Pineapple leaves to now help investigators solve crimes

Scientists have discovered that pineapple leaves can be turned into powder that forensic investigators can use to solve complex crimes.

In groundbreaking research, a team of nanomaterial chemists who specialise in making new materials from waste successfully turned discarded pineapple leaves into a powder useful for dusting invisible fingerprints at crime scenes.

“Our research filled a gap. It is the first time that an agricultural waste-derived adsorbent made into nanoparticles has been used to soak up heavy metals from water–and then reused afterwards in forensic science, at a low cost,” said Bienvenu Gael Fouda Mbanga, a Research fellow at Nelson Mandela University.

The team of scientists was seeking to solve the challenges of thousands of tonnes of pineapple leaves that are discarded by pineapple juice manufacturers every year.

They also wanted to know if the pineapple leaves could be turned into something more useful in solving crimes.

“The leaves are seen as agricultural waste and usually treated as useless. However, they can be converted into something that solves real-world problems - a powerful resource for both environmental protection and security,” Dr Mbanga wrote in The Conversation.com

The researchers observed that while some pineapple leaves are being turned into disposable diapers, most are thrown away in landfills or even burnt on site.

In countries like Kenya, it is estimated that the country generates around 80,000 tonnes monthly from leaves and peels, often disposed of through burning or decomposition. This disposal method contributes to greenhouse gases.

On the other hand, the fingerprint powder used in forensic investigations contains chemicals that pose potential health risks to the people handling them, according to the researchers.

“Police and forensic investigators need a safer, more sustainable alternative," Dr. Mbanga wrote in The Conversation. "The novelty here is the fabrication of a cheap powder from biomass waste that is eco-friendly and effective."

When dusted onto surfaces, the fine pineapple-derived nanoparticles cling to the oils left behind by human skin, revealing crisp, clear fingerprint patterns. Because the powder is derived from natural biomass, it is significantly safer for long-term use by law enforcement professionals.

The researchers are now calling for the technology to be scaled up for industrial use. They noted that pineapple waste could also be used in wastewater treatment plants, besides reducing the cost of solving crimes and the carbon footprint of the agricultural sector.

Forensic laboratories and law enforcement agencies should explore ways of including the spent adsorbent in their work in uncovering invisible fingerprints. Using the spent adsorbent instead of ordinary fingerprint powders could reduce costs,” Dr Mbanga noted.