Showing 13 results for Acetic Acid
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: In this study, EDTA-functionalized Fe3O4@SiO2 magnetic nanocomposites with core-shell structure were synthesized to remove divalent cadmium ions from aqueous solutions.
Research approach: During the first step, Fe3O4@SiO2 nanosphere core-shell is synthesized using nano Fe3O4 as the core, TEOS as the silica source and PVA as the surfactant. This strategy relies on the covalently bonding of ethylendiaminetetraacetic acid to bis(3-aminopropyl)amine and cyanuric chloride functionalized magnetic nanoparticles. In the next step, characteristics of surface functional groups, crystal structure, magnetic properties, size and surface morphology of these nanoparticles were investigated, identified and analyzed using physico-chemical characterization techniques including fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), vibration sample magnetometry (VSM) and Brunauer-Emmett-Teller (BET) surface area analyzer. The adsorbent, due to its magnetic property, could be simply separated from the reaction mixture by a permanent magnet and reused in five consecutive cycles without considerable loss in its activity.
Main results: To probe the nature of the adsorbent, various experiments were investigated like adsorbent dose and contact time were optimized. Kinetic studies and the effect of different amounts of adsorbent to remove divalent cadmium ions from aqueous solutions show a maximum adsorption of 94% at ambient temperature. Moreover, the recyclability of Fe3O4@SiO2-EDTA was investigated in order to remove the divalent cation for successive adsorption-desorption cycles. All the results of studies show that the synthetic nanocomposite Fe3O4@SiO2-EDTA is an effective, recyclable adsorbent with excellent performance for the removal of divalent cadmium.
Volume 7, Issue 1 (7-2023)
Abstract
Contamination of water and soil with heavy metals poses serious risks and threats to human health and the environment, and therefore finding an effective solution to remove these metals is very necessary. In this research, magnetic nanoparticles MnFe2O4 @ SiO2 functionalized with N-phosphonomethyl aminodiacetic acid with core-shell structure were synthesized. These nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, (TGA) thermal gravimetric analysis, transmission electron microscope (TEM), and (VSM) vibration sample magnetometer. The performance of this synthetic nanoadsorbent for removing Cr (VI), Cu (II) ions from aqueous solutions was evaluated by various parameters such as adsorbent amount, contact time effect on adsorption rate and pH effect. The results show that the adsorption efficiency increases with raising pH (2.5-5) and the best adsorbent performance in the adsorption process of Cr ((VI) and Cu (II) ions at pH 7 was observed. The amount of R in the Freundlich adsorption diagram of copper ion is higher than the Langmuir isotherm. As a result, the adsorption of copper ions on the adsorbent follows the Freundlich adsorption equation. In addition, the amount of R in the Freundlich adsorption diagram for chromium ion is higher than the Langmuir isotherm. Therefore, the absorption of chromium ions on the adsorbent follows the Freundlich adsorption equation. In conclusion, a high n value indicates a favorable and effective absorption in the Freundlich equation. The adsorption data were analyzed by the Langmuir and Freundlich isotherm model. In addition, the recyclability and reuse of the adsorbent was investigated. The results show that no significant reduction in adsorbent activity is observed.
Volume 7, Issue 24 (4-2010)
Abstract
Simple and corresponding impacts of organic acidifiers ( Lactic acid, Acetic Acid and Citric acid) with three levels( 0%,0.25% and 0.5 %) on specific volume and dough fermentative parameters was conducted by a completely randomized design with factorial arrangement and three replications. At the next stage an orthogonal comparison between selected acidified treats (having control sample) with sourdough treats was made.
The study showed that addition of each of these acidifiers had a significant effect on the mentioned property. Also statistical analyses revealed that, corresponding impacts of all the three acidifiers on the feature was significant (P<0/05).
Finally the studies distinguished that type and amount of acidifiers used in this study don’t have any bad impact on the structure of dough gluten, so that the increase of acidity of these samples resulted in increase of bread specific volume .Also, orthogonal comparison between selected acidified treats (having control sample) with sourdough group indicated that considering specific volume property, these two groups did not show any significant differences.
Volume 8, Issue 30 (7-2011)
Abstract
Kombucha is a non-dairy fermented beverage. Traditional substrate for kombucha production is sweetened black tea. Kombucha culture can also use other carbohydrates such as inulin and oligofructose as a substrate. In this study inulin and oligofructose extracted from Jerusalem artichoke tuber at 0, 2, 4, 6, 8 and 10% were used as substrates for kombucha fermentation. The chemical changes during fermentation period were compared with those occurred during traditional substrate fermentation at the same concentrations. The rate of inulin fermentation by kombucha culture was higher than that of sucrose fermentation. The pH value in kombucha produced with inulin was higher than that of traditional product. Acetic acid and lactic acid measurements using HPLC showed that the acetic and lactic acid contents of traditional product was higher and lower than the kombucha produced with inulin, respectively. Soluble protein content and antioxidant activity was higher in kombucha produced with inulin as a substrate. Thus, using inulin as a substrate for kombucha culture decreases fermentation time and produces a product with high pH.
Volume 8, Issue 31 (8-2011)
Abstract
In this study the effect of hot water, acetic acid and sodium chloride solutions on the accelerated ripening
of Mazafati date cultivar was investigated. Except for the cold storage control (Blank), other samples (control sample and samples that immerged in water, acetic acid (0.5, 1.5 and 2.5%) or NaCl (1, 2 and 3%) solutions with 60˚C for 5 min) were incubated at 39±1 ˚C for 80 hrs. The results indicated that incubation was the main factor in ripening of the date and about 85% of the control samples ripened only by incubation. Acetic acid and NaCl solutions had complementary and accelerating effects. Total solids, total soluble solids and acidity of the samples increased while the pH, water insoluble solid, hardness and color parameters (L*a*b*) decreased during ripening for all samples except for blank sample. Overall, the treatment by hot acetic acid solution (0.5%) followed by incubation at 39±1˚C can be used as a good candidate for accelerated ripening of Mazafati date.
F. Moghadami, M.r. Soudi ,
Volume 9, Issue 2 (9-2018)
Abstract
Aims: Adaptation of native bacterial strains in every climate is considerable. Evaluation of native thermotolerant acetic acid bacteria effectively influence their optimal and beneficial use. The aim of this study was to evaluate the characteristics of productive thermotolerant acetic acid bacteria with focusing on Acetobacter sp. A10.
Materials and Methods: In the present experimental study, the native thermotolerant strain of Acetobacter sp. A10 was used. For preparation of fresh culture and maintenance of thermotolerant strain glucose yeast extract calcium carbonate was used, which contained 50g glucose, 10g yeast extract, 30g calcium carbonate, and 25g agar per liter. In order to produce acetic acid by the strain of Acetobacter sp. A10, ethanol yeast extract broth culture was used. Effect of initial concentrations of ethanol and acetic acid on the production of acetic acid by Acetobacter sp. A10 was investigated, using a culture meda containing 2% to 9% ethanol and 2% to 9% acetic acid.
Findings: This strain could produce 40g/l acetic acid from 4% (WV) ethanol in baffled shake-flasks in 24h under optimized conditions of pH 4, at 33°C, and 150rpm. The strain at 37 °C was able to produce acetic acid in the presence of a 4% and 8% initial concentration of acetic acid a. The rate of fermentation was 2.5 times more than mesophilic ones.
Conclusion: Acetobacter sp. A10 is active in a different temperature range compared to mesophilic strains and it is able to withstand ethanol and acetic acid to more concentrations. In addition, it has higher efficiency, as well as greater rate and power of fermentation.
Volume 12, Issue 49 (10-2015)
Abstract
The ability of bacteria to tolerate low pH is a very important trait to survive in a variety of environments. In the literature, there is a lot of information about the acid tolerance of different bacteria. However, little is known about the acid tolerance of Morganella morganii, the most prolific histamine former in fish and seafood products. Therefore, in the present study, the effect of growth phase, type of acid and medium on the acid tolerance of M. morganii at different pHs were evaluated. To achieve this purpose, cells of M. morganii in exponential or stationary growth phases were exposed to low pHs (3, 4 and 5) adjusted by adding hydrochloric, acetic, lactic, citric or tartaric acids into TSB or PBS for one hour. Survival percentage was obtained by dividing the surviving population by the initial population. In general, results of the present study showed a high acid tolerance of M. morganii. For all the acids tested, the lower the pH of the mediums used, the lower the survival percentage observed. Cells of M. morganii in the stationary phase were more resistant to acidic conditions tested and no significant difference was observed (p<0.05) in the acid tolerance of M. morganii in TSB and PBS at different pHs. In addition, acetic acid and lactic acid showed more antimicrobial effect on both the stationary and exponential phase cells than the other acids use.
Volume 14, Issue 5 (9-2012)
Abstract
Bacteria of the genus Azospirillum are well known as plant growth promoting rhizobacteria. The ability to synthesize phytohormones is considered one of the most important mechanisms to promote plant growth and is widely distributed among plant-associated rhizobacteria.The most important phytohormone produced by Azospirillum is the auxin indole-3-acetic acid, with the L-tryptophan as the precursor. In the present study, we evaluate the capacity of eight Azospirillum strains isolated from rice and wheat, to produce in vitro auxins using plant exudates. Our results show that isolates produced auxins in tryptophan free media, but, generally, the amount produced increased when the tryptophan concentration increased. Some plants root exudates had a similar effect to tryptophan for the auxin production. In this sense, bean, rice and canola root extracts produced, respectively, 93.3%, 96.2%, and 88.31% more auxin than L-tryptophan. Azospirillum sp. isolate A3 had the maximal capacity to produce auxin. Therefore, the effect of cell free supernatant was studied on rice root development. Statistical analysis did not show any significant difference between root number and dry weight of the treated and control seedlings. However, significant differences were observed in root length and wet weight at α=0.01 and α=0.05, respectively.
Volume 16, Issue 94 (12-2019)
Abstract
The aim of this study was determining the concentration of heavy metals as Lead, Cadmium and Tin in canned peas, with pre-treatment by 5 and 10-minute blanching and using citric acid, acetic acid and phosphoric acid at concentrations of 0, 0.25 and 0.5%. The samples were manufactured and sealed commercially. The evaluation of mentioned heavy metals was carried out using by flame photometric method. The response surface method was carried out in central composite design, and data analysis was done using Design Expert software. The effect of the dependent variables in quadratic model is evaluated. According to the results, the highest levels of Lead, Cadmium and Tin were 0.43, 0.61 and 87 parts per million respectively and the lowest was zero, 0.14 and 10.43 parts per million, respectively. The results showed that increasing the blanching time reduced the lead, cadmium and tin amounts at 1% level. On the other hand, increasing the concentration of acetic acid, citric acid and phosphoric acid to its highest level would yield the best results to achieving the lowest amount of these elements during blanching.
Volume 19, Issue 123 (5-2022)
Abstract
Grape fruit contains some nutrients and high amounts of biologically active phenolic substances, but fungal decay and quality loss are important factors limiting its shelf-life for fresh-consuming and export. Rasheh vine (Vitis vinifera cv. Rasheh) is mainly grown in rainfed vineyards in the western half of Iran, and its berries are rich in anthocyanins, flavonoids and soluble solids. In this study, the effect of natural coatings of nano-chitosan and acetic acid on the post-harvest quality characteristics of Rasheh grape fruit was investigated. Nano-chitosan suspension with a particle size distribution of 5-30 nm was prepared in acetic acid solution by the conventional ionic gelation method. Grape fruits were coated by immersion in the nano-chitosan suspension (0.2%), acetic acid solution (0.5%) or distilled water (control) for 1 min and their microbial, physicochemical and sensory properties were measured during 8 weeks storage at 4 °C and 90% relative humidity. In general, the fruits coated with nano-chitosan or acetic acid had lower aerobic mesophilic bacteria count, mold and yeast count and decay percentage, and higher firmness, soluble solids, titratable acidity and vitamin C, as well as, better sensory properties, compared to the control. The nano-chitosan was more effective than acetic acid in improving the post-harvest quality and shelf life of grape fruit. No significant difference was observed in the weight loss percentage and pH values of the samples. Therefore, the nano-chitosan suspension prepared in acetic acid solution, as a natural and customer-friendly coating, is suitable for improving the shelf-life and post-harvest quality of grape fruit, but some of its beneficial effects are due to acetic acid.
Volume 19, Issue 131 (12-2022)
Abstract
Palm kernel is one of the major agricultural wastes and industrial uses of dates. Palm kernels in Iran are often disposed of as waste or used for animal feed. In this research, this low value material was investigated and a product with a high purity value of carboxymethylcellulose was produced from it. Palm kernels contain about 63% cellulose. Cellulose along with hemicellulose and lignin are its main constituents, which form a strong fibrous structure. In this study, cellulose was extracted from palm kernel powder by treating sodium hydroxide and sodium chlorite. The extracted cellulose was converted to CMC using two processes: alkaline cellulose and ether cellulose. SEM was used to study the structure of CMC, which removed the surface impurities of the fibers and the swollen spherical shape of the fibers indicated the suitability of the method used. To identify the carboxymethyl groups substituted on cellulose, FTIR spectroscopy was used, which confirms the peaks in the wave numbers of 1425 and 1612 / cm. The optimization results showed that at a concentration of 29.799% sodium hydroxide, the weight ratio of sodium monochloroacetic acid to cellulose was 1, temprature 68 ° C and a reaction time of 158 min, the highest degree of substitution and purity and efficiency were obtained. It turns out that these highest degrees of extraction and degree of purity and efficiency are 0.97, 97.99 and 166.80%, respectively. Also, the viscosity of 3% CMC solution in water at 50 rpm was 347.93 ms.
Volume 20, Issue 137 (7-2023)
Abstract
Frankincense is a resinous gum obtained from some species of the Boswellia genus. The use of frankincense for food and medicinal uses dates back to more than five thousand years ago, but despite its importance and application, only 27-35% of it is soluble in water. As most frankincense gum is insoluble, this research used the response surface method to study the effect of different chemical modification conditions (NaOH concentrations (X1), reaction temperatures (X2), and MCA concentrations (X3)) on increasing the solubility percentage. The results of the optimization process of the chemical modification of frankincense gum indicate that the conditions of maximum solubility are equal to 85.49, with a desirability rate of 0.97. Therefore, the concentration of NaOH and MCA equal to 0.048, 0.01 mol, and a temperature of 75 degrees Celsius chose as the best optimization conditions. In addition, the intrinsic viscosity and molecular weight of the native gum were higher than the modified gum under optimal conditions. There is a significant difference between the apparent viscosity of natural gum (18.02 ± 0.726 mPa.s) and modified (17.36 ± 0.681 mPa.s) (p>0.05). The results indicate that native and modified gum in optimal conditions show a shear thinning behavior with increasing shear rate, and their behavior is similar to pseudoplastic. The colorimetric test with image J software indicated that carboxymethylation of frankincense gum led to significant changes (P < 0.05) in the total color difference factor (ΔE) and whiteness index (WI), L*, a*, and b*factor.
Volume 22, Issue 1 (1-2020)
Abstract
Plant cells have enough capacity to produce many of secondary metabolites, similar to the whole plants. Elicitation is one of the most significant methods to increase the synthesis of secondary metabolites in the medicinal plants. The purpose of this study was to investigate the effect of three different hormones on alkaloids production in suspension culture of Papaver bracteatum Lindl., in order to identify the relationship between the alkaloid biosynthesis and gene expression. Inducible factors initiate BenzylIsoquinoline Alkaloids (BIAs) biosynthesis in Opium poppy. The current study investigated the accumulation of alkaloids content and Tyrosine/DopadeCarboxilase (TYDC), Berberine Bridge Enzyme (BBE), Salutardinol Acetyl Transferase (SAT), and Codeinone Reductase (COR) gene transcripts in suspension culture of P. bracteatum. Indole-3-Acetic Acid (IAA), Indole Butyric Acid (IBA) and Gibberellic Acid (GA) were used as hormonal elicitors in the suspension cultures with three different doses and two timings along with the control. This research showed the induction of morphine alkaloid in the suspension culture of P. bracteatum. Elicitation by 20 mg L-1 concentration of IAA after 48 h indicated significant increase in morphine amount. Comparison among genes revealed that the expression levels of COR dramatically increased while TYDC, BBE and SAT had no significant difference compared to the control. After elicitation by IAA, IBA, and GA, the highest levels of morphine were measured as 243.2, 207.2, and 178.1 mg g-1, respectively. The results demonstrated that timing had a significant effect on the hormonal elicitation: 48 h treatment could induce more morphine alkaloids compared to 24 hours treatments.