Showing 7 results for Beigmohammadi
Volume 16, Issue 91 (September 2019)
Abstract
In the present study, the optimization process of phenolic compounds extraction and antioxidant activity (DPPH radical-scavenging assay, FRAP test, and oxidative stability index) of Ferula persica was evaluated using ultrasound waves through response surface methodology (RSM). To optimize the extraction process from the central composite design with three independent variables including time (5, 27.5 and 50 minutes), temperature (25, 45 and 65 ° C) and ethanol ratio in water-ethanol solvent (0, 50 and 100% ) was used. In general, the results of analysis of variance showed that independent parameters had a significant effect on the DPPH radical-scavenging assay, FRAP test, and oxidative stability index of Ferula persica extract, their Correlation coefficients (R2) were 0.91, 0.94 and 0.93, respectively. However, the proposed model for total phenolic compounds does not indicate the significant effect of these mention parameters. The results showed that the optimum conditions for antioxidant activity of Ferula persica extract were at 52.9 ° C and 53.5% ethanol concentration in water-ethanol solvent with 34.1 minutes for sonication. It was also found that the experimental results were close to those predicted by the response surface methodology. Evaluation of the antioxidant activity results of various extracts of Ferula persica showed that in most conditions, it has a suitable antioxidant power.
Volume 16, Issue 91 (September 2019)
Abstract
The objective of present study was to develop a functional peach juice beverage. To this end, formulation ingredients of the beverage including whey protein concentrate (WPC) (1-5%), stevia (0.04-0.08%) as sugar replacer and inulin (4-8%) were optimized according to a central composite design (CCD) using response surface method. The results showed that the brix was profoundly promoted as the level of WPC or inulin increased but it was not affected by stevia. It was observed that while beverages with higher whey protein concentration had greater sedimentation tendency, inulin had a noticeably decreasing effect on it. However, they both significantly resulted in higher turbidity for the beverages. Moreover, stevia showed no significant effect on sedimentation degree and turbidity of the samples. Four optimum formulations including the sample with the least sedimentation (code 1), the sample with the least sedimentation and the most stevia (code 2), the sample with the least sedimentation and the most WPC (code 3) and the sample with the least sedimentation and the most stevia and WPC (code 4) were selected using response surface optimization. The results revealed that all the optimized samples had a shear-thickening behavior, albeit negligible differences were observed between their flow behavior indices. Similarly, the optimized samples did not significantly differ in terms of sensory attributes of flavor, odor and mouth feel; the sample code 2, however, received the highest score for total acceptability. In conclusion, the sample code 2 (WPC 1.19, Stevia 0.08 and inulin 7.34 % w/w) as the sample with the lowest sedimentation degree and the highest organoleptic quality could be introduced as the best sample.
Volume 17, Issue 102 (August 2020)
Abstract
In recent years there has been extensive research into the use of edible coatings in food packaging. Today, the use of edible coatings has increased due to consumers' desire to purchase products that maintain their freshness. In this research, edible coating based on different percentages of Spirulina platensis (0.5-1.5%) with constant percentages of gelatin powder (2%), chitosan powder (1%), and glycerol as lubricants was used. Physicochemical properties such as moisture content, pH, Acidity, color, total phenol, nutritional properties such as protein content, iron content and ascorbic acid content, sensory evaluation and microbial characteristics of control and other treatments were evaluated at days 0, 7 and 14 after production. The results of chemical tests showed the moisture content, acidity, phenol level were increased with increasing of Spriulina platencis in different treatments. The results of colorimetric analysis also showed that by increasing the percentage of spirulina the transparency of treatments decreased. The results of nutritional evaluation showed that there was a significant difference in protein, iron and ascorbic acid levels with increasing of Spirulina platensis (p <0.05). Increasing the amount of spirulina platensis was effective on the microbial growth as well as the taste and color of the treatments, which was diagnosed by sensory evaluation.
Volume 17, Issue 103 (September 2020)
Abstract
The pectinase enzyme has a great importance in the food industry. It is capable of decomposing Pectin significantly, which is the substantial element of turbidity of the juices. As a result, it plays an important role in clarification also ability to maintain organoleptic properties and quality of nutrients. The usage of enzymes in the industry is costly and some measures should be taken to allow the enzyme to be used several times without altering its efficiency. In this research the commercial pectinase enzyme was immobilized on calcium alginate beads. Free and immobilized enzymes activities in different temperatures and pH were determined. Then storage stability and reusability of enzyme were investigated. For optimized clarification of tomato juice by immobilized enzyme, the response surface methodology was used. Three factors including temperature (30-45°C), time (15-45 min) and enzyme concentration (2-6%) in 3 levels were used to evaluate the effect of parameters on turbidity of tomato juice as a model system, the importance of interacting the effects of factors also determined. Optimization has been conducted to achieve the lowest turbidity of tomato juice at the lowest used enzyme. Optimized conditions achieved by concentration of immobilized enzyme 2%, temperature 45◦C and time 45min, and with yield of clarification 27/09 times for tomato juice. Results showed that the best temperature and pH for free and immobilized enzymes were 45°C and 3, respectively.
Volume 18, Issue 121 (March 2022)
Abstract
Abstract
Meat and meat products are important component of the diet and provide a large part of the proteins, vitamins and mineral requirements of the human body. However, cooking creates harmful and undesirable compounds in them. Among these, polycyclic aromatic hydrocarbons (PAHs) and volatile N-nitrosamines (VNAs) have received more attention due to their high carcinogenic potential. In this study, samples of smoked beef cocktail (55%) were randomly obtained from three reputable companies (20 samples from each brand) from protein supply centers in Kermanshah. Then, the amounts of three types of nitrosamines including N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP) after extraction by
dispersive liquid-liquid micro-extraction (DLLME) and two PAHs including benzo[a] pyrene (Bap) and
benzo[a] anthracene (Ban) after separation by solid phase extraction method (SPE) were measured in samples cooked via two methods of boiling and deep frying using gas chromatography equipped with flame ionization detector ( GC-FID ). Based on the results, deep frying led to a significant increase in the amount of both nitrosamines and PAHs. However, the content of these compounds in the samples processed by boiling method was not statistically different from the control sample (p >0.05). Different brands also contained different amounts of nitrosamines and PAHs. Therefore, boiling method can be considered as a suitable and safe method for cooking meat and meat products.
Volume 19, Issue 127 (September 2022)
Abstract
Spirulina platensis is biomass rich in protein, iron and amino acids, vitamins, unsaturated fatty acids, antioxidants, and minerals. The aim of producing dairy desserts with Spirulina platensis is to create varieties in consumer food products, develop dairy products, and create enjoyable foods with nutritional characteristics appropriate for various age groups, especially children. The effect of multiple levels of spirulina (1-3% by weight), stevioside sweetener (0.5-1.5% by weight), and corn starch (1-3% by weight) on the characteristics of a dairy dessert were examined. Moreover, formulation optimization with variables at different levels was determined by applying the response surface method (RSM). The results indicated that the most influential parameter in the color, protein, and iron of dessert samples was the amount of spirulina. The amount of corn starch significantly affected the dessert tissuechr('39')s springiness, gumminess, chewing ability, stiffness, and viscosity in all samples (p<0.05). According to the results, the optimal sample formulation was selected with stevia composition at 0.05%, Spirulina platensis at 3%, and corn starch at 1% with a utility coefficient of 0.96. The optimal sample in the production laboratory and chemical, rheological, and color parameters were also evaluated. The results showed that the difference between the samples produced based on the optimal formulation and the values predicted by the software was not significant, indicating the modelchr('39')s high efficiency in predicting the quality properties of the produced dessert.
Volume 20, Issue 135 (May 2023)
Abstract
Phospholipases are important groups of enzyme with wide applications in various industries. In this study, two-step optimization including Plackett-Burman screening design and response surface methodology (RSM) optimization were done with the goal of higher production level of phospholipase by selected mutant strains of Trichoderma atroviride sp.ZB-ZH292. First step was done by screening and evaluation of seven factors affecting the enzyme activity and biomass production by selected mutant, using Plackett-Burman design at two levels each namely temperature, time, amount of soybean phospholipids (as a carbon source), peptone level (as nitrogen source), equal ratio of mono and di-potassium hydrogen phosphate (as phosphorus source), seed size, and seed age. According to the result of screening design, incubation time (P<0.01), incubation temperature (P<0.01), and soybean phospholipids as a carbon source (P<0.05), had significant effect on the enzyme activity, so they were selected and used as independent variables in central composite design (CCD) under response surface methodology (RSM). In the analysis of 20 experimental runs, the effects of three independent variables including incubation temperature (20-30 °C), incubation time (3-5 day), and phospholipid concentration (3-9%) were evaluated on phospholipase activity. Analysis of variance (ANOVA) showed that the optimum values of soybean phospholipid, incubation temperature and incubation time were 4.32%, 29.73°C, and 101.76 h, respectively. At this optimum point, the phospholipase activity was found to be 3.57 (U/ml) which is in good agreement with the predicted value (3.56 (U/ml)) by the model.
