Utilizing isotopic and elemental markers to enhance the authenticity of potatoes

Abstract

Given the economic importance of potato production, establishing the origin of unknown commercial samples declared as local, is particularly important for both producers and competent authorities. In the study presented here, stable isotopic ratios of deuterium, oxygen, carbon and nitrogen, were determined in order to develop a potato provenance methodology. Isotopic determinations were conducted in an alcohol, preceded by the enzymatic degradation of potato starch using α-amylase to yield soluble dextrins and oligosaccharides. Subsequently, the hydrolyzed potato starch underwent fermentation to produce ethanol, which was then obtained through distillation under controlled conditions. The integration of data obtained from analyzing the D/H isotopic ratios using SNIF-NMR spectroscopy in potato samples for the first time, in conjunction with measurements of the ¹³C/¹²C, ¹⁵N/¹⁴N, and ¹⁸O/¹⁶O ratios via IRMS, yielded a unique isotopic fingerprint for the potato samples under examination. Elemental analysis by ICP-OES also added important information in the dataset. The chemometric analysis by applying OPLS-DA technique, highlighted the parameters of (D/H)_II, δ¹⁸O, R and Cu as the best discriminator markers. The proposed model gave 94.07% correct classification of the samples, regarding their geographical origin. It is believed that the differentiation of local potatoes is related to the unique geological and climatic conditions existing in the island. All the above-mentioned conclusions are very promising, for the protection of local potato production.