Activated carbons: In vitro affinity for fumonisin B-1 and relation of adsorption ability to physicochemical parameters

In vitro affinity tests were conducted to assess the effectiveness of 19 activated carbons (ACs), hydrated sodium calcium aluminosilicate (HSCAS), and sepiolite (S) in binding fumonisin B-1 (FB1) from solution. Relationships between adsorption ability and physicochemical parameters of ACs (specific surface area, iodine value, and methylene blue index) were tested. When 5 mi of a 4-mu g/ml aqueous solution of FB1 was treated with 10 mg of AC, ACs adsorbed 0.46 to 100% of the FB1. HSCAS and S were not effective in binding FB1. In two saturation tests carried out with decreased amounts of sorbent (5 and 2 mg, respectively), three ACs also showed high adsorption ability (adsorbing 96.48 to 99.20% of the FB1). A general relationship between adsorption ability and the physicochemical parameters of the ACs was observed, supporting the inference of a close relationship between molecule trapping and surface physicochemical adsorption processes. The methylene blue index was more reliable than iodine number and surface area for predicting ability of ACs to adsorb FB1. In tests of simultaneous adsorption ability carried out using 5 mi of a solution containing 10 mu g/ml FB1 plus 50 mu g/ml aflatoxin B-1 (AFB(1)) and 2 or 5 mg of sorbent, ACs showed a higher affinity for AFB(1) than for FB1, However, two ACs bound ca. 100% of the two mycotoxins. When 5 mi of an aqueous extract solution obtained from naturally contaminated corn containing 1.84 mu g/ml FB1 and 0.042 mu g/ml AFB(1) was treated with 10 mg of sorbent, one AC adsorbed ca. 95% and 99% of FB1 and AFB(1), respectively. It is concluded that certain ACs have high in vitro affinity for FB1 and AFB(1) singly or in combination, and may hold promise as multi-mycotoxin sequestering agents. However, further in vivo investigations are needed to confirm the abilities of ACs to sequester the most important mycotoxins singly or in combinations, establish the amounts to be added to feeds, and determine any long-term effects they may have on gastrointestinal absorption of essential nutrients.