The moisture content of foods can have a significant impact on factors such as the taste, texture, appearance, shape and weight of the product. This has implications for legal and labeling requirements, economically important requirements, shelf life of foods or food products, food quality measurements, and food processing operations.
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Deviations from the optimum moisture content can have serious consequences on many qualities of the food product, which can have implications not only for the quality of the product but also for its safety. For this reason, water content analysis has become a key part of the food industry.
What does moisture content mean?
Moisture content refers to the number of water molecules that are incorporated into a food product. Moisture can enter a product in many ways, it can be related to the method of production of the product, the atmospheric humidity in the food production area, the method of packaging the product, or it can be related to the storage space feeding method.
Why is moisture analysis important in the food industry?
Water content has a lot to do with the characteristics of a food product, including its physical appearance (shape, color, etc.), texture, taste, weight (which can have an impact on cost). plus factors that affect product shelf life, freshness, quality and resistance to bacterial contamination.
Too much water in a food product can lead to an increased rate of microbial growth, which can not only spoil a product before it hits the shelves, but also reduce the length of time it can stay fresh. This has a significant impact on whether or not products reach their advertised expiration date.
All of these factors influence the success of a food producer. Maintaining the specific characteristics of a product is critical to customer satisfaction, loyalty, and ultimately revenue and profits.
Each factor that can be influenced by moisture content is discussed below, taking into account its impact on the food industry.
1. Legal and labeling requirements
There is legislation surrounding certain food products that places specific limits on the amount of moisture that can legally be present in the product. Cheddar cheese, for example, is one such controlled food product, and its moisture content should not exceed 40%. For food producers of controlled products, moisture analysis is essential to meet legal requirements.
2. Retention period
Shelf life is important because it informs consumers when food is safe to eat. Moisture content influences shelf life because increasing water in a product increases its susceptibility to microbes, which can rot and damage food. Therefore, maintaining a known level of moisture in a product allows producers to accurately estimate the shelf life of a product, thereby helping consumers not to consume spoiled food.
3. Food quality
As discussed above, moisture content can have dramatic effects on the quality of a food product. This can have an impact on the taste, texture and appearance of a product. Manufacturers strive to keep products as consistent as possible to ensure the same quality and avoid waste. The control of the moisture content plays a key role here.
4. Food processing operations
Too much moisture in food products can cause condensation in machines used to process food. This can lead to corrosion or blockages, which can lead to unplanned downtime while machines are being repaired. It can slow down production and increase production cost due to wasted hours.
Therefore, performing water content analysis using a robust and accurate method is essential for food production businesses. Failure to comply with this step in the food production process could have a negative impact on the quality, safety and profitability of the products.
How is moisture content measured?
There are different methods to measure the water content of foods:
A high boiling point solvent is mixed with the food sample and then distilled to obtain a quantity of water. The downside to this method is that it can potentially cause unwanted chemical reactions.
2. Dielectric method
This method consists of exploiting the electrical properties of water to measure the moisture content. The change in electric current flowing through a sample is measured to obtain a measurement. This method is often used as a control process to ensure that the known moisture content is maintained.
Hydrometry is a method that provides a measure of moisture content by measuring the specific gravity of a food sample. This technique is limited to certain types of food, such as drinks, brines, and sugary solutions.
4. Infrared spectroscopy
This method determines the moisture content by measuring the absorption of radiation by molecules in a food sample. The amount of energy reflected or absorbed is a key indicator of the amount of water present in the sample.
Measuring the refractive index in a food sample can give a measure of the moisture content. However, it is most often used to determine the sugar concentration of food samples.
6. Chemical analysis
Foods with low water content benefit from the chemical analysis method. The disadvantage of the technique is that it requires concentrated chemicals which have characteristic strong odors.
7. Drying in the oven
The last method is oven drying, where a food sample is weighed before and after being dried in an oven. This change in weight indicates the level of moisture that was contained in the sample. However, due to the long drying process, which can take up to 18 hours, it is often only used for establishing a benchmark.
Moisture analysis is essential for the food industry to control food quality, as well as shelf life, in addition to helping food manufacturing companies meet legal and labeling requirements. .
In addition, careful moisture content analysis can be used to protect their income and profits by ensuring product consistency and safety, minimizing waste, and reducing unplanned downtime of food production machinery.
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Land, K. and Steinberg, M. (1980). Calculation of the moisture content of a food system formulated for a given water activity. Journal of Food Science, 45 (5), pp. 1228-1230. onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.1980.tb06527.x