EVALUATION OF ANTIOXIDANT ACTIVITY, PHENOLICS, SUGAR AND MINERAL CONTENTS IN DATE PALM FRUITS

Potential application of modified date powder by microwave radiation, ultrasonication and chemical pretreatments as coffee substitute: its biochemical properties and consumer preferences

To consider the suitability of modified date powder as a coffee substitute, the biochemical and antioxidant properties of date powder were modified by hydrochloric acid-ethanol (HAE), alkaline hydrogen peroxide (AHP), combined with ultrasound (U) microwave (MW) radiation. The results showed that the highest antioxidant activity was observed in HAE and HAE-U treated date powders. The total flavonoid content of the date powder increased by 40.8% and 100% in response to the AHP-MW and HAE-U treatments, respectively. Fourier transform infrared spectroscopy did not show any abnormal or unknown peaks in the analyzed range of the treated samples. Therefore, modification of biochemical and sensory properties of date powder by chemical and irradiation treatments did not have a detrimental effect on changing the structure of its chemical compounds or the formation of harmful compounds in it. Sensory evaluations showed that replacing coffee powder with modified date powder by up to 25% did not have significant effects on the sensory properties of the coffee drink. Finally, the results showed that modifying the biochemical and antioxidant properties of date powder by the HAE method as coffee substitute can increase the nutritional properties of coffee drinks while also reducing the expenses of the coffee industry.

Graphical abstract

Date Fruits as Raw Material for Vinegar and Non-Alcoholic Fermented Beverages

Currently, foods and beverages with healthy and functional properties, especially those that claim to prevent chronic diseases, are receiving more and more interest. As a result, numerous foods and beverages have been launched onto the market. Among the products with enhanced properties, vinegar and fermented beverages have a high potential for growth. Date palm fruits are a versatile raw material rich in sugars, dietary fibers, minerals, vitamins, and phenolic compounds; thus, they are widely used for food production, including date juice, jelly, butter, and fermented beverages, such as wine and vinegar. Furthermore, their composition makes them suitable for the formulation of functional foods and beverages. Microbial transformations of date juice include alcoholic fermentation for producing wine as an end-product, or as a substrate for acetic fermentation. Lactic fermentation is also documented for transforming date juice and syrup. However, in terms of acetic acid bacteria, little evidence is available on the exploitation of date juice by acetic and gluconic fermentation for producing beverages. This review provides an overview of date fruit’s composition, the related health benefits for human health, vinegar and date-based fermented non-alcoholic beverages obtained by acetic acid bacteria fermentation.

Potential Functional Snacks: Date Fruit Bars Supplemented by Different Species of Lactobacillus spp

The influence of the addition of four different potential probiotic strains, Lactiplantibacillus plantarum subsp. plantarum (L. plantarum), Lactobacillus delbruekii subsp. bulgaricus (L. bulgaricus), Lactobacillus acidophilus (L. acidophilus) and Lactinocaseibacillus rhamnosus (L. rhamnosus), in date fruit-based products was investigated in order to evaluate the possibility of producing a functional snack. All bacterial strains tested were able to grow in date fruit palp, reaching probiotic concentrations ranging from 3.1 × 10⁹ to 4.9 × 10⁹ colony-forming units after 48 h of fermentation, and the pH was reduced to 3.5–3.7 or below. The viability of inoculated probiotic bacteria after 4 weeks of storage at 4 °C was slightly reduced. Some biochemical features of the fermented snacks, such as the total phenolic content (TPC), antioxidant activity and detailed polyphenolic profile, were also evaluated. After fermentation, changes in the polyphenol profile in terms of increased free phenolic compounds and related activity were observed. These results may be attributed to the enzymatic activity of Lactobacillus spp. in catalyzing both the release of bioactive components from the food matrix and the remodeling of polyphenolic composition in favor of more bioaccessible molecules. These positive effects were more evident when the snack were fermented with L. rhamnosus. Our results suggest the use of lactic acid fermentation as an approach to enhance the nutritional value of functional foods, resulting in the enhancement of their health-promoting potential.

Functional food and nutra-pharmaceutical perspectives of date (Phoenix dactylifera L.) fruit

Date palm counts among the oldest fruit crops of the world and is mainly cultivated for its highly nutritious fruits consumed as a staple food in many countries, especially in the Gulf region. Dates are enriched with numerous therapeutic bioactives and functional compounds such as phenolics, flavonols, carotenoids, minerals, and vitamins that not only provide an appreciable amount of energy required for the human body but also act as an effective therapeutic agent against several diseases. This review aimed to provide a deep insight into the nutritional as well as phytochemicals profile of date fruit and its seeds in order to explore their biological (anti-cancer, anti-diabetic, cardio-protective, anti-inflammatory properties), functional food, and nutra-pharmaceutical attributes. PRACTICAL APPLICATIONS: This review provides updated information regarding the date fruits and seeds phytochemicals composition together with highlighting dates potential as a natural therapeutic agent against several diseases. The study also urges the importance of consuming dates as a great package to live a healthy life due to the functional food and nutraceutical properties of this valuable fruit. The study also provides information first time as recommending dates to cope with the hidden hunger or micronutrient deficiency faced by the third world inhabitants. Hence, the review may further help the industry and researchers to explore the potential of dates for future medicinal and nutra-pharmaceutical applications.

Evolution of phytochemical and antioxidant activity of Tunisian carob (Ceratonia siliqua L.) pods during maturation

The Ceratonia siliqua fruits contain several substances known to have high adaptability to environmental conditions. The aim of this paper is to evaluate the changes in physicochemical properties of different Tunisian provenances of carob pulps harvested at three ripening stages. Furthermore, six provenances were investigated during the ripening process in terms of their moisture, ash, minerals, bioactive compounds, antiradical activity and sugar profile. The results demonstrated that all examined parameters are highly influenced by geographic origin. Concerning ripening impact, our data showed that water and ash content significantly decreased during the development of six provenances, as well as the bioactive and mineral contents. Thus, the total polyphenols (TP), total flavonoids (TF) and condensed tannins (CT) contents exhibited the highest levels in the unripe fruits. The antiradical activity trend was positively correlated to the behavior of the bioactive compounds content. Moreover, the sucrose, glucose and fructose were the main sugar qualified and quantified in carob pods at different ripening stages. At the maturity stage, the monosaccharide contents (glucose and fructose) were slightly reduced, while, the sucrose was rapidly accumulated. In conclusion, the ripening process diversely affected the nutritional composition and generally extended the exploitation of carob fruits. The study could provide valuable information about the suitability of carob pods at different maturity stages as potential biomaterials for nutraceutical applications.

Extraction optimization and in vitro and in vivo anti-postprandial hyperglycemia effects of inhibitor from Phoenix dactylifera L. parthenocarpic fruit

Phoenix dactylifera L. plays an important role in social, economic, and ecological Tunisian sectors. Some date palms produce parthenocarpic fruit named Sish. The aqueous ethanolic extract from P. dactylifera parthenocarpic dates demonstrated a potent inhibition of the enzymes related to type II diabetes. In this work, extraction optimization of amylase inhibitors was carried out using Box-Behnken Design. Bioactivity-guided fractionation of the 70% aqueous ethanol extract was performed to identify the active compounds. The physicochemical results by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed the presence of 13 phenolic compounds. The in vitro study showed that the extract exhibited a more specific inhibitor of α-glucosidase than α-amylase with an IC₅₀ value of 0.6 and 2.5mg/mL, respectively. The in vivo study of this extract effect on the postprandial hyperglycemia activity showed a decrease in plasma glucose levels after 30min stronger than the Acarbose effect. These results confirmed the anti-postprandial hyperglycemia activity of the aqueous ethanolic extract from P. dactylifera parthenocarpic dates, which could lend support for its pharmaceutical use.

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.

Physico-chemical characteristics and fungal profile of four Saudi fresh date (Phoenix dactylifera L.) cultivars

Physico-chemical and microbial analyses of four commercial fresh date cultivars (Sukari, Barhi, Khalas and Rothana) grown in Saudi Arabia were evaluated. Colorimetric assay indicated that Sukari had the highest total sugar content of 13.21g/100gFW while the lowest was in Rothana with 7.96g/100gFW. Total phenolic content (TPC) ranged from 76.74 to 122.20mgGAE/100gFW in Barhi and Rothana respectively, whereas antioxidant activity was highest in Sukari (105.99μgGAE/gFW) and lowest in Khalas (90.81μgGAE/gFW). The dominant fungal genera were Aspergillus sp., Rhizopus sp., Penicillium sp. and Sarocladium sp., occurring at 37, 18, 13 and 12% respectively. The highest fungal occurrence was in Barhi (30%) followed by Sukari (29%), Khalas (26%) and Rothana (15%). The TPC had a negative correlation with fungal occurrence whilst the total sugars had a positive correlation.

Antioxidant activity of various Mauritanian date palm (Phoenix dactylifera L.) fruits at two edible ripening stages

The increasing interest in plant phenolics and flavonoids outlined the necessity of determining their contents and biological activity in Mauritanian date palm fruits. Methanolic extracts of fruit of six date palm cultivars commonly grown in Mauritania were screened for their antioxidant activity, total phenolics, and flavonoid content at two edible ripening stages. Polyphenols and flavonoids were higher in theBlah stage, corresponding toKhalal in the standard Iraqi Arabic nomenclature, compared to the fully matureTamr stage regardless the cultivar. The average of total phenolics atBlah andTamr stages were 728.5 and 558.9 mg gallic acid equivalents (GAE) per 100 g dry matter (DM), whereas the average flavonoid content was 119.6 and 67.3 mg quercetin equivalents (QE) per 100 g DM, respectively. TheBlah stage also exhibited the highest total antioxidant activity with a Trolox equivalents antioxidant capacity (TEAC) value of 129.3 μmol/100 g DM founded in Bou seker's Blah date, followed by Tijib cultivar with TEAC value of 114.3 μmol/100 g DM and an average TEAC value of 107.5 μmol/100 g DM. Furthermore, a high positive correlation was found between total phenolics inTamr (r = 0.92) andBlah (r = 0.87) stages and TEAC of fruit methanolic extracts compared to the flavonoids, suggesting that phenolics were the major contributor to the antioxidant activity.

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.