This report summarizes a process development study for the extraction of extra-virgin cod liver oil (EVCLO) on a laboratory scale. The general approach was to develop an accelerated traditional rendering process that achieves high oil yields at ambient (17°C) temperature.

Fresh Atlantic cod (gadus morhua) liver was collected and delivered by Jerseymen Island Fisheries Inc. to the Marine Institute following detailed handling and tightly coordinated shipping protocols aiming at providing ultra-fresh raw material. After primary particle size reduction, the fatty tissue membranes were weakened using treatments such as sonication and freezing, before the tissue was placed into a vacuum rendering chamber for 24 hours. Different rendering set-ups were compared and a conceptual design of a pilot-scale chamber is presented.

The collected oil was rated based on yield, smell, colour and clarity and the best oil samples were selected for in-depth analysis. The oil was of excellent quality for appearance and freshness parameters as well as for the nutritional profile (fatty acid composition and vitamin content) and heavy metal content. Elevated PCB concentrations were detected, which must be removed from the product.

The report concludes with a recommendation of a phase II study to investigate process optimizations, scale-up and refining.

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