Maize syrup, used as a brewing adjunct, is produced in a process which begins with steeping viable maize kernels in a similar manner to the steeping of barley in the first stage of the malting process, but instead of being germinated the steeped maize is coarsely milled and passed through a device called a cyclone which separates the embryos (which are washed, dried and pressed to extract their oil content, producing "corn oil" used for cooking, etc.) from the crushed wet grains. These are then finely ground in a second mill and screened to remove their fibre content, leaving a slurry which is separated into its two main fractions, namely starch and protein, by a series of centrifugation treatments. The protein is used in animal feed, while the starch, after further washing and cycloning, is converted into a syrup of fermentable sugars by cooking it with either a food grade acid or a thermostable amylolytic enzyme preparation (usually of bacterial origin), followed by a second stage enzymic treatment to complete the process and prevent retrogradation. The enzyme preparation used in the second stage varies according to the type of syrup required (e.g. pullulanase to produce a highly fermentable, maltose rich syrup). Finally, the syrup is refined by adjusting its pH to facilitate the precipitation of impurities, filtering them out, then removing those impurities which remain in solution by carbon treatment or ion exchange (preferably the latter, as it removes salts which carbon does not), and concentrated by evaporation. The description of the maize syrup production process is followed by a brief survey of global trends in the use of sugar adjuncts.
Keywords : adjunct maize production syrup