From food scraps to face cream

Posted: November 15, 2024

In the bustling markets of Kuala Terengganu, Malaysian researchers search for food scraps. Fish bones and fruit peels are on their shopping list—waste that they want to turn into a precious material: collagen.

Thanks to its unique properties—mechanical strength, elasticity, and biocompatibility—collagen finds applications across many sectors, such as medicine, cosmetics, food, and pharmaceuticals.

This protein is the most abundant in the human body, maintaining the strength and elasticity of our connective tissues such as skin, bones, muscles, ligaments, and tendons. But it is also found in many marine species, such as sardines.

The Malaysian researchers have found an innovative way to extract collagen from the bones of the small oily fish, combining fish processing waste with agricultural byproducts to create a truly eco-friendly collagen source.

Traditionally, collagen extraction practices rely on harsh chemicals—such as strong acids or alkalis, generate significant waste, use large quantities of water and often rely on mammals, such as cattle and pigs. Instead, the Malaysian team uses banana peels as a natural solvent for extracting collagen from sardine bones, turning two waste products into valuable resources.

An eco-friendly collagen extraction process

The researchers collected sardine bones from a sardine processing company based in Kuala Terengganu and banana peels, along with other fruit waste, such as pineapple pomace, mango peel, and coconut husk, from local markets. They dried and ground the fruit peels and sardine bones.

The extraction method is straightforward and low-impact: researchers placed 50 grams of powdered banana peel in distilled water at 60°C, allowing it to steep for 30 minutes before filtering out a brownish filtrate. This filtrate was used as the extraction solvent for sardine bones.

The team optimized three main variables for the extraction process: temperature, the sardine bone-to-solvent ratio, and extraction time. Their findings revealed that the optimal extraction conditions were a temperature of 40°C, a sardine bone-to-water extract ratio of 1:24, and a duration of 74 hours, achieving an experimental yield of 9.82%.

To explore the versatility of this eco-friendly approach, researchers tested water extracts from other fruit wastes, including mango peel, pineapple pomace, and coconut husk. They found that different fruit extracts affected collagen yield, with pineapple pomace achieving the highest yield of 13.58%, followed by mango peel (11.79%) and coconut husk (2.10%).

Azlan Hassan, the study’s lead researcher, highlighted the transformative potential of this process in a press release: “This research demonstrates the potential of using fruit waste to extract valuable compounds like collagen. It’s a great example of how we can turn waste into wealth while promoting environmental sustainability.”

Three wins with one move

If scalable, the approach could help solve multiple issues in one go.

According to a report from the Food and Agriculture Organization of the United Nations released last June, global fisheries and aquaculture production in 2022 surged to 223.2 million tons, a 4.4 per cent increase from 2020. The increasing demand for seafood has led to a rise in waste production, primarily inedible parts such as bones and skin. Sardines, among Malaysia’s most consumed fish, contain up to 50% collagen by dry weight in their bones and scales.

Conventional collagen extraction methods, which often involve acidic treatments or enzymatic hydrolysis, can be complex and environmentally taxing due to their harsh conditions and resultant waste streams. Emerging alternatives, like deep eutectic solvents (a mixture of a hydrogen bond donor and a hydrogen bond acceptor), offer a more sustainable approach with higher-quality yields, yet their high viscosities can hinder mass transfer rates and increase handling complexity.

Banana peel, a major agricultural byproduct, shows promise for this purpose. They are one of the most consumed crops, with global production increasing from 69 million tons in the early 2000s to 135 million tons in 2022. Because banana peels account for over 40% of the fruit's weight, approximately 41.9 million tons of peel trash are produced every year. Using banana peels for collagen extraction could turn such waste in a valuable product.