Protein isolates and hydrolysates from Atlantic sea cucumber (Cucumaria frondosa): characterization and bioactivities

• Main Author: Senadheera, Tharindu Ruchira Lakni
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2020
• Subjects: Cucumaria frondosa; North Atlantic; Northwest Atlantic; Orange-footed sea cucumber
• Online Access: https://research.library.mun.ca/15719/; https://research.library.mun.ca/15719/3/converted.pdf

North Atlantic sea cucumber (Cucumaria frondosa) or orange-footed sea cucumber is a benthic marine echinoderm found in Northwest Atlantic waters. It is harvested mainly for its edible body wall and muscle bands. The aquaphyrangeal bulb or flower is considered as a secondary marketable product and internal organs including gonads, respiratory tracts and intestine are discarded as processing by-products, which generate a high volume of biological waste. However, all the body parts of the sea cucumber are rich in protein. The objective of this research was to recover the proteins from sea cucumber tissues and produce protein hydrolysates with bioactive properties associated with antioxidative and angiotensin-I-converting enzyme (ACE) inhibitory activities following a multidisciplinary approach. Proteins were isolated from the body wall, flower and internal organs of Cucumaria frondosa using a pH-shift method. Isolated proteins were evaluated for their physicochemical properties including solubility, emulsifying and foaming properties, water- and oil-holding capacities, surface hydrophobicity, content of sulfhydryl and disulfide groups along with FTIR analysis for identifying the functional groups of proteins and amino acid compositional analysis. Findings of this research revealed that sea cucumber-derived protein isolates could be used as a natural alternative to soy protein isolates as well as a source of balanced dietary proteins. Lyophilized protein isolates were then hydrolysed using food grade commercial enzymes, namely Alcalase, Corolase and Flavourzyme individually and in combination. The protein hydrolysates so prepared were evaluated for their antioxidant potential in different systems including radical scavenging assays such as the 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical, the2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation, and hydroxyl radical scavenging assays. In addition, metal chelating, the reducing power, and -carotene bleaching assays in oil-in-water emulsion as ...