Innovative analytical method based on magnetic resonance imaging and NIR to correlate hazelnuts morphological and structural characteristics with agronomic treatments, bedbug occult damage and varietal features

Several Italian Protected Geographical Indication (PGI) and Protected Designation of Origin (PDO) hazelnuts are very famous for their quality and is of a paramount importance to establish innovative analytical approaches, guaranteeing a reliable and informative quality assessment, as well as identify novel agronomic treatments, capable to preserve and improve the product quality. We innovatively explored the combination of magnetic resonance imaging (MRI) and near-infrared (NIR) spectroscopies to investigate on several aspects related to the hazelnut quality. In particular, we aimed to correlate structural and compositional characteristics of intact hazelnuts with (i) variety-specific traits, (ii) sustainable agronomic treatments, and (iii) bedbug occult damage (BOD). Results: MRI representations revealed anatomical details detecting the BOD. 2D and 3D MRI images revealed unequivocally the presence of the damage through a dramatic change in the hydrogen population which led to a neat colour modulation. MRI proton spin-lattice (T1) and spin-spin (T2) relaxation times were processed inno- vatively through a novel and advanced processing procedure enabling the mapping of spin populations which unveiled peculiar features. Such an approach not only confirmed the BOD detection (increase in T1 accompanied by a decrease in T1 and T2 intensities), but also discriminated significantly the two considered varieties (based on T2, T2 Area and T1 intensity). In addition, they also revealed the effects resulting from innovative and sustainable in-field treatments on plants. Although less powerful than MRI, NIR supplied promising results which, in many cases, represented a complementary analytical tool. NIR unambiguously recognized the hazelnuts affected by BOD and detected the hazelnuts undergone plant treatments. Significance: The proposed advanced and innovative approach can support the high-quality hazelnut producers by acting as a useful tool to detect, early and non-invasively, the presence of BOD, identify and certify high- quality hazelnuts, and conduct a varietal classification.