How to measure salt content in food using titration

Measuring salt content in food is an essential stage in food production for a wide range of products, including butter, crisps, pesto and ketchup. We explain why measuring salt content in food is important and the ideal method for salt measurement below.

Why do companies need to measure salt content in food?

Salt content has an impact on the taste, texture and formulation of food products. In addition to salt used to directly provide flavour to food, such as crisps, salt content can also be due to leavening agents such as sodium bicarbonate or preservatives such as sodium nitrite, nitrate and benzoate.

Accurate measurements of salt content in food is important for the packaging of food products, where salt, expressed as sodium chloride, is listed alongside other nutritional information to allow consumers to make informed choices about the food products they buy. In the UK it is a legal requirement for food companies to list this nutritional information with percentage reference intakes, ideally with the recommended traffic light colour system.

Testing salt can allow you to be certain of the salt content of your product, ensuring that you are adhering to government guidelines and presenting a safe measure of intake for the consumer.

Why is salt content a concern?

Salt plays a vital role in transporting water around the body, and in transmitting messages between the brain and the rest of the body. Too much salt in our diets can lead to problems such as water retention, raised blood pressure, and a higher risk of heart attack, kidney disease or stroke.

Many everyday foods are not obviously salty, but they can contain high amounts of 'hidden salt' and with growing health concerns surrounding salt posing significant health risks, people are increasingly becoming more health conscious. 

Current national health guidelines state the reference intake of salt for an adult should eat no more than 6g of salt a day (2.4g sodium) – around 1 teaspoon.

How to measure salt content

Titration is the ideal method to measure salt content in food products. Using an automatic titrator, such as the HI-931 Automatic Potentiometric Titrator from Hanna, makes testing for salt simple, providing high-accuracy and reliable measurement of salt content alongside other important parameters such as acidity and malic acid in a wide range of food samples. We provide full training on purchasing the HI-931 titrator as required, saving you time on testing.

The test for the particular food type you need to measure can be directly programmed into the titration system and saved for future use. This allows you to easily select your method from a menu after creation with no need for extensive manual setup when switching between food products. 

Example titration for salt content in butter

To perform a titration for salt content in butter with the HI-931 titrator you will need the following:

• A 200mL beaker
• HI-5148B Silver Billet electrode
• HI-70422 0.1M Silver Nitrate
• HI-70427 1.5M Nitric Acid
• A waste beaker
• A balance to measure your sample
• DI water in a rinsing bottle
• A 2mL pipette

If you do not have a method prepared for salt in butter, you can create it at this point. Our experts are on hand to support you in creating new methods.

How to measure salt content in butter with the HI-931

1. Turn on the titrator and select the ‘Salt in Butter’ method from the method list
2. Place the aspiration tube into the 0.1M Silver Nitrate bottle
3. Place the waste beaker under the dosing tip
4. Measure a 2-5g sample of butter, saving the weight
5. Add 150mL of hot DI water to the sample and swirl to mix thoroughly
6. Pipette 2mL of 1.5M Nitric Acid into the sample and swirl to mix
7. Remove the electrode cap, place the sample underneath and lower the assembly down, ensuring the electrode, stirrer and temperature sensor are submerged
8. Press ‘Start’ and add weight to begin titration, and select ‘View Curve’ to view the titration curve
9. ‘Titration Completed’ will display once titration is complete
10.  Remove the electrode assembly from the sample and rinse with DI water

To prevent damage to your burette we recommend priming with DI water if your titrator will be unused for two hours or longer. 

In the case of solid samples, such as cheese, the use of a hand blender is recommended when combining room-temperature DI water with the sample to ensure it is homogenous before titration for salt content or acidity.

Buy Titrators from Hanna Instruments UK

Hanna Instruments are specialists in titration, with a wide range of automatic titrators to suit different purposes and industry requirements.

To enquire about our range of titrators for salt content, acidity and other key food parameters, get in touch with our experts directly at sales@hannainstruments.co.uk or on 01525 850855. We can advise you on the best titrator to measure salt content in food accurately.