Valorization of bioactive compounds from shrimp shells: Comparison between ultrasound-assisted and subcritical-water extractions

Shrimp shells are an abundant residue due to the increase of its consumption on a global scale and they are mostly disposed into landfills or back into the ocean being associated with several environmental issues; therefore, it is urgent to find them a profitable end [1]. Due to its chemical composition, shrimp shells can present themselves as an interesting source of antioxidant compounds, which can be used in high-value products [2].

The main goal of the present work was to efficiently extract antioxidant compounds from shrimp shells waste. For that, two environmentally friendly extraction techniques, namely ultrasound-assisted extraction (UAE) and subcritical water extraction (SWE), were optimized and compared to conventional extraction (CE). Then, to determine which one of tested extraction techniques was more efficient, different colorimetric methods, namely total phenolic (TPC) and carotenoid content (TCC), ABTS radical scavenging activity and Ferric Reducing Antioxidant power, were applied. From the tested techniques, SWE at 200°C presented the best results, with a TPC and TCC of 5.36±0.07 mg GAE/g dw and 59.8 ±1.0 mg carotenoids/g dw, which were at least 5-fold higher than the values reported for the CE (1.2±0.3 mg GAE/g dw and 9.0±0.1 mg carotenoids/g dw). Work is in progress to identify which individual phenolic compounds can be extracted from shrimp shell waste, using high performance liquid chromatography with diode array detection.