H. Bahmanpour; S. M. Sajadiye; M. J. Sheikhdavoodi; M. Zolfaghari
Abstract
Introduction Mint (Mentha spicata L.) cbelongs to the Lamiaceae family, is an herbaceous, perennial, aromatic and medicinal plant that cultivated for its essential oils and spices. Since the essential oil is extracted from dried plant, choosing the appropriate drying method is essential for gaining high ...
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Introduction Mint (Mentha spicata L.) cbelongs to the Lamiaceae family, is an herbaceous, perennial, aromatic and medicinal plant that cultivated for its essential oils and spices. Since the essential oil is extracted from dried plant, choosing the appropriate drying method is essential for gaining high quality essential oil.Vacuum drying technology is an alternative to conventional drying methods and reported by many authors as an efficient method for improving the drying quality especially color characteristics. On the other side, solar dryers are also useful for saving time and energy. In this study the effect of two method of dryings including vacuum-infrared versus solar at three different conventional temperatures (30, 40 and 50°C) on mint plant is evaluated while factorial experiment with randomized complete block is applied. Drying time as well as color characteristics areconsidered for evaluation of each method of drying. Materials and Methods Factorial experiment with randomized complete block was applied in order to evaluate the effect of drying methods (vacuum-infrared versus solar) and temperature (30, 40 and 50°C) on drying time and color characteristics of mint. The initially moisture content of mint leaves measured according to the standard ASABE S358.2 during 24 hours inside an oven at 104 °C. Drying the samples continued until the moisture content (which real time measured) reached to 10% wet basis. The components of a vacuum dryer consisted of a cylindrical vacuum chamber (0.335 m3) and a vacuum pump (piston version). The temperature of the chamber was controlled using three infrared bulbs using on-off controller. Temperature and weight of the products registered real time using a data acquisition system. The components of a solar dryer were consisting of a solar collector and a temperature control system which was turning the exhaust fan on and off in order to maintain the specific temperature. A date acquisition system was applied to register and monitoring product weight real time. For imaging of dried samples, a semi-professional digital cameras Fujifilm Fine Pix HS55model Barzvlvshn 921000 pixel was applied. Dry samples were used to determine the RGB color model that consists of three whole red (Red), green (Green) and blue (blue) light intensity 0 to 255 (in this case, zero for black and 255 for white pixels) Finally, the average of RGB changes color index were calculated as the mean change color of samples during the drying. Results and Discussion The results showed that drying time of solar dryer is more than vacuum-infrared (averaged: 201 versus 153 minutes). For two methods of drying, increasing temperature, made reduction in drying time. The maximum drying time registered 237 minutes for solar method which was set to 30°C and minimum drying time was registered 112 minutes relating to vacuum –infrared which was set to 50°C. Color evaluation showed that the effect of drying method on the changes of colour index (before and after drying) is reasonable. Vacuumed-infrared dryer case with 8.75% color change was showed to be much efficient than solar dryer with 11.96% change. Analysis of variance was performed due to the drying temperature index mint color changes and results showed the reasonable difference. The highest and lowest color change related to the temperature of 50°C (11.767%) and 30°C (9.197%) respectively. Conclusion Drying method as well as applying temperature showed rescannable effects on daring time and color quality of mint. The vacuum-infrared method reduces drying time for all temperature treatments considered in this study. Beside this, using vacuum-infrared showed minimum changes on color characteristic and can be say more efficient in aspect of color quality especially at its lowest applicable temperature (30°C). Increasing temperature causes the samples to be more darken for both drying methods. This phenomena may be related to replacement of magnesium by hydrogen inside the chlorophyll and then causing the chlorophyll to be destroyed.
E. Ahmadi; H. Barikloo
Abstract
Introduction: Some forces and impacts that occur during transporting and handling can reduce the apricot quality. Bruise damage is a major cause of fruit quality loss. Bruises occur under dynamic and static loading when stress induced in the fruit exceeds the failure stress of the fruit tissue. Needless ...
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Introduction: Some forces and impacts that occur during transporting and handling can reduce the apricot quality. Bruise damage is a major cause of fruit quality loss. Bruises occur under dynamic and static loading when stress induced in the fruit exceeds the failure stress of the fruit tissue. Needless to say that physical and mechanical properties of fruits in the design and optimization of systems related to production, processing and packaging of the products are important. Harvesting, transport, packaging and transportation of fruits and vegetables, result in their bruising which can cause loss of marketability of the fruit by consumers. The term of ‘absorbed energy’ could be used to express the quantity of damage done on the fruit and the high the absorbed energy, the higher the damage on the fruit. The object of this research was due to the importance of apricot fruit and lack of information about the mechanical behavior.
Materials and Methods: In this study, apricot fruit variety “Ziaolmolki” was examined to determine some physical and mechanical properties. In order avoid any damage, the fruits were carefully harvested from trees and gathered in plastic boxes in a row, to prevent damage to the apricots. For determination of mechanical properties and levels of impact energy used test axial machine and pendulum device, respectively. Dependent variables (acoustics stiffness, radius of curvature, color characteristic a* and b*, Brix percentage, penetration force, penetration work and penetration deformation) and independent variables (impact energy in three levels, temperature and color in 2 levels each) were selected and analyzed by block designs with factorial structure. In the experimental design, the fruits were stored in two temperature levels, 3oC and 25oC. Two areas of any fruit (red and yellow areas) were subjected to 3 impact energy levels. For each of the 8 levels, 8 fruit samples were selected. Overall, 96 fruits {8 (number of fruit per level) × 3 (impact energy level) × 2 (both red and yellow) × 2 (at 25oC and 3oC)} was selected. In this study, using a factorial experiment in a completely randomized design, the effect of different factors (impact energy in 3 levels, temperature in 2 levels 3oC and 25°C and color in 2 levels red and yellow) on acoustic stiffness, radius of curvature, color characteristic a* and b*, precent Brix, penetration force, penetration work and penetration deformation in apricot under the quasi-static forces were studied. In order to conduct this experiment, the universal testing machine of biological materials was used. After the determination of mechanical properties of the products, the SAS statistical program (1.9) was applied to analyze and normalize the resulted data.
Factorial test also was used to determine the effects of independent variables on the dependent variables. Data analyses were performed using Statistical Package for the Social Sciences (SAS version 19.0).The variance analysis of the data was conducted in the form of multivariate factorial (2×2×3) design. The data were collected by three controlling factors: two temperature levels (3 and 20°C), two types of colour (Yellow and Red fruits) and three levels of impact energy. The Duncan’s multiple range tests was used to compare the means. The values of reducible sugars were measured by the fruit juice standard - test methods No. 2685 (Institute of Standards and Industrial Research of Iran). The apricots TSS (total soluble solids) for each temperature level by Refractomete (Model: 3820 (PAL-2), Resolution: ± 0.1% Brix) were obtained.
Results and Discussion: Respectively, the main and interaction effects of these variables were examined. The results of analysis of variance showed that,, the radius of curvature, color characteristic, acoustics stiffness, elastic modulus, percent Brix, penetration force and penetration deformation on main and interaction effects were significant at 5% and 1% probability level. According to the analysis of variance table between dependent and independent parameters, a significant effect was observed. Increasing impact energy, the penetration force and penetration deformation at 3°C was higher than at 25°C (Fig.3, 4, 7 and 8). Increasing impact energy, the red zone showed more penetration deformation and penetration force than the yellow zone (Fig.5 and 6). In a constant level of energy the higher the temperature of fruit tissue, the more energy is absorbed, due to this fact that lower temperatures can increase stiffness of the fruit, and leads to transport of absorbed energy to inside the tissue and increase the fruit bruising and final results in less needed penetration force for fruit transformation. Apricot acoustic stiffness in the temperature of 3oC was higher than in the temperature 25oC (Table 3). Fruit stiffness and tissue viscosity increases with increasing temperature. With increasing tissue stiffness, the less impact energy is absorbed and less bruising in fruit tissue is created. Because of more tissue stiffness, in order to create penetration in fruit tissue the more transformation is needed.
Conclusions: The red zone showed a higher bruise susceptibility of ripe apricots. According to the analysis of variance table between dependent and independent parameters, a significant effect was observed. Increasing impact energy, the penetration force and penetration deformation at 3°C was higher than at 25°C. Increasing impact energy, the red zone showed more penetration deformation and penetration force than the yellow zone. Apricot acoustic stiffness in the temperature of 3 oC was higher than in the temperature 25oC.
H. Mirzaee Moghaddam; M. H. Khoshtaghaza; M. Barzegar Bafroee; A. Salimi
Abstract
In this research, kiwifruits (Hayward) were selected in two mass ranges (large and small). They were placed in one-liter glass bottles in the vicinity of the polyethylene sachets containing potassium permanganate nano-zeolite (0, 0.2, 0.4 and 0.8 g) and were stored in a germinator (5°C temperature ...
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In this research, kiwifruits (Hayward) were selected in two mass ranges (large and small). They were placed in one-liter glass bottles in the vicinity of the polyethylene sachets containing potassium permanganate nano-zeolite (0, 0.2, 0.4 and 0.8 g) and were stored in a germinator (5°C temperature and 30% relative humidity). Then, the physicochemical properties of the fruits (soluble solid content, pH, moisture content and fruit firmness) and potassium permanganate nano-zeolite color (L, Hue angle, Chroma and E) were measured after t 0, 2, 4 and 6 weeks of storage. The factorial treatment structure based on completely randomized block design was used for analyzing the obtained data. The results of analysis showed that potassium permanganate nano-zeolite had a significant effect on the measured physicochemical properties, except for the moisture content (P
