Definition and composition of malt flour and malt extract

Malt flour is made from grain (barley, wheat, rye or spelt). In this process, the grain is germinated under defined conditions (humidity, temperature and time). During the germination process, enzymes are activated, especially amylases, proteases and cellulases, which convert the grain’s insoluble reserve substances into soluble compounds. After several days, the germination process is stopped and the resulting green malt is dried. The drying process is known as kiln-drying. The finished kiln-dried malt contains a variety of natural colourings and flavourings and is enzyme-active or enzyme-inactive, depending on the process. 
If the kiln-dried malt is milled and not subjected to any further thermal treatment, an enzyme-active malt flour is obtained, which can be used with flours poor in enzymes to improve dough development, crust colour and freshkeeping of baked goods. This malt flour is also known as diastatic malt flour. The enzyme activity is defined by SKB units. This is a method for determining alpha-amylase activity in aqueous solutions (Enzyme Development Corporation, 2019). 

If the green malt or kiln-dried malt is subjected to further thermal processes such as roasting or extrusion after malting, malt products with an intense flavour are obtained. The higher the degree of thermal treatment, the lower the enzyme activity, as the enzymes consisting of protein structures are denatured. Light-coloured malt flours therefore generally have low enzyme activity, while dark-coloured malt flours have no enzyme activity.

Malt extract is an additional refinement of kiln-dried malt. The malt kernels are crushed, mashed and kept at 50 - 70° C for several hours. This process step is known as mashing. During this time, insoluble malt ingredients are enzymatically broken down into soluble sugars such as maltose (malt sugar). The product is then filtered and the desired solids content is set with the aid of vacuum evaporation and targeted temperature control. Malt extract is characterised by a high proportion of reducing sugars, among other things.

The details in the following table refer to light-coloured malt flours and light-coloured malt extracts and are to be understood as orientation values.