The impact of raw material properties and process conditions on the color of a powdered formulated detergent product

The appearance of deterge nt powder plays an importa nt role in con sumer perception of powder effectiveness for cleaning applications. In this study, we investigated the influence of numerous formulation and processing conditions on product discoloration. Product color was scrutinized using the L*a*b* color space, and in particular, L* and b*. Particle size, the method for introducing the optical brightener, and the raw material grade were very important in con trolling the optical properties of detergent granules. As the particle size decreased, the light reflected to the observer appeared brighter and bluer. This was observed as increased whiteness from L*= 84.03 with a particle size of >841 μm to L*= 90.59 with a particle size of <250 μm. Reducing the level of impurities found in the raw materials by changing the material source also improved color definition. A key finding is that the optical brightener should be applied by spraying and prepared by dispersion rather than dissolution. This improves the distribution within the granules and increases the whiteness when compared with pouring the brightener into the agglomeration vessel. Additional spray applications highlighted that brightener on the granule surface influenced whiteness more than embedded brightener. In addition, we report on the effects of the drying temperature and mixer impeller speed on powder color.

Effects of laponite and silica nanoparticles on the cleaning performance of amylase towards starch soils

This work aims to understand the effect of nanoparticle-enzyme interactions and how such interactions affect starch based soil removal. Silica and laponite are used as the model nanoparticles, and s-amylase is employed as the model enzyme. The results show that, if the nanoparticles and enzyme are added simultaneously, laponite enhances the enzyme performance toward starch soil removal, whereas silica imposes a small effect on the enzymatic activity towards the same soil substrates. However, when nanoparticles are added first, the enzyme activity is not affected much by laponite but is hindered significantly by silica nanoparticles. Furthermore, sequential addition of the enzyme followed by silica nanoparticles improves soil removal. Electron microscopic analyses, measurements of the enzyme activity in suspen- sions of nanoparticles, and particle size characterisation suggest that dense coverage of soil surface by the silica nanoparticles be likely a mechanism for the experimentally observed hindrance of soil removal when silica nanoparticles are added before enzyme.