Fresh Date Fruits Research Articles

Pesticide residues in fresh Mazafati date fruit, soil, and water, and assessment of potential health risks to consumers.

A quantitative method based on quick, easy, cheap, effective, rugged, and safe technique (QuEChERS) sample extraction and ultra-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) was evolved for the determination of 47 pesticide residues in fresh Mazafati date fruits from Bam City of Kerman Province, Iran. The recoveries for selected pesticides ranged from 88 to 110% with a relative standard deviation (RSD) of less than 20% at concentrations of 0.05 and 0.1 mg kg-1. The proposed method had a linear range from the limit of quantification (LOQ) to 1.00 mg kg-1, and the LOQ of the 47 pesticides was ≤ 0.005 mg kg-1. The coefficients of determination (R2) were more than 0.99. This technique was used on 12 fresh date fruits samples, three water samples, and three soil samples with three replications per sample. Forty-seven pesticide were detected collectively, but only diazinon was detected in the date fruit samples. The mean value of diazinon residues was 0.037 mg kg-1, and the concentration of diazinon in most samples was below the national maximum residue limit (MRL) for date fruit (0.05 mg kg-1). Among the pesticides measured, diazinon residues were also detected in the water samples, but not in the soil samples. The dietary intake assessment showed no health risk to humans from the consumption of fresh date fruit concerning the pesticides investigated.

Sperm Parameters and Testicular Histology of Male Wistar Rats Treated with Phoenix Dactylifera after Consumption of Local Mmahi Salt

Phoenix dactylifera (date fruit) is one of the nutritious and healthiest fruits due to its excellent nutritional properties, and many beneficial health and medicinal properties. The aim of this study was to evaluate sperm parameters and testicular histology of male Wistar rats treated with Phoenix dactylifera after consumption of a dose of local Mmahi salt (local salt of Ebonyi State origin, in Nigeria). Fresh date fruits, Mmahi salt, rat feed, clean drinking water, and 24 male wistar rats were the main materials for this study. The rats were divided into 6 groups: Group 1 (negative control group with 0% Mmahi salt (MS) and date fruit exposure), Group 2 (positive control I that received 75mg/kg of MS for 4 weeks), Group 3 (positive control II that received 75mg/kg of MS for 4 weeks followed by 2 weeks of self-recovery), Group 4 (that received 75mg/kg of MS for 4 weeks followed by 2 weeks of 200mg/kg of date fruit), Group 5 (that received 75mg/kg of MS for 4 weeks followed by 2 weeks of 400mg/kg of date fruit), and Group 6 (that received 75mg/kg of MS for 4 weeks followed by 2 weeks of 600mg/kg of date fruit). Actively motile spermatozoa in this study had mean±SEM in G1 (65.00±2.89), G2 (55.00±0.00), G3 (45.00±2.89), G4 (63.75±2.39), G5 (55.50±2.04), and G6 (58.75±2.39). Sluggishly motile spermatozoa were low in the groups treated with higher doses of date fruit extract, but least in G1. Non-motile spermatozoa were high in G2 and G3, but lower in G1, G5, and G6. G4, G5, and G6 had higher sperm counts compared to G2 and G3, although not significant. Histological examination showed in G1 - normal histology, in G2 - moderate spermatogenic arrest, in G3 - severe distortion of testicular architecture, in G4 - enhanced spermatogenesis, in G5 - moderate distortion of the seminiferous tubules, and G6 - enhanced spermatogenesis. A high dose of Mmahi salt is detrimental to sperm parameters and testicular histology. However, this study has shown that date fruit extract can improve sperm parameters and testicular histology in male wistar rats fed with Mmahi salt.

Comparison of phenolic composition in date (Phoenix dactylifera L.) flesh and seeds extracted by an ultrasonic-assisted and conventional method

ABSTRACT Date palm (Phoenix dactylifera L.) is an important fruit of the Middle East and North Africa with a high content of phenolic compounds. This study applied ultrasonic-assisted and conventional methods to extract phenolic compounds from date flesh and seed. The efficacy of the extraction methods is compared in terms of quantity, content, and antioxidant capacity of phenolic compounds. The highest total phenolic content (TPC) was found in ultrasonic-assisted date seed samples extracted by ethanol (18.53 mg GAE/g). In contrast, the TPC content of conventionally extracted seed samples ranged from 1.30 to 14.46 mg GAE/g. The TPC and antioxidant capacity values of phenolic compounds extracted from date flesh samples were lower than those extracted from seed samples. Liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS) was used to characterize phenolic compounds. A total of 47 different phenolic compounds were identified, including 21 phenolic acids, 21 flavonoids, and 5 other polyphenols. High-performance liquid chromatography equipped with a photodiode array detector (HPLC-PDA) was used to quantify the phenolic compounds in different date samples. The highest content was found in ultrasonic-assisted date seed samples extracted in methanol solvent. The extract also contained epicatechin (36.12 μg/g), coumaric acid (27.05 μg/g), p-hydroxybenzoic acid (21.03 μg/g), syringic acid (19.85 μg/g), and epicatechin gallate (11.67 μg/g). The results showed that ultrasonic-assisted extraction could significantly increase the quantities of functional components of the extracts obtained from fresh date fruit samples.

Development of Value-Added Products Suitable for Food Applications from Fresh Date Fruit (Confitera cv.) and its Co-products

The increasing commercialization of fresh date fruits (Confitera cv) in Spain is generating important amounts of co-products which currently are discarded as waste with the corresponding environmental problem and economic losses. The aim of this work was to valorize them, in an integral way, applying non-polluting procedures (grinding, soaking, filtering, or drying) allowing their reincorporation in the food chain in function on both nutritional and technological properties. Different intermediate and stable products with high added value have been obtained: (1) Date pastes with 50% moisture content and the same amount of sugars and dietary fiber (20% approx.), good source of K, Ca, and Mg, with low Na/K ratio,whose technological properties give them a great potential to provide desirable texture properties in some foods; (2) date waters rich in sugars and minerals with potential application as natural sweeteners or as source of carbon for the microbiota in fermented foods; (3) date flours with low moisture and high TDF content (58–66%), rich in minerals, and whose technological properties allow them to be used as carrier of oils (i.e., with healthy lipid profile) or as an emulsion stabilizer in the development of new foods.

TinyML-Sensor for Shelf Life Estimation of Fresh Date Fruits.

Fresh dates have a limited shelf life and are susceptible to spoilage, which can lead to economic losses for producers and suppliers. The problem of accurate shelf life estimation for fresh dates is essential for various stakeholders involved in the production, supply, and consumption of dates. Modified atmosphere packaging (MAP) is one of the essential methods that improves the quality and increases the shelf life of fresh dates by reducing the rate of ripening. Therefore, this study aims to apply fast and cost-effective non-destructive techniques based on machine learning (ML) to predict and estimate the shelf life of stored fresh date fruits under different conditions. Predicting and estimating the shelf life of stored date fruits is essential for scheduling them for consumption at the right time in the supply chain to benefit from the nutritional advantages of fresh dates. The study observed the physicochemical attributes of fresh date fruits, including moisture content, total soluble solids, sugar content, tannin content, pH, and firmness, during storage in a vacuum and MAP at 5 and 24 ∘C every 7 days to determine the shelf life using a non-destructive approach. TinyML-compatible regression models were employed to predict the stages of fruit development during the storage period. The decrease in the shelf life of the fruits begins when they transition from the Khalal stage to the Rutab stage, and the shelf life ends when they start to spoil or ripen to the Tamr stage. Low-cost Visible-Near-Infrared (VisNIR) spectral sensors (AS7265x-multi-spectral) were used to capture the internal physicochemical attributes of the fresh fruit. Regression models were employed for shelf life estimation. The findings indicated that vacuum and modified atmosphere packaging with 20% CO2 and N balance efficiently increased the shelf life of the stored fresh fruit to 53 days and 44 days, respectively, when maintained at 5 ∘C. However, the shelf life decreased to 44 and 23 days when the vacuum and modified atmosphere packaging with 20% CO2 and N balance were maintained at room temperature (24 ∘C). Edge Impulse supports the training and deployment of models on low-cost microcontrollers, which can be used to predict real-time estimations of the shelf life of fresh dates using TinyML sensors.

A mathematical model for the optimization of agricultural supply chain under uncertain environmental and financial conditions: the case study of fresh date fruit

A mathematical model for the optimization of agricultural supply chain under uncertain environmental and financial conditions: the case study of fresh date fruit

Hot Water Treatment Improves Date Drying and Maintains Phytochemicals and Fruit Quality Characteristics of Date Palm (Phoenix dactylifera).

Fresh date fruits (cvs. Hillawi and Khadrawi) were harvested at the khalal stage and treated with hot water treatment (HWT) for different time durations (control, HWT-1 min, HWT-3 min, HWT-5 min, and HWT-7 min) to investigate the physicochemical characteristics, phytochemical properties, and sensory attributes. The results revealed that both date cultivars took less time to reach the tamar stage in response to HWT-7 min compared to control. However, Hillawi date fruit showed a higher fruit ripening index (75%) at HWT-3 min, while Khadrawi fruit had a higher ripening index (80%) at HWT-5 min than untreated fruit (10%). Higher weight loss and lower moisture contents were observed in Hillawi (25%) and Khadrawi (20%) date fruit as the immersion period increased in both cultivars. Moreover, soluble solid content was higher in Hillawi (11.77° Brix) in response to HWT-3 min and Khadrawi (10.02° Brix) date fruit immersed in HWT-5 min in contrast with the control group, whereas significantly lower levels of titratable acidity and ascorbic acid content were observed in Hillawi (0.162%, 0.67 mg/100 g) and Khadrawi (0.206%, 0.73 mg/100 g) date fruit in response to HWT (HWT-1 min, HWT-3 min, HWT-5 min, and HWT-7 min) than untreated fruit. Furthermore, noticeably higher levels of reducing sugar (69.83%, 57.01%), total sugar (34.47%, 31.14%), glucose (36.84%, 29.42%), fructose (33.99%, 27.61%), and sucrose (3.16%, 1.33%) were found in hot water-treated Hillawi (immersed for 3-min) and Khadrawi (immersed for 5-min) date fruit, respectively. In addition, total phenolic content, total flavonoids, total antioxidants, and total tannins were substantially superior in date fruits subjected to HWT-3 min (in Hillawi, 128 mg GAE/100 g, 61.78%, 20.18 mg CEQ/100 g) and HWT-5 min (in Khadrawi, 139.43 mg GAE/100 g, 72.84%, and 18.48 mg CEQ/100 g) compared to control. Overall, sensory attributes were recorded to be higher in Hillawi and Khadrawi date fruit after treatment for 3 min and 5 min, respectively. Our findings suggest that HWT is a promising technique that can be adopted commercially to improve fruit ripening and preserved nutritional quality of dates after harvest.

Investigating the Efficacy of Tasmannia lanceolata Extract in Inactivating Fungi and Prolonging the Shelf Life of Date Fruit.

Date palm (Phoenix dactylifera L.) is one of the world’s oldest cultivated plants. Post-harvest losses of date palm due to fungal contamination reached up to 50% of the total production. This study aimed to investigate the potential of the extract of Tasmanian pepper leaf (TPL) and the non-thermal treatment of photosensitization mediated by curcumin in reducing the fungal contamination and enhancing the shelf life of date palm. In the in vivo storage study, the dates were treated with three different concentrations of TPL extract 12.5, 25, and 50 µg/mL and stored at 30 °C. The findings obtained for the treatment with TPL extract exhibited potent antifungal activity against most of the tested fungi, where minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) were < 25 µg/mL for polygodial, the bioactive compound in TPL. The shelf life of date palm treated by 50 µg/mL polygodial was extended up to 21 days, thrice as much as the untreated controls. In contrast, a lower concentration of TPL extract (25 µg/mL polygodial) revealed up to a 15-day shelf life extension compared to untreated dates (7 days). The results obtained from the study suggested that using TPL extracts against pathogenic and spoilage fungi occurring in fresh date fruits is a promising treatment for the shelf life extension of fresh date fruits at room temperature.

Technological Studies on Aswan Dry Dates Products After Dehydration

Sakkoti, Bartamuda, Gondaila, Malkabii and Shamia are excellent dry date cultivars, grown at Aswan Governorate. This study was conducted to assay effect of drying methods on quality of dates products so, total soluble solids (T.S.S.), pH, acidity, color characteristics and Organoleptic characteristics were determined in prepared date products (Tamr-Elddin Date Sheets (TDS) [with / without] fiber, Date pudding and Date Jelly) from fresh date fruit (Tamar), after sun-drying for 25 days, solar drying for 14 days at ambient temperature 50°C and mechanical drying at 60°C for 9 hrs. The obtained results showed that pH decreased after sun-drying and mechanical drying, while total soluble solids (T.S.S) and acidity increased for all date products also, in generally found that the lightness (L), a (redness) and yellowness (b) values for date products from fresh dates were higher than solar dried dates, followed by sun dried dates and mechanical dried dates. So, in this study found that drying process by solar energy improved qualities attribute of all date products that had processed from Aswan dry dates.

Influence of pre-harvest foliar spray of fungal culture filtrates on post-harvest biology of date fruit harvested at Khalal stage

Abstract There is a high prevalence of saprophytic fungi in date fruit and date fruit products. Some of these fungi isolated from the infected plants in date palm orchards were identified as Aspergillus niger and Rhizophus oryzae. These fungi cause fruit loss during later stages of maturation and are responsible for severe post-harvest losses of date fruit. They may also deteriorate the overall health of plants. The fungal culture filtrates (FCF) from A. niger (ANFCF) and R. oryzae (ROFCF) were prepared and used as elicitors for the experimentation. These FCFs were foliar sprayed on the date palm plants in the field after the fruit set. Various quality attributes such as weight, firmness and total soluble solids and biochemical properties like total sugars, total proteins, total phenols, ascorbic acid, and antioxidant activity of fresh date fruit (khalal stage) harvested from the FCF treated and untreated plants were studied. The fruit harvested from plants treated with ROFCF showed enhanced levels of total sugar, total proteins, ascorbic acid, and DPPH scavenging activities followed by the fruit from plants treated with ANFCF in comparison to fruit collected from untreated plants. The shelf life of fruit from plants treated with ROFCF and ANFCF increased beyond 14 d at room temperature while the fruit from untreated plants started to deteriorate after 7 d from harvest. The study indicates that the use of fungal culture filtrates as elicitors can help the plant to build up its defense mechanism by elevating the activity of protective enzymes like, Peroxidase (POX), Polyphenol oxidase (PPO) and Phenylalanine ammonia lyase (PAL). It also enhances the growth of plant and improve the quality as well as increases shelf life of fruit.

Effect of using edible coatings on fruit quality of Barhi date cultivar

Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage). These fruits are seasonal and perishable and there is a need for extending their shelf life. This work was carried out to study the capability of some edible coatings (gelatin, chitosan, guar gum and their combinations) to delay the ripening of fruits and prolong their shelf life. The effectiveness of the coatings was evaluated by the changes in several parameters: weight loss, total soluble solids, reducing and total sugars, total chlorophyll and total carotenoids, vitamin C, total polyphenols, titratable acidity, sensory evaluation and total bacterial count. The obtained results showed that, all studied coating treatments led to extend the shelf life of Barhi date fruits comparing with control sample, but the highest effective treatments were T5 (0.5 % guar gum) and T9 (gelatin + guar + chitosan) followed by T6 (gelatin + guar). Also, all studied edible coating treatments had insignificant (p < 0.05) effect on the organoleptic characteristics of Barhi date fruits. From these findings, the application of these treatments could be suggested to extend the shelf life of Barhi date fruits.

Design and testing of an electrospun nanofiber mat as a pH biosensor and monitor the pH associated quality in fresh date fruit (Rutab)

An electrospun nanofiber mat was prepared based on polyvinyl acohol and a natural pigment from red cabbage (Brassica oleracea L.) extract (RCE) to function as a pH biosensor. Morphological properties of the nanofiber mats were characterized using scanning electron microscopy and the chemical structure was studied using FTIR. The pH sensitivity of the nanofibers was tested using a series of different pH solutions and the color spectrum of nanofiber mats at different pH values were calibrated using a colorimeter. Results showed that the designed mat could be used as a pH sensor and indicate pH values in the 2–12 range. The mat colors were reversible according to the changing pH value and hence transient changes could be monitored. Trials on fresh date fruit (Rutab) demonstrated that the pH mat responses correlated well with pH changes in packaged dates, thus enabling real-time monitoring of pH-linked changes within the package.

SURVEY OF DIFFERENT MITES AND INSECT PESTS ASSOCIATED WITH DATE PALM FRUITS IN DIFFERENT LOCATIONS OF EGYPT

he present study was conducted during two years (2015 and 2016) to shed additional light on the acarofauna and insect pests of the date palm fruits in different regions covering 9 Egyptian governorates differed in their ecological conditions. This study revealed the occurrence of 44 mite species differed in their feeding behavior infesting different fruits, belonging to 31 genera and 16 families under four suborders. Suborder Acaridida Astigmata which represented by 14 different species belonging to 9 genera and 4 families. The recorded families were Acaridae (9 species), Lardoglyphidae (one species), Glycyphagidae (3 species) and Pyroglyphidae (one species). Also, Suborder Actinidida Prostigmata presented in this study was recorded by 19 mite species belonging to 14 genera in 7 families. The families were Tydeidae (6 species); Cheyletidae (7 species), Stigmaeidae (2 species); Pyemotidae, Caligonellidae, Bdellidae, and Tarsonemidae (one species for each). On the other hand, the mesostigmatid mites (Gamasida) were represented by 8 mite species belonging to 6 genera in 4 families and the most common family was Ascidae and represented by 4 mite species. The cryptostigmatids (Oribatida) in this study included three mite species belong to two genera from Family Oribatidae. In this study, 12 insect species in 3 orders and 8 families are surveyed as important insect pests of date palm fruits. The most abundant family was Nitidulidae (5 species), while, the rest collected families (Scolytidae, Silvanidae, Ptinidae, Tenebrionidae, Muscidae, Eulophidae and Pteromelidae) were represented as one species for each. The stored date fruits were attacked by Carpophilus hemipterus (L.), Carpophilus mutilates Eribhson, Coccotrypes dactyliperda F., Oryzaephilus surinamensis (L.), Lasioderma serricorne (F.) and Tribolium confusum Jacquelin du Val. While, the fallen fruits were infested by Carpophilus hemipterus (L.), C. Obsoletus Eribhson, Carpophilus mutilates Eribhson, C. dimidiatus (F.), Carpophilus sp., Coccotrypes dactyliperda F. and Lasioderma serricorne (F.). On the other hand, Lasioderma serricorne (F.), Fannia incisurata (Zetterstedt), Tetrastichus sp. and Pteromalus sp. were observed associated with the fresh date fruits. The most common insects in this study were C. hemipterus, C. mutilatus and T. confusum, as, they infested fruits throughout the period of study with very high abundance, while C. dactyliperda was least abundant insect.

The effect of photosensitization mediated by curcumin on storage life of fresh date (Phoenix dactylifera L.) fruit

The effect of photosensitization mediated by curcumin (CUR) in sanitizing the fresh date fruit surface was investigated. Approximately 3–4 μl CUR solution ranging from 1000 to 1800 μM was sprayed on the date surface, followed by irradiation using blue light at 420 nm for 10 and 15 min at light dosages of 180 J/cm2 and 270 J/cm2 respectively. After irradiation, the date was stored at 4 °C and 30 °C until fungi was visually observed. The combination of CUR and light resulted in significant (p < 0.05) extension of the shelf life and quality of fresh date. The shelf life of date fruit photosensitized by 1400 μM CUR for 10 min and stored at 30 °C lasted for 14 days in comparison to the 7 days for the control, while date stored at 4 °C lasted 98 days for the photosensitized fruit compared to the control of 28 days under the same conditions. In addition, no changes in physico-chemical characteristics were observed after treatment. The sanitization treatment of photosensitization mediated by CUR indicated a promising strategy in extending the shelf life of fresh date fruit. Clean and green technologies that are environmentally friendly like photosensitization are preferred by consumers to the synthetic chemicals used in conventional practices for sanitizing food.

Effect of edible co-polymers coatings using γ-irradiation on Hyani date fruit behavior during marketing

The present work introduces a preparation of coating fruits film from natural biodegradable materials with evaluation of its efficiency in keeping the quality of fresh date fruits. Triple blend (Tb) which involved PVA, chitosan (Cs) and tannic (TA) acids was studied in preservation of Rutab (Hyani) date. Antimicrobial characters besides decay of fruits during a cold storage were determined. The blend solutions were exposed to the γ–irradiation (5.0 to 20 kGy) before casting or use. The effects of polymer composition and irradiation dose on the mechanical and thermo-mechanical properties were studied. The obtained results showed that γ-irradiation and the addition of tannic acid (TA) increased the mechanical properties of the films and the shelf-life of Rutab (Hyani) date during the marketing period (12 ± 2 °C, 98%, RH) from one week to one month of marketing period for consumers with accepted freshness and quality.

Occurrence of Mites and Insects Associated with Date Palm Fruits in Different Governorates of Egypt

The present study was conducted during four years (2013, 2014, 2015 and 2016) to throw some light on the acarofauna and insects of the date palm fruits in different regions covered 9 Egyptian governorates differed in their ecological conditions. This study revealed the occurrence of 84 mite species differed in their feeding behavior infested different fruits, belonging to 51 genera and 25 families under four suborders.Suborder Astigmatawhich was represented by 21 different species belong to 11 genera and 4 families. The recorded families were Acaridae (13 species), Lardoglyphidae (one species), Glycyphagidae (6 species) and Pyroglyphidae (one species). Suborder Prostigmata was represented in this study by 38 mite species belonging to 26 genera in 11 families: Tydeidae (12 species), Cheyletidae (12 species), Cunaxidae (3 species), Stigmaeidae, Camerobiidae and Rhagididae (2 species for each), Pyemotidae, Caligonellidae, Bdellidae, Eupodidae, and Tarsonemidae (one species for each). On the other hand, the mesostigmatid mites were represented by 22 mite species belonging to 12 genera in 9 families and the most common family was Ascidae represented by 12 mite species. The cryptostigmatids in this study includedthree mite species belong to Family Oribatidae. The obtained results indicated that the fallen fruits harbored the most abundant mites (53), followed by stored fruits with 34 mites and fresh fruits infested by 18 species. The study showed that there were two mite species associated with residue fruits on the tree, while the Agwa product included one mite only. Regarding the different study regions, it was found that El-Menofia governorate included 47 different mites, followed by El-Behira governorate which harbored 38 mites, Giza governorate with 17 mites, El-Dakahlia (14 species), El-Sharkia (7 species) and Damietta (6 species), Beni Suief (3 species), Sohag (5 species) and Cairo (3 species). In this study, 12 insect species in 3 orders and 8 families are listed as important pests of date palm fruits during different times. The most abundant family was Nitidulidae (5 species), as the rest collected families were represented by one species for each. The stored date fruits were attacked by Carpophilus hemipterus, Carpophilus mutilatus, Coccotrypes dactyliperda, Oryzaephilus surinamensis, Lasioderma serricorm, and Tribolium confusum. While, the fallen fruits were infested by C. hemipterus, C. immaculatus, C. mutilatus, C. dimidiatus, Carpophilus sp., Coccotrypes dactyliperda, and Lasioderma serricorm. On the other hand, L. serricorm, Fannia incisurata, Tetrastichus sp. and Pteromalus sp. were observed associated with the fresh date fruits. The most common insects in this study were C. hemipterus, C. mutilatus and T. confusum, as they appeared on infested fruits during all study periods with very high abundance, while C. dactyliperda was least abundant insect.

Incidence and etiology of postharvest diseases of fresh fruit of date palm ( Phoenix dactylifera L.) in the grove of Elx (Spain)

The incidence and etiology of postharvest diseases affecting fresh date fruit in the palm grove of Elx (Spain) were determined under local environmental conditions. Latent and wound pathogens were assessed for two consecutive seasons on fruit from two important commercial cultivars, ‘Boufeggous’ and ‘Medjool’, grown in different orchards. Healthy dates were either surface-disinfested or artificially wounded in the rind and placed in humid chambers at 20oC for up to 7 weeks. Irrespective of cultivar, season, orchard, and type of infection, the most important causal agents of disease were Penicillium expansum , Alternaria alternata , Cladosporium cladosporioides , and a black aspergillus species belonging to the Aspergillus niger clade. These fungi were identified by macroscopic and microscopic morphology and/or DNA amplification and sequencing. Their pathogenicity was demonstrated by fulfilling Koch’s postulates. Disease development at 20 and 5oC was characterized on artificially inoculated dates.

Modelling the effect of temperature, water activity and carbon dioxide on the growth of Aspergillus niger and Alternaria alternata isolated from fresh date fruit.

To quantify and model the combined effects of temperature (T) (10-40°C), water activity (aw ) (0·993-0·818) and CO2 concentration (9·4-55·1%, v/v) on the growth rate of Aspergillus niger and Alternaria alternata that cause spoilage during the storage and packaging of dates. The effects of environmental factors were studied using the γ-concept. Cardinal models were used to quantify the effect of studied environmental factors on the growth rates. Firstly, the cardinal parameters were estimated independently from experiments carried out on potato dextrose agar using a monofactorial design. Secondly, model performance evaluation was conducted on pasteurized date paste. The boundary between growth and no-growth was predicted using a deterministic approach. Aspergillus niger displayed a faster growth rate and higher tolerance to low aw than Al.alternata, which in turn proved more resistant to CO2 concentration. Minimal cardinal parameters of T and aw were lower than those reported in the literature. The combination of the aw and CO2 effects significantly affected As.niger and Al.alternata growth. The γ-concept model overestimated growth rates, however, it is optimistic and provides somewhat conservative predictions. The developed model provides a decision support tool for the choice of the date fruit conservation mode (refrigeration, drying, modified atmospheric packaging or their combination) using T, aw and CO2 as environmental factors.

English

Fresh date fruits (Barhi cultivar) at Khalal stage of maturity were frozen by two different methods; individual quick freezing (IQF), and conventional slow freezing (CSF). The frozen dates were stored for 9 months at -20°C and -40°C, through conventional and individual quick freezing methods, respectively. Texture profile analysis parameters (hardness, elasticity, chewiness and resilience), color, and nutrition (enzymes and sugars) properties for fresh and frozen dates were measured after every three months of frozen storage. IQF technique showed better result in quality maintaining of fresh date fruits than CSF. Color and textural parameters of the frozen dates were affected by the freezing method and the frozen storage period. IQF method is superior in preserving the fresh Barhi fruits color values, textural parameters and nutritional aspects compared

Using Date Palm (Phoenix dactylifera L.) by-products to Cultivate Lactobacillus reuteri spp.

Lactic acid bacteria (LAB) are used by industry to produce fermented food products. The standard media used to cultivate LABs is DeMan Rogosa Sharp (MRS). However, it is expensive. Alternative low-cost media must be developed for industrial use. A good source for growth media components are by-products generated during the production of agricultural goods, such as dates. Our objective was to investigate the use of date by-products for cultivating Lactobacillus reuteri. Date palm extract (DPE) was prepared by pressing fresh date fruits for one week and diluting 1:2 with diH2O, centrifuging at 4696 x g and 4°C 25 min, and autoclaving the supernatant at 110°C for 15 min. An MRS-based buffer solution was added to DPE make a date palm medium (DPM). DPM was then enriched with various amounts phytone peptone (0, 0.2, 0.4, 0.6, and 0.8 %, w/v). The enriched DPMs were used to cultivate three strains of Lactobacillus reuteri: DSM 20016, CF2-7F, and SD 2112. Our results showed that in the DPM minus phytone peptone, bacterial counts reached 3.18 ± 0.5 log CFU/mL. Addition of lower amounts of phytone peptone did not improve bacterial growth. However, DPM medium supplemented with 0.8% phytone peptone improved the bacterial counts, which reached 6.94 ± 0.1 log CFU/mL, similar to what was observed with MRS (7.90± 0.24 log CFU/mL). There was no significant difference in the growth of LAB in MRS and phytone peptone enriched media DPM (p &gt; 0.05). Date by-products are potentially alternative low cost components of LAB growth media.