Stability and staining property of gel from roselle calyx extract and butterfly pea flower

Roselle calyx and Butterfly pea flower are among plants which have been used for coloring of food and beverage. The combination of the water extraction of the two plants present tanning color and was found interesting to study the property of an herbal staining gel. The herbs were extracted with boiling water for 2 hours, filtered and lyophilized until dried. The gel base was prepared by using combination of sodium carboxy methyl cellulose gel base and hydroxyethylcellulose 4000 gel base in 1:1 ratio. The herbal extractions were varied amount to add to the gel base. The color number in an expanded color chart were use to evaluate the usable color. The staining gel was tested for cracking, precipitation, changing of color, changing of pH before and after heating cooling cycle. The gel was tested for staining property by applied 0.5g of gel on the pig skin and left for 1 hr then determine the color by using a color scale.The Mexameter MX 18 was used for determined of color uniformity of skin. The permanent of staining was tested by stirring the pig skin after staining for 24 hrs with 500 millilitres of water for 20 minutes and compare the color change. The gel with 1.35% of roselle extracted and 0.15% of butterfly pea extract was selected to be a staining gel. The color pH and physical property of gel are not changing after freeze and thaw for 3 cycles. The gel present consistency and permanent of staining.

Acknowledgement: The faculty of pharmaceutical science Khon Kaen university for supportive of grant.

References: 1. Kazuma K et al (2003) Phytochemistry 64: 1133–1139.

2.Therkildsen P et al (1998) Skin Res Technol 4: 174–179.