Pineapple peel extract stripped 95.6% of colour strength from carmine-dyed cotton in laboratory discharge printing trials, marginally outperforming two conventional chemical agents. Researchers at Bangladesh University of Textiles (BUTEX) in Dhaka ran the study, published in the journal Discover Chemistry, on knitted cotton dyed with carmine and navy reactive dyes.

The finding matters for wet-processing units. Discharge printing normally relies on synthetic reducing agents to destroy dye in printed areas, and these chemicals rank among the more problematic inputs in effluent loads from textile mills.

What did the trials test?

The BUTEX team applied orange and pineapple peel extracts to reactive-dyed cotton and measured colour removal against standard commercial stripping agents. The pineapple peel result on carmine-dyed fabric — 95.6% reduction in colour strength — slightly exceeded the performance of both conventional agents in the comparison.

The trials covered two dye shades, carmine and navy, on knitted cotton. Both fruit peel extracts showed colour-removing capability, offering a potential bio-based substitute for the petrochemical-derived agents currently in use.

Why does this concern Bangladesh's mills?

The research comes from the world's second-largest apparel exporter, where dyeing and printing operations face mounting effluent pressure. Bangladesh's textile wet-processing sector discharges into rivers that supply water to farming and households, and regulators alongside buyer-driven compliance programmes have tightened scrutiny of chemical management at tier-two and tier-three processing facilities.

Fruit peel feedstock carries a practical appeal: orange and pineapple processing waste is abundant, low-cost and non-toxic. If extraction can be scaled, mills could cut effluent treatment costs at the same time as reducing hazardous chemical inventories flagged under buyer restricted substance lists.

What remains unproven?

The results come from laboratory trials on two reactive dyes on cotton. The study does not yet demonstrate:

• performance across the full reactive dye palette mills run commercially;
• behaviour on woven fabrics, blends or synthetic fibres;
• cost, consistency and shelf-life of peel extracts at industrial volumes;
• compatibility with existing printing equipment and discharge paste formulations.

Scale-up from a laboratory bench to a production rotary screen or digital discharge line typically requires repeatability trials, supplier qualification and buyer chemical approval before adoption.

What decision does this force?

For sourcing directors and mill compliance teams, the study is a watch item rather than a switch trigger. Chemical managers at dyeing and printing units in Bangladesh and beyond should track whether peel-based stripping agents progress to pilot-scale trials and earn certification under standards such as ZDHC's Manufacturing Restricted Substance List framework.

Buyers pushing supplier chemical-reduction targets — and mills seeking to lower effluent treatment spend — have a reason to ask their printing partners whether bio-based discharge agents are on the trial roadmap. The 95.6% figure gives procurement a benchmark; the gap between lab cotton and commercial production now defines the commercial question.