Antinutritional factors and functionality of protein-rich fractions of industrial guar meal as affected by heat processing

Proximate composition analysis and antinutritional factor composition of different fractions of industrial guar meal: raw churi (IRC), heated churi (IHC), final churi (IFC) and guar korma (IGK) were studied and compared. Protein content was found to be very high in IGK (52.7%) when compared to the churi fractions (32-33%) and the trypsin inhibitor activities were found to be negligible in all the fractions (0.58-1.8 mg/g). Single fraction (IGK) was selected for further studies, based on the protein content. The antinutritional factors of selected fractions were significantly reduced by different heat treatments. Heat treatments significantly increased the water absorbing capacity of IGK, but reduced the nitrogen solubility, emulsifying and foaming capacity. Highest L∗ value was observed for boiled IGK, highest a∗ and b∗ values for roasted IGK, during colour measurement. FTIR spectral analysis revealed the presence several aromatic groups in IGK and slight modifications in the molecular structure during heat treatments.