Functional tomato sauces enriched with glycated pumpkin seed protein concentrate: Physicochemical, nutritional, and digestibility assessment

This study examined the impact of pumpkin seed protein concentrate (PSPC), in both unmodified and glycated forms, on the nutritional and functional properties of reformulated tomato sauces. Four tomato sauces with different PSPC added formulations were examined: a control (no additional PSPC) sample (TS-C), unmodified PSPC (TS-U), allulose-glycated PSPC (TS-A), and fructose-glycated PSPC (TS-F). Various standard analyses examined the physicochemical, rheological, and structural properties of the sauces. The results demonstrated that the conjugated PSPC addition significantly improved protein solubility and lycopene content. TS-F and TS-A samples also exhibited higher °Brix values while maintaining suitable pH levels. Their enhanced scavenging activity (SA, g/100g), total phenolic content (TPC), and reducing power suggest a potential to contribute dietary antioxidants. Furthermore, both TS-F and TS-A showed improved digestibility compared to TS-U, likely due to their increased solubility in the sauce matrix. This is the first study to incorporate glycated PSPC into tomato sauces using glycation agents (allulose and fructose), a rarely studied matrix for protein fortification. Additionally, Time-Domain Nuclear Magnetic Resonance (TD-NMR) provided new insights into protein-water interactions in complex sauce systems. These innovations contribute to the development of functional, plant-based, and clean-label products that are aligned with current market and consumer demands. • Glycated pumpkin proteins improved the functional properties of tomato sauces. • Conjugates enhanced the in vitro digestibility of the tomato sauce matrix. • NMR analysis revealed changes in water mobility and interactions. • Conjugated proteins may serve as natural alternatives to food additives. • Pumpkin protein conjugation enables value-added, functional food products.