OPTIMASI SABUN CAIR ANTIBAKTERI EKSTRAK ETANOL RIMPANG JAHE MERAH (Zingiber officinale Rosc. var. rubrum) VARIASI VIRGIN COCONUT OIL (VCO) DAN KALIUM HIDROKSIDA (KOH) MENGGUNAKAN SIMPLEX LATTICE DESIGN

Abstract

Antibacterial liquid soap help prevent the infection of pathogenic bacteria, such as S. aureus
and E. coli that can cause skin infection and diarrhea. Red ginger is one of natural plants that has
the potential as an antibacterial agent in soaps and also known to have antibacterial activity. Soap is
formed from the reaction between a fattty acid and base so its quality is affected by the perfection of
that reaction. The purpose of this study was to determine the optimum composition of VCO and
KOH using Simplex Lattice Design (SLD) and its physicochemical properties. The extraction was
done by soxletation method using ethanol 96%. Antibacterial test showed that the optimum
concentration of the extract was 50 mg/mL. Soap with variation of the VCO and KOH had specific
gravity 0,955-1,045; viscosity 0,3-2,1; pH 9,366-10,566; and free alkali 7,48x10
%.
The composition of the VCO and KOH that predicted by SLD is 26,386 g VCO and 6,414 g KOH.
This optimum formula had specific gravity 1.03148; viscosity 0.723; pH 10,066; and 0.0086% free
alkali. Independent two-sample test between the physicochemical properties resulted from the test
and results predicted by SLD showed no significant difference (p>0,05). The antibacterial activity
of optimum formula didn"™t differ significantly with the control (p>0,05).

Keywords:   liquid soap, red ginger, virgin coconut oil, potassium hydroxide, simplex lattice design