Nutrition & Food Sciences

Biography

Biography: Mona Ahmed J. Alzahrani

Abstract

Nitzschia laevis is used to extract highly pure eicosapentaenoic acid (EPA) for commercial use in food and pharmaceutical applications, and the biowaste is used for animal feed. This research focuses on the aqueous production of bioactive proteins and hydrolysates from the by-product of EPA production from N. laevis.  A comparison of antioxidant and antihypertensive activities was established between the extracts of N. laevis and other well-known microalgae that are used as food ingredients/supplements.  In this study: 1) Proteins were extracted from N. laevis,  2) Hydrolysates were produced from proteins extracts using Alcalase^®CLEA™, Flavourzyme^® and Trypsin, 3) Proteins and hydrolysates were purified and partially characterized, 4) in vitro bioactivities were screened using chemical and enzymatic assays. The hydrolysis process enhanced the antioxidant and antihypertension activities in general, especially those obtained using Alcalase^®CLEA™. Nitzschia showed the highest total phenolic content and reducing capacity (2.4±0.02mg GAE/100g) after 90 minutes of hydrolysis with Alcalase^®CLEA™. Moreover, hydrolysates at 120 minutes showed the highest ABTS scavenging activity (66.77±0.003%), but DPPH was low (29.599±0.024%). A correlation study was established between DPPH and ABTS scavenging activity with total phenolic contents, trypsin hydrolysates showed the highest positive correlation. The antihypertensive activity was significantly enhanced after hydrolysis; Alcalase^®CLEA™ hydrolysates of N. laevis showed higher ACE inhibition activity after 30 minutes (64.81% ACE inhibition) and Flavourzyme^® hydrolysates also showed high activity after 60 minutes (60.81% ACE inhibition) compared to controls. The interactions between proteins and hydrolysates with other residues are likely to contribute to the measured antioxidant and antihypertension activities.