Valorization of sea buckthorn seed protein to hydrolysates: Impact on morphological, structural, functional, and antioxidant properties

Background

Increasing concerns about nutritional deficiency, food security, and sustainability have emphasized work on exploring alternative and sustainable sources of protein. In this study, an initiative to extract and utilize protein concentrates, and hydrolysates from sea buckthorn seed, otherwise a waste material, is undertaken. The effect of hydrolysis using various enzymes namely pepsin (pH 2.0 and 37°C), trypsin (pH 7.0 and 37°C), and protamex (pH 7.0 and 50°C), for different time durations, namely, 30, 60, 90, and 120 min, on the structural and functional properties of sea buckthorn seed protein concentrate (SSPC), was elucidated.

Results

The emulsifying activity index and solubility of pepsin-hydrolysed SSPC increased significantly and were higher than those of trypsin and protamex hydrolysed SSPC samples. A Fourier transformation infrared study revealed that the enzyme hydrolysis treatment reduced the peak intensity in amide I, II, and III bands. A significant change was found in the β-sheet, β-turn and random coiling of the secondary structure of SSPC protein by enzymatic hydrolysis. The particle size ranged from 295.8 to 440, 388 to 713.6, 399 to 890 nm for pepsin, trypsin, and protamex, respectively. The microstructure of pepsin-treated samples showed a more porous and loose structure than native, trypsin and protamex. Antioxidant activity increased significantly for all the samples with enzyme treatments carried out for different periods.

Conclusion

The results indicate that the protein-rich hydrolysates could create new opportunities for the development of effective techno-functional additives for use in a wide range of food formulations.