Hydrolytic Enzyme-Facilitated Mass Spectrometric Investigation of Metals in Processed Food Matrices

Greater access to processed foods worldwide poses challenges for regulatory bodies while feeding debates about the effect of such foods on human health. In contrast to their raw material ingredients, processed food matrices possess vastly more complex biochemical profiles. In this work, we demonstrate the ability of hydrolytic enzymes to facilitate the enhanced release of metals from three different processed food matrices. Our approach relies on the ability of the hydrolytic enzymes to cut or loosen biopolymeric components present in the processed food items, followed by the mass spectrometric detection of released metals. A combination of cellulase, pectinase, xylanase, and amylase disrupted the surface and overall architecture of the processed food items as indicated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Hydrolytic enzyme treatment resulted in the measurement of significantly higher levels of Cu, Mn, Zn, Cr, and As and between 20 and 250% higher levels of Pb and Sn across all three food matrices. We used RSM and ANOVA to optimize the conditions underlying hydrolytic enzyme treatment, for example, for Pb as pH 7, incubation time of 30-48 h, and enzyme concentration of 50 mg/mL. We analyzed the food product packaging materials as a prospective source of lead and tin and observed commensurate levels in the packaging to those measured after hydrolytic enzyme treatment of the contained foods. Treatment of the processed foods with immobilized hydrolytic enzymes results in a similar profile of the elements as obtained with the use of soluble enzymes, thereby promising the adaptability of our method to a reusable format. The approach presented in this work lays the groundwork for an important sample treatment strategy for the superior chemical analysis of processed foods.