Comparison of ultrasonication, fermentation and acidification on extraction of protein from defatted white sesame press cake and its impact on structural modification and functionality

Sesame oil cake, a protein-rich by-product of oil processing, is represented as an overlooked resource with the potential to change beyond conventional feed application into next-generation food systems. However, its utilization is constrained by limitations in extraction efficiency and functionality. Hence present study investigated the influence of targeted pre-treatment techniques on protein structure modification and their effects on extraction efficiency, and techno-functional behaviour of white sesame oil cake protein (WSPI). This systematic comparative study revealed that the protein functionality is governed by modified molecular rearrangements, particularly sulfhydryl group reactivity and surface hydrophobicity, which control protein unfolding, interfacial interaction and hydration behaviour. Controlled structural modification enhances protein recovery (up to 40.1%) along with functional properties like WHC (4.39 g/g) and OHC (3.81 g/g). Notably, these structural transitions improve bioactive properties exhibiting higher antioxidant activity (DPPH scavenging up to 84.13%) and also improve in vitro digestibility (94.4%). In contrast, excessive denaturation resulted in aggregation, reduced functionality and bioactive properties. These findings reveal sesame protein as a structurally tuneable and functionally adaptable protein isolate for food applications. By establishing the relation between molecular restructuring and functionality, this study shows a systematic approach to protein valorization for the development of sustainable, high-performance, plant-based ingredients.