Determination of the physical and mechanical characteristics of some strawberry varieties grown in Aydın province for harvest and post-harvest processing

Objective: In this study, some selected physical properties, mechanical properties and moisture content of five different strawberry cultivars reared in Aydın provience were determined while harvest and post-harvest classification, packaging, and transportation aimed at find parameters that will help the design of mechanization systems. Material and Methods: A total of 1300 samples, 260 of each of Festival, Fortuna, Rubygem, Sabrina, and 406 strawberry cultivars were used in the study. In order to measure the fruit firmness and fruit holding coefficient in fruits a digital device with a capacity of 20 kg, respectively a digital handheld dynamometer with a 6 mm thick penetrating and has tensile and compression forces with a metric scale a hand type dynamometer with a measurement capacity of 10 kg and a sensitivity of 0,05 kg was used. The moisture content of strawberries was kept at 70 °C until they reached the constant weight and calculated on a wet basis. The sizes of the strawberries were calculated with the help of a caliper device, their weights with precision scales, and their volumes with the help of a measuring cup and distilled water. By were calculated taking digital photographs of the strawberries on a 1 cm2 calibration surface, some dimensional properties in the ImageJ image processing program. Friction coefficients with the help of a friction angle measuring device and behaviors under load were also determined by compression at different rates with a Zwick-Roell Universal Test device with a maximum measurement limit of 500 N. In the study, pendulum mechanism was used to determine the impact parameters of fruit. Results: In the study, the highest moisture content among strawberry cultivars was found in 406 cultivars (%89,99), the highest value of the fruit holding Fortuna (3N), and the highest value of fruit flesh firmness value was found in Sabrina cultivar (10,10 N). As a result of the physical parameters obtained in the study the mass, volume, vertical and lateral projection areas, geometric mean diameter, and surface area values of 406 strawberry cultivars were found to be higher than the other cultivars. The sphericity and density values were highest in Festival and Fortuna cultivars among the cultivars. The mass values between the cultivars were subjected to analysis of variance and were found to be significant according to the p<0.05 significance level. In the study, the friction coefficient values were found in the 0,43 Sabrina cultivar. On four different surfaces used in the study, the highest coefficient was found in cardboard and the lowest in wood. According to the analysis of variance between the cultivars as a result of the parameters obtained, the friction coefficient value was found to be significant according to the p>0,05 importance level in the cultivars, while the surfaces used were found to be no significant according to the p>0,05 significance level. In the impact tests the injury areas, elasticity coefficient and absorbed energy values of strawberry cultivars impacted on different surfaces from different heights were calculated by using the pendulum mechanism. In the study, it was observed that the injury area and absorbed energy increased in the fall height and the elasticity coefficient decreased. Strawberry varieties were compressed between two platforms, one stationary and the other moving in two different positions and at five different deformation percentages %5, %15, %25, %35, and %45, and their behavior under load was determined. As a result, compression process, according to the type of compression direction and percent deformation dependent variables; deformation and maximum compression force (Fmax) values were found to be significant at p<0,05 significance level. The deformation energy was found to be no significant at the p<0,05 significance level. Conclusion: Strawberry cultivars differed among themselves in terms of both physical and mechanical properties. Different dimensional values were obtained by examining the physical properties. According to the friction coefficient values of the varieties on four different surfaces in two different positions, the relationship between the surfaces and the varieties was found and it was found that the surfaces affected the friction coefficient. In the impact parameters it was found that the injury area and the absorbed energy increased while the elasticity coefficient decreased with the increase in the falling height of strawberries. In the compression test on the other hand with the increase of compression deformation percentages the number of compressed cells increased, and the amount of deformation and deformation increased and maximum forces were obtained. In addition, the lowest and highest values were found by looking at the moisture content adhesion strength and flesh firmness of the cultivars.