Chapter 5 - Fish roe from sea urchin: composition, processing, and quality aspects

Abstract

Sea urchins comprise a large number of species that occupy coastal open ocean water worldwide. Sea urchins have been harvested for their edible gonads, commonly referred to as roe, for a long time, mainly in the Mediterranean and parts of Asia, with the Japanese being the main consumers. With increased interest in sushi fine cuisine worldwide, wild stocks of sea urchins have declined, prompting investment in aquaculture. Sea urchin reproduction involves male and female gonads from which sperm and eggs are released into the seawater. During early development, sea urchin larvae are freely motile in the ocean, then as juveniles attach to suitable rock surfaces in coastal water adjacent to their kelp food source. Harvesting and processing of mature sea urchins to obtain the edible roe are labor intensive. Only the best quality roe attracts the highest prices, particularly in Japan. Roe quality is highly dependent on sensory attributes such as color, appearance, size, texture, and taste, that are influenced by seasonal harvesting, as well as a roe from different sea urchin species exhibiting different attributes. A number of studies have reported on the molecular composition of roe, and as with other marine animals, the sea urchin roe contains substantial amounts of health-promoting polyunsaturated lipid. In more recent times, genomic, transcriptomic and proteomic studies have provided opportunities to obtain a better understanding of sea urchin genetics, and along with aquaculture trials aimed at manipulating sensory attributes, such as the color of the roe, have future potential to supplement the declining wild stocks of sea urchin, and provide roe product for the market that is more consistent in sensory attributes, that is quality assured in heath and microbiological safety.