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).
Zahra Sheikholeslami; Mahdi Karimi; Toktam Hejrani; Mehdi GhiafeDavoodi; Hamed Fatemian
Abstract
Introductıon: Hydrocolloids have been employed for reduction of moisture migration from the crumb to crust, added to the formulation, improved texture, prevent ice Crystallization and delay staling (Ba´rcenas et al 2003, 2004, Hager, and Arendt, 2013). However, given the importance of their role still ...
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Introductıon: Hydrocolloids have been employed for reduction of moisture migration from the crumb to crust, added to the formulation, improved texture, prevent ice Crystallization and delay staling (Ba´rcenas et al 2003, 2004, Hager, and Arendt, 2013). However, given the importance of their role still trying to find new resources will continue to create the best quality. Today, researchers introduced new technologies such as modified atmosphere packaging, frozen technology and using different additives to produce bread with higher quality, longer shelf life and high nutritional value. Production of the part baked frozen bread is a method which interrupted baking process, the first stage is the crumb formation and the crust color is not developed. The aim of this study was to evaluate the effect of Ocimum Bacilicum and tragacanth at 3 levels (0, 0.3 and 0.5%) (W/W flour basis) on the quality of part-baked Barbari bread after frozen storage and re-baking.
Materials and methods: The Ocimum Bacilicum seeds were cleaned, then were firstly soaked in distilled water to obtain a water to seed ratio of 37:1 at 40˚C and pH 7. Separation of the hydrocolloid from the swollen seeds was achieved by passing the seeds through an extractor equipped with a rotating plate that scraped the gum layer on the seed surface. The extracted solution was then filtered and dried in an air forced oven at 60˚C and finally the powder was milled, sieved using a mesh 18 sifter, packed and kept at cool and dry condition (Karazhiyan et al., 2010, Sahraiyan et al., 2013). Tragacanth purchased from the local market as a tape shape after milling and sieve (70 mesh) were used. Bread prepared as part baked, freezing in -18°C and storage for 15 days, after this time samples were thawing and full baked. The test includes moisture content, specific volume, porosity, firmness, image analysis and sensory properties was measured. For Data Analysis used SPSS software and Duncan test, for mean comparisons.
Results and discusions: The results obtained from volume, texture, moisture content and sensory properties showed Tragacanth gum at 0.5 concentrations and Ocimum Bacilicum gum at 0.5 levels improved moisture content. Using tragacanth at 0.3% and Ocimum Bacilicum gums at 0.5 % concentration improved the specific volume, porosity, firmness, and sensory properties. The hydrocolloids are highly hydrophilic nature, it made hydrogen link between the water available in the system, prevent the movement of water from crumb and improved the firmness and improved the quality of bread (Manadala et al., 2008). The hydrocolloids capable to strengthen the gluten matrix surrounded cell gas as result maintenance them during part baked and frozen storage. Hydrocolloid, coalescence of gas cells as a result of expansion during the proofing step and increase the volume and porosity of bread (Shillini & Laxemi, 2007).
Conclusion: Addition of Ocimum Bacilicum and tragacanth to bread recipe improved the crumb texture of the bread that obtained from part-baking, frozen storage and re-baking. In addition, the presence of gums improved the specific volume, texture and the overall quality of the product during frozen storage, removing the negative effects of that process conditions. The Ocimum Bacilicum in comparison of tragacanth had the greater concentration effect on PBF Barbari bread on improved the quality. The interaction of tragacanth and Ocimum Bacilicum (0.3 and 0.5 %) respectively had the best result to improving the all parameters that investigated in part baked and freezing storage of Barbari bread. This study provides insights into the complexity of interactions between tragacanth and Ocimum Bacilicum as a new source of hydrocolloids and their combined influence on bread characteristics, thereby serving as a guide for future research on the other bread
Fahimeh Tooryan; Maryam Azizkhani
Abstract
Introduction: There have been great efforts to find safe and potent natural antioxidants from various plant sources. There is, at present, increasing interest both in the industry and scientific research for spices and aromatic herbs because of their strong antioxidant and antimicrobial properties, which ...
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Introduction: There have been great efforts to find safe and potent natural antioxidants from various plant sources. There is, at present, increasing interest both in the industry and scientific research for spices and aromatic herbs because of their strong antioxidant and antimicrobial properties, which exceed many currently used natural and synthetic antioxidants. Medicinal plants are complex natural mixtures which contain compounds at quite different concentrations, have antioxidant activities These properties are due to many substances, including some vitamins, flavonoids, terpenoids, carotenoids, phytoestrogens, minerals, etc. and render spices and some herbs or their antioxidant components as preservative agents in food and they were proposed as potential substitutes of synthetic antioxidants in food stuff. The number of contributions to isolation methods, techniques and activity testing of plant-origin antioxidants has significantly increased in recent years. Antioxidants are also widely used as additives in fats and oils and in food processing to prevent or delay spoilage of foods regarding to the harmful effects of synthetic preservatives on consumers’ health, there is an increasing attention, both in food industry and authorities, to medicinal and aromatic plants as natural preservatives in food products. Oxidation is one of the major causes of chemical spoilage, resulting in rancidity and deterioration of the nutritional quality, colour, flavour, texture and safety of foods .Oxidation occurrence in cheese especially full-fat types causes rancid odor and taste and loss of nutritional quality. The objectives of the present study were evaluation of aerial parts of basil (Ocimum basilicum) and clary sage (Salvia sclarea) essential oils (EOs), study their antioxidant effect on the lipid oxidation and sensorial acceptability when applied to Iranian white cheese.
Materials and methods: Investigations were carried out to assess the efficiency of two plant essential oils; clary sage and basil as natural food preservatives. In this study, the antioxidant effect of clary sage (Salvia sclarea) and basil (Ocimum basilicum) essential oils in Iranian white cheese shelf-life, at 26 ° C for 39 and 4 ° C for 90 days, were examined. Samples at three levels 0.5%, 0.75%, 1% (w/v) were treated, negative control cheese without antioxidant and positive control sample with synthetic antioxidant (BHT) 0.05% were selected. The Essential oils chemical composition were determined by gas chromatography equipped with mass spectroscopy (GC/MS). GC-MS analysis of the essential oil was performed using Agilent-Technologies 6890N Network gas chromatographic (GC) system, equipped with Agilent Technologies 5975 inert XL Mass selective detector and Agilent-Technologies 7683B series auto injector (Agilent- Technologies, Little Falls, CA, USA). The antioxidant capacity of the essential oils were assessed by measuring their scavenging abilities to 2,2 diphenyl-1-picrylhydrazyl stable radicals using DPPH method and anti-oxidative stability with peroxide value (PV) and thiobarbituric acid (TBARS) test were evaluated.
Results & discussion: Main components of clary sage EO included linalyl acetate, linalool, α-terpineol and α-pinene and the major aroma constituents of basil EO consisted of linalool and α-cadinol, eugenol ,α –Bergamotene and 1,8- Cineole. Linalyl acetate and linalool (oxygenated monoterpenes) showed stronger antioxidant activities than did the other components tested in the assays. Maximum free radical scavenging activity for clary sage and basil EOs at 1% concentration was 84.66% and 72.72% respectively that was weaker than (BHT) free radical scavenging activity (95%) by DPPH test. At 1% concentration, clary sage and basil EOs were most effective treatment at 4 and 26 C°, in free radical scavenging activity comparing to other concentrations. At 4 C° there is no any difference between all treatments up to 30th days in PV and TBARS number. The most effective treatment against lipid oxidation was at 0.75, 1% concentration basil and 1% saliva EOs at 90th days observed. Finally it seems that Basil EO was more effective than clary sage EO at both 0.75 and 1% concentration. At 1% concentration of basil EO according at 90th day storage time not observed significant difference in peroxide value and tio barbituric acid number comparing to first day. At 26 C° highest antioxidant activity was obtained at 1% concentration of basil EO. Final peroxide value (meq O2/Kg oil) and tio barbituric acid (m mol/gr oil MD) number using basil and saliva EOs was 1.379, 0.0680 and 1.817, 0.096 respectively. That significant deference was observed comparing to control sample (p
