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 beta-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.