Influence of processing and pH on amino acid profile, morphology, electrophoretic pattern, bioactive potential and functional characteristics of alfalfa protein isolates.

Protein isolates were prepared from wet heat processed (APIp) and unprocessed alfalfa seeds (APIc) and characterized for composition and functionality at different pH. APIc and APIp exhibited high content of all the essential amino acids. Antinutrient content of APIp was lower in comparison to APIc and marked reduction in the trypsin inhibitor (85.97%) and lectin activity (100%) was observed. Processing did not cause much reduction of bioactive constituents and antioxidant activity of APIp. Alfalfa protein isolates exhibited complex polypeptide banding ranging from molecular weight of 11-75 kDa. APIp exhibited change in the conformation of protein discerned as alteration in interrelated nuances of ATR-FTIR spectra, XRD-pattern, morphology, charge on proteins and reduced solubility in comparison to APIc due to processing. APIp exhibited marked improvement in the functional properties in comparison to APIc discerned as improved hydration, surface active and gelation properties. Highest hydration and surface active properties were exhibited at pH 9.0, even though APIp at pH 7.0 showed fairly similar functional properties as APIc and APIp at pH 9.0. APIp exhibited reduced least gelation concentration in comparison to APIc at pH 7.0 and also engendered gelation at pH 4.0 and 9.0 contrary to APIc.