Influence of high-pressure processing on the physicochemical and the emulsifying properties of sarcoplasmic proteins from hake (Merluccius merluccius)

Abstract

The sarcoplasmic proteins from hake (Merluccius merluccius) were subjected to high-pressure treatments (200, 400 and 600 MPa for 6 min at 20 °C). The physicochemical changes and the emulsifying capacity of sarcoplasmic proteins were evaluated. High-pressure processing increased the surface hydrophobicity and the reactive sulfhydryl group content of sarcoplasmic proteins above 200 MPa. Likewise, conformational changes were induced on the secondary structure of sarcoplasmic proteins at 400 MPa. High-pressure denaturation of sarcoplasmic proteins promoted their aggregation. The electrophoretic patterns showed that some sarcoplasmic proteins (78, 73, 63, 58, 37, 32 and 22 kDa) were the most pressure labile. However, the carbonyl content of sarcoplasmic proteins was not affected by high-pressure treatments. The pressure-induced denaturation affected the emulsifying properties of sarcoplasmic proteins, which was dependent on pressure. In contrast to high-pressure levels (400 and 600 MPa), sarcoplasmic proteins treated at 200 MPa produced emulsions with enhanced stability, greater consistency index, and shear-thinning behavior. These results suggested that high-pressure denaturation can affect the functional properties of sarcoplasmic proteins.