Titratable acidity Flashcards
Titratable acidity
The total acid concentration contained within a food sample (total acidity). Is determined by titration of the food and is a good predictor of acid impact on flavor.
Food acids are often ______, but can also be _____ and _____.
Organic acids, Phosphoric and carbonic
4 effects of acids on food functionality.
Flavor, shelf life/preservation, texture, and food colors
titratable acidity and sugar content are used as an indicator of what?
Maturity of fruits
Titratable acidity is determined by….
neutralizing the acid present in a know weight or volume of product with a standard base
Potentiometric end point
End point of titration is when the titration reaches a target pH.
Colorimetric end point
End point is determined by a color change of an added indicator dye.
Colorimetric end point
End point is determined by a color change of an added indicator dye.
Neutralization reaction
Reaction of an acid with a base to form water and a salt
Equivalent weight
The molecular weight divided by the number of equivalents in the reaction.
Molarity
The number of moles of solute per liter of solution.
Normality
The number of equivalents of solute per liter of solution.
Normality
The number of equivalents of solute per liter of solution.
Phenolphtalein changes color to _____ between the pHs ___ and ____.
pink, 8-9.6
Phenolphtalein changes color to _____ between the pHs ___ and ____.
pink, 8-9.6
Stock NaOH
50% NaOH in CO2 free water
What is KHP commonly used for?
To standardize the titrant.
Titratable acidity is stated in terms of the ________ acid .
Predominant
What is the titratable acidity of fresh milk?
0.18-0.23%
What is the titratable acidity of fresh milk?
0.18-0.23%
Volatile acidity
Is determined using 2 titrations, one before and one after boiling off volatiles on low heat. Volatile acidity = titratable acidity - fixed acidity
Volatile acidity
Is determined using 2 titrations, one before and one after boiling off volatiles on low heat. Volatile acidity = titratable acidity - fixed acidity
What is the titratable acidity and pH of fresh milk?
0.18-0.23% and 6.4-6.6
Volatile acidity
Is determined using 2 titrations, one before and one after boiling off volatiles on low heat. Volatile acidity = titratable acidity - fixed acidity
HPLC
High performance liquid chromatography
Methods of determining tiratable acidity
Basic titration, automatic titrators, HPLC, Electrochemical methods
Methods of determining tiratable acidity
Basic titration, automatic titrators, HPLC, Electrochemical methods
pH
Is a measure of the acidity or bacisity of an aqueous solution. Is defined as the negative logarithm of the hydrogen ion concentration.
Most foods are in the pH range of ____.
4.6-7
Methods for measuring pH.
Litmus paper, pH indicator strips, pH meter/probe
Alkaline error
At pH above 10, high con
Alkaline error
At pH above 10, high concentrations of ions affect the structure of the electrode, and a lower pH value is measured than it actually is. Alkaline error increases with temperature.
Acid error
At pH below 2 the membrane absorbs acid molecules and decreases the activity of the H+ ions, and the pH measurement is higher than it should be.
Alkaline error
At pH above 10, high concentrations of ions affect the structure of the electrode, and a lower pH value is measured than it actually is. Alkaline error increases with temperature.
Acid error
At pH below 2 the membrane absorbs acid molecules and decreases the activity of the H+ ions, and the pH measurement is higher than it should be.
