Natural stabilizers for functional foods: The role of optimized date seed extracts in nanoemulsion applications

This study explores the potential of date seeds as natural stabilizers in nanoemulsion-based functional foods. Six pre-treatments (control, overnight stirring, high-speed homogenization, ultrasound, microwave, and pH-shift) were investigated to determine the best method for aqueous extraction of date seeds for nanoemulsion optimization and stability studies. The ultrasonic pre-treatment was found to enhance total polyphenols content and antioxidant activity and produce stable nanoemulsions with minimal size variation. A D-optimal design was used for nanoemulsion optimization using varying high-pressure homogenization (HPH) pressure, date seed powder (DSP) concentration, and oil content. The optimal nanoemulsion was formulated at 493.21 bar, with 15% DSP, and 4.13% oil. This nanoemulsion demonstrated stability over a week under refrigerated conditions, particularly at pH 6 and with NaCl concentrations below 100 mM. Our findings indicate that date seed extract can be an effective natural ingredient to stabilize nanoemulsions, promoting the development of novel functional foods. Future studies on enhancing the functional attributes and understanding the properties of the nanoemulsions, including sensory and rheological characteristics and long-term stability across a broader pH range and salt concentrations, would broaden the potential of date seeds as natural stabilizers in nanoemulsion-based functional foods.