Removal of Aflatoxin B1 Using Alfalfa Leaves as an Adsorbent Material: A Comparison between Two In Vitro Experimental Models

Abstract

An adsorbent material derived from alfalfa leaves was prepared and further characterized, and its efficacy for removing aflatoxin B1 (AFB1) was investigated. Characterization consisted of the use of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), environmental scanning electron microscopy (ESEM), X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), point of zero charge (pHpzc), zeta potential (ζ-potential), UV-Vis diffuse reflectance spectroscopy, and spectral analysis. To determine the adsorption capacity against AFB1 (250 ng AFB1/mL), pH-dependent and avian intestinal in vitro models were used. The adsorbent inclusion percentage was 0.5% (w/w). In general, the pH-dependent model gave adsorption percentages of 98.2%, 99.9%, and 98.2%, evaluated at pH values of 2, 5, and 7, respectively. However, when the avian intestinal model was used, it was observed that the adsorption percentage of AFB1 significantly decreased (88.8%). Based on the characterization results, it is proposed that electrostatic, non-electrostatic, and the formation of chlorophyll-AFB1 complexes were the main mechanisms for AFB1 adsorption. From these results, it can be concluded that the adsorbent derived from alfalfa leaves could be used as an effective material for removing AFB1 in in vitro digestion models that mimic the physiological reality.