Abstract
M.Tech. (Food Technology)
Beer is an alcoholic beverage made from cereal grains (especially malted barley) and consumed worldwide including South Africa. However, beer consumption could be accompanied by moderate to severe mycotoxin exposure amongst consumers which originates principally from contaminated cereals used as ingredients for beer production. Aflatoxins (AFs), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA) and fumonisins (FBs) have been found to be the most significant mycotoxins associated with beer contamination. They are produced by some mycotoxigenic fungal strains belonging mainly to the Aspergillus, Penicillium and Fusarium genera. Ochratoxin producing Aspergillus and Penicillium species have been recognized as the most prevalent fungi in South African barley and are thus implicated as principal sources of OTA in beer made from malted barley.
Ochratoxin A, like some other mycotoxins, occasionally finds itself into the beer but its levels may be reduced during the brewing process. Decreases of less than 20% of OTA can be achieved during this process. Adsorption to particulate matter during various filtration processes has been noted as the major means of mycotoxin decontamination during beer manufacturing. Therefore, the beer filtration stage, a finishing stage of beer processing, is a very important and effective stage for mycotoxin removal, with filter aids playing a significant role. However, no studies have been reported on their effectiveness to remove certain mycotoxins, especially OTA during beer processing in South Africa and elsewhere.
In this study, a laboratory beer filtration method using two filter aids currently used in breweries worldwide was adopted. Among the suitable filter aids employed for precise beer filtration, diatomaceous earth (DE) Celite® 577 (C577) and rice hull ash (RHA) Pattern II described as an emerging filter aid proposed as an alternative to DE; similar in their chemical composition were selected in this study and tested against OTA removal during beer filtration. Secondly, OTA adsorptive capacity test was also performed following the adsorption isotherm method to better understand the mechanism of OTA removal. The filtration method was adopted and validated following the laboratory vacuum filtration system, utilizing a Buchner funnel containing a filtration medium constituted by a septum (filter paper) supporting the filter aid cake, then tested on the removal capacity of OTA on distilled water and a beer samples spiked with OTA (100...