Internal vs. External Standard Reference Compounds: Quantification Performance

Due to climate change, there is an increased frequency of adverse environmental phenomena such as drought, salinity, extreme temperatures, and UV radiation, which negatively affect crop growth and yield. To counteract these stresses, many plant species accumulate osmotic metabolites such as betaine, which plays a fundamental role in the stability of enzymes and mem- branes, favoring the osmotic adaptation of plant species. Betaine accumulates in chloroplasts, protecting proteins involved in pho- tosynthesis and reducing the risk of electron overreduction, in quite all plants, including wheat. Different wheat varieties show different betaine levels; thus, betaine could work as a possible cultivar biomarker. In this presentation, the results of a task of the Project “Iper- durum” will be shown. The suitability of a 1H NMR protocol for betaine quantification will be discussed with particular at- tention to the analysis of two autochthonous Apulian cultivars of Triticum estivum (cvv. Iride and Marco Aurelio). Different approaches, including internal and external standards, were ap- plied and validated. The results obtained suggest that 1H qNMR is a promising tool for measuring bioactive metabolites, allowing the characterization and traceability of natural products even after processing, increasing their commercial value.