Towards Full Utilization of Sea Cucumber (Cucumaria frondosa): Protein Hydrolysates & their Antioxidant Potential

Orange-footed sea cucumber (Cucumaria frondosa) which belongs to the phylum Echinodermata and class Holothuroidea is the most common sea cucumber species found in northwest Atlantic waters. This benthic marine invertebrate contains a wide array of high-value nutraceuticals and pharmaceuticals with various biological properties. However, this species is mainly fished for its edible body wall and muscle and its processing generates a high volume of biological wastes. The present study investigates the potential application of enzyme technology in sea cucumber processing by-products for producing hydrolysates. Enzymatic hydrolysis was performed using readily available commercial enzymes, Alcalase, Flavourzyme, and Colorase. The hydrolysates were produced from different sea cucumber body parts including body wall, aqua pharyngeal bulb, and viscera at optimum pH and temperature conditions. Protein hydrolysates so produced were evaluated for their antioxidant activity in food and biological model systems. Furthermore, their in-vitro antioxidant capacity was investigated using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and hydroxyl radical scavenging assays as well as metal chelating abilities. Our findings showed that hydrolysates possess better antioxidant activities compared to their untreated counterparts. Hence, protein hydrolysates from sea cucumber have the potential to serve as natural functional ingredients and that enzymatic modification provides an effective means for upgrading of by-products and generation of novel bioactive molecules. Thus, these findings pave the way for full utilization of harvest with promising economic return.