How to optimise food and beverage analysis

Today’s food and beverages are much more than just simple ‘organic fuels’ needed for survival. With an ever-increasing number of processed foods, food quality and safety aspects are becoming more important. All the more, because foods are highly complex materials — prone to degradation and contamination — that contain myriads of compounds.

Analytical chemistry makes sure that consumers obtain safe and sanitary food in compliance with regulatory requirements. From the process point of view, analytical chemistry supports the manufacturer to improve yields and optimise quality by offering robust, efficient and sensitive instrumentation.

Here are four ways to help manufacturers optimise their food analysis and meet the requirements of the public health regulatory authorities, from sample preparation, nutrient testing to labelling.

1. Test your salt — titration

In recent times, the negative impact of high levels of dietary sodium on human health outcomes has attracted increased attention from public health regulatory authorities. In many jurisdictions, there is a requirement for food manufacturers to state the total sodium content of the product on the package.

For large-scale contract labs, this can easily be analysed by AAS or ICP; however, these techniques require staff with analytical backgrounds and relatively high operation costs.

Smaller food producers or large-scale manufacturers without a large laboratory have opted for a simple titration using silver nitrate to analyse salt. While this has been recognised as the titration method for salt analysis over a long period, it is actually an accurate representation of chloride, not of sodium.

To make performing titrations easier and reliable, it is recommended to use automated titration as it is more reproducible than manual titration. Automatic titration is more accessible and affordable. Metrohm’s Eco Titrator Salt plus performs the analysis fully automatically and makes titration simple, safe and reliable. It provides users with a complete package for the analysis of chloride in a wide variety of samples and provides GLP-compliant results to meet the requirements of the public health regulatory authorities. Metrohm Eco Titrator is a titrator for all standard potentiometric titrations that is robust, precise and affordable.

2. Labelling requirements — allergen testing

All packaged foods sold in Australia and New Zealand must comply with the labelling requirements of the Australia New Zealand Food Standards Code. Current regulations and standards are used to safeguard food safety and ensure that consumers have quality products of high added value.

Food allergens and gluten are protein substances from different sources that can cause mild-to-severe immune reactions when consumed by sensitive individuals, even at low concentrations. Potentially allergenic foods are listed in Annex II of Regulation (EU) 1169/2011 and in bodies of regulation around the world, and labelling is compulsory.

It is estimated that 2 to 4% of adults and 6% of children have some kind of food allergy, a trend on the rise in recent years. Consequently, these substances must be detected in raw materials and finished products to ensure consumer safety.

To avoid a public health risk, food hazards are tested using a variety of techniques, among them, immunoassay due to its reliability, easy management and low cost. BioSystems’ ELISA (enzyme-linked immunosorbent assay) kits are a rapid, efficient tool for analysing the presence of substances at very low concentrations, due to the specificity of antigen-antibody binding reactions.

3. Sample preparation — homogenisation

Food products are available in a great variety of forms and consistencies and are usually inhomogeneous. To determine nutritional values or detect hazardous substances, for example, homogeneous and representative samples are required to obtain reproducible and meaningful results. Samples, which are often very complex, need to be homogenised and reduced to a suitable particle size prior to analysis.

Most analysis techniques only require a few milligrams or grams of sample material which must represent the entire original sample. The composition of the analysis sample may vary, depending on which part of the original sample it was extracted from. Muesli bars, for example, consist of a variety of ingredients which all need to be represented in the part sample to ensure correct determination of the nutritional values. This is achieved by thoroughly homogenising the cereal bars prior to analysis. Basically, the sample preparation process should be adapted to the sample characteristics as well as to the subsequent analysis technique to avoid falsified results.

Grinding parameters and accessories should be selected with regard to preserving the sample properties to be analysed. A basic rule is to only grind the sample as fine as necessary and not as fine as possible, as this always generates more effort (energy input, time, heat, wear). For a quick and reproducible homogenisation and characterisation of complex samples, it is recommended to use mills and grinders suitable for the different requirements of food analysis.

RETSCH offers a variety of mills and grinders which offer results with minimum standard deviation, variable speed, autoclavable grinding tools and they are suitable for sample volumes up to 700 or 4500 mL. With simple and intuitive handling and quick and easy cleaning, the instruments help to increase efficiency in the food sample preparation.

4. Qualitative and quantitative analysis — Raman spectroscopy

In recent years, there has been a dramatic increase in the need for analysis of food quality and safety, as well as composition and authenticity of food products; all of which can be done non-destructively with Raman spectroscopy. A couple of examples include the presence of contaminants in food, and the identification of food additives and ingredients, including cellulose, sorbitol, stearic acid and starch. The composition of edible oils and the amount of fatty acids present in those oils is an important indication of their value as well as identity. Raman spectroscopy provides a means of quantifying the composition of fatty acids in food products, as well as other components in food, such as flavours.

The Metrohm B&W Tek spectroscopy portfolio includes laboratory near-infrared spectroscopy (NIRS) analysers, and handheld and portable Raman analysers.

The nutritional composition of feed, including quantitation of protein in grain and fat in milk, can be determined using Raman spectroscopy:

• Measuring chain length and extent of saturation of fatty acids in edible oils
• Meat product quality analysis
• Product authentication and contamination
• SERS analysis of food contaminants including bacteria, antibiotics, dyes, etc
• Analysis of components in grain kernels
• Raw material identification/verification for the food and beverage industries.

Image credit: ©stock.adobe.com/au/karandaev