Shima Nasiri; Saman Abdanan; Mokhtar Heidari
Abstract
Introduction: Texture represents one of the four principal factors defining food/fruit quality, together with appearance, flavour and nutritional properties (Bourne, 2002), and plays a key role in consumer acceptability and recognition of quince. Textural characteristics of quinces defined by “crispness”, ...
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Introduction: Texture represents one of the four principal factors defining food/fruit quality, together with appearance, flavour and nutritional properties (Bourne, 2002), and plays a key role in consumer acceptability and recognition of quince. Textural characteristics of quinces defined by “crispness”, “juiciness”, “hardness”,“firmness” and “mealiness” are often key drivers of consumer preference. Many non-destructive methods, including image analysis, spectroscopy, ultrasound and sound techniques, have been developed to diagnose internal and external defects in fruits and vegetables. Cheng and Haugh (1994) used a frequency of 250-kHz, rather than 1-MHz, to detect hollow heart. They were not able to transmit successfully the ultrasound wave through the whole tuber using 1-MHz transducers but found the 250-kHz transducers to be practical for a transmission path length of up to 89.7 mm. In a research an acoustic setup was developed to simultaneously detect the resonant frequencies from equator and from calyx shoulder of pear. The researchers proposed index based on these two frequencies was used for firmness evaluation of non-spherical pear; Compared with two types of single frequency-based indices, the firmness sensitivity of the dual-frequency index is mostly close to that of MT penetration test. The firmness index can classify pears with a high total accuracy (93.4%), making it suitable for nondestructive detection of firmness of differently shaped pears (Zhang et al., 2018). The goal of this study was to develop a nondestructive method based on acoustic impulse response of quince fruit using genetic programming and artificial neural network during storage. Materials and Methods: In the experiment 120 quince fruits (Cydonia oblonga) were harvested from a field near Isfahan 181 days after full flowering of the trees. For each cultivar, only samples of similar size and without visible external damage were chosen. The samples were packed in sterile nylon bags and stored at 4°C. Non-destructive test (acoustic response) as well as destructive test (chemical measurement and penetration test) were performed every 15 days for 4 months (Akbari Bisheh et al., 2014). Total soluble solids (TSS) were determined by a hand refractometer device (model: MT03 Japan) and expressed as °Brix. Ascorbic acid of the juice was measured by titration with copper sulfate and potassium iodide based on the Barakat et al. (1973) procedure. Titratable acidity was measured according to the AOAC method. To determine the total phenol content of juice, the Waterhouse method (2000) was used. Determination of the pH of the fruit extract using a pH meter (Portable Model P-755, Japan). Physical attributes of the samples including volume as well as major, minor, intermittent diameters and mass were calculated using the relations proposed by Stroshine and Hammand (1994). Penetration test was conducted by the material test machine (SANTAM, STM-20 model, Iran).In order to analyze the response sound signal of quince in time and frequency domain, a system equipped with a sample holder with foam rubber covered surface, an impact mechanism, a microphone and an electronic circuit was utilized. To record impact sound features a microphone was positioned next to the fruit and was hit at three speed level (0.3, 0.9 and 1.5 m/s). After recoding sound, five features (acoustic peak, maximum acoustic pressure, mean acoustic pressure and natural frequency) were extracted and used as inputs for models. In order to predict the stiffness, four methods of genetic programming, neural network and existing mathematical models (FI and SIQ-FT) were used. In order to carry out statistical analysis, analysis of variance (ANOVA) and Duncan's multiple range test at 5% probability level were performed according to the completely randomized design (CRD). Results and discussion: In this study, Duncan's multiple range comparison test was used to investigate the significant difference between destructive and non-destructive parameters at 5% probability level. According to the results, acoustic peak, maximum acoustic pressure, mean acoustic pressure and natural frequency were decreased by increasing storage time. Statistical analysis of the destructive tests also showed a decreasing trend at the 5% level. In several papers, two mathematical equations have been used to obtain the relationship between the mass resonance frequency and the sound of impact. In this study, genetic programming and neural network modeling were used to compare the results of these relationships. The regression coefficients between the actual and the predicted values for the resonance-mass relation and the effect of the sound from the collision were R2= 0.601 and R2= 0.754, respectively. Also, the regression values obtained from genetic programming and neural network modeling were R2= 0.9567 and R2 = 0.933, respectively. In a research, the overall R2 value amounts for stiffness prediction was reported to be 0.79 (Schotte et al., 1999). Abbaszadeh et al. (2013) evaluated watermelons texture using their vibration responses. They declared their proposed method could predict textural acceptability of watermelons with determination coefficients 0.99. According to the obtained values, the best methods for stiffness prediction were genetic programming and f neural network methods, respectively.
Farhad Fatehi; Asghar Mahmoudi; Adel Hosseinpour; Hadi Samimi Akhijahani
Abstract
Introduction: Strawberry is one of the native and small fruits of moderate regions, which its cultivation has been increased in all over the world including Iran. Due to the abundance of vitamin C and mineral materials, it is very useful for some diseaseses. Lack of the knowledge in production ...
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Introduction: Strawberry is one of the native and small fruits of moderate regions, which its cultivation has been increased in all over the world including Iran. Due to the abundance of vitamin C and mineral materials, it is very useful for some diseaseses. Lack of the knowledge in production management, harvesting, cooling, transportion, storage, marketing and processing equipments and connection between these different parts are the main problems throgh industrial production of strawberry fruit (Salami et al., 2010). According to the various studies, the parameters such as color, shape, size and mass are not sufficient for the consumer to purchase the fruit (Abbot, 1991). They would like to have more information about the fruit which is supposed to be purchased (Voca et al., 2008). Several researchers have been investigated physical and chemical properties of different varieties of strawberry fruit (Wojdylo et al., 2009; Salamat, 2011; Nemzer et al., 2018). According to the litrature, any international standard classification for Parus strawberry (which is mostly cultivated in Iran) based on physical and chemical was not found. In this study, some physical, mechanical and chemical properties of strawberry fruit Parus variety, as well as the relationship between them, were investigated. The classification was performed based on the appearance features including color and size with the opinion of the expert in six classes. Materials and methods: In Kurdistan province strawberry fruit is often grown in open area and cultivated areas of Parus variety due to many reasons are increasing. To classify the strawberries, six classes were considered. Physical and mechanical properties such as dimensions, density, porosity, stiffness and biological yield point were measured at least at five replications. The porosity of the strawberries was also calculated through the division of the difference between actual and apparent density to actual density. Also, the stiffness and biological yield point were measured using Universal Instron Testing Machine (Zwick/Roll). Chemical properties of Parus strawberry including vitamin C, acidity, total soluble solids and flavor index were investigated at five replications. Results and discussions: The analysis of variance showed that all chemical properties including ascorbic acid, acidity, total soluble solids, and flavor index, were strongly influenced by the class. The LSD mean comparison showed that the highest levels of vitamin C were related to the ripe fruits which had a direct relationship with fruit size. The acidity values between the classes varied from 0.55 to 1.08, and the lowest value was related to the first, second and third classes, respectively. The total soluble solid material (TSS) was affected by some factors: sugar (as main part), organic acid and organic pectins and was increased by growing strawberries and increasing the amount of sugar. For the first, second and third classes, TSS was higher than those of the fourth, fifth and sixth clases. The flavor index value for the lower classes (first, second and third) is higher than the higher classes (almost 2 times). The analysis of variance for all physical and mechanical properties indicated that all parameters are affected by the classes. Due to its more soluble materials, the maximum value for actual density was related to the third and second classes, respectively. The apparent density of agricultural products depends on various factors such as geometric shape, size, surface properties, moisture content and measurement method. The apparent density for the first and fourth classes were 561.743 and 498.408 gr.mm-3, respectively. The maximum and minimum value of stiffness was related to first (about 5.2 N.mm-2) and fourth (about 28.2 N.mm-2), respectively. For biological yield the maximumvalue was related to the fourth class, as well. Conclusion: In this study, the classification of strawberry, variety of Parus was investigated based on physical, mechanical and chemical properties. All properties were affected by changing the classes. The results of this research can be used to design and construct post-harvest and sorting mechanisms of agricultural products which require comprehensive information about physical, mechanical, chemical properties.
