Showing 3 results for Pajohi-Alamoti
Volume 20, Issue 135 (May 2023)
Abstract
In this research, the effect of ultrasound time and dryer type (hot-air and infrared) on the drying time, effective moisture diffusivity coefficient and rehydration of wheat sprouts were investigated and drying kinetics were modeled. To apply ultrasound pre-treatment, the sprouts were placed inside the ultrasonic bath machine for 0, 5, 10, and 15 minutes, and after leaving the machine and removing extra moisture, the samples in thin layers were placed in the hot-air (with a temperature of 70°C) and infrared (power of 250 W) dryers. The results showed that sonication up to 5 minutes, causes an increase in moisture removal rate from the sprouts, an increase in the effective moisture diffusivity coefficient, and as a result, reduces the drying time. By increasing sonication time from zero to 5 min, the average drying time of sprouts in the hot-air and infrared dryers decreased from 126.7 min to 120.0 min, and from 25.7 min to 21.3 min, respectively. The average drying time of the samples in the hot-air dryer was 150.8 min and in the infrared dryer was 28.0 min. Also, the average effective moisture diffusivity coefficient calculated for the samples placed in the hot-air dryer was equal to 1.65×10-10 m2s-1 and for the infrared dryer it was equal to 8.59×10-10 m2s-1. The time of ultrasound and drying treatment had significant effects on the rehydration of samples, and the value of this parameter was higher for samples dried in the hot-air dryer. In order to investigate the drying kinetics of wheat sprouts, mathematical models were fitted to the experimental data, and the Page model with two parameters (k and n) was chosen as the best model based on the highest accuracy. Generally, 5 minutes pre-treatment by ultrasound and then using an infrared dryer is the best condition for drying wheat sprouts.
Volume 20, Issue 136 (June 2023)
Abstract
The purpose of this study was to investigate the conformity or non-conformity of traditional liquid Kashks supplied in Hamedan city with the national standard of Iran. To carry out this research, Kashk samples from manufactures of traditional dairy products (in Hamedan city) were prepared in two stages and transferred to the food quality control laboratory for examination. Microbial population (total count, staphylococcus, coliform, and mold-yeast), chemical properties (total solids %, salt, acidity, and pH) and color parameters including lightness (L*), redness (a*) and yellowness (b*) of tradition Kashk was examined and after statistical analysis, their results were reported. The average number of microorganisms (total count), staphylococcus and coliform in the Kashk samples were 7.28 Log cfu/g, 4.09 Log cfu/g, and 1.64 Log cfu/g, respectively. According to the national standard of Iran, the maximum number of mold and yeast in liquid Kashk should be 2 Log cfu/g, but the average number of mold and yeast in the prepared Kashks were 7.39 Log cfu/g, which is much higher than the specified standard for this product. The average of total solid of Kashks were 21.15%, which was less than the defined standard (at least 25%) for it. Also, the average of moisture, salt, acidity, and pH of examined Kashks in this research were 78.85%, 1.98%, 1.90%, and 4.09 respectively. Color parameters of Kashk samples were examined and the average color indexes including lightness, redness, and yellowness of the samples were 84.52, 1.53 and 6.43 respectively. Of course, no statistically significant difference was observed between the color indexes values of the samples (p>0.05).
Volume 20, Issue 142 (December 2023)
Abstract
Today, the desire to use ozone as a strong antimicrobial compound, cost-effective, and eco-friendly innovation, has increased to increase the shelf life of food products. This study was conducted in order to evaluate the chemical and microbial properties of thermally pasteurized skim milk treated with pressurized ozone injection at concentrations of zero, 1.5, 5, and 10 ppm. The chemical, microbial and sensory characteristics of the treated milk samples were evaluated on days 0, 4, 7 and 15 of storage in the refrigerator. The total viable count (TVC) in the treated samples with ozone compared to the control had a noticeable decrease in all storage days. The highest antimicrobial effect was observed on the 15th day of storage with 10 ppm ozone and the lowest effect was observed on the 4th day with 1.5 ppm ozone. However, there was no significant difference in pH (6.8-6.88) and acidity (0.16-0.18) between treated and control samples. Although the peroxide number (PV) in the treated samples and the control samples was higher than the standard, but its reduction was evident in the treated samples compared to the control samples. Also, by comparing the sensory characteristics among the samples, no significant differences were observed. In general, treatments with 5 and 10 ppm ozone had the best efficiency in increasing the shelf life of pasteurized milk. According to the results, ozone can be used as an auxiliary method to increase the effectiveness of thermal processes in pasteurization and increase the shelf life of milk.