Colorimetric Indicator Solution from Sappan Heartwood (Caesalpinia sappan L.) Extract for Milk Quality Monitoring

Abstract

This study utilizes Caesalpinia sappan L., traditionally valued for its culinary and medicinal uses, to develop a colorimetric indicator solution for monitoring milk spoilage. The indicator provides real-time updates on milk freshness through color changes induced by biochemical alterations during spoilage. The color of the indicator solution transitions distinctly from orange-red to orange to yellow as the pH shifts from 7.00 to 5.50 to 3.50, correlating with progressive stages of spoilage. An orange-red color was observed for the fresh stage, orange color for about to be spoilt, and yellow color for the spoilt stage of milk samples. The colorimetric changes are attributed to the presence of Brazelin in Caesalpinia sappan L. Digital images of the indicator solution treated with milk samples were analyzed using RGB (red, green, and blue) indices, with the green chromatic shift serving as a reliable parameter for quantifying color changes, providing reliable assessment of milk spoilage. Findings of this study highlight a simple, accessible, and accurate method for milk quality monitoring that requires no specialized equipment or trained personnel, making it suitable for food safety practices in resource-limited settings.