Alkali-Assisted Extraction of Date Seeds for Stabilizing Bioactive-Rich Oil-in-Water Emulsions

Abstract

Date seeds are the major byproduct of the date palm industry, posing both environmental and economic concerns. Therefore, this study aimed to valorize date seeds through alkali-assisted extraction for stabilizing bioactive-rich oil-in-water emulsions. Using an I-optimal design, the effects of pH (7–11), temperature (30–50 °C), date seed concentration (DSC) (5–25%), and extraction time (30–150 min) on total polyphenol content (TPC) and the Sauter mean droplet diameter (D[3,2]) of emulsions were optimized. Results showed that alkali-assisted extraction significantly increased the TPC and minimized D[3,2], with the optimal conditions being pH 8.5, 50 °C, 5% DSC, and 30 min extraction time. At these conditions, submicron emulsions were achieved, which were highly stable at mildly acidic pH (6–7) over 3 weeks but exhibited reduced stability at lower pH (<6) and increasing salt concentrations. These findings demonstrate that date seeds are a promising, sustainable resource for natural emulsifiers, capable of stabilizing emulsions with extended shelf life.