جستجوی مقالات مرتبط با کلیدواژه "خشک کن تحت خلاء" در نشریات گروه "صنایع غذایی"

Cornelian cherry is a seasonal fruit which has the durability potential after harvest for 2 to 3 weeks. One way for keeping and increasing shelf life of fruit is preparing fruit leather (pestil). The aim of the present study was to investigate the different drying methods on quality of the formulated cornelian cherry leather (pestil). in the current study, effect of three different formulations (1% salt, 2% sugar, the mixture of 2% salt and 4% sugar) and control sample were investigated in two kinds of dryers (hot air dryer and dryer under vacuum) at the constant pressure of 200 mb in 55° C, 65° C and 75 ° C. Then drying curves, effective moisture diffusivity, total anthocyanin content, hydroxymethyl furfural, color and sensory properties of the prepared samples were evaluated. The results showed that the highest anthocyanin content and the lowest hydroxymethyl furfural accumulation and color changes were observed in vacuum dryer samples. Comparison of the treated samples in both dryers also showed that the control samples were the most favorable in terms of chemical and physical properties and the samples formulated with a mixture of 2% salt and 4% sugar were the most unfavorable. According to the drying curves, the samples formulated with a mixture of 2% salt and 4% sugar had the lowest and the control sample had the highest drying rate. Organoleptic properties showed that the best formulation was 2% sugar and 2% salt and 4% sugar formulation. According to the results, vacuum drying enables some distinctive characteristics such as higher drying rate and effective moisture diffusivity, lower oxygen medium and activation energy and hence high quality and nutritive dried samples. Thus among the selected methods for drying, vacuum dryer was more suitable.

Garlic( Allium Satirum L) is one of the most important agricultural products in Iran and one of the major sources of foreign exchange for the country. Due to the high waste in this product to maintain, increase shelf life, and keep its quality, it is necessary to use appropriate storage methods such as drying. In this study, a thin layer of garlic slices was dried at 50, 60, 70 ° C, and in two types of dryers (vacuum and hot air). The most suitable model was developed to describe the drying kinetics of garlic flakes as a thin layer in the temperature range and type of dryer used. Effective moisture penetration coefficient, amount of activation energy, shrinkage, water reabsorption of garlic samples were measured during the drying process. in the present study, by examining 9 different experimental models and calculating the statistical criteria of R2, RMSE, x2 between the experimental data and the results predicted by each model, the most appropriate model describing the drying kinetics of garlic thin slices was the Page model. The results showed that the effective diffusion coefficient of garlic leaf moisture for different temperatures and in two types of dryers was in the range of  1.5* 10-9 to 6.6 * 10 -9 m2/s. Changes in the moisture diffusion coefficient were described as a function of drying air temperature with Arrhenius and the amount of activation energy was calculated between 14.673 and 53.175 kJ / mol. The results also showed that the shrinkage of the product was not dependent on air temperature and the type of dryer and the water re-absorption capacity of garlic samples increased slightly by decreasing their moisture content.