Quality Characteristics of Fresh Date Palm Fruits of "Medjoul" and "Confitera" cv. from the Southeast of Spain (Elche Palm Grove)

The quality characteristics (physical, techno-functional, and chemical) of date fruits (at the tamar stage) of two cultivars ("Confitera", autochthonous and unknown vs. "Medjoul", widely distributed and well-known), grown in the Southeast of Spain (Elche palm grove) were evaluated in order to reinforce decisions aimed at organizing the production of fresh dates from Elche by selecting the most profitable cultivar. Morphologically, Confitera dates were longer and with higher pulp yield than Medjoul dates (4.58 cm vs. 3.88 cm, and 84% vs. 78%, respectively) (p < 0.05). Nutritionally, both dates are a good source of carbohydrates (total sugars (43-48%) and dietary fiber (20-22%)), with small amounts of fat and proteins. The main free sugars in dates from both cultivars were glucose and fructose (reducing sugars). The most abundant mineral found in both date fruits were K, followed by Ca or Mg (depending on the cultivar; Ca in Medjoul and Mg in Confitera). Confitera dates showed a higher total antioxidant activity than Medjoul, corresponding with their higher (p < 0.05) content in polyphenolic compounds, mainly flavonoids (catechin and epicatechin predominantly). Confitera dates should be promoted in this region not only for their contribution to sustainable agricultural development and biodiversity, but also for their higher overall quality.

Patterns of Volatile Diversity Yield Insights Into the Genetics and Biochemistry of the Date Palm Fruit Volatilome

Volatile organic compounds are key components of the fruit metabolome that contribute to traits such as aroma and taste. Here we report on the diversity of 90 flavor-related fruit traits in date palms (Phoenix dactylifera L.) including 80 volatile organic compounds, which collectively represent the fruit volatilome, as well as 6 organic acids, and 4 sugars in tree-ripened fruits. We characterize these traits in 148 date palms representing 135 varieties using headspace solid-phase microextraction gas chromatography. We discovered new volatile compounds unknown in date palm including 2-methoxy-4-vinylphenol, an attractant of the red palm weevil (Rhynchophorus ferrugineus Olivier), a key pest that threatens the date palm crop. Associations between volatile composition and sugar and moisture content suggest that differences among fruits in these traits may be characterized by system-wide differences in fruit metabolism. Correlations between volatiles indicate medium chain and long chain fatty acid ester volatiles are regulated independently, possibly reflecting differences in the biochemistry of fatty acid precursors. Finally, we took advantage of date palm clones in our analysis to estimate broad-sense heritabilities of volatiles and demonstrate that at least some of volatile diversity has a genetic basis.

Date fruit processing waste and approaches to its valorization: A review

In the Middle East and North Africa, dates are a traditional and economically valuable crop, playing an essential role in people's daily diets. Date fruit production and related processing industry generate a large quantity of waste; for illustration, the date juicing industry produces roughly 17-28% Date press cake (DPC), which is mainly discarded in open lands and drains. Considering the generation volume and the nutrient content of DPC, this organic by-product stream can be valorized through the production of a wide range of products with a great market appeal, such as volatile fatty acids, activated carbon, organic acids, etc. To provide an insight into the feasibility of the application DPC as a green precursor for various chemical and biological processes, the chemical and nutritional composition of dates and DPC, an overview of the date processing industries, and common practices conducted for DPC valorization addressed and thoroughly discussed, in this review.

Evaluation of some nutritional quality criteria of seventeen Moroccan dates varieties and clones, fruits of date palm (Phoenix dactylifera L.)

Date fruit is known to be the staple food in the Arab countries. It provides a lot of potential health benefits and can be the essential source of nutrients. The majority of Moroccan varieties are not characterized for their chemical, biochemical and quality properties. The aim of this work was to assess the chemical composition of 17 varieties of Moroccan date fruits (Phoenix dactylifera L.) and to determine their nutritive components. The analysis showed that the dates are rich in sugars (51.80-87.98%), they contain low concentration of proteins (1.09-2.80%) and lipids (0.16-0.39%). The predominant mineral is potassium (1055.26-1604.10 mg/100 g DW). Moreover, they contain high concentrations of malic acid (69.48-495.58 mg/100 g (DW)), oxalic acid (18.47-233.35 mg/100 g DW) and tartaric acid (115.70-484.168 mg/100 g DW). These results suggest that the date fruit are nutritious and can be an excellent source for human nutrition and health benefits.

Antioxidant Capacity and Phenolic and Sugar Profiles of Date Fruits Extracts from Six Different Algerian Cultivars as Influenced by Ripening Stages and Extraction Systems

The study investigated the phenols, sugar and the antioxidant capacities of date fruit extracts obtained by organic solvents and by hydrothermal treatment from six different Algerian cultivars at two ripening stages for the first time. The analyzed cultivars exhibited potent antioxidant properties (ferric reducing antioxidant power (FRAP), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging capacities) and different phenols regardless of the solvents and the maturity stages. About 18 phenols were identified and quantified, mainly in the hydrothermal extracts. The earlier stages were characterized by high amounts of o-coumaric acid, cinnamic acid and luteolin, with a noticeable absence of quercetin. The tamr stage presented the highest sugar content (78.15–86.85 mg/100 mg dry weight (DW)) with an abundance of glucose. Galactose was present only in some cultivars from the kimri stage (tamjouhert). Uronic acids were mostly detected at the tamr stage (4.02–8.82 mg gallic acid equivalent/100 mg dried weight). The obtained results highlight the potential of using date fruit extracts as natural antioxidants, especially at industrial scales that tend use hydrothermal extraction.

Chemical characterisation and the anti-inflammatory, anti-angiogenic and antibacterial properties of date fruit (Phoenix dactylifera L.)

ETHNOPHARMACOLOGICAL RELEVANCE

Date fruit, Phoenix dactylifera L. has traditionally been used as a medicine in many cultures for the treatment of a range of ailments such as stomach and intestinal disorders, fever, oedema, bronchitis and wound healing.

AIM OF THE REVIEW

The present review aims to summarise the traditional use and application of P. dactylifera date fruit in different ethnomedical systems, additionally the botany and phytochemistry are identified. Critical evaluation of in vitro and in vitro studies examining date fruit in relation to anti-inflammatory, anti-angiogenic and antimicrobial activities are outlined.

KEY FINDINGS

The ethnomedical use of P. dactylifera in the treatment of inflammatory disease has been previously identified and reported. Furthermore, date fruit and date fruit co-products such as date syrup are rich sources of polyphenols, anthocyanins, sterols and carotenoids. In vitro studies have demonstrated that date fruit exhibits antibacterial, anti-inflammatory and anti-angiogenic activity. The recent interest in the identification of the numerous health benefits of dates using in vitro and in vivo studies have confirmed that date fruit and date syrup have beneficial health effects that can be attributed to the presence of natural bioactive compounds.

CONCLUSIONS

Date fruit and date syrup have therapeutic properties, which have the potential to be beneficial to health. However, more investigations are needed to quantify and validate these effects.

Metabolome based volatiles profiling in 13 date palm fruit varieties from Egypt via SPME GC-MS and chemometrics

Dates (Phoenix dactylifera L.) are distributed worldwide as major food complement providing a source of sugars and dietary fiber as well as macro- and micronutrients. Although phytochemical analyses of date fruit non-volatile metabolites have been reported, much less is known about the aroma given off by the fruit, which is critical for dissecting sensory properties and quality traits. Volatile constituents from 13 date varieties grown in Egypt were profiled using SPME-GCMS coupled to multivariate data analysis to explore date fruit aroma composition and investigate potential future uses by food industry. A total of 89 volatiles were identified where lipid-derived volatiles and phenylpropanoid derivatives were the major components of date fruit aroma. Multivariate data analyses revealed that 2,3-butanediol, hexanal, hexanol and cinnamaldehyde contributed the most to classification of different varieties. This study provides the most complete map of volatiles in Egyptian date fruit, with Siwi and Sheshi varieties exhibiting the most distinct aroma among studied date varieties.

Metabolomics of dates (Phoenix dactylifera) reveals a highly dynamic ripening process accounting for major variation in fruit composition

BACKGROUND

Dates are tropical fruits with appreciable nutritional value. Previous attempts at global metabolic characterization of the date metabolome were constrained by small sample size and limited geographical sampling. In this study, two independent large cohorts of mature dates exhibiting substantial diversity in origin, varieties and fruit processing conditions were measured by metabolomics techniques in order to identify major determinants of the fruit metabolome.

RESULTS

Multivariate analysis revealed a first principal component (PC1) significantly associated with the dates' countries of production. The availability of a smaller dataset featuring immature dates from different development stages served to build a model of the ripening process in dates, which helped reveal a strong ripening signature in PC1. Analysis revealed enrichment in the dry type of dates amongst fruits with early ripening profiles at one end of PC1 as oppose to an overrepresentation of the soft type of dates with late ripening profiles at the other end of PC1. Dry dates are typical to the North African region whilst soft dates are more popular in the Gulf region, which partly explains the observed association between PC1 and geography. Analysis of the loading values, expressing metabolite correlation levels with PC1, revealed enrichment patterns of a comprehensive range of metabolite classes along PC1. Three distinct metabolic phases corresponding to known stages of date ripening were observed: An early phase enriched in regulatory hormones, amines and polyamines, energy production, tannins, sucrose and anti-oxidant activity, a second phase with on-going phenylpropanoid secondary metabolism, gene expression and phospholipid metabolism and a late phase with marked sugar dehydration activity and degradation reactions leading to increased volatile synthesis.

CONCLUSIONS

These data indicate the importance of date ripening as a main driver of variation in the date metabolome responsible for their diverse nutritional and economical values. The biochemistry of the ripening process in dates is consistent with other fruits but natural dryness may prevent degenerative senescence in dates following ripening. Based on the finding that mature dates present varying extents of ripening, our survey of the date metabolome essentially revealed snapshots of interchanging metabolic states during ripening empowering an in-depth characterization of underlying biology.

Identification of pheromone synergists for Rhynchophorus ferrugineus trapping systems from Phoenix canariensis palm volatiles

Trapping systems for the red palm weevil, Rhynchophorus ferrugineus Olivier, rely on the use of natural plant odor sources to boost the attractiveness of the aggregation pheromone. The identification of the key odorants involved in attraction is essential in the development of a synthetic pheromone synergist to replace the nonstandardized use of plant material in traps. Canary Islands date palms (Phoenix canariensis) have become preferred hosts for R. ferrugineus in Europe; thus, the volatile profile of different P. canariensis plant materials, including healthy and infested tissues, is investigated in the present work by means of solid phase microextraction (SPME-GC-MS), aimed to identify pheromone synergists. The electroantennography (EAG) response of the compounds identified was recorded, as well as the preliminary field response of several EAG-active compounds. The so-called "palm esters" (ethyl acetate, ethyl propionate, ethyl butyrate, and propyl butyrate) elicit the strongest EAG responses but performed poorly in the field. Mixtures of esters and alcohols give evidence of better performance, but release rates need further optimization.

Date fruit: chemical composition, nutritional and medicinal values, products

Date fruit has served as a staple food in the Arab world for centuries. Worldwide production of date fruit has increased almost threefold over the last 40 years, reaching 7.68 million tons in 2010. Date fruit can provide many essential nutrients and potential health benefits to the consumer. Date fruit goes through four ripening stages named kimri, khalal, rutab and tamer. The main chemical components of date fruit include carbohydrates, dietary fibre, enzymes, protein, fat, minerals, vitamins, phenolic acids and carotenoids. The chemical composition of date fruit varies according to ripening stage, cultivar, growing environment, postharvest conditions, etc. The nutritional and medicinal activities of date fruit are related to its chemical composition. Many studies have shown that date fruit has antioxidant, antimutagenic, anti-inflammatory, gastroprotective, hepatoprotective, nephroprotective, anticancer and immunostimulant activities. Various date fruit-based products such as date syrup, date paste, date juice and their derived products are available. Date by-products can be used as raw materials for the production of value-added products such as organic acids, exopolysaccharides, antibiotics, date-flavoured probiotic-fermented dairy produce, bakery yeasts, etc. In this paper the chemical composition and nutritional and medicinal values of date fruit as well as date fruit-based products are reviewed.