Generally, there are three ways to make soap stock: 1) saponification of oils/ fats, 2) neutralization of fatty acids, and 3) saponification of fatty acid methyl esters. Route (2) is more widely used, being the simplest and fastest, while (3) produces the best quality product although at somewhat greater cost. A conventional clear bar soap is prepared by combining a fatty acid-based soap with polyol or combination of polyols (i.e. sugars, sorbitol and glycerine) and glycols (i.e. propylene glycol and ethylene glycol) to impart transparency to the soap. In a new method developed by MPOB, soap stock from route (2) is used instead. Dihydroxystearic acid (DHSA), either crude or purified, is added to clear bar soap to further improve its transparency. DHSA is a dihydroxy saturated fatty acid derived from palm oleic acid. Therefore, it is environmentalfriendly. The clear bar soap with DHSA (Figure 1) has shown good transparency, detergency and foaming power compared to a commercial clear bar soap.

Main Research: Norashikin Ahmad