Ultrasound-Assisted Extraction of Inorganic Elements and Antioxidants from Gingerbread Cookies Using Natural Deep...

In the present study, ultrasound-assisted extraction using deep eutectic solvents was proposed for the preparation of uniced and iced gingerbread cookies prior to the determination of four macronutrients (potassium, sodium, magnesium, calcium), four micronutrients (manganese, zinc, iron, copper), the presence of toxic metal (cadmium), and antioxidant capacity. With the addition of 30% water in each green solvent, three acidic deep eutectic solvents, comprising xylitol with malic acid, choline chloride with malic acid, and choline chloride with lactic acid, were tested for their efficiencies in the simultaneous extraction of elements and antioxidants. The synthesized deep eutectic solvents were characterized by infrared spectroscopy, which provided evidence of generating new hydrogen bonds between two components of these solvents. Element profiles were analyzed by inductively coupled plasma-mass spectrometry after the extraction using green solvents and the microwave-assisted acid digestion of gingerbread samples. It was found that two deep eutectic solvents containing malic acid exhibited high abilities for solubilization of macronutrients and manganese from the samples studied, while the best extraction efficiencies for Zn, Fe and Cu micronutrients were achieved when the lactic acid-based deep eutectic solvent was used. However, the antioxidant capacity, evaluated by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and cupric reducing antioxidant capacity (CUPRAC) methods, led to the selection of choline chloride-lactic acid as the most promising green solvent for extracting antioxidants from two types of gingerbread cookies. The deep eutectic solvent-based extraction conforms to the principles of green chemistry and is suitable for releasing elements and antioxidants from gingerbread cookies.