High intensity ultrasound (HIU)-induced functionalization of foxtail millet protein and its fractions

Foxtail millet protein constitutes the second most important component and has remarkable essential acid composition. Out of which prolamin and glutelin forms the major portion of this protein. In the present study, foxtail millet protein was obtained with a recovery yield of 70.79%, and prolamin and glutelin fractions constituted 31.10 and 34.69% of total protein. The objective of this study was to efficiently modulate the protein properties using high-intensity ultrasound (HIU) (amplitude = 5 and 10%; duration = 5, 10 and 20 min). Here, a significant (p < 0.05) alteration in the structural, physicochemical and functional properties (FTIR spectra, solubility, particle size, zeta potential, surface hydrophobicity, emulsifying properties, foaming properties and thermal denaturation) was achieved with HIU processing in foxtail millet protein concentrates, prolamin and glutelin fractions. The findings revealed that protein characteristics were different from prolamin and glutelin, and also that the protein, prolamin and glutelin samples treated at higher HIU intensities possessed improved properties, as compared to the ones left untreated or treated at lower HIU intensities. The results indicated that HIU processing of protein and its fractions can be used to functionalize foxtail millet protein. Functionalizing protein and its fractions from foxtail millets can enhance its potential as a plant protein source. This would pave a way for further utilization of millets as a sustainable and cheap source of protein in food and feed industries.