Deglet Noor Dates Research Articles

Effect Of Soil And Water Salinity On The Quality Of Deglet Noor Dates in Biskra Region, Algeria

The Biskra region in Algeria is known for the production of very good quality Deglet Nour dates. This quality is the result of the interaction of several ecological and agronomic factors. Our work aims to study the impact of hydro-edaphic parameters on the quality of Deglet Noor dates, produced in the region of Biskra. The study is carried out in three stations: Tolga, Sidi Okba and Ouled Djelel. Three farms are chosen in each station. The methodological approach is based on Soil, water, biometric and biochemical analyzes on sampled dates. The results shows that the water irrigation have a high salinity in Sidi Okba station. The statistical analyzes (ACP) shows that, the high salinity of irrigation water is the main cause of soil salinization. This salinization reduces the biometric characteristics of dates (length, width and weight), and increases their total sugar content.

Effect of potassium application on Deglet Noor date production and quality

ISHS XXX International Horticultural Congress IHC2018: VII International Symposium on Tropical and Subtropical Fruits, Avocado, II International Symposium on Jackfruit and Other Moraceae and II International Symposium on Date Palm Effect of potassium application on Deglet Noor date production and quality

Freezing Treatments for Ectomyelois ceratoniae Mortality and Maintenance of Deglet Noor Palm Date Quality

Background. Insect infestation caused by Ectomyelois ceratoniae or carob moth is one of the main postharvest problems that can lead to a decrease of the marketable quality of dates. The control of carob moth is a mandatory process for exported fruits, and the main chemical method used to prevent pest diseases of palm date is treatment with methyl bromide. However, its use is being restricted due to direct harmful effects on the environment and indirect effects on humans. Freezing treatments could be physical alternatives to methyl bromide and other chemicals. Three freezing treatments at −18°C (50 h, 77 h, and 125 h) were studied for E. ceratoniae mortality in Deglet Noor date fruits. Results. The results showed that freezing at −18°C led to 100% mortality of all the stages of E. ceratoniae found in naturally infested dates. Fruit quality was examined under a selected sanitizing freezing treatment (50 hours at −18°C). This freezing treatment induced an increase of monosaccharides and a reduction in antioxidant activity (40 to 45%, measured with FRAP and DPPH assays). However, other parameters such as color, amino acids, total phenolic content, and microbial and sensorial quality were not affected by that treatment. All samples remained above the limit of marketability as there was no chilling injury. Conclusion. This treatment can be recommended as a green alternative to chemical treatments to control carob moth while yielding optimum-quality Deglet Noor date fruits that could be exported to developed countries.

Production and Characterization of a Polyphenol Enriched Date Palm Extract from California Date Palm

Date palm (Phoenix dactylifera) is an important food cultivated in the Coachella Valley in Southern California. Medjool and deglet noor dates are the two most popular varieties and both pack an impressive list of nutrients, including vitamins, minerals, lipids and proteins. Dates are also rich in phenolic compounds including phenolic acid, flavonoids, tannins, anthocyanins and carotenoids. These compounds are associated with a variety of beneficial health effects. However, very few studies have identified the molecular mechanisms underlying these observed effects. Therefore, the aim of the present study was to produce and characterize a date palm extract (DPE) made from California dates that can then be used in subsequent in vitro and in vivo studies to elucidate the mechanisms by which dates confer beneficial health effects. California dates were harvested during the 2014 and 2015 harvest seasons and freeze‐dried date extract was produced from equal part medjool and deglet noor dates by means of liquid extraction and solid phase separation. The extracts were characterized using High Performance Liquid Chromatography (HPLC) and Matrix‐Assisted Laser Desorption Ionization Time‐of‐Flight Mass Spectrometry (MALDI‐TOF MS).HPLC chromatograms show that the predominant polyphenols present within the extracts have spectral characteristics indicative of hydroxycinnamic acids; specifically, the UV‐Visible spectra has a maximum absorbance in the range of 320–330nm. The extracts also have spectral characteristics indicative of proanthocyanidins (PAC). Specifically, the UV‐Visible spectra have an absorbance at 280nm and resolve as a poorly eluting ‘hump’ rather than well‐defined individual peaks. The qualitative and quantitative presence of PAC in the date extract was detected by butanol‐HCl and by separation of the extract on a Sephadex LH20 column prior to HPLC and MALDI‐TOF MS analysis. This separation provides an enriched PAC fraction, which helps with the subsequent characterization of PACs, providing sufficient separation of compounds to allow for the detection of PAC oligomers from 3–7 degrees of polymerization by MALDI‐TOF MS. HPLC chromatograms of the PAC fraction at 280 nm show two broad and unresolved humps, due to the structural heterogeneity of the PAC oligomers. Furthermore, positive reflectron mode MALDI‐TOF MS exhibited a series of compounds which appear to be oligomeric in nature with repeatable extension units. We propose that this mass may correspond to suberin compounds, specifically an ester of ferulic acid with long‐chain w ‐ hydroxyfatty acids (C16, C18, C20). The pattern of MALDI peaks suggests the presence of a series of w ‐ hydroxyfatty acids varying in degree of unsaturation.This study shows that date palm fruits are a good source of phenolic compounds mainly hydroxycinnamic acids, PAC and lipophilic polyphenols, and that this extract can be used for further in vitro and in vivo analysis.Support or Funding InformationFunded by California Date Commission

Anti-atherogenic properties of Deglet Noor Date seeds (Phoenix dactylifera) Methanol extract on Diet-Induced Hypercholesterolemic Rats

This is the first study to investigate the completely anti-atherogenic effect of Deglet Noor Date seeds methanol extract administration on diet-induced hypercholesterolemic rats. About 24 male Wistar rats were divided into 6 groups. The normal control (NC) group, Hypercholesterolemic Control (HC) group was given high cholesterol diet, and Simvastatin Control (SC) group was given 0.18 mg/200g simvastatin after high cholesterol diet induction. The treatment groups of T0.25, T0.5 and T1 were given supplementation of 0.25, 0.5 and 1 g/kg of dates seed extract after high cholesterol diet induction, respectively for 21 days. Blood was collected from orbitals plexus vein for plasma lipid profile analysis. The levels of Total Cholesterol (TC), Low-Density Lipoprotein (LDL) and Atherogenic Index (AI) values were significantly decreased (p<0.05) on diet-induced hypercholesterolemic rats after supplemented with date seeds extract (T0.25, T0.5 and T1) but not in Triglycerides (TG). Along with that, High Density Lipoprotein (HDL) level was significantly increased (p<0.05). However, the T1 group was the best anti-atherogenic activity in compared to other groups. Results showed that plasma lipid profile was significant to get better after supplemented with date seeds extract.

Effect of hot air on Deglet Noor palm quality parameters and on Ectomyelois ceratoniae

Insect infestation caused by Ectomyelois ceratoniae or carob moth is one of the main postharvest problems that lead to a decrease of marketable quality of dates. The control of carob moth is a mandatory process for exported fruits, and the main chemical method used to prevent pest diseases of palm date is methyl bromide. However, its use is being restricted due to direct, harmful effects to the environment, and indirect effects on humans. Hot air treatments (HATs) could be physical alternatives to methyl bromide and other chemicals. Three HATs (55 °C for 30 min, 60 °C for 15 min, 60 °C for 20 min) were studied on Deglet Noor date fruits when stored for 45 d at 2 °C followed by a retail period of 4 d at 23 °C. The results showed that the use of HATs led to 100% E. ceratoniae larvae mortality in naturally-infested date. These HATs did not cause any damage on fruit quality and reduced mesophilic bacterial counts (<1 log CFU g−1). These HATs, especially the combination of highest temperature and longer time of application (60 °C for 20 min), decreased the antioxidant activity (25% in DPPH and 14% in FRAP assay). Storage time also had a significant impact, reducing color (h°), antioxidant activity, and total phenolic content of date fruits (39%). When this storage was accompanied by a retail period at 23 °C, the firmness and sensorial parameters of date fruits was significantly reduced. Nevertheless, all date fruits from HATs and control treatments maintained their marketability quality for 45 d at 2 °C followed by a retail period of 4 d at 23 °C. Results show that HATs are a physical, non-chemical, treatment for E. ceratoniae larvae mortality that maintained date fruits' postharvest quality.

Hot water treatments combined with cold storage as a tool for Ectomyelois ceratoniae mortality and maintenance of Deglet Noor palm date quality

Insect infestation caused by Ectomyelois ceratoniae or carob moth is one of the main postharvest disease pests of date fruit and causes serious economic losses during storage and export. Methyl bromide is the most widely used fumigant on stored dates in several countries although it will be withdrawn in 2015 in developing countries. Heat treatment technologies, such as hot water treatment (HWT) are currently a relatively simple, non-chemical alternative that can kill quarantine pests (insects and fungi) in perishable commodities. In this article, the proper HWT treatments (dose and time) that causes E. ceratoniae mortality while avoiding quality losses in Deglet Noor fruit when stored for 30d at 2°C followed by a retail period of 4d at 23°C was studied. The results show that the use of HWT of 50°C for 10min, 55°C for 5min and 60°C for 3min lead to E. ceratoniae mortality, also lowering the microbial growth (<1logcfug−1 for mesophilic and <2logcfug−1 for yeasts and molds). HWT induced a slight reduction in skin color (luminosity and hue angle), antioxidant activity (10–15% in FRAP and 17–22% in DPPH) and total phenolic compounds (9–14%). Overall quality was slightly reduced using 60°C for 3min although all treatments remained above the limit of marketability as there was no heat damage. Storage time also reduced these parameters, as well as monosaccharides (glucose and fructose) and the concentrations of some amino acids such as alanine, aspartic acid and proline. HWT used as an alternative to chemical treatments to control carob moth yielded optimum-quality Deglet Noor date fruit that could be exported to developed countries.

Effects of hydro-edaphic environment on the rooting of date palm (Phoenix dactylifera L.) Deglet Noor in the Ouargla Basin (south-east algeria)

During the last decade, the Ouargla basin went through a problem of groundwater rise that had prejudicial consequences on the oasis environment. We studied the impact of hydroedaphic environment on root systems of the Deglet Noor date palm in the date-producing areas of Ouargla basin. The results indicated that 53.9% of date-producing farms showed a water table depth between 29 and 119.4 cm. Root distribution of date palms 80 cm far from the trunk showed that 56.9% of the palm plantations exhibit a rooting depth between 27 and 119 cm, including 3% of which is caused by the gypseous and gypseous-calcareous crusts alone, 10.8% of which is caused by the water table combined with the gypseous and gypseous-calcareous crusts and finally 43.1% of which caused by the water table. Electric conductivity of groundwater varied from 10 to 39.7 dS. m-1. The correlation analysis confirmed that lower water table depths and, gypseous and gypseous-calcareous crusts caused a decrease in the root system depth. Roots avoided both water saturation zone and mechanical resistance in the crusts, causing them to develop in the side direction. Salinity of groundwater proved to be less important to rooting of the date palm compared to level of the ground water.

The Deglet-Noor Date Polyphenoloxidase Activity Is Very Thermolabile and Exhibits Peculiarities in Its Thermal Inactivation Kinetics

In our current research on the preservation of the Deglet-Noor date quality during thermal processing, the heat inactivation of the polyphenoloxidase in enzyme extracts of this fruit was investigated. In contrast to previous studies on this enzyme in this exotic fruit, we performed full kinetic analyses at different temperatures (25–70°C) and enzyme activity was measured by the initial velocity methodology. The heat-inactivation of the polyphenoloxidase from the Deglet-Noor date does not obey a simple “one step-two stages” mechanism. All the recorded kinetics were described using a simple three parameters-biexponential model that we previously showed to be a common arranged form of kinetic expression for the known wide diversity of mechanisms of enzyme deactivation. The values of the two rate constants of the model were collected for four temperatures, ranging from 25 to 70°C and their variation was analyzed through the ARRHENIUS's law to determine the Ea values (11.83 and 54.71 kJ mol−1, respectively). Possible explanations and implications of such low values are discussed. These results are compared to other results from laboratory as well as elsewhere in the literature.

RF Impedance Sensing of Moisture Content in Individual Dates

Measurements of the impedance at 1 and 5 MHz of a parallel-plate electrode assembly with individual dates between the electrodes predicted date flesh moisture content with a standard error of about 1% moisture content (m.c.) over the range from 13 to 22%. The predictions on California Deglet Noor dates from the 1990 crop were based on a calibration equation developed previously on dates from the 1988 and 1989 crops. Combining data on dates of 12% m.c. or higher from all three crop years provided a new calibration, which permits computation of m.c. from measurements of capacitance only at the two frequencies. The instantaneous, nondestructive m.c. sensing technique is recommended for further development for on-line sorting to reduce the skilled-labor requirements in the sorting and grading of fresh dates.

Sensing Moisture Content in Dates by RF Impedance Measurements

The moisture contents of the flesh and pits of Deglet Noor dates, with flesh moisture contents ranging from 13 to 30%, wet basis, were determined by vacuum oven drying. Impedance measurements at frequencies of 1 and 5 MHz were made on a parallel-plate capacitor with individual whole dates and pitted dates held between the capacitor plates. Moisture content of the dates was related to the impedance measurements by a stepwise multiple regression technique. Linear single-variable models were developed that provide an instantaneous and nondestructive determination of moisture content with standard errors of about 1% moisture content. The technique is recommended for potential development and application in reducing the skilled labor requirements for manual sorting and grading of dates.

Changes in total volatile aldehyde content with storage of Deglet Noor dates

Changes in total volatile aldehyde content with storage of Deglet Noor dates

Enzymatic improvement of date quality. Use of invertase to improve texture and appearance of “sugar wall” dates

Abstract“Sugar wall” dates, which have crystalline sucrose present in the tissue, were improved in quality and market value by treating the fruits with food grade invertase. Enzyme concentration, temperature, time, and the degree of sucrose hydrolysis necessary to prevent recrystallisation during subsequent storage were studied in Deglet Noor dates. Native invertase activity, which can be reactivated by spraying or vacuum hydration was not sufficient to bring the ratio of sucrose: reducing sugar to a level low enough to prevent subsequent sucrose recrystallisation.

Polygalacturonase Content of Dates and Its Relation to Maturity and Softness

SUMMARY: The changes in polygalacturonase (PG) activity during ripening and the relationship between its activity and the quality of Deglet Noor dates were studied. PG activity, which was virtually absent at the green stage, began to develop as maturity progressed. The greatest part of the development occurred at the late red stage and activity reached its maximum when the fruits commenced softening. Among the four grades of dates used in this study the activity was highest with natural, followed by waxy, number 1 dry and number 2 dry grades. The dates contained 0.9‐1.3 units of PG per g of fresh tissue. The results of chemical and physical analyses related to the texture are also reported.

Banks Grass Mite, Oligonychus pratensis, on Dates in California1

The Banks grass mite, Oligonychus pratensis (Banks), according to published reports, has been found on many varieties of grain and grasses. It has a wide distribution area extending from Washington to California eastward to Kansas and Texas. In Florida it has been collected on sugar cane. These mites are the most recurrent pests of Deglet Noor dates in the Coachella and Imperial Valleys of California; large populations cause serious losses by lowering fruit quality. Although sulfur dust when applied correctly reduces mite injury, carbophenothion, tetradifon, and Kelthane® (1,1-bis ( p -chlorophenyl) -2,2,2-trichloroethanol) used as dusts or sprays gave comparable results. Sulfur used as a spray on dates had some advantages over conventional sulfur dusting. Sprays are more readily applied to date bunches high on the tree, and wettable sulfur sprays are less irritating to the eyes.

Studies on Domestic Dates. II. Some Chemical Changes Associated with Deteriorationa,b

SUMMARYSome chemical changes in Deglet Noor dates during storage at 49° C were studied. Darkening is the combined result of both oxidative and non‐oxidative browning. The former, which constitutes about 10–20% of the total darkening, can be inhibited by storage in inert gas atmospheres. The decrease in pH of the tissue is primarily the result of nonoxidative nonenzymic reactions. Sucrose inversion, the result of invertase action, can be prevented by a mild heat treatment. Oxygen absorption and carbon dioxide production are due to both enzymic and nonenzymic reactions. Apparent phenolase activity increased during storage, whereas apparent peroxidase activity decreased.

Developmental Anatomy of the Fruit of the Deglet Noor Date

1. The development of the fruit of the Deglet Noor date from pollination to maturation in 1941 was divided into seven periods. The calendar dates for each period refer to the fruits examined in 1941 and may be expected to vary somewhat with the district where grown and in different growing seasons. 2. Period I, from March 18 (pollination) to April 30, is an interval of little enlargement, during which some cell division occurs throughout the mesocarp. Period II, May 1 to 23, is initiated by organization of a meristematic zone at the base of the fruits. Cell division ceased in the apical half of the mesocarp by May 8. At the close of this period the endosperm, previously free-nuclear, became cellular. Period III, May 24 to June 15, is initiated by a sharp increase in rate of enlargement of the entire fruit and all cells of the mesocarp, including those of the basipetal meristem, which, however, continue to divide. At the close of this period the fruits become susceptible to checking (minute cracks involving the cuticle, epidermis, and outer cells of the hypodermal layer). Period IV, June 16 to July 13, begins with inactivation of the basipetal meristem of fruits destined to mature earliest and ends when a meristematic zone is no longer present in any of the fruits. This period is also characterized by the highest rate of fresh-weight increase of the season. Period V, July 14 to August 22, starts with a marked increase in rate of elongation of the previously meristematic cells at the base of the fruits and ends as those cells approach maximum length. At the end of this period the fruit is no longer susceptible to checking, and the color changes from green to pink. Period VI, August 23 to September 21, is distinguished by little apparent anatomical change. Marked increase in percentage of dry matter occurs. Period VII, September 22 to November 3, is characterized by softening as a result of continued dehydration of the fruit and partial dissolution of cell walls. The color changes from pink to brown.

Growth and composition of Deglet Noor dates in relation to water injury

does not appear. First page follows. Introduction Under the present economic conditions the quality of fruit is of more importance than the quaantity produced. One of the chief factors affecting the quality of dates is a physiological disease known as “water injury” which consists of two types: checking, which predisposes the fruit to blacknose (see p. 328); and tearing, which exposes the pulp to microorganisms that bring about fermentation and decay. Studies were made on the growth and chemical composition of date fruits at various stages of development. Growth was measured quantitatively as to length, diameter, fresh weight, dry weight, and ash content. Determination of the inorganic constituents and the sugars, together with the discovery regarding the location of the meristematic tissue in the fruit, form a basis for the study of water injury. The analyses furnish some concept regarding the amounts of the various constituents in the fruit and the portion of these amounts wasted as a result of late thinning of the fruit bunches. Experiments were conducted in the field and in the laboratory to study the factors influencing the cause and control of checking and tearing. These experiments involved the following factors and their relation to water injury and fruit quality: the measurement of water loss due to transpiration of the fruits, the effect of time and type of bagging, and the results of aeration.

A BUD VARIATION IN THE DEGLET NOOR DATE PALM

Journal Article A BUD VARIATION IN THE DEGLET NOOR DATE PALM Get access A.D. SHAMEL A.D. SHAMEL Principal Physiologist Office of Horticultural Crops and Diseases, U. S. Department of Agriculture Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Heredity, Volume 21, Issue 4, April 1930, Pages 164–166, https://doi.org/10.1093/oxfordjournals.jhered.a103311 Published: 01 April 1930