TEA STAIN REMOVAL
Besides water, black tea is the most widely consumed beverage on a global basis. Prepared as an infusion of fermented tealeaves in hot water it contains a number of polyphenolic compounds giving the characteristic astringent fl avour and the brown-red colour. On cooling down in cups and pots, components such as thearubigins and theafl avins in combination with water hardness ions form a brown scum. Further oxidation reactions take place at the water/air phase leaving brown stains on porcelain surfaces which are hard to remove. Supported by the universal cleaning power of phosphates, commonly used oxygen-based bleaches are able to break down the stain at high temperature. However, being a chemical reaction, teastain removal becomes more diffi cult at declining temperatures. The well-known TAED system (a combination of the bleach activator tetraacetyl ethylenediamine with a persalt, e.g. sodium percarbonate(SPC)) was introduced in ADD formulation several years ago. It effectively removes tea stain in the temperature range of 60 to 70°C and is gentle to enzymes; two reasons for its use in almost all European ADD tablets and powders. At55&de ...