title: Matrix binding of ochratoxin A during roasting.
abstract: The mycotoxin ochratoxin A is degraded during coffee roasting by up to 90%. During this process, the two known degradation products, 14R-ochratoxin A and 14-decarboxy-ochratoxin A are formed. However, there is still an unexplained loss of more than 50% ochratoxin A. Here, we describe the binding of ochratoxin A to coffee polysaccharides via esterification as a further thermal reaction. This ester formation was studied by heating ochratoxin A with methyl α-d-glucopyranoside, a model compound to mimic polysaccharides. From this experiment, (22 → 6') ochratoxin A-methyl-α-d-glucopyranoside ester was isolated and characterized as a reaction product, showing the general ability of ochratoxin A for esterification with carbohydrates at roasting temperatures. Subsequently, a sample preparation protocol for the detection of ochratoxin A saccharide esters based on an enzymatic cleavage and purification using immunoaffinity chromatography was developed and applied. The detection was carried out by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Using this method, it was possible to detect ochratoxin A polysaccharide esters formed during roasting of artificially contaminated coffee, confirming the results of the previous model experiments. Thus, the formation of ochratoxin A esters is a further explanation for the loss of ochratoxin A during coffee roasting.
authors: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstraße 45, D-48149 Münster, Germany.
authors: Andrea
authors: A
authors: Bittner
authors: Benedikt
authors: B
authors: Cramer
authors: Hans-Ulrich
authors: HU
authors: Humpf
mesh_terms: D040503:Coffea / Q000737:chemistry*; D003296:Cooking; D005506:Food Contamination / Q000032:analysis; D006358:Hot Temperature; D009793:Ochratoxins / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*
chemical_list: D009793:Ochratoxins; C025589:ochratoxin A