showed the lowest pH changes over time (p <0.05). Therefore, it can be concluded that acid production by Lactobacillus bacteria in samples containing extract during storage period was higher than control. The results of this study were in agreement with the results of Mortazavian et al., (2007) and Voosogh et al., (2009). The acidity of the doogh samples increased significantly over time (P<0.05), while the addition of the extract significantly prevented the acidity increase over time (P<0.05). Sensory properties are the main factors of acceptance and satisfaction of many products. In this study, the mean viewpoint of doogh samples containing the combination of the three above mentioned extracts in terms of taste, odor, color and general acceptance are acceptable. Additionally, it was found that about 90% of participants were willing to use it. Although studies of the overlapping or synergistic effects of medicinal plant extracts in real food environments are not extensive, their results have shown that, the addition of different medicinal plants compounds can increase antibacterial effects. Therefore, the simultaneous use of these extracts can be used in effective control of food pathogens as a complementary method. The results of this study were in agreement with the results of Karimi (2007).
