Use of inulinases to improve fermentable carbohydrate recovery during tequila production

For tequila production, blue agave heads are cooked to hydrolyse their fructan content and release fermentable carbohydrates. However, this hydrolysis is not complete and the juice generated during cooking (cooking honey) contains fructans incompletely hydrolysed. Several distilleries perform an additional acidic hydrolysis on honey to improve fermentable carbohydrate recovery, but this treatment presents many disadvantages. As an alternative, we describe an enzymatic treatment with Fructozyme L, a preparation of inulinases. Optimal laboratory conditions for agave fructan hydrolysis using this preparation were 60 °C and a pH of 4.0–5.0. A concentration of 0.02% (V/V of honey) was needed to achieve more than 90% of fructan hydrolysis in the honey, after a 12 h treatment. These conditions were validated by two industrial trials during which enzymatic hydrolysates were successfully fermented and distilled, and volatile compound composition and sensory qualities of the tequila were assured.