Acidity Testing in Food

Accurate Acid Content Determination and Acidity Measurement in the Laboratory

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Acidity Measurement in Food


 

Acidity Analysis Guide
The acidity of certain foods and drinks compared to other common household products
The acidity of certain foods and drinks compared to other common household products
pH Measurement

Item

pH range

Ketchup

2.00 – 2.60

Vinegar

2.40 – 3.40

Fruit jellies

3.00 – 3.50

Strawberries

3.00 – 3.90

Apples

3.30 – 4.00

Apple juice

3.35 – 4.00

Fruit jams

3.50 – 4.50

Pickled cucumbers

4.20 – 4.60

Tomato puree

4.30 – 4.47

Tomatoes

4.30 – 4.90

Cucumber

5.12 – 5.78

Tofu

7.20

 

pH Sensors
Titrating Total Acidity

Acid base titration

Acid-base titrations utilize pH sensors to quantify the titrant necessary to react with malic, tartaric, citric, acetic and other organic acids present in fruit, juices, vinegar-based condiments and wine, to name a few. It can be determined by titrating the sample with a strong base that neutralizes acid present in the sample.

Redox titration

Generally, redox titrations are performed for ascorbic acid determination in beverages and sulfite content determination in wines. Ascorbic acid is titrated with 2,6-dichlorophenolindophenol (DPI) where it undergoes a redox reaction and exchanges two electrons. The electron exchange is detected by a sensor, and once all the ascorbic acid is consumed by a titrant, the change in potential of the sensor is observed, indicating the equivalence point of the titration.
 

Colorimetric titration

For a food or beverage acidity determination, acid-base titration can also be monitored by the change in a color indicator such as phenolphthalein. Such a titration is performed using a strong base. As soon as the acid in a food sample is neutralized, a Phototrode sensor  observes the exact color change, which corresponds to a change in potential. This change in potential provides the titration’s equivalence point. Phototrode sensors can also be used for precipitation or turbidity measurements.

Sensor for Total Acidity Determination

Pipettes

Sample preparation is often liquid-based, and METTLER TOLEDO offers a number of systems for handling solutions ranging from aqueous to highly viscous and volatile. Particularly in F&B where processing volumes can be as large as 20 mL or as small as 20 µL, we offer a comprehensive array of single- and multi-channel pipettes, benchtop systems and consumables to meet almost any sample preparation need. Learn more about pipettes.
 

Moisture analyzers

Food industry grading often includes determining both acidity and moisture content to fulfill quality and safety parameters. Our instruments help you perform fast and accurate moisture determinations with features such as integrated control limits, automatic data transfer and user guidance for ease of use, while our innovative QuickPredict functionality enables informed results prediction for faster moisture analysis and decision-making. Learn more about moisture analyzers.

Analytical balances

Accurate sample preparation is a crucial prerequisite for obtaining reliable measurements. With gravimetric sample preparation, both the solid and solvent are weighed-in, providing much more accurate solutions. This helps to eliminate variability among samples and reduces out-of-specification results. You gain increased confidence in your analytical outcomes and more reliably meet safety and quality-control requirements. Learn more about analytical balances.

Acidity in Bread
Acidity in Beer
Acidity in Corn Flour
Acidity in Milk
Acidity in Honey
Acidity in Wine
Acidity in Fruit Juice


 

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