Ultra-high Pressure LC Method to Determine Astaxanthin in Shrimp By-Products and Migration Evaluation from an Active Plastic Film Produced with Shrimp Waste to Fatty Food Simulants

Carotenoids have antioxidant properties allowing protection of tissues from oxidative damages and they are also beneficial in cardiovascular, immune, inflammatory and neurodegenerative diseases. Astaxanthin (3,3’-dihydroxy-β-β´-carotene-4-4´-dione) is a carotenoid classified as xanthophyl and it is one of the major carotenoids in crustaceans. The project ‘Preparation of active packaging with antioxidant and antimicrobial activity based on astaxanthin and chitosan’ aims to develop a methodology for the incorporation of compounds obtained from shrimp waste in plastic matrices for the development of an active packaging with antimicrobial and antioxidant properties. In the frame of this project, shrimp by-products were fermented and the silage was centrifuged. Three fractions were obtained and the upper phase, corresponding to the lipid fraction, was further analysed to determine astaxanthin content. The aim of the present work was to optimize a method to determine astaxanthin as well as seven other carotenoids and two vitamins (A and E) by ultra-high pressure liquid chromatography (Ultra Performance Liquid Chromatography, UPLC) with diode array detection (DAD) method in shrimp by-products. The chromatographic separation is achieved using a vanguard pre-column (UPLCÒ BEH, 1.7 µm particle size) and a column (UPLCÒ BEH, 2.1 x 50 mm, 1.7 µm particle size) at 20 °C. The mobile phase is a gradient of A (dichoromethane/methanol with ammonium acetate/acetonitrile 5:20:75 (v/v)) and B (ultrapure water) with a flow rate of 0.5 mL/min. The optimized UPLC method allows excellent peaks separation. Shrimp by-products (lipid fraction of shrimp waste, head and shell of cooked and raw shrimp) have been analysed. Moreover, low density polyethylene plastic films produced by extrusion with different amount of the lipid fraction of shrimp waste were prepared and tested regarding migration into fatty food simulants. Migration tests were carried out with isooctane and ethanol 95% (v/v), both alternative fatty food simulants. No migration was detected at the conditions tested, which are conventionally considered the most severe when the food contact material is intended for use at room temperature.