Preparation and Evaluation of Antioxidant Activity of Haematococcus pluvialis Hydrolysate

In order to make high value use of the algal residue, this paper presented a study on the preparation of antioxidant enzymatic hydrolysate from Haematococcus pluvialis residue. Single factor investigation and the response surface methodology (RSM) were used to optimize the hydrolysis process of H. pluvialis residue, including substrate concentration, dosage of proteases, dosage of proteases, temperature, pH and time. The resulting hydrolysates were comparatively evaluated for their ABTS scavenging capacity and degree of hydrolysis. Subsequently, the antioxidant ability and amino acid composition of the optimal hydrolysate were investigated. The results showed that under the optimal hydrolysis conditions: Substrate concentration of 9% (w:v), dosage of proteases of 0.7% (w:w), temperature of 40 ℃, pH11.5 and time of 3 h, the highest ABTS scavenging activity with IC₅₀ of 481.574 μg/mL and FRAP value of 19.641 μmol FeSO₄·7H₂O /g (concentration of 1000 μg/mL) were obtained. Antioxidant enzymatic hydrolysate with 34.4% essential amino acid not only contained high nutritional value but also involved many hydrophobic amino acids closely related to antioxidant activity. This research provides a reference for high value-added applications of H. pluvialis.