Does hydration of 'Deglet Nour' date palm fruits improve their quality and help to reduce waste?

This work investigates the quality change of date palm fruits after hydration treatment which is commonly applied to enhance the hard textured 'Deglet Nour' fruits that are unacceptable for consumption. Date palm fruits were treated at 60-62 °C with saturated steam for 4 h in three different processing units (DPU). Mid Infrared Spectroscopy (MIR) giving a global spectral evaluation discriminates samples from the three DPUs and highlights date palm fruits of the first DPU regarding hydration treatment. Treatment led to a decrease of fruit firmness, skin lightness, and of sucrose and malic acid contents whereas citric acid and procyanidins contents and procyanidins 'degree of polymerization increased. Thermal treatment had no effect on glucose and fructose contents, on cell wall content and composition and on minor phenolic groups. Significant differences existed on dates from the three DPUs, discriminating dates presenting high firmness. Hydration treatment improve dates texture as expected while nutritional parameters were quite stable, confirming that is very promising and could be highly recommended to valorise fruit that are currently not commercialized. However, optimisation is needed for the very hard-type dates.

Effect of Date (Phoenix dactylifera L.) Pits on the Shelf Life of Beef Burgers.

A new ingredient from date palm coproducts (pits) was obtained and tested as a preservative in burgers. Different concentrations of date pit (0%, 1.5%, 3%, and 6%) were added to beef burgers, and its effect on the safety and quality was evaluated during 10 days of storage. The incorporation of date pit was able to improve the shelf life and the cooking properties of the burgers. The date pit stabilized the color, lipid oxidation, and microbial growth of the burgers during the storage time due to the antioxidant activity and the phytochemical content of the date pits. For the consumer panel, the color and the off-odors were improved, and the addition of 1.5% and 3% date pit in cooked burgers obtained similar scores. Based on the obtained results, the new ingredient from date pit may have potential preservative properties for enhancing stability during shelf life and could improve the composition of bioactive compounds (fiber and phenolic content) of beef burgers.

Phytochemicals in date co-products and their antioxidant activity.

The date agro-industry needs to find appropriate techniques to give value to their co-products. This study analyzes twelve intermediate food products (IFPs) from date co-products, Medjool and Confitera cv. at several ripening stages, blanched and unblanched, for their content in bioactive compounds (phenols, tannins, flavonoids, carotenoids and anthocyanins) and the antioxidant activity (AA). IFPs from the more unripe stages had the highest AA and phytochemicals content, mainly phenols, up to 1.4 g GAE/100 g, with high proportions of tannins. Flavonoids were found in high amounts, up to 874 mg RE/100 g. Among the AA are significant the antiradical efficiency (4.62 mM TE/100 g) and chelating activity (252 µM EDTA/100 g). Blanching was beneficial for Confitera IFPs. A positive correlation was found between phenols, tannins and flavonoids and the AA; and their content could be used as indicator of the AA. Date IFPs have potential use as an antioxidant functional ingredient.

Characterization of novel intermediate food products from Spanish date palm (Phoenix dactylifera L., cv. Confitera) co-products for industrial use.

The nutritive, physicochemical and technological characteristics of several intermediate food products (IFPs) from Spanish Confitera fresh date co-products were investigated. Three IFPs were obtained, two from unblanched dates in different ripening stages (Khalal and Rutab), and a third one from blanched Khalal fruits. The IFPs were rich in dietary fibre (13-16%, dry matter), phenolics (0.56-4.26g GAE/100g dry matter) and sugars (55-82%, dry matter), with glucose and fructose as the predominant sugars. Malic acid was the major organic acid, and potassium was the main mineral. Blanching Khalal dates aided to prevent browning in the IFP, but also the thermal treatment modified the sugars profile. The results indicated that both maturity stages yield IFPs with potential in the food industry; and according to their sugar and phenolic content they could be suitable for the elaboration of new ingredients with different industrial applications. In addition, it would be recommendable blanching unripe fruits.