Search

Bread is the main food in providing energy and protein in the diet of Iranian society. Therefore, the consumed bread must be of good quality, and one of the effective factors in its quality is the consumed flour gluten quality and quantity, which unfortunately, these factors are not desirable for wheat produced in Iran. One of the ways to decrease this problem is to use enzymes in the bread production flour. In this research, the effects of adding glucose oxidase (GO) and trans glutaminase (TG) enzymes in amounts of 0 to 30 ppm, α-amylase (AM) in amounts of 0 to 50 ppm and xylanase (XA) in amounts of 0 to 100 ppm on rheological properties of the Barbary and Lavash bread dough were prepared and analyzed using the response surface method (RSM) and the properties of the resulting dough were studied by farinograph, Falling number and alveograph rheological tests. The results of statistical analysis using Design Expert software showed that in different amounts of TG and GO, increasing AM caused a decrease in falling number. AM and XA decreased the amount of water absorption based on farinograph, but their interaction was not significant. At high amounts of AM and TG, farinograph index (FQC) was at its highest value. The increase of AM decreased the P index of the alveogram, whereas, the increase of GO and XA when used individually increased this parameter. The interaction effect of the last two enzymes was also significant and the median value of both which decreased P index. In Barbary and Lavash bread, the values of TG and GO in the maximum amounts (30 ppm) and AM in the values of 16 and 23 ppm were the most effective. The effect of XA enzyme was not significant in Barbary bread, but 23 ppm of XA showed a positive effect in Lavash bread. [ABSTRACT FROM AUTHOR]

Introduction: Glucose oxidase (GOX) is considered a commercial enzyme in the medicine, pharmaceutical, and food industries. Optimization of the fermentation medium and conditions is important to increase heterologous GOX production. The current study aimed to optimize GOX production in a ‎recombinant strain of Yarrowia lipolytica via statistical techniques. Materials and Methods: Response surface methodology (RSM) as a statistical technique for the design of the experiment was used for the optimization of recombinant GOX production by Y. lipolytica. Then, the optimized conditions were used for the production of GOX in bioreactor cultivation. Results: GOX production was increased up to 570 U/L after optimization of the medium in flask culture which is 2 times more than the non-optimized medium. In the bioreactor culture using optimized medium containing glucose and sucrose as carbon sources, GOX production was reached 720 and 730 U/L after two and six days, respectively. Discussion and Conclusion: Results of the study provided valuable information about the statistical optimization of bioprocess development for the production of heterologous protein in Y. lipolytica.

Honey is a natural product that has long been used for treatment in addition to nutrition. In this regard, the antimicrobial effect of some Iranian kinds of honey against antibiotic-resistant bacterial strains and the relationship between this effect and the enzymatic activity of honey samples were evaluated. In this study, the protein content of 20 honey samples before and after extraction was determined and analyzed by SDS-PAGE technique. Then the activity of glucose oxidase, amylase, invertase, and catalase enzymes of each honey was measured. Inhibition of the tested bacterial strains in the presence of honey was investigated by ager well diffusion method and the relationship between enzymatic activity with antibacterial effect and freshness of honey was evaluated. The protein content of the samples before extraction ranged from 0.4 06 0.06 to 1.0 64 64.19 mg/g honey and after extraction this amount decreased by about 50% or less. In the protein profile of all kinds of honey after electrophoresis, 3 bands related to amylase, invertase, and glucosidase enzymes were visible. The activity of enzymes was assigned to glucose oxidase> invertase> amylase> catalase, respectively. The selected honey samples did not affect Staphylococcus epidermidis and had the least effect on Pseudomonas aeruginosa. After honey inoculation, the inhibitory pattern of Escherichia coli and Enterococcus faecalis were similar, but a different inhibitory pattern was observed from Staphylococcus aureus strain. This study showed that glucose oxidase plays an important role in bacterial inhibition, but this role fluctuates in catalase-positive strains. Also, Amylase and invertase enzymes can be a measure of the freshness of honey. [ABSTRACT FROM AUTHOR]

The polyaniline-glucose oxidase (PANI-GOD) electrode has been investigated in the present work. Polyaniline (PANI) film via cyclic voltammetric method was synthesized at room temperature, in a standard three-electrode cell. Aniline films were deposited from 1 M acidic (H2SO4) aqueous media containing0.2 M aniline by voltammetric sweep between −0.1 V and 1 V, Ag/AgCl, at 50 mV/s. The sweep was stopped after 30 cycles at −0.1 V Ag/AgCl and the working electrode was deposited by polyaniline. Platinum plate (0.4cm×0.4cm), platinum rod and Ag/AgCl electrodes were used as working, counter and reference electrodes, respectively. The synthesized PANI films were characterized by electrochemical technique, electrical conductivity, UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS). A simple technique was used for fabrication of a glucose sensor. In this method glucose oxidase as an enzyme was immobilized by glutaraldehyde 0.1% as cross-linking agent and kept pH around 7 using 0.1 M phosphate over polyaniline thin films, glucose oxidasewas deposited on a platinum plate in phosphate or acetate buffer. The results of EIS indicated the successful immobilization of enzyme over polymer films. Effects of some experimental variables such as cross-linking agent volume content, pH, applied potential, and temperature on the amperometric response of the sensor were investigated. It was obsereved that the activity of modified electrodes changed with various amounts of cross-linking agent volume percent. The activation energy for polyaniline-modified electrode in acetate and phosphate buffer were obtained as 41 and 37 kJ/mol, respectively. A maximum current response was resulted at pH 7 and potential 0.65 V (versus Ag/AgCl).

Background and Objective: According to recent changes in diagnostic criteria for diabetes, the harmonization of results obtained from various methods and systems by considering their accuracy and precision is essential. This study aimed to evaluate the accuracy, precision and consensus of some routine laboratory glucose kits in comparison with Hexokinase reference method. Material and Methods: The participants were 38 diabetic patients with fasting blood sugar (FBS) ≥126 mg/dl, nine prediabetic patients with FBS of 100-125 mg/dl, 15 non-diabetic people with FBS of 60-100 mg/dl and 9 hypoglycemic patients with FBS of ≤60 mg/dl. Their FBS were measured by four routine laboratory glucose kits: Glucose oxidase on BT3000 analyzer with an open system and Hexokinase reference method on a close system (COBAS INTEGRA®400plus analyzer, Roche kit). Accuracy and precision were determined and compared with reference method. Results: Glucose oxidase methods showed a good agreement with the reference method, in Correlation Coefficient>0.99. based on regression analysis, the slope of 1.114 for Pars Azmoon, 1.105 for Bionik, 1.121 for Elitech and 1.087 for Human were reported (P<0.05). Error of the mean for ParsAzmoon was 12.79, for Bionik 10.86, for Elitech 12.58 and for Human were 8.46. Coefficient of Variation showed more imprecision for Bionik and Human kits. Conclusion: given the same almost standard errors, standard devisions and regression analysis, the precision in four methods is the same but in comparison with Hexokinase, reference method has not the accuracy. [ABSTRACT FROM AUTHOR]