Aquaphotomics based screening of tomato powder extracts reveals susceptibility to bulking and coloring agents

Abstract

Gaining prominence as indispensable culinary ingredients, tomato powders aren't exempt from fraudulent practices. While the complexity of conventional authentication methods hinders their adoption as routine assessment tools, our study examines the efficiency of aquaphotomics as a potential alternative, that entails limited preparation steps and involves no solvent extractions. Tested across three tomato varieties, aqueous blends comprising concentrations in the range [0%–20%] of two adulterant types (bulking agent, coloring agent), added separately or concurrently, were considered. Upon scanning with an XDS Near infrared spectrometer operating in transmission mode, the data was subjected to chemometrics based analysis over the 1st and 2nd water overtone ranges. While attempting to perform classification based on the level of adulteration, running hybrid principal component analysis and linear discriminant analysis (PCA-LDA) qualitative modeling on single adulterant mixtures allowed for recognition and prediction rates varying from [97.76%–100%] and [88.59%–100%], respectively. Slightly lower accuracies were obtained when coupling the bulking and coloring agent. Partial least squares regression (PLSR) models gave good estimates of the extent of adulteration, with respective R2 and RMSECV values reaching at best, 0.98 and 0.45%w/w. The aquagrams revealed distinctive spectral patterns highlighting the gradual level of adulteration. Assuredly, these findings ascertain the contributions aquaphotomics promises in ensuring the authenticity of tomato powders, when analyzed in their liquid state.