Starch-soiled stainless steel cleaning using surfactants and α-amylase

• Dry starch soiled stainless steel cleaning with surfactants and α-amylase was studied.
• Surfactants effects on enzymatic activity, including anionic ones, were negligible.
• Using α-amylase allowed for better starch removal under milder operation conditions.
• Surfactants did not improve washing efficiency of α-amylase solutions.

The cleaning of dry starch adhered to stainless steel has been studied in a device which simulates a CIP system. The influence of an α-amylase, two polyoxyethylene lauryl ether carboxylic acids, a linear alkyl benzene sulfonate, a fatty ethoxylated alcohol, an alkylpolyglycoside, and two polyoxyethylene mono- and diglycerides has been analysed. The variables analysed were temperature, enzyme concentration, and different surfactants. The enzyme allowed for milder washing conditions improving starch removal. Surfactants, including the anionic ones, did not meaningfully alter the enzyme activity. Furthermore, they did not significantly modify the detergency in the presence or absence of enzyme, except for ethoxylated alcohol and polyoxyethylene(3) lauryl ether carboxylic acid solutions which decreased the detergency of the enzyme solutions. Temperature increase improved detergency either in the presence or absence of enzyme or surfactants. The experimental results advised interactions between those surfactants, the enzyme and the substrate, which could affect washing performance, basically at high washing times.