Post Harvesting Technology
Mohammad Momeni Arani; Abbas Rezaei Asl; Azim Ghasemnezhad
Abstract
Introduction Drying is one of the important stages after harvesting of plants and agricultural products, which plays an important role in the quantity and quality of the active ingredients. The purpose of drying is to reduce water to a certain level for low and stop the microbial activity. Therefore, ...
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Introduction Drying is one of the important stages after harvesting of plants and agricultural products, which plays an important role in the quantity and quality of the active ingredients. The purpose of drying is to reduce water to a certain level for low and stop the microbial activity. Therefore, in laboratories the effects of different levels of temperature and time are investigated on different plant properties during drying operations with laboratory dryers and ovens. It can be said that the principled and thorough drying of medicinal plants is necessary in order to reduce moisture, increase the shelf-life and increase the quantity and quality of the active ingredients. Today, many control algorithms are used to control temperature, which is much more efficient than the on-off. Fuzzy control is suitable for fast control and high accuracy of proper nonlinear processes. Likewise, the type of ventilation and the placement of thermal elements are also very influential on the heating system and the temperature of the chamber. Today as foreign companies, in addition to focusing on the type of control system and intelligence ovens, many studies have been done on how the element is placed, on its type, the shape of the fan, its type, and the design of the air channels. Materials and Methods The dryer was designed with software Solid Works and constructed in manufacturing workshop of the Bio-System Mechanics Engineering Department of the Natural Resources and the Agricultural Sciences University of Gorgan, Iran. The device has a fuzzy control system, a ventilation, and fan system. The built-in dryer has two mechanical and electrical parts. This dryer has an external chamber with dimensions of 74 × 50 × 60 cm and internal chamber dimensions of 40 × 35 × 50 cm. The device was insulated with thermal spray foam. The electronic circuit was designed using Proteus simulation software and implemented on the board. The main piece of information processing and controlling the algorithm in the dryer control system is the microcontroller. The microcontroller programming was written by C software and transmitted to the microcontroller with the Code Vision software. The tests were performed at three levels of 60, 80, 90 °C. The programmability of the device was also evaluated simultaneously for four different temperatures and times. The device was evaluated at 4 levels of 90, 70, 50 and 30 °C and four levels of the time were done respectively 10, 10, 10, and 20 min. Also, in the process of increasing temperature, the temperatures of 40, 60, 80 and 90 °C respectively were tested. Also, the stability function and the time to reach the temperature were compared with two samples of the laboratory dryer (oven) imported Memmert and Bender models which had a fuzzy control system and a ventilation system and a built-in oven model in the interior. Results and Discussion Because exactly as wasted, the temperature of the chamber walls is applied to the chamber, the device is capable of maintaining the temperature of the chamber at the set point. The result of the evaluation in the energy waste from the wall of the device showed that after about 200 min, the temperature of the internal chamber (which was at 80 ° C) was equal to the outside temperature of the chamber. The results showed that during temperature stability, the difference in temperature between different points of the compartment (places where laboratory samples are placed) is less than ±0.5. The programmability of the device was evaluated at 4 levels of 90, 70, 50 and 30 °C; after reaching the temperature of 90 °C, and at the end of the scheduled time, the temperature is reduced to a minimum, reaching the next temperature. Reducing the temperature for other temperatures was also done according to the program. The results of the programmability of the device were shown in the incremental step of the temperature; in the incremental process, as the temperature decreases, the temperature difference between the points is very small and reaches the temperature stability as soon as it reaches the regulated temperature. The control system used can properly maintain the temperature in a stable state. The results of the comparison of the performance of the dryer control system made with other experimental dryers at a temperature of 80 ° C showed that the dryer was able to stabilize the inside of the compartment at the desired point, in comparison with other ovens. The built-in dryer function is compatible with the Memmert UFE500 and the Binder FE53 ovens. Due to the cost of the device, its use will be very useful for conducting research in research centers. Conclusion The fuzzy control system used in the dryer was able to properly control the temperature of the chamber according to the program. The control system of the device was able to control the temperature of the chamber at a regulated point with a minimum temperature variation (less than half a °C). The built-in dryer was able to reduce and increase the temperature step by step in a given temperature range according to the given program. The performance of the dryer, compared with other ovens, showed that it could match the best of imported ovens.
Post Harvesting Technology
Armin Ziaratban; M Azadbakht; Azim Ghasemnezhad
Abstract
Background and objective Unlike engineering materials, apples are living tissues which survive after harvesting. Thus, post-harvest processes such as transporting and packaging should be carried out in a way that makes them less vulnerable. Among the agricultural products, fruits and vegetables are the ...
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Background and objective Unlike engineering materials, apples are living tissues which survive after harvesting. Thus, post-harvest processes such as transporting and packaging should be carried out in a way that makes them less vulnerable. Among the agricultural products, fruits and vegetables are the commodities that due to their low resistance to the shell and high humidity, have a high sensitivity against mechanical damages that occur when processing them. In order to minimize waste, proper post-harvest management and convenient techniques for transport and storage are required. Mechanical damages can occur in three major ways, including pressure, impact, and abrasion. The pressure during the harvest may impose on the fruits by pickers or occur when fruits are stored in the bottom of the box. External damages may happen due to the weight of picked apples in the baskets in deep boxes or when transporting the boxes by hooks. In fruit packaging stations, pressure, impact, and vibration can occur when packaging of fruits in boxes, as well as the washing and waxing fruits. Pressure forces usually happen during transport and storage of the fruit. This study was undertaken to study the impact on sugar, phenol, acidity and fatigue area that play a major role in the final quality of the product. Materials and methods Static and dynamic impacts and storage time were considered as the independent factors in this study and their effects were analyzed on the chemical parameters including sugar, phenol, acidity and fatigue area. The static impact was conducted by Instron Sntam with three loading speed 5, 7, and 10 mm/min for 1min. The dynamic impact was conducted by a pendulum that simulated the energy applied to apples that dropped. The amount of energy was equivalent to 2.25, 3 and 3.75 J. Apples that underwent impacts, were kept for 20, 40 and 60 days to measure the impact on changes of chemical parameters and determine the area of fatigue. After each storage period, the samples were photographed. The area of fatigue was measured using image processing techniques and Image J software. The image processing consists of two parts: hardware and software. The hardware of computers, cameras and imaging chamber is formed. The camera was connected by cable to a computer and the images were stored on a computer's permanent memory. Used computers used running windows seven, five-core central processing unit, and RAM was 4 Giga bytes. Computer is the processing of the data and the image acquisition step to the final step, the output data is the most important role. The used camera was a Canon, made in Japan, was mounted vertically inside the box. Shooting box was used just because all the photos must be taken in a constant condition of light regarding light intensity of surroundings and distance of apples from the camera. The Chamber was made of wood and shaped like a cube with dimensions of 45 × 45 × 45 cm, which is just an open area. Three eight-watt fluorescent lamps for lighting inside the box was fixed to the ceiling box around the triangle mounted camera. Image J analyzer is a powerful software with various uses. This software can calculate the area and pixel value statistics of user-selected portions of the image. Factorial experiments were carried out in a completely randomized design with three replications. Results Results revealed that acidity changes and fatigue area during the storage under static and dynamic impacts were significant at 0.01 and 0.05% and for phenol and sugar were significant at 1 and 5%. Also, in this test, sugar content and acidity were generally reduced over time, and phenol and fatigue area increased. Conclusion In order to avoid excessive reduction in sugar and fruit quality, maintenance time should be reduced as much as possible. Phenol increased during storage, after applying impact; its oxidation when contacting air results in toxic compounds that are harmful to humans. Therefore, packaging using the pads and increasing the quality of the harvesting and transporting is necessary in order to reduce the damages to the fruit. Fruit acidity during storage after the impacts showed the significant changes that could negatively affect the taste of the fruit and as a result, its marketability.
