Direct Moisture Determination of Food and Feed Using a TGA Analyzer

The analysis of moisture content within food and feed provides an indication of their quality, lifespans, and the presence of nutrients. It is important the moisture in these products is controlled to ensure their safety, as too much moisture can encourage the appearance of bacteria, improve the management of manufacturing procedures, and follow specific regulations. A direct moisture determination of food and feed can be undertaken through the application of a thermogravimetric analyzer. By increasing the temperature of a sample, an opportunity arises to understand its levels of moisture. This is through observing any changes in weight caused by the evaporation of liquid. Join us as we consider thermogravimetric analyzers in more detail and how they are used to make direct moisture determinations for feed and food.

Introduction to Thermogravimetric Analysis

Thermogravimetric analysis (TGA) is a type of thermal analysis where the mass of a sample is monitored as a function of temperature or time under a controlled atmosphere. Its primary use is to characterize materials and assess their thermal stability. This is through measuring the weight changes that occur as the sample is heated or held at a constant temperature. Thermogravimetric analysis is particularly useful for the analysis of polymeric materials, including foods and feeds, where moisture content is a critical parameter.

Principle of Moisture Determination Using Thermogravimetric Analysis

In the context of moisture analysis, thermogravimetric analysis measures the amount of weight loss as a sample is heated. This is typically in an inert atmosphere to prevent oxidation. The procedure involves heating the sample from room temperature to a predetermined endpoint. Temperatures range usually between 100°C to 160°C, depending on the volatility of other components in the sample. This temperature is sufficient to evaporate water but low enough to prevent the decomposition of most organic substances.

During a TGA moisture analysis, the sample’s weight is continuously recorded as the temperature increases. The weight loss observed during this process is primarily due to the evaporation of moisture. Plotting the weight loss against temperature helps distinguish between different types of weight loss events. This includes the loss of water versus the decomposition of organic components.

Methodology of Moisture Analysis in Thermogravimetric Analysis

The typical methodology for conducting moisture analysis using thermogravimetric analysis can be outlined in several key steps:

• Sample Preparation: Samples are prepared to a known mass. That way the measurements of the changes in weight are accurate and representative of the whole sample.
• Baseline Determination: Before introducing the sample, a baseline is recorded at the start temperature. This is to ensure any drift in the balance or other systemic errors are accounted for.
• Heating Protocol: The sample is heated according to a specific temperature program. Ultimately, the rate of heating and the final temperature are critical parameters. They must be optimized based on the nature of the food or feed being analyzed.
• Data Collection: Data on weight loss is collected continuously as the sample is heated. Advanced thermogravimetric analysis systems can automate data collection and analysis, enhancing both accuracy and efficiency.
• Analysis and Interpretation: The thermogravimetric curve is analyzed to learn about moisture content. Here the area under the curve is integrated to quantify the total moisture. This area corresponds to the temperature range where water loss occurs.

Applications of Thermogravimetric Analysis in Food and Feed Analysis

The versatility of thermogravimetric analysis allows its application in various aspects of food and feed analysis:

• Quality Control: Thermogravimetric analysis provides a quick and reliable method for moisture content determination. This is crucial for assessing the quality and shelf life of food products.
• Nutritional Analysis: Understanding moisture content is essential for calculating other nutritional parameters correctly, such as caloric content on a dry basis.
• Research and Development: New food formulations often require rigorous testing to optimize shelf life and stability.

Advantages and Limitations

Advantages:

• Accuracy and Precision: Thermogravimetric analysis offers high accuracy and precision in moisture determination, which is crucial for quality control and regulatory compliance.
• Speed: Compared to traditional drying methods, thermogravimetric analysis is considerably faster, providing results in minutes rather than hours.
• Minimal Sample Preparation: This technique requires minimal sample preparation. Therefore, the risk of errors or contamination is reduced.

Limitations:

• High Initial Cost: The primary limitation of thermogravimetric analysis is the high cost of equipment and maintenance.
• Technical Expertise Required: Proper operation and interpretation of TGA data requires technical expertise in thermal analysis techniques.

Undertaking Direct Moisture Determinations with Thermogravimetric Analysis

Thermogravimetric analysis is a reliable technique offering in-depth insights on the levels of moisture in a sample. For those requiring the use of feed, such those for pets, this information can help ensure the feed is safe for use and contains the right amount of nutrients. Making a moisture determination through a TGA analyzer can also be useful for those wanting to understand how to manage the quality of their food products. TGA analyzers used to assess food, like chocolate and flour, or provide a moisture determination are located on our website. At XRF Scientific, the xrTGA 1100 is available and can be used to examine moisture within different materials. It has a large throughput, having the capability to undertake an analysis of 30 materials at a time, is designed to be quick with heating and cooling, and complies with CE regulations. The xrTGA 1100 can be found on our website, alongside additional information on thermogravimetric analysis. Thermogravimetric analysis is the method needed to ensure the moisture levels of your materials are at a satisfactory standard. So, utilize the capabilities of our equipment to discover more about your samples and how they react under thermogravimetric analysis.