Environmental-friendly analytical methodology for isothiocyanates analysis in Brassicaceae vegetables

FUSARI, CECILIA; LOCATELLI, DANIELA; JORGELINA C. ALTAMIRANO; PAULA BERTÓN; ALEJANDRA B. CAMARGO

Concordia

Conferencia; International Conference on Food Innovation, Food Innova; 2014

Several biological activities attributed to Brassicaceae vegetables are related to one of their hydrolysis products, the isothiocyanates (ITCs). High efficiency and recoveries are very important factors for routine determinations of ITCs in plant tissues. Robust analytical procedures are required for their extraction from vegetables. The aim of this study was to develop analytical technique based on the direct extraction of ITCs from Brassicaceae fresh samples to an aqueous phase. The technique was optimized using an experimental design: initially, a full factorial (2k) design was used to select those variables that significantly influence on the response, followed by a Central Composite Design (CCD) to find the optimum conditions. The evaluated variables were: homogenized time, ultrasound bath probe, sodium chloride addition, and solvent (water) to sample ratio. Total ITCs concentration was determined by liquid chromatography after their cyclocondensation with 1,2-benzenedithiol. The selected conditions for ITCs extraction from Brassicaceae vegetables were: homogenization time: 9 min; ultrasonic time: 5 min; and solvent to sample ratio: 200 mg mL-1.The optimized method exhibits good analytical performance in terms of linearity, precision (RSD < 2.4%), and limits of detection (26 nmol g-1 wet weight (w.w.)). The analytical technique was applied to: broccoli, cauliflower, cabbage and watercress samples, with recoveries higher than 85%. The main advantages of the optimized extraction procedures are their simplicity, speed, reliability and low cost. In comparison with traditional technique used for ITCs extraction, higher ITCs levels were achieved by using the proposed technique (187±12 vs. 444±13 nmol g-1 w.w.).