Showing 8 results for Sarabi Jamab
Volume 2, Issue 3 (Autumn 2019)
Abstract
Molecular imprinting is a novel technique for preparing specific absorbents with selective sites for binding to the target molecule. Molecularly imprinted polymers, because of their high selectivity and stability, low cost and easy methods of preparation, have been widely employed in separation procedures. In this study, we evaluated the synthesized electrospun imprinted membrane (MIM) as a specific sorbent for herbicide mecoprop (MCPP). The films were prepared using methacrylic acid (MAA) as functional monomer and polyethylene terephthalate (PET) as a main part of polymeric solution and in the presence of dichloromethane (DCM) and Trifluoroacetic acid (TFA) as the solvents. The template was extracted through washing, results in the free specific memory sites within the films. Then, the synthesized electrospun imprinted membrane (MIM) was evaluated as a specific sorbent for herbicide mecoprop (MCPP). The results showed that the solution with 20% w/v of PET was the optimal solution for electrospinning process and at all different MCPP/MAA molar ratios (1:2, 1:4. 1:6 and 1:8), MIM had higher removal ability for template molecule (p<0.05) compared to NIM. The template/monomer ratio of 1:4 had the best binding amount. We also investigated the capability of MIM to be used as sorbent for pesticide 2,4-D, that is, the analogue of the main template molecule and diazinon, that is, the pesticide with different structure to the template. In addition, we used synthesized MIM and NIM films to extract MCPP analyte from environmental aqueous samples (bottled water and groundwater) and the results indicated successful performance of MIM compared to NIN.
Volume 13, Issue 61 (3-2016)
Abstract
Volume 16, Issue 90 (August 2019)
Abstract
This study was carried out to determine the sources of microbial contamination in Doogh production line during a year in a dairy factory. Samples were taken from different control points from the beginning to the end of the production line including raw milk, pasteurized milk, water, culture, Doogh yoghurt, pasteurized Doogh, packed Doogh, filler and filling air duct, storage hall for pasteurized Doogh, and filling and storage rooms. The microbial analysis of the samples was performed to determine the total count of microorganisms, mold and yeast, coliforms, E. coli, Psychrophilic and thermophilic microorganisms, lactic acid bacteria and coagulase positive staphylococci in accordance with national standards of Iran. The results showed that Doogh health quality depends on the quality of raw milk, the adequacy of heat treatment, microbial quality of the ingredients and packaging materials, doing suitable CIP and disinfectantion of processing surfaces and factory environment. The results indicate that the assessment of critical control points and the organization of automatic control systems are necessary in order to eliminate or minimize the risk of microbial contaminats.
Volume 17, Issue 101 (july 2020)
Abstract
Due to the growing demand for biocompatible natural ingredients, the use of hydrocolloids in the food industry is on the rise. Restructured foods are one of the most important aspects of the food industry, involving a complex mix of ingredients, as well as texturing and structuring processes. Achieving an optimal formula for gel formation with appropriate elastic texture can allow for the industrial application in various stuffed products such as olives and related products. Therefore, in this study, gelatin as a gelling agent at 3, 4 and 5 wt% and guar gum as a thickening agent at 0.5 and 1.5 wt% in 1 wt% citric or lactic acid were selected as restructured Ricotta cheese formulation and evaluated of textural properties and shelf-life. Tests included textural characteristics, gel stability, and shelf-life of the restructured cheese. Therefore, the appropriate formula of restructured cheese with appropriate textural properties was selected and evaluated for microbial properties. Due to the importance of sensorial properties of this restructured product, its sensory characteristics were also investigated. Process conditions during storage of samples were also investigated in citric and lactic acid. Finally, the formula containing 4% gelatin and 0.5% guar gum in the solution containing 1% citric acid was selected as the desired sample.
Volume 17, Issue 108 (February 2021)
Abstract
In this research extraction of Salvia leriifolia leaf was carried out using two extraction methods including traditional solvent extraction (with different solvent ratio of water /ethanol 50:50, 60:40 and 70:30 at temperature 70, 80 and 90 ºC and time duration of 30, 75 and 120 min), and superheated solvent extraction (at temperature 130, 145 and 160 ºC, time duration of 10, 20 and 30 minutes and solvent ratio of water/ethanol 60:40, 80:20 and 100:0) and the antimicrobial activity of extracts against some of food microorganisms using minimum inhibition concentration and minimum bactericidal concentration methods were measured. In both extraction methods, the MIC of most microorganisms was 0.5 mg/ml, while the MBC, depending on the microorganism, was between 5 and 500 mg/ ml. In the conventional solvent extraction procedure, the treatment was carried out at a temperature of 80 ° C, 75 minutes, and equal ratio of two solvents, and in superheated solvent extraction method, treatment including temperature of 160 ° C, time of 20 minutes, and water/ Ethanol ratio of 80 to 20 showed the most antimicrobial activity. Based on the results, it can be stated that the type of plant extraction method has a significant effect on inhibiting or preventing the growth of food borne or spoilage microorganisms, and if any of the plant extraction technique are optimized, they can be better used to increase the shelf life of food.
Volume 18, Issue 120 (February 2021)
Abstract
Gamma aminobutyric acid (GABA) is a non-protein bioactive compound that can be effective in controlling many diseases such as Alzheimerchrs, hypertension, stress, etc. The main stimulus for the production of GABA is the enzyme glutamic acid decarboxylase (GAD), which is highly active in lactic acid bacteria. Also, the presence of monosodium glutamate (MSG) can act as a substrate for this enzyme and increase its activity. In this study, the production potential of gamma aminobutyric acid by Lactobacillus brevis PML1 in MRS medium was investigated. In order to optimize the fermentation process, culture medium containing MSG (1, 3 and 5%) was examined at 24, 48 and 72 hours. after fermentation, thin layer chromatography method was used to identify GABA produced by bacteria. Spectrophotometric method was used to quantify the bands in thin layer chromatography. The results of studies at the level of 95% significance showed that the optimal treatment included a culture medium containing 5% monosodium glutamate and a time of 72 hours at 37 ° C, in which the amount of GABA production was approximately 300 ppm; Therefore, the desired strain not only has the potential to produce gamma aminobutyric acid under normal conditions (control sample) but also by adding different percentages of monosodium glutamate to the culture medium, the amount of this production can be increased.
Volume 19, Issue 128 (October 2022)
Abstract
In this study, the extract of Hypericum Perforatum aerial organs was prepared by hydro alcoholic solvent and the extract was coated in calcium alginate nanoparticles and the antimicrobial properties of the extract and nanoparticles on four gram-positive, gram-negative yeast and mold groups were investigated and Nanocapsules containing extract were evaluated on the shelf life of white cheese. To prepare Nano-extracts, the emulsion production method of alginate-calcium Nanocapsules containing the extract was used. The production of Nanocapsules containing the extract was done by adding calcium chloride nanoparticles to the alginate Nanoemulsion containing the extract in a ratio of 1 to 6 for 4 hours. To prepare the cheese, Staphylococcus aureus, Escherichia coli, and Candida albicans yeast are inoculated separately into the milk at a rate of 103 CFU / ml and then added calcium chloride, Rennet enzyme, extract and Nanocapsules containing extract to milk were done and the microbial properties of the cheese samples were evaluated on the day of production and up to seven days after. The results of particle size determination, particle size dispersion index, and potential and efficiency of encapsulation for the production of Nanocapsules containing Hypericum Perforatum extract and its microscopic examination confirmed the production of nanoparticles with appropriate efficiency of encapsulation. Also, the results showed that for all three microorganisms tested, the sample containing Nano-extract was able to reduce about one logarithmic cycle of the inoculated microorganism and during the shelf life of gram-positive, gram-negative and yeast had a downward trend (P <0.05). The results of the present study showed that using plant extracts containing antimicrobial compounds such as extracts of aerial organs of Hypericum Perforatum plant, especially in Nanoparticle and in appropriate quantities, as an alternative to synthetic preservatives, produce a healthy food product and with longer shelf life, it will be possible.
Volume 20, Issue 5 (7-2018)
Abstract
The present study aimed to evaluate effectiveness of Superheated Solvent Extraction (SSE) compared with instant Controlled Pressure Drop (DIC) assisted Solvent Extraction (DIC-SE) on total phenolic, flavonoids, and anthocyanins compounds from pomegranate peels. The effects of temperature, extraction time, and water:ethanol ratio for SSE method, and temperature and heating time for DIC-SE were studied. The highest phenolic compounds, flavonoids, and extraction yields by SSE was achieved at 160˚C, ethanol: water 50:50 and 20 minutes, subsequently in the DIC-SE, the most effectiveness was approached at 150˚C for 5 seconds (P< 0.05). The SSE improved the total phenolic compounds (563.16±1.04 mg g-1), anthocyanins (285.11±1.02 mg 100 g-1), extraction yield (68.7%) and shortened the extraction times compared to DIC-SE, but flavonoid content was more in DIC-SE extract (439.07±0.05 mg g-1). Based on HPLC analyses, gallic acid was not detected in any of the obtained extracts, but the amount of ellagic acid and punicalagin A and B in DIC-SE extract was higher than SSE. The current study clearly shows that the SSE is an effective extraction method to obtain phenolic compounds and the DIC is an advantageous pretreatment for extraction of flavonoids from pomegranate peels.
