Effect of freezing rate on the quality properties of Medjool dates at the tamr stage
Samir Mowafy, M. A. Sabbah, Yahia S. Mostafa, Atef Mohamed Elansari
Abstract
Medjool date fruit is one of the new varieties to be grown in Egypt. An air-blast freezing system was used to investigate the effect of the freezing rate (FR) at three different setting freezing temperatures (−20, −25, and −30°C) on quality parameters of Medjool. The overall FR at the three forenamed setting temperatures were determined to be 2.61, 3.51, and 4.35°C min−1, respectively. A texture profile analysis (TPA) test was conducted on fresh and thawed fruits for determining the mechanical properties of fruits, as affected by FRs. Hardness, Gumminess, and Chewiness were significantly influenced by FRs. The least effect was found at the highest FR. Adhesiveness, Cohesiveness, and Springiness index were not significantly affected by FRs. The effect of FR on color, total soluble solids (TSS), and electrolyte leakage (EL) was also investigated. The highest FR was the most conserving rate to color, TSS, and EL. Practical applications Freezing time and FR data are essential in designing the freezing systems. Clarifying the effect of FR on the Medjool dates quality is important for the operators of the date freezing systems. Applying the proper freezing conditions depends on the targeted fruit quality after freezing and the consuming purpose (fresh table or processing).