Ultrasound‐assisted extraction of essential and toxic elements from pepper in different ripening stages using Box‐Behnken design

The influence of extraction parameters on the ultrasonically assisted extraction (UAE) of K, Na, Ca, Mg, Zn, Cu, Fe, Mn, Cr, Se, Mo, Li, Al, B, Pb, Hg, Cd, As and Ni was studied to determine the conditions when a minimum of essential and maximum of toxic elements is leached from peppers, depending on its ripening stage. The effect of process variables was investigated by using Box–Behnken design. Each essential element had a different optimal condition for minimal leaching, while the toxic elements were predominantly extracted with acetic acid solution as extractant. The highest correlation between extraction conditions and concentration of extracted elements was found for aqueous extracts of mature green pepper. The concentration of acetic acid highly influenced the leaching of elements and a strong correlation between the concentration of Al, B, Fe, and Mn and the UAE experimental conditions were observed.