Aquaphotomics is the classification of samples solubilised in water by the effective change of the water’s NIR spectrum. In this proof of concept study (open access) the authors successfully applied the technique to in-house samples of tomato powder that had been adulterated with bulking agent (cornflour) and/or colouring agents to mask the adulteration (a selected range of red food dyes were tested). They found that after principle component analysis and linear discriminant analysis (PDA-LDA) the technique could discriminate adulterated from unadulterated samples at ranges from 0.5 – 20% adulteration. They repeated the study for three different varieties of tomatoes. Each classification model is specific to an individual tomato variety. The authors conclude that this could be the basis for a quick and cheap field test for adulterated tomato powder, a concern in countries where fresh tomatoes are unavailable out of season and thus powder is popular as a culinary ingredient.
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