Systematic study on date palm seeds (Phoenix dactylifera L.) extraction optimisation using natural deep eutectic solvents and ultrasound technique.

Natural deep eutectic solvents (NADES) are emerging, environment-friendly solvents that have garnered attention for their application in extracting phenolic compounds. This study investigated the effects of four synthetic NADES on polyphenols extracted from date seeds (DS) using choline chloride (ChCl) as a hydrogen-bond acceptor and lactic acid (La), citric acid (Citri), glycerol (Gly), and fructose (Fruc) as hydrogen-bond donors, in comparison with DS extracts extracted by conventional solvents (water, 70% methanol, and 70% ethanol). The antioxidant activity (DPPH), total phenolic content (TPC) and 6 phenolic compounds were determined using HPLC. The results showed that the ChCl-La and ChCl-Citri systems exhibited a high extraction efficiency regarding TPC, and DPPH in the DS extracts extracted by NADES compare to those DS extracts extracted with conventional solvents (p ˂ 0.001). HPLC results demonstrated that DS extracted by ChCl-La contained all measured phenolic compounds. Also gallic acid and catechin were the major compounds identified in the DS extracts. In addition DS extracted by ChCl-Citri and ChCl-Gly had the highest concentration of catechin. In conclusion, combining NADES is a promising and environment-friendly alternative to the conventional solvent extraction of phenolic compounds from DS.

Effects of Ajwa date seeds on the oxidative stability of butter.

Butter is a widely used food product. However, owing to its rich fatty acid content (saturated and unsaturated fatty acids), it is prone to lipid oxidation, which may affect the quality of butter-containing products. Because of the possible toxic properties of synthetic antioxidants, recent research has focused on the use of natural antioxidants. This study aimed to evaluate the effects of Ajwa date seeds as natural antioxidants to retard lipid oxidation in butter. Date seeds as either a powder or extract were added to butter at concentrations of 0.5 % and 1 %; 100 % butter was used as the control. The samples were stored at 60 °C for 21 d. Radical scavenging activity, peroxide value, acid value, and thiobarbituric acid value (TBA) were analysed every 7 d. This study revealed a strong relationship between storage period and oxidative stability parameters. After 21 d, butter containing date seed powder exhibited higher radical scavenging activity than date seed extract. A reduction in peroxide, acid, and TBA values was also observed in butter samples containing date seed powder. In conclusion, date seed powder increased the oxidative stability of butter. Therefore, adding date seed powder to butter-rich food products can increase their shelf-life and stability.

Comparative chemical and biochemical analysis of extracts of Hibiscus sabdariffa.

Hibiscus sabdariffa extracts have attracted attention because of potentially useful bioactivity. However, there have been no systematic studies of extraction efficiencies of H. sabdariffa. The nature of extracts used in different studies has varied considerably, making comparisons difficult. Therefore, a systematic study of extracts of H. sabdariffa made with different solvents was carried out using water, methanol, ethyl acetate and hexane in the presence/absence of formic acid, using different extraction times and temperatures. The extracts were analysed for total polyphenol content, antioxidant capacity using DPPH, FRAP and TEAC assays, and specific anthocyanins were determined using HPLC and LC-MS. The results showed the highest antioxidant capacities were obtained by extracting using water, with or without formic acid, for 10 min at 100°C. These extracts provided the highest concentrations of cyanidin 3-sambubioside and delphinidin 3-sambubioside. It will be important to use extraction conditions giving optimal extraction efficiencies for subsequent bioactivity experiments.