Short answer is that "it depends".

If you can process your harvested samples immediately, there is no need to do that from a freshness perspective.

However, if you cannot process everything rapidly, then best to freeze and freeze dry to preserve the samples until you can process them. Some things don't maccerate well when dry, so sometimes best to chop them up when wet.

Also - if you have high moisture samples, it may be better to freeze dry these before extraction so that there is less water in your solvent extracts.

Watch out - high sugar / fat containign samples (fruits mainly) do not freeze well due to the high sugar / fat levels working like an antifreeze.

Dear Jonathan,

Generally yes, however other drying strategies are equally valid (e.g., drying in an oven with air circulation). The idea is to eliminate moisture for proper concentration calculation.

Yours sincerely.

As my colleagues says, it depends !

I'll just add an important detail in favour of a freeze dry approach.

In some matrixes, when harvested, several enzymes can begin their work and transform some compounds, or degrade some of them. For example, glucosinolate compounds are found in fresh plant but degrade quickly after harvest.

So beware when you work with plants ! Freeze drying can prevent this phenomenon, but it'll take time and have a cost... Si it's always a balance between pro and cons ! :)

Maël

Rob Darrington Lucas Almir Cavalcante Minho Maël Gainche

thank you so much for your insights!