Yeah, you're right because i think defrosting it in a microwave oven will just destroy the compounds in the extract, high temperature will cause chemical reaction which we don't want. Try defrosting it in a room temperature and just leave it there until it will defrost. the essential compounds in the extract will not be gone or be broken because you are not placing it in the intense heat.

~ I hope it helps.

Defrosting the extract indrastic temperatures (sudden temperature change) only causes denaturation. u can gradually defrost it in RT, that will help you. All the best.

Thanks a lot, but i think that defrost in RT because of long time can change it drasticly. I was searching and found that defrosting in 40 Centigrade for a short time is best way.

Plant compounds are often highly resistant to temperature changes, this helps plants to adapt to different environmental conditions. But once that you are working with hydroextracts you have to be very careful with the growth of micro-organisms (like bacteria and fungus) they growth fast at room temperature and may change your extract composition. So my advise is to defrost your sample in a water bath (maximum 50ºC) as soon as you get it defrost filtered with a 0.2um filter to eliminate micro-organisms and spores. Then keep it on a fridge until use.

good luke

Change to the extract depends upon the type of compounds it contains. Some might be photosensitive, even exposing it to light might decompose the compound. Some are heat sensitive. Antioxidant compounds are usually photosensitive. You must take care not to expose your extract to too much light. So, my advice is you might have already had an idea what type of compounds you might encounter in your extract. Check the literature for how to deal with these class of compounds. Most of the compounds can withstand temperatures up to 40 C. You might think about using a rotavap, although it takes a while to dry the aqueous extract but the best method regularly used for this purpose.

Hope it helps.

Thanks for your care, i did it, and now I put it in the vaccum oven.

Changes in the hydroextract can also be due to the type of freezing carried. Rather than normal freezing your hydroextracts in freezer, try doing it with Nitrogen if possible. Using nitrogen is an expensive method but will also assure your extracts free from any sort of microbial contamination also. This way, you can keep the extracts in good condition & for a longer duration without any harm. And than further allow it to defrost at RT & use vacuum oven. This is the process which we followed during our research & does not affect the any functional antioxidative properties ...

You have not mentioned the method of preparation of the hydroextract. If you have used some thermal methods for your extraction, then I believe you can dry the material at a temperature not exceeding 40 degrees. But if you had used some non thermal methods for extraction, then I suggest you to go for drying the product in a desiccator. Follow the literature to understand the class of compounds already reported for that particular species. Normally, the aqueous extracts contain carbohydrates, proteins and amino acids, tannins and phenolic compunds, flavonoids and ocassionally some glycosides. These class of compounds are normally heat stable.

For organic material can be useful defrost at 37° C. I.E. serum at - 20? put directly in 37°C.

Same method for living cells: -170 to 37°C.

Room temperature to 37 ºC and darkness, if possible