Bioactive stability of microalgal protein hydrolysates under food processing and storage conditions

The stability of antioxidant protein hydrolysates from Spirulina sp. LEB 18 was evaluated under food processing conditions and after in vitro digestion. Protein hydrolysates with degrees of hydrolysis of 50.6% and 60% were obtained after 90 and 120 min of reaction, respectively, with Protemax 580 L. The results indicated that the antioxidant activity of protein hydrolysates was maintained following application of heat treatment (- 18 °C, 63 °C, and 100 °C). Moreover, the ability of protein hydrolysates to inhibit the 2,2-diphenyl-1-picrylhydrazyl radical was increased by nearly 25% upon exposure to acidified media (pH 4 and pH 6). In general terms, the protein hydrolysates were bioavailable after digestion with pepsin and pancreatin. This study supports the incorporation of bioactive peptides from microalgae into functional foods by demonstrating the maintenance of their biological activities in the face of food processing conditions and gastrointestinal digestion.