Physicochemical, structural, and functional characterization of guar meal protein isolate (Cyamopsis tetragonoloba).

Guar korma and churi protein isolates were assessed for their physicochemical, nutritional,
functional, structural, and digestibility properties for their application in the food industry. The
water extracted protein isolate of guar korma showed a protein content of 89.7 % and a yield of
48.7 %. Water extracted protein isolate of guar korma showed an excellent protein efficiency
ratio, essential amino acid/total amino acids (34.35 %), amino acid score, and protein digestibility
corrected amino acid score values, suggesting the existence of high-quality proteins.
Water extracted protein isolate of guar korma contains all the essential amino acids except
Methionine and Cysteine, according to World Health Organization recommendations for children
and adults. The protein profiling of water extracted protein isolate of guar korma was analyzed
using 12 % sodium dodecyl sulfate polyacrylamide gel electrophoresis and indicated the presence
of eight major protein bands in the range of 17–100 kDa. In vitro digestibility of water extracted
protein isolate of guar korma showed the complete digestion of the abundant protein bands
within 15 min. Further, the foaming capacity, water/oil holding capacity, and emulsifying stability
of water extracted protein isolate of guar korma were comparable with soy protein isolate.
Fourier Transform Infrared and Circular Dichroism spectral analysis revealed the presence of
several aromatic groups and β-sheets, random coils respectively in water extracted protein isolate
of guar korma. The morphological nature of the guar protein isolate was characterized by
Scanning Electron Microscopy. Overall, these findings support that water extracted protein isolate
of guar korma has excellent functional and nutritional properties and could be a potential
alternative plant protein in food industries.