Date Palm Fruits as a Potential Source of Functional Dietary Fiber: A Review

Abstract

Date palm fruits and their seeds are excellent sources of dietary fiber (DF). Date fruits contain 8.1 -12.7 % Total DFs (of which 84-94 % is insoluble and 6-16 % soluble DF) and is very rich in phenolic antioxidants (1-2 %). Date fruit fibers are composed of cellulose and NSP. Moreover, date DF has important functional properties, such as water-holding capacity and oil-holding capacity. Date seeds contain about 15 % fiber, characterized by a high level of water-insoluble mannan fibers. It has been suggested that date fruits and seeds can be exploited in some food applications. In order to improve fiber yields, pretreatment procedures can be applied, which give excellent results in the case of date palm fibers. Date fruits are widely available in the global market, but there is still room for improvement, particularly in the revalorization of date processing waste, and secondary cultivars. The incorporation of date fruits and seeds as food ingredients would promote the presence of dates in the modern's consumer shopping basket. Present knowledge about different aspects of date DF, and suitable extraction methods and applications of date fiber (flesh and seed), will be the focus of this report.Abbreviations: DF (dietary fiber); IDF (insoluble dietary fiber); SDF (soluble dietary fiber); WHC (water-holding capacity); OHC (oil-holding capacity); DSF (date seed fiber).

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 diminution of UAC after the thermal treatment concurs with the results of Mrabet et al [7] who found that the UAC of three cultivars was affected by the thermal treatment.…”

“…In this context, the highest levels of total phenolic and condensed tannins contents were found in methanol:water 80:20 v/v date fruit extracts, while the highest total flavonoid contents and antioxidant activities were found in acetone:water 70:30 v/v [4]. Similarly, extracts obtained from hydrothermally treated date fruits had higher phenolic contents and stronger antioxidant activities [7]. Even though a growing body of literature has highlighted the impact of extraction solvent or the ripening stage on the antioxidant capacities of date fruits, none of them investigated the effect of maturity status and extraction solvent simultaneously on their phenolic pattern, sugar profile and antioxidant capacities.…”

“…In fact, the degradation process starts at temperatures above 60 • C. This was confirmed in our study by the apparition of some degradation products such as hydroximethylfurfural (HMF) and furfural. In this context, Mrabet et al [7] reported the diminution of sugar content for three thermally treated date cultivars and the increase in the diminution percentage with the severity of the thermal treatment (140, 160 and 200 • C).…”

“…Besides nutritional value, date fruits are rich in bioactive compounds possessing various biological properties [5]. Phytochemical investigations have revealed that these fruits contain secondary metabolites such as phenolic acids, flavonoids, tannins, terpenoids, alkaloids, saponins, sterols or glycosides that are known to have in vitro antioxidant, antimicrobial, anti-inflammatory, anti-proliferative and enzymatic activities [5][6][7].…”

Impact of ground Ajwa (Phoenixdactylifera L.) seeds fortification on physical and nutritional properties of functional cookies and chocolate sauce

“…Consequently, date seeds were suggested to be used in food fortification to enhance their fiber content. The beneficial role of dietary fibers on human health and prevention of cardiovascular disease, diverticulosis, constipation, irritable colon, colon cancer, and positive effects for lowering obesity and blood glucose was previously documented (Al‐Farsi et al., 2007; Mrabet et al., 2019).…”