Optimizing sodium metabisulfite in pale crepe rubber processing: Toward cleaner and consistent product quality for agroindustrial applications

Pale crepe rubber, a premium-grade natural rubber product, requires high visual quality, brightness, and uniformity to meet export and medical-use standards. Conventional bleaching agents used to enhance color often pose challenges related to cost, odor, or safety. This study evaluates the use of sodium metabisulfite (SMBS) as an alternative bleaching agent in pale crepe rubber production to achieve optimal product quality while considering practical and environmental aspects. Fresh field latex was bleached with SMBS at varying concentration and the quality of crepe rubber was characterized and compared to international standard. The results show that SMBS effectively improves brightness and visual consistency when applied at an optimal concentration, producing crepe rubber that meets international quality specifications. Compared with conventional agent, SMBS offers a safer and more affordable approach suitable for small to medium scale processing. Overall, the study highlights a context-appropriate innovation that supports cleaner production practices and promotes sustainable value addition in the natural rubber agroindustry.