Detecting corn syrup in barley malt extracts

Methods for detecting corn syrup in barley (Hordeum vulgare L.) malt extrac t were: evaluated. Twelve samples representative of commercially available 2-rowed and 6-rowed malting barleys were malted. Extracts prepared from the finely ground malts were analyzed for C-13/C-12 ratios, expressed as delta C-13, and concentrations of protein and sugars. The C-13/C-12 ratios were sufficiently different to distinguish corn syrup from malt extract. By calc ulating the mean values for the barleys, it was determined that a delta C-1 3 > -24.3 parts per thousand indicated that the malt extract had been adult erated with corn syrup (99% confidence). Protein concentrations <4.5% (2-ro wed malt) or <5.0% (6-rowed malt) of the extracts also indicated probable a dulteration with corn syrup, which is devoid of protein. Because of differe nces in sugar concentrations between the malt extracts and corn syrup, carb ohydrate analysis also indicated probable mixtures. These findings were con firmed by analysis of extracts from composite 2-rowed and 6-rowed barley ma lts that had been mixed with known quantities of corn syrup. The regression s for delta C-13, protein concentration, and most sugar concentrations agai nst percent dilution with corn syrup in the mixtures were significant.