Introduction
An important category of by-products from seafood processing includes crustacean ones. Approximately 6-8 million tons of crustacean waste is produced worldwide every year (FAO, 2014) Shrimp and prawns are one of the most important internationally traded seafood products, and one of the few that can be considered a “commodity”, with a value of US$10 billion (or 16% of world fishery exports) (Gillett, 2008). Shrimp by-products represent important natural sources of carotenoid, among which astaxanthin (ASX) is the major one. Recently, pulsed electric field (PEF) treatment showed to be a promising method for the isolation and extraction of several components from seafood by-products such as calcium, chondroitin sulphate, collagen, chitosan, and protein (Bruno et al., 2019). Accelerated solvent extraction (ASE) is considered a green technique to recover bioactive and nutritional compounds in plants and food matrices (Sun et al., 2012). The main objective of the present study was to apply PEF and ASE using two different organic solvents (dimethyl sulfoxide, DMSO and ethanol, EtOH) to recovery ASX from shrimp by-products, and evaluate the effects of these technologies used independently or in combination on the ASX content and antioxidant activities of the extracts.
Materials and methods
In this study, fresh samples of red shrimp (Aristeus antennatus) and camarote shrimp (Melicertus kerathurus) were obtained from a local market in Valencia, Spain. Dimethyl sulfoxide (100% DMSO) or ethanol absolute (EtOH) were used as organic solvents. The combined and independent effects of the emerging technologies PEF and ASE using different solvents (EtOH and DMSO) on the extraction of astaxanthin were evaluated for each shrimp species. ASE (50 °C, 15 min, 103.4 bar) and PEF (3 kV/cm, 100 kJ/kg, 74 pulses) were used as extraction technologies. The antioxidant capacity of the extracts was evaluated by and Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays. Experimental data were subjected to one-way analysis of variance (ANOVA) to determine the significant differences among samples. Tukey HSD (Honestly Significant Difference) multiple range test, at a significance level of p < 0.05, was applied.
Results
Preliminary results showed that ASE and PEF increased the astaxanthin content in the extracts for both shrimp species and solvent used, and the higher recovery was obtained using their combination (Fig 1).
Both technologies seem to be an effective tool to recover astaxanthin and antioxidant extracts from shrimp by-products. However these promising results should be confirmed by extending the study to other valuable compounds from crustacean by-products.
References
Bruno, S. F., Ekorong, F. J. A. A., Karkal, S. S., Cathrine, M. S. B., & Kudre, T. G. (2019). Green and innovative techniques for recovery of valuable compounds from seafood by-products and discards: A review. Trends in Food Science and Technology, 85(June 2018), 10–22. https://doi.org/10.1016/j.tifs.2018.12.004
FAO. (2014). The state of world fisheries and aquaculture: Challenges and Opportunities. In Food and Agriculture Organization of the United Nations. https://doi.org/92-5-105177-1
Gillett, R. (2008). Global study of shrimp fisheries (Vol. 475). Food and Agriculture Organization of the United Nations Rome.
Sun, H., Ge, X., Lv, Y., & Wang, A. (2012). Application of accelerated solvent extraction in the analysis of organic contaminants, bioactive and nutritional compounds in food and feed. Journal of Chromatography A, 1237, 1–23.