Effect of Defatting Method on Japanese Quince (Chaenomeles japonica) Fruit Seed Protein Isolate Technological...

Fruit seeds are often an underutilized side-stream of fruit processing. The most common approach to seed valorization is oil extraction due to the relative simplicity of the process. The partially or fully defatted seed meal is rarely further processed, even though seeds generally contain more protein and fiber than oil. The present study used single-screw extrusion (oil press), supercritical CO₂ extraction, and a combination of the two, to defat Japanese quince (Chaenomeles japonica) seeds, and evaluated the defatted meals as sources of functional protein. Defatting with oil press and CO₂ extraction proved similarly effective (reduced seed flour fat content from 11.75% to 6.40% and 5.32%, respectively); combining the two methods reduced fat content to 0.90%. The yield was minimally affected, but protein extract purity was defined by defatting efficiency (65.05% protein from non-defatted versus 82.29% protein from a combination-defatted meal). Defatting did not significantly affect amino acid composition but had a significant effect on every tested functional property (solubility, water, and oil binding capacity, apparent viscosity, foaming capacity, and emulsifying activity index). Of the tested defatting methods, supercritical CO₂ extraction and the combination provided the best results from most aspects.