KEY METHODS FOR FOOD ANALYTICS

Plus: Measuring Analytes, Food Labeling Draft & Solving Production Challenges

The long-awaited SA Regulatory food draft labeling R2986 is pending and looks set to take effect in 2025.

The anticipated South African Regulatory food draft labeling R2986 is expected to take effect in 2025. This new draft mandates front-of-pack warnings on pre-packaged foods with high levels of sugar, salt (sodium), saturated fat, and artificial sweeteners.

To comply with current and upcoming safety and quality regulations and improve product quality and profitability, measuring relevant analytes throughout the food and beverage production process is essential. These requirements are based on the specific needs of the South African market and are usually harmonised with international standards. Quality and safety also require continuous monitoring of factors like temperature, pressure, humidity, moisture, pH, and other parameters that impact the manufacturing process.

Relevant analytes in food products

Determination of sugar/carbohydrate content

The total sugar content is measured as a sum parameter and expressed as brix value, determined either as density or refractive index. The Bellingham & Stanley high-performance digital handheld refractometer offers a wide range of scales for various applications. Additionally, the NIR method, using Buchi’s NIR Proximate, can determine sugars like sucrose in chocolate or lactose in milk products, among other applications. Total carbohydrate content of food is typically calculated by difference, rather than by direct analysis. Another parameter within the carbohydrates is the total dietary fibers (TDF). They are determined with enzymatic-gravimetric methods. Different fiber types, such as ADF or NDF, can be determined by NIR spectroscopy.

Determination of other analytes in food products

Depending on the food matrix, additional analytes; such as oil, salt or pH, mV, ORP and temperature measurements, influence the process quality. The Thermo Scientific Orion VersaStar Benchtop meter, with pH/ISE, conductivity, and dissolved oxygen/RDO modules, meets demanding applications for pH, ion concentration, conductivity, dissolved oxygen, and temperature. Orion Star Com software can also transfer measurements and calibration data from the meter to a computer easily.

Alcohol content must be determined in food and beverages due to legal and taxation purposes or for monitoring fermentation processes. Alcohol determination can be achieved using a steam distillation technique combined with a density meter or via NIR analysis. The content of volatile acids is an important parameter for wine quality. Volatile acidity can be determined by steam distillation. Other analytes, such as sulfite are monitored as potential allergens. Cyanide content is assessed in almond-based products due to potential toxicity. Vicinal diketones are quality indicators in beer production, whereas essential oils, which are often used for food flavoring, are found in citrus juices.

Determination of shelf life & stability

High water activity content can enhance microbial activity, leading to early food spoilage. The Novasina LabMaster water activity meter can be used to investigate the source of product spoilage, texture failures, or rancidity. Seasonal differences, different climatic zones, and a variety of temperatures during manufacturing, transport, storage, and use can affect the food products’ shelf life and stability. Weiss Technik climate test chambers will test the influence of temperature and humidity on food properties, function, and lifespan. Labotec’s IncoTherm incubators and low-temperature incubators are suitable for microbiology, QC, and stability testing, with sizes ranging from 40-liter benchtop to 700-liter floor-standing incubators, operating from 37°C to 110°C.

Determination of fat content

Fat is an important parameter in food products, such as oilseeds, meat, dairy, and others. Fats have a high energy content, play a vital role as transporters of flavour, and substantially contribute to the mouthfeel of food. Soxhlet extraction is the reference method for the measurement of free or total fat, and is preceded by an acid hydrolysis step. The fat is then extracted with an organic solvent. Other methods for fat determination include NIR, NMR, or specific extraction methods depending on the sample type (e.g. Mojonnier for dairy).

Determination of protein content

Proteins are essential nutrients for both humans and animals and an important quality parameter in food production. The primary reference method for measuring protein content of foods is the Kjeldahl method. In this method, protein is broken down to ammonia, the nitrogen content is measured and this value is multiplied by a specific factor to obtain the protein content. Besides the Kjeldahl method, NIR is a well-established technology to determine nitrogen/protein.

Determination of moisture

The moisture content of raw materials, such as grains or finished products can be an indication of their storage stability. Moreover, moisture is one of the parameters that can generate the highest production margins. If there is a limit on the amount of moisture in a product, it is profitable to keep the water content as close to this limit as possible without crossing it. The water content is traditionally measured with moisture balances or titration. Moisture content is also one of the prime examples for NIR analyses, especially for fast and reliable at- and on-line measurements.

Labotec’s Precision Moisture balances measure moisture content, while the Orion Star T940 all-in-one titrator provides flexible pH, redox, and ion concentration titrations. Pairing the titrator with premium ROSS pH electrodes or Orion redox and ion-selective electrodes offers enhanced measurement capabilities.

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