Smartphone-based colorimetric study of adulterated tuna samples

In this work, a colorimetric analysis of adulterated tuna samples is carried out using both a spectroradiometer and a smartphone as capture devices. Yellowfin tuna (Thunnus albacares) slices were treated with nitrate and nitrite salts, as well as with two different vegetable extracts (beetroot and radish), and the resulting NO2- and NO3- concentration was analysed using HPLC-DAD. The results indicate that both nitrite and beetroot treatments work properly as colouring agents in tuna, being nitrate also effective. When assessing the effect of radish, the final flesh had a more whitish colour. Overall, this approach allows to obtain colorimetric data which can distinguish among the different adulterating agents.