A form of near infrared imaging technology pioneered by the military could provide food manufacturers with a more powerful tool to measure the distribution of components such as moisture, fat and protein in foods where they are not evenly distributed.
It could also be used to grade products for freshness and quality, according to Campden BRI, which has been working with several food manufacturers on trials of hyperspectral near infrared (NIR) imaging using equipment from Gilden Photonics.
Campden BRI cereals and milling sciences manager Dr Martin Whitworth told Foodmanufacture.co.uk: “NIR spectroscopy has been around for a long time, but it is only useful for bulk samples or where you are trying to get an average fat or moisture content.
"By contrast, hyperspectral NIR imaging can provide rapid, non-destructive, in-line analysis of components that are not uniformly distributed, such as fat around French fries or doughnuts, moisture in baguettes and fat penetration in meat.”
NIR spectroscopy relates to the interaction of electromagnetic radiation with matter in the 750-2,500 nanometre wavelength region.
As this region contains information related to molecular bonds that form the basis of proteins, carbohydrates, fats and water, it can be used to determine their relative quantities in food samples, he said.
Although NIR hyperspectral imaging relies on the same technology, it also produces an image of the food components, thus allowing quantification of their spatial distribution, said Whitworth, who has been using it to compare moisture migration in part-baked baguettes that were stored under different conditions.
Scientists at Campden have also been using it to analyse fat uptake in fried foods such as chips and doughnuts.
While analysing total fat content in such products was relatively easy, said Whitworth, NIR hyperspectral imaging enabled firms to determine the distribution of the fat in the food – which was potentially useful because the internal structure of foods might impact on fat uptake.
By understanding how this structure mattered, it could then potentially be manipulated to alter fat uptake, he said.
Fat uptake in chips
For chips, it could be used to assess how different frying times, temperatures, preparation techniques and potato varieties impacted fat uptake, he said.
The technology could also be used to assess sugar properties within composite bakery or confectionery products, he said. “You can look at the form of sucrose. Is it crystalline or has it been absorbed?”
Food manufacturers had shown a lot of interest in the technology, he said.“The costs vary depending on what wavelengths are being covered. If you were just using it for looking at freshness in fish, for example, you wouldn’t have to cover the whole wavelength relevant to some other applications.
"I could see it being used in-line for grading purposes.”