Yakup Ozkan

Physical and Mechanical Properties of Some Walnut (Juglans regia L.) Cultivars

The physical properties of nuts and kernels of three Turkish walnut varieties (Juglans regia L.) such as dimensions, weight of nuts and kernels, sphericity, bulk density, volume, and coefficient of friction were determined. The resistance of the nut and kernel of walnut varieties to damage was determined by measuring the average rupture force, deformation and rupture energy along the X-, Y- and Z-axes at different compression speeds (30 and 60 mm/min). Both the static and dynamic coefficient of friction values were greater for the sheet iron surface than the galvanized one for all walnut varieties. The highest nut rupture force, deformation and rupture energy among the three walnut varieties occurred for Kaman loaded on the Y-axis. The results indicated that when testing the effects of compression axes the rupture force is highly dependent on walnut varieties. The lowest force needed to rupture the nut or kernel was found in walnut varieties with Sebin that were tested at a compression speed of 60 mm/min.

Physico-mechanical Properties and Colour Characteristics of Apple as Affected by Methyl Jasmonate Treatments

Physical (geometric, volumetric and colour) and mechanical properties of apple (cv. Fuji) as affected by Methyl Jasmonate treatments were analyzed. Geometric mean diameter, fruit mass, sphericity and surface area ranged from 71.36 to 69.97 mm, 196.53 to 194.83 g, 1.126 to 1.129, and 161.32 to 158.11 cm2 with MeJA doses, respectively. The bulk and fruit densities varied from 383.65 to 364.22 kg/m3 and from 967.96 to 954.63 kg/m3, with MeJA treatments. L*, a*, b* value of skin apple changed from 50.76 to 46.89, from 28.06 to 30.35, and from 24.58 to 22.43, respectively with MeJA doses. The skin and flesh firmnesses varied from 101.49 to 112.60 N and 74.18 to 72.71 N, respectively. The sphericity and projected area increased with MeJA doses used. As the MeJA doses increased, the bulk and fruit densities decreased, whereas volume increased. L*, b* and hue angle characteristics of skin apple were found to decrease, whereas a* was found to increase with MeJA doses. The fruit-removal-force was decreased linearly with increasing MeJA doses. The rubber surface offered the maximum friction followed by plywood and galvanized metal for MeJA doses.

The effect of NAA (1-naphthalene acetic acid) and AVG (aminoethoxyvinylglycine) on physical, chemical, colour and mechanical properties of Braeburn apple

Abstract Recently, plant growth regulators have been used for multiple purposes in tree fruits. NAA (1-naphthalene acetic acid) and AVG (aminoethoxyvinylglycine) have been widely used in apple fruit. NAA and AVG have been used to control preharvest fruit drop and improve the quality of fruit. In this study, the effects NAA (20 mgL–1), AVG (500 mgL–1) and control (non treatment) treatments on physical, chemical, colour characteristics and mechanical properties of apple (cv. Braeburn) were investigated. The higher length, width, thickness, geometric mean diameter, fruit mass, surface area, projected area, volume, fruit and bulk densities were obtained in AVG treatment. Total acidity, total soluble solid content and starch starch index were higher in control as compared to NAA and AVG treatments. Total phenolic content of the flesh apple was higher than the other treatments. While total antioxidant activities of skin and flesh fruit were higher in AVG according to FRAP method, total monomeric anthocyanin was lower in AVG as compared to the other treatments. AVG treatment generally had positive impacts on fruit removal force, skin and flesh firmnesses because retarding the fruit ripening.

Effects of Pre-Harvest Methyl Jasmonate Treatments on Bioactive Compounds and Peel Color Development of “Fuji” Apples

The present study was conducted to investigate the effects of pre-harvest methyl jasmonate treatments on peel color formation, total anthocyanin, total phenolics, total antioxidant capacity, and other selected fruit quality parameters of “Fuji” apples. Results revealed significant decreases in color parameters (L*, chroma, and hue values) with methyl jasmonate treatments. Total anthocyanin, total phenolics, and total antioxidant capacity of methyl jasmonate-treated fruits were significantly higher than control fruits. Methyl jasmonate concentrations increase linearly with increase in total anthocyanin, total phenolics, and total antioxidant capacity with high correlations. Ethylene synthesis-promoting impact of methyl jasmonate increased with increasing implementation doses. Methyl jasmonate treatments also increased fruit flesh firmness. While 1120 and 2240 mg/L methyl jasmonate treatments did not cause any significant changes in the starch degradation, 4480 mg/L methyl jasmonate treatment delayed the starch degradation. All methyl jasmonate treatments did not cause any or much significant changes in fruit mass, geometric mean diameter and soluble solids content of the fruits but yielded significant increase in titratable acidity values.