1. Methods for Reliable and Accurate Measures of pH
pH Measurement
Methods for Reliable and
Accurate Measures of pH

2. Definition of pH
A way to measure acids (acidic) and bases (alkalinity) in food.
Expression of the concentration of hydrogen (H+) and hydroxide ions (OH-) in an aqueous solution (water-based).
Uses a scale between 0 and 14
A pH Measurement

3. Measurement Method– Litmus Paper
1. Used by dipping litmus paper into solution
2. Turns yellow to red in acidic solution (acid)
3. Turns green or blue in alkaline solution (base)
4. Easy method
5. Not completely accurate
A pH Measurement

4. Measurement Method – Indicator Strips
Dip the strip into the aqueous (liquid) food being tested for a few seconds.
Remove strip from test solution and compare color segments to center color printed on the strip.
A pH Measurement

5. Measurement Method – Indicator Dye
Organic dyes
Done with dropper
Acidic (acid) -- pink or red
Alkaline (base) -- green or blue
Neutral solution may turn lilac
Not totally accurate
A pH Measurement

6. Measurement Method – pH Meter
Digital reading
Accurate
Some units are expensive
Easy and sanitary
A pH Measurement

7. Measure Method – Titratable Acidity
1. Add base with know pH to an acid.
2. Use burette.
3. More difficult to calculate.
4. Use if have chemistry knowledge.
A pH Measurement