Laundry soap production from the respective tallows of goat, sheep and cow: evaluation of physicochemical properties for the best

Abstract

Tallow mainly consists of triglycerides, whose major constituents are derived from stearic, palmitic and oleic acids, and its usage reduces production cost of soap, adds lather stability and hardness to soap. Laundry soaps were produced with variation on amount of tallow (sourced from cow, sheep and goat) and labelled as A, B, C, D and E formulations. The respective tallows were characterized in terms of saponification value and acid value and determined to be 192.14 and 2.24mg KOH/g (cow tallow); 200.56 and 2.38mgKOH/g (sheep tallow) and 197.75 and 1.96 mgKOH/g (goat tallow). The physicochemical properties of soap which determine its area of usage and cleansing properties were determined. The properties considered in this work were hardness, moisture content, foam capacity, pH, free acidity content, and total fatty matter. The hardness, moisture content, foam capacity, pH, free acidity content and total fatty matter of the produced soaps were determined and ranged between mild-deep penetration level; 11-21%; 1-9cm; 8-10.5; 0.16-0.82% and 40-86% respectively. From the comparative analysis, soap made from sheep tallow has the lowest penetration level (with formulations B and E), lowest free acidity content of 0.16% (with formulation A), highest total fatty matter of 86% (using formulation E), highest foam height of 9cm (with formulation A), lowest moisture content of 11% (with formulation A) and mild alkalinity of 8 (with formulations A, B and E). These results showed that the soaps produced from sheep tallow are the best in terms of hardness, lather and skin friendliness, due to its high degree of longer carbon chain lengths of fatty acids. These values satisfy the standard limit set for good quality laundry soap by National Agency for Food and Drug Administration and Control and Encyclopaedia of Industrial Chemical Analysis, respectively.