Malt hydrolysates for gluten-free applications: Autolytic and proline endopeptidase assisted removal of prolamins from wheat,barley and rye

Cereal based products intended for gluten sensitive individuals, particularly to celiac disease patients, tend to have poor organoleptic qualities and they contain low levels of healthy whole grain compounds. Adding whole grain ingredients, such as malt hydrolysates, could compensate these defects provided that the ingredients are adequately free from toxic prolamin epitopes. Here we demonstrate that the level of toxic prolamin epitopes in the malt autolysates (wheat, barley, rye) were substantially lower than in the native malts but too high to allow “very low in gluten” labelling. To further eliminate the residual levels of toxic prolamin epitopes, a proline-specific endoprotease from Aspergillus niger was added to the malt autolysates. In the resulting malt hydrolysates (of wheat and rye but not barley), the prolamins were indeed greatly reduced and were below the very low gluten limit of 100 mg/kg. Malt hydrolysates with adequately low gluten levels may potentially be used as novel ingredients within gluten-free foods.