Hello,

When we determined the dry weight for fatty fish (over 20%), we used one old standard method: mixing of sample with sand (approx 1.0 mm diameter) and drying it at 105.0 C in oven (3 hours approx).

I the case of freeze -drying I would recommend to increase the temperature in the end of the process up to 40 C or higher as soon as some water will remain in tissues at low temperature drying (It can form a matrix with solids which is very difficult to evaporate).

Regards

Ignat

When I was in Universidad Politécnica de Valencia (Spain) during my sabbatical stance in 2007-2008, I assisted to a conference of a Norway Professor on fish drying with dry air at 1-5 oC in a heat pump tray drier. The air was in a close cycle of humidification (in drying chamber) and des-humidification in a cool system. Unfortunately, I don’t remember the name of Norway Professor but he was invited by ASPA Group of “Departamento de Tecnología de Alimentos”.

Probably, it was Trygve Eikevik or somebody from his research group?

Sorry for off-top.

To avoid freeze drying or oven drying you could use some strong desiccants and cut the liver very thin to enhance the water exchange. Also you can use a fan to speed up the drying process.

To prevent spoilage you can place the installation in the refrigerators. I constructed such installation using a large lab desiccators and placing inside a fan from computer. The fan was alimented from a phone charger.

Hadil Ossama Elsayed : Hi, curious to see what worked for you finally. I am having a similar issue, I want to dry shark liver samples for mercury analysis. I have already freeze dried and secondary dried (48 hrs) them. But some of the samples have a thick oily layer on them. Any advise appreciated. Thanks.