Abul Hossain - January 7, 2019
Effect of High-Pressure Processing on Phenolics and Antioxidant Activity of Sea Cucumber (Cucumaria frondosa)
Sea cucumber belongs to Phylum Echinodermata and Holothuroidea class which contains numerous bioactive components. In particular, body wall of sea cucumber is a rich source of glycosaminoglycan, whereas aquapharyngeal bulb (tentacle) and viscera are the important sources of phenolics, where the viscera are considered as processing discards. The most common sea cucumber found in North Atlantic region is “Cucumaria frondosa” which is also known as orange footed sea cucumber. This study aimed at investigating the free, esterified, and insoluble-bound phenolics from different body parts (body wall, aquapharyngeal bulb, and viscera) of sea cucumber (Cucumaria frondosa), as affected by high-pressure processing (HPP). Sea cucumbers were pretreated with high-pressure (6000 bar, 5 min), followed by separation into the three aforementioned parts followed by freeze-drying. The contents of total phenolics and flavonoids were determined, and antioxidant activity of their various phenolic fractions evaluated using in vitro free radical scavenging methods, namely DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)), and hydroxyl radicals activities. Their metal chelating activity was also monitored. Compared to untreated samples, those treated with HPP exhibited increased total phenolics, flavonoids, and antioxidant activities by an order of magnitude. Free phenolic fraction was the predominant form present in all body parts examined. The highest amount of phenolics and antioxidant activity was observed in aquapharyngeal bulb in the free phenolic fraction, whereas esterified and insoluble-bound fractions were more abundant in the body wall. Identification of individual phenolics responsible for the observed effects is in progress.