NMR analysis for authenticity assessment and adulteration detection in honey samples from Paraná state

Honey is a naturally sweet and has been used since ancient times. It consists of a mixture of sugars, mostly glucose and fructose, and other substances, including vitamins, proteins, organic acids, amino acids, enzymes, water (usually 17 – 20%), and other small molecules1. A honey definition stated by the Codex Alimentarius says that “honey is a natural sweet substance produced from the nectar of plants or secretions of living parts of the plants that are stored and dehydrated by honey bees to improve its nutritional properties and become consumable for humans”2. Honey is an important energy food, but its use goes beyond of nutrition; it is also an important medicine. According to literature, honey has pharmacological properties such as antioxidant, anti-inflammatory and anticancer activities. Honey consumption also enhances the immune system and helps to relieve a sore throat, cough, and cold2. Due to all the properties of honey and its sweet flavor, honey consumption has considerably increased. Popescu and colleagues (2023) have published a study about the honey trade market among the main exporting countries and in 2021, Brazil occupied the fifth position in honey exportation3. Therefore, in order to boost their cash income by increasing its volume, honey adulteration has become frequent. According to the U.S. Food and Drug Administration (FDA), the honey market became part of an economically motivated adulteration (EMA) system. The main type of EMA involves diluting honey with other less expensive sweeteners, such as corn, cane, or different types of syrup4. The authenticity of honey is influenced by its chemical composition, geographical location, floral types, or bee genus species. Therefore, it is important to study different honey samples, and based on this type of data, we can differentiate between honey samples and trace which adulterants have been most used. NMR spectroscopy has been shown to be a powerful technique to study honey adulteration, differentiate its geographical location, quantify substances, and more. Additionally, the NMR results associated with multivariate techniques have been presenting important outcomes to identify trends and honey adulteration. For this reason, this research aims to conduct a partnership between UDC, UNILA and UFES to study different honey samples, detect possible adulterants, and in the future, compare both honeys from Paraná and Espírito Santo. The qNMR spectra were acquired using a 9.4 T (400 MHz) Varian/Agilent spectrometer equipped with a 5 mm broadband probe with auto-tune and match utilizing 90o pulse. All analyses are being performed with 1 mL of 50 mM NaH2PO4/Na2HPO4 buffered D2O at pH 7.2, as the solvent, and 64 scans.