Effect of high-pressure homogenization optimized by response surface methodology on the techno-functional properties of protein concentrate isolated from date seed

The study investigates the impact of high-pressure homogenization (HPH) optimized using response surface methodology (RSM) on the techno-functional properties of protein concentrate isolated from date seeds. The protein concentrate was subjected to HPH at various pressures (50, 100, and 150 MPa) and protein concentrations (1 %, 2 %, and 3 %) to optimize solubility, emulsifying activity, and antioxidant properties. RSM indicated optimal conditions at 150 MPa and 1 % protein concentration, resulting in significant enhancements in solubility (14.10 % to 43.69 %) and antioxidant activity (60.5 TE/g to 71.67 TE/g). The emulsifying activity index (EAI) increased from 11.92 m2/g 2 /g to 22.29 m2/g, 2 /g, though the emulsion stability index (ESI) slightly decreased from 17.63 min to 16.15 min. Besides, HPH improved oil-binding capacity (1.73 g/g to 3.02 g/g) while reducing water-binding capacity (2.76 g/g to 1.38 g/g). Structural analysis revealed that HPH caused partial protein unfolding and aggregation, indicated by changes in FTIR spectra, reduced fluorescence intensity, and increased surface sulfhydryl content (1.58 mu mol/g to 2.65 mu mol/g). These findings highlight HPH as an effective method to enhance the functional properties of date seed protein concentrate for potential applications in the food industry. In addition, the current study can lay a foundation for future HPH applications in other protein- rich by-products such as soybean cake, rapeseed cake, wheat bran, and others.