pH Sample Preparation - How To?
This may be a silly question, but why do you want to measure the pH of a dry mixed product? When prepared by the customer, does the final product have to meet a pH spec?
Bawdy.
rgds
AS Nur
We recently purchased a simple pH Test Meter and I would like to know how to prepare a dry, bake mix to be tested. Is there a set weight of mix to be added to a set volume of distilled water? I've seen a few bits of information that seem to contradict one another. 5 g mix to 10 ml distilled water perhaps. Many thanks for your assistance.
Dear dan,
It's a good question. I don't recall ever seeing a "universal" preparatory method for foods, or even solid items per se.
Not my area of expertise but the nearest i could find to yr situation is the procedure below for flour taken from one of the classic texts - Pearson - chemical analysis of foods (1962).
Shake 10g or 20g of flour with 100 ml H2O and allow to stand for at least 30min. filter and determine the pH of the filtrate either visually or with a pH meter. The pH of flour usually falls within the range 6.0 -6.8. Bleaching of flour with chlorine gas causes a fall in the pH value.
I saw similar quantities used elsewhere for bread and sourdough but without filtration, maybe depends on the electrode type ?. Easy to compare i guess
Baking people here probably have better idea on this.
Rgds / Charles.C
PS I think some labs would automatically blend mixtures as a routine procedure.
To illustrate the complexities which can occur for other (rather different) products, can try this link -
http://www.accessdat...h.cfm?fr=114.90
Note that the proportions used are sort of reversed for reasons as per the comments in (ii) presumably. Might be interesting to compare results with Pearson procedure.
Iv read that they should be tested at 20 degrees
How do companies measure the ph if the product is hot, is it that samples are taken to be tested once they have cooled
Does it matter that the batches may be packaged by the time the ph test is done
As long as it's in the perimeters
Iv read and understand procedures on the handling and calibration of a test meter but need to put in place a procedure to test sauce and garlic products which are cooked at high temps, then train and monitor the testing