Protein isolate from basil seeds (Ocimum basilicum L.): Physicochemical and functional characterisation

Protein was isolated by isoelectric precipitation from basil seeds (after mucilage and oil extraction) and investigated for its physicochemical and functional properties. The protein content of basil seed protein isolate (BPI) was 89.08%. High performance liquid chromatography (HPLC) showed presence of essential amino acids. Glutamic acid (17.40%), threonine (13.65%), and arginine (11.32%) were abundant. Sodium dodecyl sulphate polyacrylamide gel (SDS-PAGE) analysis showed molecular weights in the range of 11.5 to 77.6 kDa. Differential scanning calorimetry (DSC) of basil seed protein isolate revealed a high denaturation temperature (95.34 °C). The Fourier transform infrared spectroscopy (FTIR) indicated presence of amide I, II, and III groups. Characteristic peaks for β- sheet conformation were also observed. Results showed that BPI had high emulsifying ability index (298.4 m2/g) at pH 10. Solubility was lowest at pH 9 (10.69%). Functional properties such as protein solubility, foaming, and emulsification properties were high at pH 10. An increasing trend was observed from pH 2 to 5. High bulk density (0.799 g/ mL) and low water absorption capacity (0.51 g/ g) was observed.