Oxidised starches E 1404 are the most popular food modified starches, but in the literature available, there are no reports referring to enzyme susceptibility of these derivatives, neither are known functional properties of the oxidised products of enzymatic hydrolysis. The objective of this research was to study possibilities of applying a membrane bioreactor in the process of enzymatic hydrolysis of oxidised starches, and to assess surface properties of the products obtained. The hydrolysis process was carried out in a membrane bioreactor equipped with an ultrafiltration module of a tubular configuration. Single-step and two-step hydrolysis processes were investigated; various amylolytic enzymes were used in the processes studied. For the purpose of assessing adsorptive properties, surface tension was investigated using a ‘du Noüya’ ring method. It was stated that the oxidised starches underwent hydrolysis in the enzymatic membrane bioreactor; furthermore, it was proved that it was not necessary to apply the initial liquefaction of starches with an α-amylase to achieve an effective progress of the hydrolysis process. During the single-step hydrolysis the products obtained showed a relatively low degree of saccharification. As for the two- step hydrolysis, the complete process effectiveness depended on the optimal degree of liquefaction with an α-amylase during the first stage of the hydrolysis. The phenomenon of fouling did not significantly impact the separation efficiency of maltodextrin produced. The oxidised products of hydrolysis, as well as the raw material showed surface activity, and caused the reduction in the surface tension at the water-air interface.
enzymatic hydrolysis, membrane bioreactor, oxidised starch, surface activity