Paper mills usually buy modified starch for surface treatment of paper & board. With enzymes they can prepare it in-house for cost and flexibility benefits. 

Surface sizing with starch improves the printability and integrity of the paper surface. Coating adds desirable optical and performance properties. The paper and board industry uses modified starches for surface sizing and as a component of coating color. 

The starch used in the formulation needs to be modified from its native form. This modification gives it the viscosity needed for effective application. Controlled modification with alpha-amylases is an economical alternative to chemical methods. Mills can perform enzymatic modification as part of their own batch or continuous starch cooking processes.