مجله تحقیقات مهندسی صنایع غذایی
سال بیستم شماره 1 (پیاپی 70، بهار و تابستان 1400)

Yoghurt is a high consumed fermented milk product which has positive effect on health due to high nutritional value. Donkey milk is rich in nutritional and therapeutic properties and is used in enrichment of various food products. The aim of this study was to evaluate the effect of using different rates of donkey milk and cow milk on quality properties of set-type yoghurt. For this purpose, yoghurt samples were manufactured using different rates of donkey milk and cow milk with the ratios of 100:0, 0:100, 50:50, 75:25 and 25:75, respectively. Yoghurt samples were stored in refrigerator (4±1°C) for 15 days and their physicochemical, texture and sensory properties were evaluated at 1st, 8th and 15th day of storage. The results of different analysis showed that increasing the rate of donkey milk in yoghurt samples caused to significant decrease (p<0.05) in pH, fat (%), protein (%), dry matter (%), water holding capacity (%), viscosity (centipoise), hardness (N) and odor and flavor and significant increase (p<0.05) in acidity (% LA) and syneresis (g/25g). For yoghurt samples manufactured with cow milk and donkey milk with the ratios of 100:0 and 0:100, the amounts of pH were 3.95 and 4.15, acidity were 1.47 and 1.26, syneresis were 8.39 and 6.36 and viscosity were 3890 and 17860 in 15th day of storage. In conclusion, yoghurt samples manufactured from the combination of donkey milk and cow milk at 25:75 and 50:50 ratios had acceptable points regard to physicochemical, texture and sensory properties.

The aim of this study was to investigate the effects of ultrasonic waves, reducing the temperature and lowering the time in the refining of canola oil, compared to the conventional method. In this study, an ultrasonic bath was used for degumming, neutralizing and oil bleaching. The temperature of 45 and 65 °C and time of 30 and 60 min for degumming, the temperature of 40 and 55 °C and time of 20 and 30 min for neutralization of degumming oil, the temperature of 45 and 60 °C and time of 20 and 30 min for bleaching of neutralized oil were used. At all stages, an ultrasonic bath with 100 Watts power and a frequency of 20 kHz was used. The acid index, peroxide value, and fatty acid composition of oils were determined. The acid index did not change significantly (p > 0.05) in the degumming process, but the peroxide value was increased (p < 0.05). In the process of neutralizing with ultrasound, the free fatty acid content was significantly reduced (p < 0.05), but the peroxide index was increased (p < 0.05). In the bleaching process by ultrasound, the free fatty acids and peroxide levels did not increase significantly in this treatment. The combination of fatty acids did not change with the ultrasonic waves after three refining processes. Ultrasonic waves can be used as a safe method in the process of oil refining and do not affect the composition of oil fatty acids.

The rate of static pressure drop of air passing through the mass of agricultural products is one of the basic data for selecting the fan used in aeration or dryer systems. In this study, the amount of static air pressure drop through the masses of Agria and Marfona cultivars was measured using a simulator device consisting of an air compressor, a rotameter, a cylindrical bin, and a U-shaped barometer and their regression relationship with some parameters such as depth of mass, moisture content and percentage of unwanted materials (soli &, etc.) were defined by using of Shedd’s model. According to these tests: As the air velocity increases from 0.085 to 0.53 (m/s), the static air pressure drop increases too. By each 25 cm increase in the depth of Agria and Morfona potatoe piles, the static pressure will be dropped by 1.49 and 1.53 times respectively. With each 2% increase of soil and other impurities in the potato pile, the rate of air pressure drop in the potato mass of Agria and Marfona increases 1.36 and 1.33, respectively. At similar airflow rates, potatoes with higher moisture content showed fewer static pressure drops. The airflow resistance of the Agria potato piles measured 4 to 6% more than the Marfona cultivar, at the same condition.

Preparing ready- to -eat foods with higher quality and nutritional value is one of the purposes of food technology. In order to achieve this goal, the producing functional foods, especially snacks prepared from wheat flour, is so important. The aim of this research was to find out the possibility of producing functional fermented doughnut by using chia seed flour in levels of 0, 5 and 10% and replacing kombucha beverage with water in levels of 0, 50, and 100%. Physicochemical and sensorial characteristics of final product were evaluated in the form of a completely randomized design with factorial arrangement (P ≥0.05). The results showed that by increasing the amount of chia seed flour and the replaceing of kombucha beverage with water in fermented doughnuts, the moisture content, the total phenolic compounds and the antioxidant activity of final products were increased. In addition, the samples containing of 5% chia seed flour and 100% of kombucha beverage had the highest amount of specific volume and porosity and lowest firmness during 1, 3 and 7 days after preparation. The amount of oil in the final product decreased by increasing kombucha beverage. Also, by adding chia seed flour and replacing kombucha beverage with water, L* and a* values decreased and increased respectively, while the b* value increased by using 100% kombucha beverage. Finally, the panelists accepted the samples containing 5% of chia seed flour and 100% of kombucha beverage as the best samples.

From harvesting time to distillation, Rosa damascena is subjected to evaporation and fermentation; the enzymatic activities occur in Rosa damascena affect the essential oil content and its components. Statistical analysis using factorial method, with three replications was carried out to determine the effects of storage of flower on essential oil content at 25°C, 4°C and - 5°C during 0, 1 and 3 days of storing. Gas chromatography analysis was also carried out for each treatment. Results indicated that the  flowers lost 6.4% of the moisture content, and 50% of essential oil content 24 hours after storage at 25°C. The loss was not significant during two days of storage at 4°C and - 5°C. Citronellol content increased from 31.72% in fresh flower to 39.2% during three days of storage at 25°C. The ratio of citronellol to geraniol was 1.4, 8.55, and 14.4 at the harvesting time, after one day and after three days of storage at 25°C respectively, while the ratio did not meet significant change for the flower stored at 4°C and - 5°C. Storing the flowers at 4°C for one day could save relatively essential oil content and its components.

In this research, sage seed gum was extracted using the dry method (friction-based) and the extraction conditions was optimized by the response surface method and using the box-Behnken design. Dry extraction method was used to achieve an economical, inexpensive, fast, eco-friendly (green technology), continuous, easy usage and automated method. The independent variables in this research were rotor speed (750, 825, 900 rpm), angle of friction (0, 10, 20 degree) and friction distance (1.5, 2, 2.5 mm). The effects of these variables on extraction yield, protein content and apparent viscosity (at a shear rate 46 1/s) were investigated. The results showed that quadratic polynomial models adequately explained the data variation and represented the actual relationship between independent variables and responses. The optimum conditions with maximum extraction yield and apparent viscosity and minimum protein content were achieved when the rotor speed, angle of friction and friction distance were 900 rpm, 6.9 degree, 2.2 mm, respectively. At the optimized conditions, the extraction yield, protein content and apparent viscosity were obtained 10.61%, 7.02%, and 112 mPa.s, respectively

Considering the economic importance of preserving the desired characteristics of sugar beet in silage, it seems necessary to use appropriate methods to keep better this product in storage. This study was done in 2 different stages to show the environmental effect on sugar beet storage and the result of using 2 chemicals on keeping quality attributes of sugar beet. In the first phase of this study, the effects of temperatures 4, 12 and 24 degrees Celsius during 15, 30 and 45 days of storage on sugar content, respiration rate, and weight loss, and in the second phase, using chemical treatments with different levels of calcium Chloride (2, 4 and 6%) and milk of lime (5, 10 and 15%) on sugar content (%), percentage of loss weight and total number of mold and yeast were investigated. The result shows that the effect of calcium chloride and milk of lime on keeping and improve the quality of sugar beet was effective.

Barley were ranked fourth among the cereals, and due to their beneficial and nutritious properties their consumption is increasing in most countries of the world. In order to replace the new and risk-free methods to extend the shelf life of cereals (instead of chemical pesticides), the use of ozone gas. in this study the effect of ozone gas with two variables of ozone concentration (25, 50 and 75 ppm) on ozonation time (1, 3, 5 and 7 days) in barley (Reyhaneh cultivar) compared to the control sample by determining storage characteristics of barley in terms of control of fungal, insects growth, germination power and changes in grains quality characteristics. The results showed that increased ozone concentration and ozonation time increased control of fungal growth, spread of fungal toxins (aflatoxins) and increased effect of ozone on storage pests grains. The mean comparison test showed that this increase was not significant at concentrations greater than 50 ppm and 3 days ozonation time in both grains (P<0.05). Also, the use of 75 ppm ozone at 1, 3, 5 and 7 days caused significant oxidative changes compared to the control in fat (acidity and peroxide) and starch (carboxyl index) barley. The different ozonation conditions up to 50 ppm concentration and all time had no significant effect on protein content in barley compared to control (P<0.05). The results of seed germination evaluation showed no significant decrease in seed germination at 50 ppm concentration up to 5 days of ozonation compared to control and ozonation at 75 ppm and at 7 days compared to the control sample reduced germination to 31.5%. Therefore, based on the results, it was suggested to use ozone concentration of 50 ppm for 3 days of ozonation for storage of barley grains.

Prosopis farcta is a kind of subaltern silk flowers that due to its healthful effects and its use in the prevention of chronic diseases, this plant can be used as a natural and safe food additive. Main component and major constituent of this plant root is luteolin which is a flavonoid. The objective of this research was to determine the antioxidant and quality characteristics of set-yogurt samples containing aquatic extract of prosopis farcta root (T1: 0.01, T2: 0.03 and T3: 0.05%v/v) and luteolin (T4: 0.005 and T5: 0.01%v/v) stored at 4°С for 15 days. After storage, the starter bacteria count in yogur samples containing aquatic extract of prosopis farcta root was more than that in yogur samples containing luteolin and control (p< 0.01). DPPH radical scavenging activity increased upon increasing the content of the aquatic extract of prosopis farcta root and lutelin. In sensory evaluations, T1 gave the highest overall acceptability score (after control) among the experimental groups. The results of this study thereby demonstrate that aquatic extract of prosopis farcta root can be used to improve the antioxidant capacity of set-yogurt.

Consumers are seeking healthy, natural and fresh food matterials requiring minimal energy and time to be prepared. Onions and their products, rank first among edible alliums due to their medicinal properties. The aim of this study was to investigate the effects of disinfection, packaging and storage period on physicochemical properties of onion puree. For this purpose, onion puree were disinfected with different solutions including: (chlorine + citric acid + ascorbic acid), (nisin + citric acid), (acetic acid + menthol), (sodium sulfate + ascorbic acid + citric acid + calcium chloride), (calcium chloride + calcium Ascorbic + citric acid + water (80 ° C) and (control, without pretreatment). The products were then packaged in low density polyethylene in two ways under normal vacuum and conventional atmospheric packaging and stored for 21 days. The total amount of soluble solids (Brix), weight loss of total phenolic compounds, antioxidant activity (%) and microbial test (total microbial count and mold and yeast) were measured on the samples once a week. Statistical analysis of data by factorial experiment in a completely randomized design showed that in all treatments, chemical properties decreased during storage and the total number of live microbes and the total number of mold and yeast increased. The results showed that in onion puree sample, pretreated with calcium chloride (0.5 g / 100 ml) + ascorbic acid (1 g per 100 ml) + citric acid (1 g per 100 ml) at 80 °C, chemical, phenolic compounds, antioxidant properties were preserved and had the lowest rate of microbial growth. Quantitative, qualitative and microbial properties in vacuum packaging were more appropriate than in conventional atmospheric packaging.

Corn seed contains almost 5.5% of oil of which about 85% can be found in germs of seeds. Proper steps are necessary to take, from the point of view of harvesting time and percentage of moisture retaining in the seed during harvestinh time, to improve the quality of oil extracted from the seeds. In the present study, the effects of temperature at four levels (45, 55, 65 and 75 °C), seed moisture content at harvest time at three levels (30, 35 and 40% (d.b)), and hot air velocity at two levels (1 and 2 m/s) on the total oil content, oil color, free fatty acids and peroxide value were investigated. A factorial experiment in a completely randomized design was used to analyze the data and the mean comparison was conducted by Duncan's multiple-range test at α = 5%. Based on the results, the most appropriate drying temperature was found 55 °C, and the best moisture content at harvest time was found 30% d.b and the best hot air velocity was found 2 m/s. The peroxide value of samples (before drying and in all dried samples) was not significant because the treatments were not given enough time to begin the oxidation mechanism.

In the present work, the influences of microwave power and samples thickness on the mass transfer parameters of potato slices were studied using the analytical model suggested by Dincer and Dost. Four microwave powers of 200, 400, 600 and 800 W were practiced to dry mono layer of the slices with thicknesses of 3.5, 5, 7 and 9 mm. The Biot number was obtained to be in the range of 1.299–4.096; where decreased following the increment in microwave power and increased with increasing samples thickness. The moisture diffusivity and convective mass transfer coefficient were found to be significantly (P < 0.05) increased with increasing microwave power and the slices thickness, and varied in the ranges of 2.389×10-8–14.681×10-8 m2 s-1 and 2.246×10-5–7.116×10-5 m s-1, respectively. The activation energies for moisture diffusion and surface mass evaporation were determined to be in the ranges of 1.452–1.746 W g-1 and 0.712–1.323 W g-1, respectively.

Food security, which is directly related to the health of people, has always been a concern of all nations. Eggs are consumed in many food industries and are in the daily diet of many people, so detection their freshness is very important. In this study, the capability of the acoustic system as a non-destructive method for egg freshness detection was investigated. Samples were stored at room temperature for 1, 4, 7, 10, 13 and 16 days. After data collection, all audio signals were converted to images, using spectrogram. In this study, the freshness of samples was evaluated using two criteria; Haugh unit and air cell height as a destructive test. The results of destructive test showed that all samples stored for 16 and 13 days and also 80% of samples stored for 10 days faced with quality losses during storage. According to grading criteria, these samples were considered as unfresh eggs. Therefore, the samples were divided into two groups: fresh eggs (stored for 1, 4 and 7 days) and unfresh (stored for 10, 13 and 16 days). Four pre-trained deep learning networks AlexNet, VGGNet, GoogLeNet and ResNet were used in this study among which ResNet had the best classification accuracy with an average of 71.5%.