Ash Content in Food Analysis

Ash content in food is essential to determine so that the full nutritional value, quality and stability of the food can be established. 

In this article we define the ash content in food, methods to determine the ash content and explore Precisa’s prepASH for ash content analysis.

What is ‘Ash Content’ in food?

The ash content in food refers to the minerals and inorganics left after the food sample has been heated to a very high temperature removing moisture, volatiles, and organics. The most common minerals and inorganics are calcium, magnesium, sodium and potassium but in smaller quantities there can also be traces of manganese, zinc, iron and others.

Food normally has around 7% ash content, however this can vary. Ash content in food can be an indication of how much processing has taken place as natural foods have a lower ash content compared to more processed food. Pure oils and fats can have an ash content as low as 0% but processed dried meats can contain up to 12% ash.

Why Measure Ash Content in Food?

Measuring the ash content in food is important for a few reasons. Ash content can affect different characteristics of food including physiochemical and nutritional properties.

Determining the ash content in food samples is part of the proximate analysis necessary for nutritional evaluation. This ensures the safety of foods, making sure there are no toxic minerals present. The ash content in food can also impact the taste, texture and stability of foods so it is vital to know the mineral content for quality control purposes.

Determination of Ash Content in Food Sample

To determine the ash content in food, the sample must be heated to a very high temperature, around 600 °C to remove all moisture and volatiles (as vapour) and organics (as carbon dioxide and oxides of nitrogen). The remaining inorganics can then be analysed as necessary.

Using Precisa’s prepASH for thermogravimetric analysis makes this process quick, easy and reliable in just 3 steps:

1. Method Selection and Weighing

Select your predefined method and place the crucibles into the sample holder. The crucibles will automatically tare, and you can then start loading and weighing your samples.

2. TGA Analysis

Carry out the ash content analysis by simply pressing start. The prepASH will run the programme without any need for user intervention. It will continue with measurements until the ‘How to Stop’ criterium has been reached. If you wish, you can follow the analysis live on the connected PC. Once the programme has finished running, allow the system to cool down before opening the lid.

 3. Report Preparation

Once the analysis is complete, you can print out a copy of the report or save it to your computer. The report outlines all parameters, graphics, weighing curves and results for each sample. As the weighing curves are recorded over time, an automatic end time is established, controlling the drying and ashing process.

Ash Analysis in Food with Precisa

Precisa’s prepASH Thermogravimetric Analyzer (TGA) is ideal for the determination of ash content in your food sample.

The prepASH combines a drying oven, desiccator, muffle furnace and analytical balance in one unit, minimising the equipment you need to carry out your ash content analysis.

To save you time, the prepASH is able to hold up to 29 samples per cycle, and the built-in balance will automatically weigh samples and record the results. The fully automated system will operate itself once it has been loaded and started so samples can be measured at any time. With permanent recording and automatic recording of results, you can access data at any time.

If you’d like to hear more about how the prepASH could be beneficial to your lab, contact us today and we will be happy to discuss your requirements further.

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