Antimicrobial Effectiveness toward the Natural Dyes Stock Solution from Rambutan (Nephelium lappaceum) Peel Extract

摘要

Rambutan peel contains flavonoid as a natural pigment. The utilization of rambutan peel is an effort to process rambutan peel waste into natural dyes which are environmentally friendly, and obtain new color variations. Natural dyes are often sold in solid form from its plant. Thus, it takes long time and much energy to prepare the natural colors from solid form into liquid extract. Some batik makers want to supply natural dyes in the form of stock solution which are ready to use, and have the same quality with fresh natural dyes that have just been extracted. This study aimed to produce natural dyes stock solution from rambutan peel with good quality and long storage time. The effects of preservative tyoe (citric acid, sodium benzoate, potassium sorbate and tamarind) and preservative concentration (1%,3%, and 5%) on the storage resistance of natural dyes stock solution were investigated until 3 months of storage. The results show that the addition of sodium benzoate and potassium sorbate was the most effective preservative for extending the shelf life of natural dye stock solution from rambutan peel extract during 3 months storage time with counts of total yeasts <1 colony/ml respectively.