فهرست مطالب بیژن خورشیدپور

Determining the mechanical properties of various agricultural products is necessary to analyze their behavior during transport, processing and precision design of machines to minimize waste. Therefore, in this study, the effect of mass at the levels of m> 500 and m≤ 500 g as well as the loading speed at the levels of 4.5, 7.5 and 10.5 mm/min on some mechanical properties of sugar beet such as rupture force, deformation at rupture point and rupture energy were examined. Then, for data analysis, factorial experiment based on a completely randomized design was used and the comparison of means was performed by Duncanchr)s multiple range test at α=1%. According to the results, the effect of loading speed on all mechanical properties was significant, but except for the rupture force, different mass levels did not have a significant effect on the deformation at rupture point and rupture energy. In this regard, the highest rupture force (72.3 N) in samples with mass of m>500 g and in the loading speed of 4.5 mm/min, but the lowest amount (42.4 N) in samples with mass of m≤500 g  and in the loading speed of 10.5 mm/min was measured. In this regard, the highest deformation at the rupture point (25.28 mm) in samples with mass of m > 500 g and in loading speed 4.5 mm/min and the lowest amount (16.4 mm) in samples with mass  m≤500 g  and in speed ‌Load 10.5 mm/ min was obtained. Also, the highest (82.1 mJ) and lowest (26.48 mJ) values of rupture energy were determined in samples with mass of m > 500 g and loading speeds of 4.5 and 10.5 mm/min, respectively.

Milk and fermented milk products play a major role in nutrition and human health at all stages of life. Kefir is one of the oldest fermented milk products. The aim of this study was to investigate the effect of polydextrose and galactofructose on the viability of probiotic bacteria and physicochemical and sensory properties of synbiotic kefir drink.

Different concentrations (0.5 and 1%) of polydextrose and galactofructose (solely or in combination together) were used in kefir production. The samples were kept at 4˚C for 2 weeks and their microbial, physicochemical and sensory properties were evaluated.

The results showed that the use of polyextrose and galactofructose increased the viability of probiotic bacteria, pH and viscosity and decreased acidity of the test samples compared to the control sample (p≤0.05). In the kefir samples containing polyextrose and galactofructose, the viability of Lactobacillus acidophilus was more than Bifidobacterium lactis during storage. During storage, acidity and ethanol increased but pH decreased significantly (p≤0.05). The sample containing 0.5% polydextrose had the highest viability of probiotic bacteria on the 14th day. Sensory evaluation of kefir samples showed that the use of polyextrose and galactofructose caused a significant increase in overall acceptance score (p≤0.05).

The sample containing 1% galactofructose and the sample containing 0.5% galactofructose + 0.5% polydextrose had the highest overall acceptance score. Since the number of probiotic bacteria in the above mentioned samples was 107-108 CFU/ml, these samples were selected as the best samples.

Kefir is one of the fermented milk products that plays a major role in nutrition and human health. The aim of this study was to investigate the effect of adding asparagus extract and green tea extract on survival of probiotic bacteria, antioxidant activity and sensory properties of kefir. Different concentrations (0.5, 1 and 1.5%) of asparagus extract and green tea extract were used in kefir and the samples were stored at 4˚C for two weeks.The results showed that addition of herbal extracts decreased pH and increased acidity and antioxidant activity of the samples (p≤0.05). The highest antioxidant activity was related to the sample containing 1.5% green tea extract. During storage time, pH of the samples decreased, but acidity increased significantly (p≤0.05). There was no significant difference between samples in terms of viability of Bifidobacterium lactis and Lactobacillus acidophilus (p>0.05). The viability of probiotic bacteria decreased significantly (p≤0.05) during storage but in all samples, the number of bacteria was more than 108 CFU/ml until the end of the storage period. The sample containing 1.5% asparagus extract had the highest score of overall acceptance. Therefore, this sample was selected as the best treatment.

Probiotics are living microorganisms that, by settling in the intestinal environment, inhibit the activity of noninfectious and pathogenic microorganisms. The main purpose of this study was to consider the probability of producing probiotic juice containing Lactobacillus acidophilus and Lactobacillus casei based on apple, cranberry and sour cherry mixture.

In the present research, Lactobacillus acidophilus and casie (0, 35, 50, 65,100% levels) were used at a density of 107, at the temperature of 4oc in juice made from mixed sour cherry, cranberry and apple. The physical, chemical, microbiological and sensory properties of the produced juice, during production period were all measured in the first, second, third and fourth week (28 days).

The number of probiotic bacteria in the juice increased over the time. Physicochemical properties such as brix, sugar, pH, acidity, turbidity and color had significant changes. Brix, sugar, pH decreased whereas acidity, turbidity of the juice increased. It was also found that the addition of bacteria has somewhat weakened the sensory (organoleptic) characteristics.

Among the samples, the sample containing 100% Lactobacillus acidophilus bacteria was identified as the best bacterial growth treatment and in terms of sensory properties, the sample containing 35% acidophilus 65% casei was introduced as a superior sample.

Among the baking products, breads and cakes are the highest-consuming products but long-term use of them will lead to obesity and health problems. Therefore, in this research the possibility of using different levels of Chia seed (Salvia hispanica L.) mucilage (zero, 0.5%, 0.75%, 1%, 1.25%) were studied as a fat replacement on rheological properties of dough (viscosity and density), physicochemical (moisture, fat, ash, protein, calorie, specific volume and colorimetric), staling and sensory properties (color, taste, texture and general acceptance) of oil cake samples. A completely randomized design was used to analyze experimental data and means were compared by Duncan's multiple range test (α = 1%). According to the results, by adding Chia seed mucilage concentration, moisture content, viscosity, specific volume and staling of cake samples were increased but the amount of fat, density of dough and color indices (L*, a* and b*) were decreased in comparison to the control sample. Also in evaluating the sensory properties, by increasing the level of chia seed mucilage replacement, the acceptability of the samples decreased. Based on the results, fat replacement in the formulation of cake with Chia seed mucilage up to 20% (containing 0.5% Chia mucilage) retained the functional and sensory properties of the product, so this treatment introduced as the superior treatment.

For many years, there have been concerns about side effects of sugar on human health, such as cardiovascular diseases, diabetes, obesity and tooth decay and the human mind is always to provide safe alternatives to replace sucrose. The aim of this study was production of dietetic chocolate cream using natural sugar substitutes. In dietetic chocolate cream different amounts of stevia (rebaudioside A), inulin and sucralose were used. Physicochemical and sensory characteristics of the samples were studied. The results showed that the lowest pH was related to control sample. Sample containing 0.004 % stevia + 0.17% inulin + 0.47% sucralose had the highest viscosity. The highest dry matter was related to the control sample. The scores of flavor, color, texture and overall acceptability of control sample was significantly (P<0.05) higher than other samples. Among dietetic cream samples, sample containing 0.006 % stevia+0.21% inulin+0.47% sucralose was awarded the highest sensory scores. Therefore, this sample can be selected as the best treatment.

Fermented layered doughs are made in a method in which fat is scattered between dough layers in process of rolling and laminating giving the final product with a flak texture, the use of natural antioxidants including herbal extracts have been widely used to prevent fats and oils oxidation in food products. Rosemary and thyme are two valuable medicinal plants that are widely used in traditional medicine. In this study, the chemical components of rosemary and thyme extracts were determined by HPLC and different volumes of the extract (0.1, 0.15, 0.2 %) in combination, was added to the croissant dough formulation and characteristics of the final product was examined. 11 phenolic compounds in thyme and rosemary extracts was identify that Carnosol (0.307%) and gallic acid (6.7%) had the highest amount in extracts of rosemary and thyme. The results of the rheological tests showed that the highest dough development time, Dough stability time, farinograph quality, and the lowest degree of dough loosening, belonged to sample A4-(croissant +0.15% rosemary extract and 0.10 % thyme extract) and A6 (croissant +0.15% rosemary extract and 0.20 % thyme extract), respectively. samples A4 and A6 had highest maximum resistance to extension (P≤0/05) on all days of the highest oxidative stability of the A4 and A6 samples, respectively.The staling of croissant showed that in first and seventh days of test, force required to compress samples A6 and A4 were significantly lower than other samples (p≤0/05). the highest sensory scores in factors of color, taste, smell and texture of the samples A4 and A6 and treatment A4 can be introduced as a better treatment.

Many products are produced from corn that sweet popcorn is one of them. One of the approved methods for the production of this product is removing of sucrose and glucose and replaces it with a mixture of low-calorie sweeteners. In this research, the effect of different levels of maltitol and sucralose were studied on some of physicochemical and sensory properties of sweet popcorn that was produced by sweet explosive method. Based on the results, the amount of moisture, ash and acid insoluble ash in sample containing 100% sucralose was higher than other samples which were reduced sensory satisfaction. The lowest moisture was observed in control sample and containing 100% maltitol. The highest values of syrups brix was observed in control sample and after in (100% maltitol) and (25% sucralose, 25% maltitol, 50% equal mix of sucrose and glucose). Most of the simple sugars and the highest taste rating, sweetness and total sensory attributes were observed in the control sample and then in (25% sucralose, 25% maltitol, 50% equal mix of sucrose and glucose). The samples containing (80% sucralose, 50% maltitol) and (100% sucralose) had the lowest fractureability and fragility and total sensory attributes, respectively. The results showed that the coated popcorn with sucralose and 25% maltitol syrup containing 25% and 50% mixture of sucrose, glucose closest to the results of sensory and physicochemical properties of the sample was obtained.

Acidified milk drinks have low pH with healthy properties. These properties might be expanded and improved by fortification of these products with soy milk, probiotics and Whey Protein Concentrate. The aim of this study is to investigate the impact of transglutaminase (TG) and Whey Protein Concentrate (WPC) on physicochemical, sensory and microbial properties of functional drink from mixture of cow's milk and soya milk.
Cow's milk and soya milk with equal proportion were used for producing probiotic drink containing Lactobacillus casei. Different concentrations of transglutaminase (150, 200 and 250 ppm) and WPC (0.5, 1 and 1.5 % w/w) were added and the viability of probiotic bacteria and physicochemical and sensory properties of the drink samples were studied during three weeks of cold storage.
The results showed that the addition of enzyme and WPC increased the viscosity significantly (p˂0.05). Samples containing 1.5% WPC and 200 ppm enzyme and 1.5% WPC and 250 ppm enzyme had the highest acidity and the lowest pH. The highest number of L. casei belonged to the sample containing 0.5% WPC and 150 ppm enzyme. Moreover, this sample had the highest score of overall acceptability during storage. During the storage time, the viability of L. casei and pH decreased significantly (p˂0.05) whereas acidity and viscosity increased significantly (p˂0.05). The population of probiotic bacteria of the samples during storage was more than 106 CFU/ml.
The addition of 0.5% WPC and 150 ppm transglutaminase resulted in production of a functional drink with the highest viability of probiotic bacteria and sensory quality.

Sugar play importance role in increasing blood sugar level. Fruity candy is a product that need a lot of sugar for make . the purpose of this research is replacement stevia and isomalt instead of sugar and glucose in producing fruity candy .So 10 different fruity candy formula according to different proportions of stevia(0.01%, 0.025%, 0.15%), isomalt(94%, 96%, 98%) and 1 control sample was prepared. The experiments of chemical , physical , senory, colorimetric, texture and microbial analysis were done and the results of experiment in format of completely random in method factorial with 3 repeatation were analysed p

Today, Stevia, as a natural sweetener, is used in many low calorie foods as a substitute for sugar is accepted in order to decrease the increasing trend in obesity and diabetes. The aim of the present study was to investigate the effect of using Stevia as a replacement for sucrose on the sensory and physicochemical properties of carbonated orange soft drink.
In this study, to select the best natural sweetener with the least aftertaste, three samples of imported Stevia were analyzed using high-performance liquid chromatography (HPLC). The sample with higher rebaudioside A content was selected for use in the formulation of the soft drink. Formulated orange soft drinks were produced through the substituition of 30%, 50%, and 70% sucrose with Stevia sweetener and stored at 4 °C, 25 °C, and 37 °C for 1, 2, and 3 months. All of the prepared samples were analyzed in terms of pH, total soluble solids, density, titratable acidity (TA), and sensory attributes.
Findings: Results showed that with the substitution of sucrose with natural Stevia sweetener, significant changes occurred in pH, brix, density, and acidity, but aroma and color were not affected. In addition, the storage of the drinks for the defined duration and at the determined temperature resulted in a significant decrease in pH and increase in brix. By increasing Stevia sweetener at the 30% substitution level, no significant changes were observed in overall acceptability of the drinks. However, in higher levels of substitution, acceptability decreased significantly.
It can be concluded that by substitution of sucrose with natural Stevia sweetener and production of soft drinks containing 30% Stevia and 70% sucrose the caloric value of the end product can be reduced. Therefore, the end product will be more suitable than commercial soft drinks.