Physicochemical, techno-functional, biochemical and structural characterization of a protein isolate from groundnut (Arachis hypogaea L.) paste treated with high-intensity ultrasound.

The objective of this research was to evaluate the effect of ultrasound (HISound) (200, 400 and 600 W; 15–30 min) on the physicochemical, biochemical and structural techno-functional properties of a groundnut paste protein isolate (GPPI). HISound increased the contents of free sulfhydryls (552.22 %), total sulfhydryls (124.68 %) and α-helix (389.75 %), as well as molecular flexibility (50.91 %), hydrophobic surface (38.99 %), and particle size (171.45 %) of GPPI, which improved protein solubility by 8.05 %, oil holding capacity by 73.54 %, emulsifying stability index by 226.25 % and foaming capacity by 216.00 %, compared with non-sonicated GPPI. Also, the microstructure analysis revealed smooth structures, with molecular weights in the range of 13.88–67.07 kDa. Pearson analysis determined some highly significant correlations (r ≥ 0.90, p < 0.01) between some GPPI protein properties. The improvement of GPPI properties by HISound could contribute to its use as an ingredient for human consumption. [Display omitted] • A protein isolate (GPPI) was obtained from de-oiled peanut paste. • Ultrasound (HI-U) induced structural changes in GPPI proteins. • HI-U increased the particle size and hydrophobicity of GPPI proteins. • The composition of the secondary structure of GPPI proteins was modified by HI-U. • The structural modifications of GPPI proteins influenced their functionality. [ABSTRACT FROM AUTHOR]