Mohsen Azadbakht; Mohammad Vahedi Torshizi; Mohammad Javad Mahmoodi
Abstract
This research was aimed to study the effects of loading force and storage period on the physiological characteristic of pears. In this experiment, the pears were subjected to quasi-static loading (wide-edge and thin-edge) and different storage periods (5, 10 and 15 days). The amounts of the fruits’ ...
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This research was aimed to study the effects of loading force and storage period on the physiological characteristic of pears. In this experiment, the pears were subjected to quasi-static loading (wide-edge and thin-edge) and different storage periods (5, 10 and 15 days). The amounts of the fruits’ total phenol, antioxidant and vitamin C contents were evaluated after each storage period. In the present study, multilayer perceptron (MLP) artificial neural network featuring a hidden layer and two activating functions (hyperbolic tangent-sigmoid) and a total number of 5 and 10 neurons in each layer were selected for the loading force and storage period so that the amounts of the total phenol, antioxidants and vitamin C contents of the fruits could be forecasted. According to the obtained results, the highest R2 rates for thin-edge and wide-edge loading in a network with 10 neurons in the hidden layer and a sigmoid activation function were obtained for total phenol content( =0.9539- =0.9865), antioxidant ( =0.9839- =0.9649) and vitamin C ( =0.9758); as for wide-edge loading in a network with 5 neurons in the hidden layer and hyperbolic tangent activation function, the highest R2 rate of vitamin C content was obtained equal to =0.9865. According to the obtained results, the neural network with these two activation functions possesses an appropriate ability in overlapping and predicting the simulated data based on real data.
Mohsen Azadbakht; Mohammad Javad Mahmoodi; Mohammad Vahedi Torshizi
Abstract
Introduction: The study of relationship between physical properties such as mass and volume and other physical properties, such as geometric dimensions, has been the subject of numerous studies by researchers. The fruit size, shape and mass are important in sorting and measuring fruits, and it determines ...
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Introduction: The study of relationship between physical properties such as mass and volume and other physical properties, such as geometric dimensions, has been the subject of numerous studies by researchers. The fruit size, shape and mass are important in sorting and measuring fruits, and it determines that the fruits can be put in boxes of transport or plastic bags by a specific size. Damage to the fruit may be due to various causes, including Impact, pressure and vibration, all of which cause physical damage at moment or at storage time, the amount of damages depends on location of impact, the size and volume. Also, the volume and physical properties of agricultural products are very important for storage. On the other hand, cell damage and forces involved in fruits reason bruising in fruits, which can be controlled by physical properties. Quality assessment is usually carried out using a combination of destructive and non-destructive methods, generally done by the product manufacturers or the first purchasers, and includes the separation of materials based on specific size and weight. Among non-destructive methods used, the use of CT and X-rays, which allow a person to examine bruises at different times in the fruit, is increasing. Due to the fact that mass and volume of fruits for storage, transportation, packaging and etc are of great importance, in this research, the relationship between pear fruit volume and mass with bruise percentage during the storage period was studied using non-destructive CT scan tests due to dynamic loads.
Materials and methods: Firstly, the pendulum and the required masses were made in a workshop. The fruits were placed in the desired position and then the device arm was raised to the desired angle (90°), and in the controlled state of the arm impact the pear. The pendulum had a 200 g and three different attachment masses of 100, 150, and 200 g for knocking. It should be noted that air resistance and friction were neglected through this procedure. In this research, via CT scan, the relationship between mass and volume of pears (Before and after the impact) due impact loading and storage times with bruise was investigated. Before loading and storing, 50 pears were examined using Scan CT and 27 pears with zero bruise percentage were selected, the next chosen pears were subjected to impact loading with a pendulum with three weight of 300, 350 and 400 g and 5, 10 and 15 days storage was used to investigate the effect of impact on pears. Then, after impact and storing, with the use of CT scan in each period of storage, the rate of pear bruise was calculated.
Results and Discussion: The pears volume before impact with the bruise percentage for all three weights had a negative and non-significant correlation and the decrease pear mass percentage with the bruise percentage for all three weights has a positive correlation and pears mass before impact with the bruise percentage for all three weights had a positive and non-significant correlation. Any decrease in pear mass percentage had a positive correlation with caries percentage for all three weights. The correlation test showed that with the increase in pear volume, the bruise percentage was decreased and a direct correlation was found between the decreasing percentage volume and the bruise percentage. –also The effect of 5-day storage duration was found considerable on the bruise percentage subject to the exertion of 350 g and higher impact rates
