Should I add preservatives to jams/fillings before or after cooking?

should I add potassium sorbate or sodium benzoate to jams/fillings before or after cooking?

I understand that the sublimation temp of those preservatives is about 60-80 degrees(celsius),

and their melting point is about 120-140 degrees.

I cook up to 94 degrees and drop temperature is 70-75 degrees.

I am afraid that I loose them as volatile compounds.

d guy,

Welcome to the forum. Introduce yourself to the community in "New Members" topic.

About your doubt, I can not give you a precise answer, but I can tell you that some critical ingredients could be added at later stages in the process.

For example, citric acid could be added separated from the inicial mixture to give precise pH control, or some volatile flavoring can be added after evaporation stage to avoid evaporation loss.

If you can´t control/measure the amount of loss, and have some mixture stage after evaporation, add the preservatives after.

Rgds.

Thanx for the response RuiM.

I worry that after gelation occurs the preservatives might not be ditributed evenly all over the batch because of the viscosity.

I am trying to avoid "last minute additions" in the process.

I'll ask it like this,

since these preservatives are very common, how do you(addressing everyone) use them in cooked foods?

Does anyone have serious reference or personal experience about preservative loss due to volatilty?

Dear dguy,

I have zero experience with making jam but I did try a brief net search for yr OP. Somewhat surprisingly found little direct info other than a few caveats regarding additive health issues. No doubt the heavyweight food processing texts would say more.

However following yr latest post, I hv attached one seemingly knowledgeable procedure for a specific jam product which I did notice. More of a “home” methodology but maybe implies one answer to yr query.

Apple Jam Procedure.pdf   305.42KB   55 downloads

Rgds / Charles.C

thanx charles.
when it comes to jams based on pectin i agree with you, since pectin harden when it cools.
I'll do that for the jams.
when it comes to fillings,which are based on modified starch I still have the problem of distribution.
I myself found a link saying the same thing(page 7)

http://www.lotioncra...ium_Sorbate.pdf
I was surprised not to find anything in text books, besides the link above.

I sent my filling to external lab(sample added before cooking,and one after) and got non-reliable results(got more the I put their in the first place). Also the sample after cooking had less preservatives than the one before cooking.

Ladies and gentlemen, I come to conclusion.

I made a small experiment of my own.

method:

I cooked sucrose+water+citric acid+potassium sorbate+sodium benzoate thoroughly up to 95C and evaporated about half its water content(using seb saucier). this sample was called "evaporated sample"

then added the same weight of dry substances, and added water just to reach the final weight of the first sample. the substances were heated in a small covered cup in a microwave, so there was no evaporation. this sample was called "not evaporated sample".

I sent it again to the laboratory for a chemical test(Nestle LI 00-031-2).

The results were that both sodium benzoate and potassium sorbate lost about half of their quantity during evaporation.

I understand that this small experiment has no statistical significance, because I had only 2 sample, but that about ended the resources I could spent on the subject.

Preservatives should added at the final step of the cooking process.

I would ask the question as to do you even need preservatives?  Are you talking about commercial jam making or for home use?  Ive been making jam for some time now.  Jam boils at a fairly high temperature and by the times its ready its pretty much sterile, so adding it to sterile glass jars means that for home use at least, you do not need preservatives.  I still have a jar of jam in my fridge that I made early last year and it still hasnt gone mouldy.