Utilizing dry heating Maillard reaction approach to modify the functional and structural properties of sunnhemp protein isolate-dextran conjugates

Abstract

Abstract Sunnhemp protein isolate (SHPI) was prepared by utilizing alkaline extraction acid precipitation method. SHPI-dextran conjugates (1:1 w/w ratio) were prepared by dry heating method with Maillard reaction at 60°C for 0, 1, 3, 5, 7, and 9 days of incubation at 79% relative humidity. The functional properties of SHPI-dextran conjugates like solubility, emulsifying, foaming, water and oil binding capacities, dispersibility, and gelation were improved as compared to pure SHPI. Increment in browning index values of SHPI-dextran conjugates were observed with increase in Maillard reaction time. Conjugated SHPI reduced the percentage of α-helix and increased the content of β-sheet, β-turn and random coils content. FTIR spectroscopy confirmed the formation of covalent bonds between SHPI and dextran via Maillard reaction. XRD analysis indicated both semicrystalline and amorphous structure of SHPI-dextran conjugates as the incubation time was increased from 0 to 9 days. Decreasing trend in the values of surface hydrophobicity values were found with increase in incubation time. Free and total sulfhydryl content of SHPI was increased after conjugation with dextran up to 5 days and thereafter decreased. Incubation time of five days at 60°C and 79% RH was optimized on the basis of improvement in functional characteristics and extent of Maillard reaction time. Overall, the present study showed that conjugation of sunnhemp protein isolate with dextran successfully improved the functional characteristics of SHPI.