Literature review

This literature review will focus on the different studies conducted on laundry detergents. Laundry detergent is a common product that is purchased regularly by nearly every household in Singapore. With a large commercial market and many brands of choices, companies have developed their laundry detergent formulas to make their products more competitive in the market. It has been researched from consumer reviews that the stain-lifting power of detergents is the determining factor of whether a detergent is good. Household laundry detergents in the current market comprise of complex formulations containing many different ingredients. These ingredients can be categorized into several components: surfactants, builders, enzymes, bleaching agents and auxiliary agents such as dye-transfer inhibiting ingredient, optical brighteners, anti-redeposition agents, dispersing agents, and fabric softening clay [1]. All these components play various roles in the process of washing and cleansing of dirty clothes. In fact, extensive research has been done in detail on the specific components, as to the most effective or most suitable ingredient under a category that could be added into the detergent formulas.
Research by Schweiker et al. has shown that detergent builders play a predominant role in removing stains in the washing process [2]. Smulders et al. supports this and elaborates that the main purpose of builders is that of supporting surfactants action. It performs in stain removal, particularly soil and fats. [3]. Enzymes are also added as an effective method of breaking down stubborn stains; mostly food stains. For example, amylases to remove stains created by polysaccharides and proteases that remove stains caused by proteins [4]. There exist many different types of enzymes and builders, and a lot of research has been done, for example on the suitability of the properties of many individual enzymes specifically for laundry detergents. The degree
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