Valorization of Rapana venosa Viscera Through Enzymatic Production of Protein Hydrolysates

The veined rapa whelk (Rapana venosa) is an invasive marine gastropod with commercial value, particularly in the Black Sea region. During processing, its viscera are typically discarded as waste. This study aimed to valorize the viscera by producing protein hydrolysates through enzymatic hydrolysis and lyophilization. Proximate analysis showed that the viscera contained 22.61% protein, 2.87% fat, and 2.95% ash. The hydrolysates were analyzed for amino acids using LC-MS/MS and minerals via ICP-MS. Glutamic acid, aspartic acid, and phenylalanine were the most abundant amino acids, with essential amino acids accounting for 52.4% of the total. The mineral profile revealed high levels of magnesium, calcium, and iron, along with elevated concentrations of copper and cadmium. Fatty acid analysis identified 24 components, with saturated fatty acids (SFAs) being the most abundant group, followed by polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs). Major fatty acids included palmitic acid (C16:0, 13.69%), oleic acid (C18:1n-9, 3.21%), eicosapentaenoic acid (EPA, 4.56%), and docosahexaenoic acid (DHA, 8.15%). EPA and DHA together made up 12.71% of total fatty acids, highlighting the nutritional potential of the viscera. These findings support the potential use of Rapana venosa viscera hydrolysates in nutraceutical and functional food applications, although further investigation into heavy metal content is required.