Variations in physicochemical and microbiological characteristics of ‘Mejhoul’ dates (Phoenix dactylifera L.) from Morocco and new countries of its expansion

Mejhoul’ date cultivar originated from Morocco and largely spread around the world. It is of high commercial value and is considered to be one of the best-exported dates concerning its fruit quality and size in comparison with other cultivars. This study aims to investigate variations within the physicochemical and microbiological characteristics of ‘Mejhoul’ dates sampled from its original growing areas in Morocco and other countries, where the cultivar is expanded in the recent years. Dates samples were collected from the most important production areas of the ‘Mejhoul’ cultivar in Morocco (Figuig, Bouanane, Boudnib, Difat Ziz, Rissani and Zagora) and the United States of America, Kingdom of Saudi Arabia, Jordan and Palestine. Variance analysis of pH, moisture, ash and sugar content show a significant difference (p < 0.05) within ‘Mejhoul’ cultivar samples. Statistical analysis (Principal Component Analysis “PCA”) allows the classification of samples into three groups. The first group holds ‘Mejhoul’ samples from Morocco, including Figuig, Boudnib and Difat Ziz, characterized by high water content and high density of TVC and Yeasts. The second group is composed of all international samples (Palestine, Jordan, USA and KSA) in addition to samples from Rissani (Morocco), presents reverse characteristics compared to the first group. The third group includes ‘Mejhoul’ from Bouanane and Zagora (Morocco). Despite the availability of favorable conditions, making Morocco an ideal area for ‘Mejhoul’ production. However export of this date cultivar remains limited from Morocco due to uncontrolled production techniques and environmental factors

Effect of harvesting and post-harvest practices on the microbiological quality of dates fruits (Phoenix dactylifera L.)

In Morocco, many dates varieties are produced and marketed, including local and imported dates, mainly Deglet Nour variety. The present study aimed to evaluate microbiological contamination on ten varieties of dates from four different production areas in Morocco, from the date market of Marrakech, and from the imported Deglet Nour variety, and to show effects of harvesting and post-harvest practices on the microbiological quality of dates. Physicochemical data presented that the pH of studied varieties varies between 5 and 6 and water activity from 0.28 to 0.62. Microbiological analysis displayed that samples from Tata region presented the highest microbial spoilage with Total Viable Counts (TVC) ranging from 4.2 log CFU.g-1 to 2.6 log CFU.g-1 and yeast/moulds reaching 2.99 log CFU.g-1. Deglet Nour dates imported from Algeria, and Tunisia were less contaminated (TVC <1.0 log CFU.g-1, yeasts/moulds <1.0 log CFU.g-1). Coliforms, Bacillus sp. and Staphylococcus were not found in any sample. Results revealed that some varieties produced and marketed in Morocco are affected by microbial spoilage, which can be assigned to uncontrolled dates processes of harvesting and post-harvesting practices

Calibration of Thermal Dissipation Probes for Date Palm (Phoenix dactylifera L.)

The quantification of water flow through the stem is vital for date palm (Phoenix dactylifera L.) to promote a good water stress management. The thermal dissipation probe (TDP) method developed by Granier is widely used to evaluate transpiration of forest trees; however, there are contradictory reports regarding its reliability. Considerable errors in estimated sap flux density, which might be due to a lack ofspecies-specific calibrations. The TDP method uses a mathematical model that is based on an empirical equation to estimate sap flux density, which is claimed to be applicable to all tree species, independently of wood structure and anatomy. At the laboratory, we compared the rate of water uptake by cut stems with sap flux estimates derived from the TDP method to assess the validity of the method.Our calibration results were considerably different compared to the Granier’s original equation. Moreover, sap flux density was overestimated by 18.2 ± 0.5% when the original calibration parameters of Granierare employed. However, using new calibration parameters improved the accuracy of sap flow measurements. Our results indicated that it is not appropriate to use a general equation for different species. Therefore, previous estimations of date palm’s water requirement through thermal dissipation probes should be revised

Calibration of Thermal Dissipation Probes for Date Palm (Phoenix dactylifera L.)

The quantification of water flow through the stem is vital for date palm (Phoenix dactylifera L.) to promote a good water stress management. The thermal dissipation probe (TDP) method developed by Granier is widely used to evaluate transpiration of forest trees; however, there are contradictory reports regarding its reliability. Considerable errors in estimated sap flux density, which might be due to a lack ofspecies-specific calibrations. The TDP method uses a mathematical model that is based on an empirical equation to estimate sap flux density, which is claimed to be applicable to all tree species, independently of wood structure and anatomy. At the laboratory, we compared the rate of water uptake by cut stems with sap flux estimates derived from the TDP method to assess the validity of the method.Our calibration results were considerably different compared to the Granier’s original equation. Moreover, sap flux density was overestimated by 18.2 ± 0.5% when the original calibration parameters of Granierare employed. However, using new calibration parameters improved the accuracy of sap flow measurements. Our results indicated that it is not appropriate to use a general equation for different species. Therefore, previous estimations of date palm’s water requirement through thermal dissipation probes should be revised

Effect of pre-harvest practices on physical and colorimetric characteristics of date fruit (cv. ‘Aziza Bouzid’) in Figuig oasis

Dates represent a very important energy source that contains a wide range of functional, nutritional, bioactive, and aromatic components. Dates characteristics have been widely studied but none has been conducted on the pre-harvest factors responsible for the quality variation. The aim of this study is to evaluate the effect of pre-harvest practices on physical and colorimetric characteristics. The analyses were conducted on twelve samples of ‘Aziza Bouzid’ cultivar and collected at Tmar stage from Figuig oasis. Results obtained for physical parameters show a significant variation between different samples. Weight of ‘Aziza Bouzid’ varied from 5.44 g to 9.04 g. Geometric mean diameter and Porosity varied from 13.08 mm to 17.01 mm and 31.88 % to 42.3 % respectively for ‘Aziza Bouzid’. Highest Chroma and hue values registered for ‘Aziza Bouzid’ were 38.14 and 83.22 and the lowest were 21.1 and 67.15. This study contributes to develop good agricultural practices, help improve the quality and increase the quantity of Moroccan date production

Effects of irrigation systems on yield and physical characteristics of date (

The shortage of irrigation water pooled with the effect of climate change and inadequate management in oases; affects the sustainability of the oasis ecosystem. Irrigation, as practiced in these oases, is not conducted according to the real water requirements of the crops, this management can induce water stress which affects the physical characteristics of the dates cultivated and consequently yield production, or on the contrary a significant water intake and a waste of the resource. This study investigated two irrigation systems; drip-irrigation, which is currently applied under date palms in the Moroccan oases, and the newly introduced underground irrigation (Micro-porous irrigation) .The aim of this work, was to assess the effects of different types of irrigation system on yield and physical quality parameters of ‘Medjool’ dates. Fruit quality assessment including fruit weight, length, breadth, pulp thickness, stone weight, length, breadth, number and average weight of bunches fruit per tree were evaluated, to identify the most effective irrigation system for date palm

Calibration of Thermal Dissipation Probes for Date Palm (<i>Phoenix dactylifera</i> L.)

The quantification of water flow through the stem is vital for date palm (Phoenix dactylifera L.) to promote a good water stress management. The thermal dissipation probe (TDP) method developed by Granier is widely used to evaluate transpiration of forest trees; however, there are contradictory reports regarding its reliability. Considerable errors in estimated sap flux density, which might be due to a lack ofspecies-specific calibrations. The TDP method uses a mathematical model that is based on an empirical equation to estimate sap flux density, which is claimed to be applicable to all tree species, independently of wood structure and anatomy. At the laboratory, we compared the rate of water uptake by cut stems with sap flux estimates derived from the TDP method to assess the validity of the method.Our calibration results were considerably different compared to the Granier’s original equation. Moreover, sap flux density was overestimated by 18.2 ± 0.5% when the original calibration parameters of Granierare employed. However, using new calibration parameters improved the accuracy of sap flow measurements. Our results indicated that it is not appropriate to use a general equation for different species. Therefore, previous estimations of date palm’s water requirement through thermal dissipation probes should be revised