Food Quality Analysis

To ensure that every single delivery is flawless, food producers must review their goods as early as possible in the production process. This poses a challenge especially for emerging countries, as the analysis of goods in a professional laboratory is hardly affordable and suitable for everyday use and is therefore not an option for farmers and producers. With Axetris Infrared Sources, food producers can now keep control over the quality of their products and produce in a simple and affordable way.

An affordable and portable solution

Infrared spectroscopy based on transmission spectroscopy or attenuated total reflectance (ATR) technique offers an affordable and user-friendly solution. These straightforward techniques enable us to design tools, which are compact, robust in handling and provide reliable measurements. Furthermore, sample preparation, consumables or reagents are not required, and a measurement is conducted within seconds. Thus, much broader and earlier control with minimal running costs is possible, reducing risks in the value chain and ultimately ensure higher food quality.

The operating principle of transmission spectroscopy

In transmission spectroscopy light travels through a medium to a detector. The radiation is absorbed depending on the media and the thickness of the sample cell.

Depending on the chemical composition of the sample, the spectral fingerprint will change accordingly. The sample can be brought to the cell by bypass stream or manually. In cost-sensitive applications multi-channel, line array or Fabry–Pérot interferometer (FPI) approaches can be applied. Herein thermopiles or pyroelectric detectors with band pass filters or interferometers are used to read the information.

How does attenuated total reflection (ATR) work?

In the attenuated total reflectance approach light is guided to a crystal, where the light will have one or multiple total reflections and then exit to the detector. At the point of total reflection, the light will interact with the medium on the other side of the boundary.

The setup consisted of two EMIRS200 IR sources built into a Pyreos PY0727 ATR spectroscopy evaluation kit. The IR energy from the light source was passed through a multi-reflection zinc selenide ATR crystal and received by a Pyreos PY0728 128 pixel linear array. The infrared array sensor had an integrated linearly variable filter (LVF) from 1800 to 900 cm-1 (5.5 to 11 µm). A chemometric model was calibrated and tested with validation samples. The root-mean-square error of prediction was 0.11 g/l, which is comparable to commercialized devices in the market.

Ammonium sulfate in milk measured with a low-cost ATR setup

Ammonium sulfate is used in milk adulteration to mask the concentration change after water is added. The limitations of a low-price spectrometer setup (a fraction of a standard spectrometer such as FTIR) was tested by spiking UHT milk with ammonium sulfate.

The setup consisted of two EMIRS200 IR sources built into a Pyreos PY0727 ATR spectroscopy evaluation kit. The IR energy from the light source was passed through a multi-reflection zinc selenide ATR crystal and received by a Pyreos PY0728 128 pixel linear array. The infrared array sensor had an integrated linearly variable filter (LVF) from 1800 to 900 cm-1 (5.5 to 11 µm). A chemometric model was calibrated and tested with validation samples. The root-mean-square error of prediction was 0.11 g/l, which is comparable to commercialized devices in the market.