From seed to solution: Enhancing techno-functionality and digestibility of pumpkin seed protein isolate through high-intensity ultrasound, high-pressure processing, and pH-shifting

This study investigated a novel approach combining pH shifting with high-intensity ultrasound (HIUS) or high-pressure processing (HPP) to enhance pumpkin seed protein isolate (PSPI) properties. PSPI, derived from defatted pumpkin seed flour, was treated using pH shifting, HPP, HIUS, or their combinations. The pH shifting + HIUS treatment yielded the most significant improvements, including enhanced protein solubility (69.1 %), surface hydrophobicity (251.1), free sulfhydryl content (5.88 μmol/g), antioxidant activity (17.2 %), and total phenolic content (3.1 mg catechin/g). A heatmap analysis showed that this combination achieved the most substantial structural changes and functionality enhancements, followed by pH shifting + HPP. In comparison, pH shifting alone induced moderate changes, and individual treatments like HIUS or HPP were less effective than their combinations. Untreated PSPI, used as a baseline, exhibited minimal structural changes, larger particle size, lower solubility, and less desirable functionality. These findings highlight the superiority of combined treatments, particularly pH shifting + HIUS, in improving the properties and potential applications of PSPI.