Summary:
Fish protein hydrolysates (FPH) possess various bioactivities making them a desirable ingredient in health foods. Saithe is an underutilized fish species and an excellent candidate for FPH. To produce high quality FPH removing undesirable components prior to the hydrolysis process is preferred and possible via the pH-shift process. The objective was to produce and investigate the properties of hydrolyzed protein isolates produced from minced saithe trimmings. Saithe trimmings were minced, homogenized in water and subjected to two variations of a pH shift process with (A) and without (B) dewatering. The latter process has the advantage of being less complicated and less expensive which is beneficial to the industry. Both systems were adjusted to 3% protein, pH 8 and 45 ° C and subjected to enzyme hydrolysis. Both hydrolysis processes led to almost identical SDS-page peptide makeup. Both FPHs had similar antioxidant activities evaluated using oxygen radical absorbance capacity (ORAC), iron chelation ability and (DPPH) radical scavenging ability assays. FPH from process A had significantly higher ACE inhibition ability compared to FPH from process B.
These results demonstrate that saithe FPH has good antioxidant activities and a strong ability to inhibit ACE, and may thus have a potential as a bioactive food ingredient.