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Showing 20 results for khomeiri


Volume 2, Issue 3 (7-2016)
Abstract

Background: Masske is a traditional Iranian butter made from yoghurt. The first aim of this study was to isolate and identify the nonlactic pathogenic microflora by culture and molecular methods of identification, and the second purpose was to identify genetic similarity of the isolated bacteria in Masske.
Materials and Methods: In order to detect pathogenic dominant indicator microorganisms, a number of 150 bacterial isolates from three Masske samples, which may comprise the repetitive isolates and could grow on appropriate media for Staphylococci and E.coli, were classified into 8 groups according to their phenotypic characterization followed by chemical tests. Then 2approximately similar isolates from each group were chosen (total 18 isolates; we selected 3 isolates from 2 groups of eight), and the sequencing of 16S rRNA gene was done for subsequent analysis.
Results: Among 18 bacterial isolates, Staphylococcus hominis was the most frequently isolated species during the manufacture of Masske as the presence of this bacterium was confirmed in 14 out of 18 samples. Also, the presence of Staphylococcus epidermidis and Escherichia coli was identical across the samples (for each one, 2 out of 18).
Conclusion: Our results based on cultural and molecular methods suggest making some improvements to the hygiene of Masske manufacture due to the high population of minor pathogens.

Volume 13, Issue 50 (5-2016)
Abstract



Volume 13, Issue 51 (7-2016)
Abstract

The aim of this study was to evaluate the quality characteristics of bread produced by yeasts and  lactobacillus isolated from native Iranian sourdough. Initially for the preparation sourdough, fresh microbial cells with certain number of colonies, by centrifugation were isolated of initial culturing bacteria and yeasts. Then equivalent 10% weight flour ,microbial cells mixed with equal amounts of water and flour. After processing identical samples to assess the quality characteristics of bread used  of  sensory evaluation test, image processing and Texture analysis. The experiments in a completely randomized design and completely randomized block with three replications were performed. The results showed that the samples significant effect  on the quality characteristics. The results indicate that sourdough can be  increasing the porosity of the sample So that e treat with 42 percent  had the highest degree of porosity also sourdough delaying staling. According to the results from this study, treatment of Lactobacillus reuteri and Saccharomyces cerevisiae had  best Sensory evaluation, porosity and texture.

Volume 13, Issue 57 (0-0)
Abstract

There is currently a very high demand for all forms and preparations of medicinal plants worldwide. Accordingly, hops has been drawing significant attention in recent years. Hops is a medicinal plant with various applications in traditional medicine. In the present research work, antifungal effect of hops flower ethanolic extract on S. cerevisiae and some bread spoilage molds (Aspergillus niger, A. flavus, Penicillium chrysogenum, P. citrinum, Rhizopus oryzae and Rhizomucorspp. ) was investigated. The antifungal effect was determined by using broth dilution susceptibility test. Results showed that the ethanolic extract of hops flower had the ability to prevent mold growth on bread samples. Inhibitory concentration of the extract was in the range of 1.875 to 3.3 mg/ml. The extract had no effect on Saccharomyces cerevisiae in the concentrations of 0-15 mg/ml. It was concluded that ethalonic extract of hops flower has remarkable negative effects on food spoilage mold growth, especially bread spoilage molds. To apply this extract as a natural food preservative, further researches are required.

Volume 14, Issue 7 (Supplementary Issue - 2012)
Abstract

 The antioxidant properties and total phenols’ content of 80% methanol, acetone and water extracts of olive leaves procured through Microwave Assisted Extraction (MAE) were examined. Two varieties of olive namely: Cronaiky and Roghani were the ones studied. Various experimental models were employed for antioxidant activity evaluation of the extracts. The results revealed the highest phenolic content (230.50 mg tannic acid equivalent g-1 extract) and the lowest IC50 in DPPH (86.81 µg ml-1 of extract), reducing power (166.45 µg ml-1 extract) and total antioxidant capacity (128.32 µg ml-1 of extract) indices were attributed to the methanol extract of Cronaiky variety. The efficacy of the extracts at three experimental levels (200, 500, 1,000 ppm) in blocking the oxidation process was investigated using peroxide value and thiobarbituric acid index for sunflower oil during its heating at 70°C (oven test method). The lowest peroxide value and thiobarbituric acid index was observed for the methanol extract of Cronaiky at its 1,000 ppm concentration. This extract was competitively comparable with BHA and BHT at either of the tested levels (100, 200 ppm). Thus, methanol extract of Cronaiky olive variety can be employed in place of synthetic antioxidants to establish oxidation stability in edible oils.

Volume 14, Issue 62 (4-2017)
Abstract



Volume 14, Issue 62 (4-2017)
Abstract

The present research work was aimed to evaluate  the effects of whey protein concentrate (WPC) at different levels of  0, 2, and 4%, as a protein based fat replacer, soy protein isolate (SPI) (0, 1, and 2%) and microbial transglutaminase (MTG) (0, 1, and 2%) on some physical properties of  a low fat  vanilla ice cream (4% fat). Electrophoresis pattern of ice cream proteins and effect of MTG on proteins were analyzed by SDS-PAGE. Total solids of all formulations was adjusted on 34%. Results showed that application of WPC in formulation of low fat ice cream significantly  increased  hardness and melting values, while SPI significantly (P<0.01) increased  hardness and reduced melting value. MTG decreased hardness and melting of ice cream samples compared to the control (P<0.01). Results showed that application of MTG in low fat ice cream was more useful than the utilization of SPI and WPC in terms of hardness and melting properties.

Volume 16, Issue 87 (5-2019)
Abstract

In recent years, infrared radiation (IR) has been considered as one of the suitable methods for drying and decontamination of different spices. However, the low penetration depth of the IR limits its use for food processing in the industry. Due to the importance of Carum carvi as a spice with medical properties, this research aimed to determine the effect of the sample’s structure (powder and seeds), water activity (0.24, 0.56 and 0.89) and the power of IR emitter (222 to 960W) on the penetration depth of the IR into Carum carvi For this propose, the heat fluxes received by copper black body that placed under samples with different thickness was measured. Afterward, the penetration depth was calculated through a mathematical model. The results indicated while aw of the sample, the IR power, and their interaction had a significant effect on the penetration depth of the IR, the structural properties of the sample had no significant effect on it. Increasing the infrared power to 601W enhanced the penetration depth in all of the samples. The highest penetration depth into the powder and the seeds of Carum carvi with aw 0.24 was achieved at the IR power of 601W, and was recorded 4.07±0.27 and 3.85±0.23mm while the samples with aw 0.89 were shown the highest penetration depth when they were irradiated by IR power of 845W) 4.12±0.18 and 4.09±0.13mm). According to the results, determining of IR penetration depth in the spice can be used to determine of their optimal thickness during the infrared food process.

Volume 16, Issue 89 (7-2019)
Abstract

Some lactic acid bacteria (LAB), in particular proteolytic strains, in raw milk have useful technological properties and play important role in developing desired characteristics in the final products. However, they are mostly lost during heating and technological processes. Therefore, it would be important to be isolated and maintained for further applications as pure adjunct cultures. In this study, after selective isolation of LAB from raw cow’s, ewe’s and goat’s milks on MRS agar and M17 agar, Gram-positive catalase-negative were selected and maintained as pure cultures. Then, the isolates were screened according to their proteolytic activities on skim milk agar (well-diffusion method). The potent Gram-positive, catalase-negative proteolytic strains were identified via 16S rDNA gene sequencing and antibiotic resistance (10 antibiotic agents, disc-diffusion method) and hemolytic activities (on blood agar containing 5% sheep blood) were evaluated. BLAST analysis resulted in identification of Lactobacillus delbruekii (five isolates), L. delbruekii subsp. bulgaricus, L. fermentum, L. reuteri, L. curvatus, Lactococcus lactis subsp. Lactis, and Streptococcus lutetiensis. L. lactis subsp. Lactis obtained from cow milk showed the highest proteolytic activity as a 23-mm halo zone was observed on skim milk agar plate after 48 h incubation at 37 °C. In case of hemolysin production, only Lactobacillus fermentum showed α-hemolytic activity and the others showed no activities. All the identified isolates were sensitive to tetracycline, ampicillin, erythromycin, vancomycin and gentamycin with the exception of L. reuteri and lactococcus lactis subsp. lactis that found to be resistant to vancomycin and gentamycin, respectively. About penicillin, chloramphenicol, clindamycin, kanamycin and gent streptomycin, the results were varied. Our results verified diversity of wild proteolytic LAB strains in raw milk, as reported before. Although LAB mainly belong to the GRAS list, strains isolated from raw milk should be re-checked for their safety-related properties.

Volume 16, Issue 92 (october 2019)
Abstract

Abstract
Common purslane (Portulacaoleracea L.), a member of Portulacaceae,is a drought and salt-tolerant annual plant,which contains high amounts of beneficial omega-3 fatty acids and antioxidant compounds. In this study, the effect of replacement purslane oil (0.5, 1, 1.5 and 2v/v) to yoghurt on some physicochemical,antioxidant and sensory properties were investigated.The enriched yogurt was examined for 21 days at 4°C. Physicochemical and sensory properties of the yoghurt were investigated at 7 day intervals. The results showed that the effect of treatment and storage time on physicochemical and sensory properties were significant.The pH of the samples containing 2 and 1 v/v purslane oil, decreased during storage; however the synersis of all samples increased. At the first day, the highest viscosity was related to the yoghurt containing 1% purslane oil (5706.7 cantipous). The viscosity of the rest of the samples decreased compared to the control, but on the day 7 until the day21, the highest viscosity was related to the treatment 1.5 v/v. Also, adding 1% v/v purslane oil increased the free radicals scavenging property, but the samples containing 1.5 and 2 v/v had no increasing effect in this regard. In addition, increasing the percentage of purslane oil, increased the amount of linoleic,oleic and α-linolenic fatty acids. Also suitable for increasing the percentage of purslane oil, created significant improvement in sensory properties in the enriched yoghurt. Among the various formulation of yogurt is enriched and controlled, samples containing 1% purslane oil, had the highest degree of desirability in terms of the sensory properties. Therefore, according to the results, it is possible and recommended to add purslane oil as good source functional compounds for the enrichment of yogurt before heating process. The main goal of this study, is to change the degree of non-saturated  and increase the amount of omega-3 in yogurt.

 

Volume 16, Issue 92 (october 2019)
Abstract

Fungal spoilage plays an essential role in the deterioration of food and in the creation of foodborne disease. In addition, the production of various mycotoxins by fungi can cause serious dangers such as carcinogenic, teratogenic, immunotoxic, neuromastoxic, toxic dead, mycotoxicosis and Kashin Beck disease. On the other hand, despite the increasing resistance of molds to synthetic preservatives, that may produce carcinogenic nitrosamine, no effective strategy has been proposed to safely reduce of microbial growth for public health. Therefore, due to the safe and probiotic properties of the lactic acid bacteria that have been approved (GRAS and QPS), can be used as natural preservatives to prevent fungal spoilage of food. The ability to prevent and inhibitory fungal spoilage by lactic acid bacteria is mainly due to the production of antimicrobial compounds such as organic acids, fatty acids, hydrogen peroxide, phenyllactic acid, cyclic delpeptide, proteinaceous compounds, diacetyl, bacteriocin and reuterin. Also, the most important inhibitory mechanisms of lactic acid bacteria against fungal corruption include membrane  destabilization, proton  gradient interference,  enzyme  inhibition,  and  creation  of  reactive  oxygen  species. Therefore, in this paper, it has been tried to overview of antifungal metabolites and their chemical structure, inhibitory mechanisms and probiotic properties of the lactic acid bacteria.

Volume 16, Issue 93 (November 2019)
Abstract

Masske butter or butter derived from yogurt is a traditional butter used in southern Khorasan with a wide range of lactic bacteria. The aim of this study was to investigate the antibacterial effect of lactate isolates against of Staphylococcus aureus and Salmonella enterica. In this research, lactic isolates were first detected by PCR method, and then microdilution method was used to evaluate the antimicrobial activity of the isolates. BLAST of sequences of S16 rDNA gene with sequences stored in the NCBI database led to the identification of the genus Lactobacillus bulgaricus, Enterococcus faecium, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus delbrueckii and Enterococcus hirae. The results of antimicrobial activity evaluation against Staphylococcus aureus and Salmonella enterica bacteria showed that all isolates were able to inhibit the growth of these two pathogens, and their inhibitory percent from 55/46 to 84/49 and from 55/46 to 56/55 respectively was variables. Also, the results showed that Lactobacillus plantarum B38, Enterococcus hierae B224, Lactobacillus delbrueckii B37 had the highest inhibitory effect against Staphylococcus aureus (P>0.05) and Lactobacillus plantarum B38 showed the highest percentage of inhibition against Salmonella enterica (P<0.05). In addition, it was found that the inhibitory effect of all isolates against Staphylococcus aureus was significantly higher than Salmonella enterica (P< 0.05). Therefore, lactic acid bacteria isolated from the Masske butter can be used to control the food borne pathogens and food spoilage microorganisms.
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Volume 18, Issue 1 (1-2016)
Abstract

This study was carried out to evaluate how various amounts of nanozeolite decrease the effects of Aflatoxins (AF) on color and oxidative stability of the broiler thigh meat. Three hundred and thirty six one-day-old Ross 308 male broiler chickens were divided into six groups including a control group, which received diet without AF and nanozeolite, and five treatment groups that received diet with 0.5 ppm of AF, as well as 0, 0.25, 0.5, 0.75, and 1% of nanozeolite. Results showed that broilers fed by AF contaminated diet without nanozeolite had the highest rate of L* and a* values and the lowest rate of b* value (P> 0.05). AF contaminated diet without nanozeolite increased ThioBarbituric Acid Reactive Substances (TBA-RS) significantly, compared to the control group and the treatment groups that received AF and nanozeolite (P< 0.05). Results suggest that nanozeolite (especially 0.75 and 1%) is able to reduce the adverse effects of AF on meat quality, especially lipid oxidation.

Volume 19, Issue 126 (August 2022)
Abstract

In this study, the effect of adding different percentages of malt extract (1.5, 3, 4.5, 6 % v/v) to apple juice on the survival of the probiotic bacterium Lactobacillus plantarum during four weeks of storage at 4 ° C was investigated. In addition, in order to evaluate the physicochemical and sensory properties of the produced juices, pH, acidity, brix, total sugar and sensory evaluation tests were performed. The results showed that with increasing the concentration of malt extract in apple juice, the amount of acidity, brix, total sugar increased and the pH decreased. In addition, the highest acidity and the lowest pH belonged to the apple juice sample containing 6% (v / v) of malt extract. Also, the addition of malt extract improve survival of probiotic bacterium and increased its population in apple juice samples compared to the control sample. Moreover, no significant difference was observed between the populations of L. plantarum probiotic bacteria in apple juice samples containing malt extract at the end of cold storage. In the sensory evaluation test, the highest overall acceptance score by the panelist members was assigned to apple juice samples containing 1.5 and 3% of malt extract, respectively. According to the results of adding malt extract on the properties of probiotic apple juice, the produced juice in this study can be a good alternative to juices available in the market with functional properties.
 

Volume 19, Issue 128 (October 2022)
Abstract

Bioactive peptides are released by proteolytic enzymes of lactic acid bacteria (LAB) during fermentation process which some have antioxidant activity according to their amino acids sequences. The aim of this study was to investigate the proteolytic activity of Lactobacillus rhamnosus GG and Lactobacillus paracasei in drinking dessert mix and to evaluate the antioxidant capacity of this synbiotic drinking dessert in two types of fermented and low-lactose non-fermented. Proteolytic activity of probiotic bacteria was evaluated using the OPA indicator for amino acid residues by optical absorbance. The antioxidant activity also evaluated by optical absorbance method according to DPPH radical scavenging activity. In fermented sample, proteolytic activity of L. paracasei during fermentation time was not significant (P < 0.05), but L. rhamnosus GG had the highest proteolytic activity after 17 h of incubation. During storage time, the highest proteolytic activity for L. paracasei was in 7 and 4 days after storage (P < 0.05) and for L. rhamnosus GG was in the first day of storage. In non-fermented sample the most activity of L. paracasei was related to the first day of storage (0.5). But L. rhamnosus GG proteolytic activity was much less (0.12) and was related to the second day. Antioxidant activity of fermented dessert was not significant which shows that these two probiotic bacteria has no significant antioxidant activity. Comparing the fermented sample and non-fermented drinking dessert, the non-fermented one exhibited higher antioxidant activity due to containing cocoa powder which has antioxidant component. 

Volume 19, Issue 132 ( February 2023)
Abstract

Evaluation of probiotic properties of lactic acid bacteria (LAB) isolated from fermented pseudocereals has crucial importance to prepare microbial cultures. In the present study, after molecular identification, probiotic properties of the predominant LAB isolate were investigated. Sequencing results of the PCR products led to the identification of Lactobacillus brevis SKA01 as the predominant LAB. The survival of the LAB isolate after continues treatment of acid and bile reached to 106 compared to the control sample (108 CFU/mL), and it showed the highest antibacterial effect on Staphylococcus aureus. Meanwhile, there was no significant difference (P>0.05) between inhibitory zone diameter of the S. aureus and Listeria monocytogenes in the present of the LAB isolate.  LAB isolate was capable of good auto-aggregation (36.19%) and co-aggregation with S. aureus (71.24%), and it had no hemolytic activity. Furthermore, it was resistant to most of the tested antibiotics. By considering the proper probiotic potentials of the L. brevis isolated from fermented amaranth, it is possible to use the isolate as microbial starter or probiotic culture in fermentation industries.

Volume 21, Issue 5 (9-2019)
Abstract

In the present research work, the potential probiotic properties of Lactococcus lactis KMCM3 and Lactobacillus helveticus KMCH1 isolated from raw camel milk and traditional fermented camel milk (Chal), respectively, were studied. The probiotic properties of isolates that were investigated included the hemolysis, antibiotic resistance, antibacterial features, resistance to low pH and bile salts, survival under simulated GastroIntestinal Tract (GIT) conditions, adhesion ability to hydrocarbon, and their auto-aggregation and co-aggregation rates. None of isolates exhibited hemolytic activity. They were susceptible against tetracycline, penicillin, ampicillin, chloramphenicol, erythromycin and vancomycin. Lac. lactis KMCM3 and L. helveticus KMCH1 retained their viability at pH 3.0 (8.68 and 8.6 log cfu mL-1, respectively), 0.3% w/v bile salts (8.23 and 8.58 log cfu mL-1, respectively) and under simulated GIT conditions (8.31 and 8.46 log cfu mL-1, respectively). Both of these isolates inhibited the growth of E. coli, S. aureus, L. monocytogenes, B. cereus and S. enterica subsp. enterica serovar Typhimurium with MIC values of 6.25 to 25 mg mL-1. In addition, They exhibited an ability to adhere to hydrocarbon (xylene), and possessed a high auto-aggregation and co-aggregation rate (more than 40%).
 

Volume 21, Issue 156 (February 2025)
Abstract

Protein hydrolysate is a valuable source of bioactive peptides. The production of protein hydrolysate through fermentation is an environmentally friendly approach preferred over enzymatic and chemical hydrolysis in most cases. This research employed Bacillus species, including Bacillus pumilus, Bacillus coagulans, Bacillus licheniformis, and Bacillus subtilis, to hydrolyze sesame meal protein. The investigated tests included measuring the concentration of peptides by the OPA method, DPPH radical inhibition, and iron ion reducing power, total antioxidant activity, and iron ion chelating activity. The concentration of peptides was evaluated after 24 h for Bacillus species. The lowest peptide concentration (0.656 mg/mL) was associated with the fermented treatment by B. licheniformis, while the highest value (1.38 mg/mL) was observed for the hydrolyzed treatment with B. subtilis. A significant difference (p<0.05) was observed among all the treatments. Results of DPPH radical inhibition showed the highest inhibition was associated with the samples hydrolyzed by B. coagulans (76.6%), and the lowest value was attributed to the hydrolysate by B. licheniformis (57.36%). The sample fermented with B. pumilus exhibited higher reducing power (0.992 absorbance at 700 nm) with a significant difference (p<0.05) observed between the treatments. The highest chelating activity (85.6%) was observed in the sample fermented with B. subtilis. The total antioxidant activity demonstrated that the protein hydrolysate with fermentation by B. coagulans had the highest absorbance value at 695 nm with a significant difference between the treatments (p<0.05). In conclusion, the fermentation of sesame meal protein by Bacillus species resulted in the production of protein hydrolysate with substantial antioxidant activity, positioning it as a promising source for inclusion in food formulations.

Volume 21, Issue 156 (February 2025)
Abstract

The aim of the current research was microencapsulation of Streptococcus thermophilus and Lactobacillus bulgaricus bacteria by coacervation complex method and sodium caseinate and pectin coatings. Sodium caseinate and pectin have electrostatic attraction together at pH=4 and form a complex. Using a scanning electron microscope, the morphology of coacervates was investigated. The properties of pectin and sodium caseinate complexes were investigated by infrared spectrometry tests and measuring the size and distribution of particles. Physicochemical characteristics such as water absorption, pH and acidity and sensory characteristics were also investigated. The results showed that the efficiency of microencapsulation of bacteria by coacervation method was 66.6%. The particle size was 1.565 micrometers and the zeta potential was reported as -16 mV. Electron microscope images showed spherical coacervate without holes and wrinkles on the surface. The results of infrared spectroscopy also showed the creation of electrostatic interactions between pectin and sodium caseinate. Also, microencapsulation of bacteria caused a significant change (p>0.05) in pH (4.6 ± 0.091) and yogurt acidity (1.1 ± 0.03) compared to pH (4.6 ± 0.1). And the acidity of yogurt (0.8±0.01) produced with free bacteria did not. The water content of yogurts produced with microencapsulated bacteria (40±1.1) was reduced compared to yogurts produced with free bacteria (45±0.9) (p<0.05). Bacterial encapsulation has a negative effect on color sensory characteristics. It did not have the smell and taste of the produced yogurts (p>0/05), but a significant difference was observed in the texture of the yogurts produced with microencapsulated bacteria compared to the yogurts produced with free bacteria (p<0/05).
 

Volume 22, Issue 158 (April 2025)
Abstract

Ready-to-feed liquid infant formula  (LIF) is used for preterm infants when human milk is unavailable. However, sterilization of liquid infant milk using ultra-high temperature  (UHT) treatment leads to the formation of Maillard reaction products  (MRPs), which may negatively impact the immune system and kidney development. In this study, infant liquid milk, after being prepared at the Pegah Tehran pilot plant, was subjected to UHT treatment  (137°C for 3 seconds). The color indices, nutritional content, and initial Maillard reaction products were examined before and after the UHT process. The findings revealed that there were significant differences in the numerical values of L*, a*, and b* indices before and after thermal processing  (p<0.05). The available lysine content before and after UHT treatment was 2.30±0.23 and 1.99±0.05 % in dry matter, respectively  (13.48% reduction). The amount of Furosine  (early-stage indicator) before and after UHT treatment was reported as 60.64±0.91 and 178.57±1.51 mg per 100 grams of protein, respectively. Vitamin C levels, another nutritional index, decreased during the UHT process  (before and after UHT treatment were 147.15±0.49 and 128.29±1.65 mg per kilogram, respectively). Overall, while UHT treatment has benefits for food safety, it significantly reduces the nutritional value of infant liquid milk through Maillard reaction products.


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