Firmness Coefficient Research Articles

ELASTIC PROPERTIES OF THREE VARIETIES OF DATE FRUITS DURING THREE DIFFERENT RIPENING STAGES

The aim of this research work was to determine the physical and elastic properties of date fruits (Phoenix dactylifera) cv (Talees, Khudari and Taghit) during three ripening stages (Khalaal, Rutab and Tamr) to develop a technique that can predict the packing height to protect fruits from mechanical damage.The physical properties include date mass, volume, dimensions, moisture content, bulk density, flesh thickness, and kernel mass. The elastic properties of date fruit include Young's modulus of elasticity (E), firmness coefficient (FC), bioyield stress (σb), bioyield strain (eb), rupture stress (σr), rupture strain (er) and rupture energy (RE). For different varieties, the results showed that ripening stages have a significant effect on physical and elasticity properties. The values of E, FC,σb, σr and RE were decreased from Khalaal to Rutab stage, while they increased from Rutab to Tamr stage. Accordingly, the maximum heights of packing box were 141, 106, and 121 mm for Talees, Khudari and Taghit respectively.

ELASTICITY PROPERTIES OF DATE FRUITS UNDER DEFICIT IRRIGATION TO PREDICT PACKAGE HEIGHT

The aim of this work was to determine the effect of deficit irrigation on the physical and elasticity properties of date fruits (Phoenix dactylifera, cv. Khudary) during three stages of repining (Khelaal, Rutab and Tamr) for two years (2014 and 2015) to predict the package height of date fruit. Four irrigation treatments were studied: (ET1): 1.0 ETc ) one time potential crop evapotranspiration(, ET2: 0.85 ETc, ET3: 0.75 ETc and ET4 :0.65 ETc). The physical properties included date mass, volume, dimensions, moisture content, bulk density, solid density, flesh thickness, flesh mass and elasticity of fruits. The elasticity properties of fruit included young's modulus of elasticity (E), firmness coefficient (FC), bio-yield stress point (σb), bio-yield strain point (eb), rupture stress point (σr) and rupture strain point (er). The results showed that the deficit irrigation affected both physical and mechanical properties, therefore, affected on package height of date fruits. The maximum packing heights for Khellal, Rutab and Tamr were 6360.51, 654.2 and 1850 mm with ET1, ET2 and ET3, respectively. While, the minimum packing heights for Khellal, Rutab and Tamr were 3738, 206.6 and 1411 mm with ET4, ET3 and ET1, respectively.

EFFECT OF DEFICIT IRRIGATION ON THE ELASTIC PROPERTIES OF TOMATO FRUITS

The aim of this research work was to determine the physical and elastic properties of tomato fruits (Lycopersicon esculentum) cv under four water regimes (ET100, ET90, ET80 and ET70 of water requirements) to develop a technique that canpredict the packing height to protect fruits from mechanical damage.The physical properties of tomato include mass, volume, dimensions, bulk density, soild density and geometric mean diameter. The elastic properties of tomato fruit include Young's modulus of elasticity (E), firmness coefficient (FC), bioyield stress (σb), bioyield strain (eb), rupture stress (σr), rupture strain (er) and rupture energy (RE). The results showed that the different water regimes have a significant effect on physical and elasticity properties.The values of E, FC, σb and RE were increased with decreasing water level, while, σr was increased with increasing water level. Accordingly, the maximum heights of packing box were 177.4, 353.6, 456.5 and 526.4 mm for ET100, ET90, ET80 and ET70, respectively.