Carcinus maenas , commonly known as green crab, is an aggressive invasive species found on the east coast of North America . The proliferation of this species has led to significant habitat loss and predation of economically significant bivalves such as soft shell clam . Mitigation efforts have focused on finding marketable uses for green crabs, including the recent development of a soft shell fishery. Although this pathway holds significant potential to decrease green crab levels while increasing revenue for fishers, the financial viability of a soft shell market relies on the valorization of catch unsuitable for this use. Investigations of alternative uses for excess crab have included development of value-added products such as broth and jerky products . The purpose of this study was to assess the feasibility of producing a fish sauce-style condiment from invasive green crab .
Fermented fish sauce is a staple of Southeast Asian cuisine, consisting in its simplest form of a spontaneous fermentation of salted, whole fish. Whole crabs were caught off the coast of Maine and frozen until use. Crabs were finely chopped in a bowl cutter and combined with Kosher salt (10, 20 or 30% w/w). All treatments were prepared in triplicate and were fermented at 24ºC . The product was sampled after 60, 90, and 120 days of fermentation. Prototype product, as well as several commercial fish sauces, were assessed for characteristics including pH, moisture content, water activity, browning index, total volatile base nitrogen, amine nitrogen, presence of biogenic amines (determined by HPLC using a Waters AccQ· Tag) and level of proteolytic microorganisms. Experimental sample data was analyzed by MANOVA in R studio followed by Tukey’s HSD post hoc test to determine the effects of fermentation time and salt level.
No significant differences
(p>0.05) in histamine content at different salt concentrations or time points were observed, the average histamine content in experimental samples being 67.1 ± 16.4 μ g/mL. The population of proteolytic microbes was significantly lower in high salt treatments, compared to 10% salt samples. The majority of tests conducted, including amine nitrogen, a marker for protein degradation characteristic of the fish sauce fermentation, were unchanged between days 60 and 120, indicating that the majority of proteolysis occurred early on in the fermentation. Data from this study suggest that a fermented condiment resembling commercial fish sauce can be prepared from green crab. Additional characterization of sensory qualities of such a product should be completed to assess market potential.