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Bioactive compounds from native South American by-products are ‘underestimated’, says researcher

Article-Bioactive compounds from native South American by-products are ‘underestimated’, says researcher

© AdobeStock/adil-perkasa Background of cocoa pod husk waste
Despite the term “circular economy” becoming a buzzword in recent years, many important bioactives from native South American foods and their by-products – such as cocoa husks and açaí press cake – have been largely underestimated, says Chilean researcher Professor Adriano Costa de Camargo, who is calling for the creation of a reliable phenolics database to address this.

A history of sustainability: Disrupting the linear economy

The industrial revolution of the 18th century brought about great advances in terms of productivity, but also an economic model based on extraction, transformation, use, and disposal. This linear model has led to the over-exploitation of resources and the contamination of the planet, with consequences for both economic and social development, as well as for agricultural production.

The first environmental movements began in the 1960s with the publication of Silent Spring by Rachel Carson, which questioned the indiscriminate exploitation of resources and the excessive use of toxic substances in the environment. It is around this time that the concept of sustainable development was created.

Gaps in the data: Phenolics missing in action

Plant foods contain a host of phenolics, a sizeable number of which occur in the insoluble-bound form; it would follow, then, that their occurrence in plant foods and by-products deserves attention when developing new products. However, in general, insoluble-bound bioactives are ignored in medical research. A search for papers using “phenolics” as a key word on the Web of Science shows that between 2011 and 2020, more than 85 articles were published in this area; the same is not true of a search for “insoluble-bound phenolics”.

“This is where we find one of the most important gaps in the field of phenolic compounds with regard to quantification of phenolic bioactives,” Costa de Camargo said.

He argued that the limited inclusion of individual insoluble-bound phenolics in databases such as Phenol-Explorer or the USDA database is likely to lead to underestimation of their real dietary intake.

He pointed to a 2012 study in 3 Biotech looking at the concentration of phenolic compounds in different grape cultivars: up to 79% of the phenolic compounds in grape by-products were present in insoluble form. As insoluble-bound phenolics were up to 15 and 10 times more effective as antioxidants than those of free and esterified fractions, these would appear to be worthy of research by practitioners in other fields, but he cast doubt on whether physicians and nutritionists have the necessary information to do so.

© AdobeStock/Imago PhotoFresh Acai fruit in Amazonian rainforest

Fresh Acai fruit in Amazonian rainforest

Closing the circle: How to optimise resources

Costa de Camargo discussed his earlier work on optimising the extraction of polyphenols from açaí press cake – the by-product that remains when the juice from açaí, a nutritious fruit native to Brazil, is mechanically pressed – and evaluating its biological activities. He also discussed his 2021 research in which the presence of insoluble-bound phenolic and insoluble-bound alkaloids in raw cocoa nibs and husk was reported for the first time. The insoluble-bound fraction contributed up to 40% of the antioxidant properties of the tested materials.

Writing in the journal Food Bioscience, his team concluded:

“A reliable database for the phenolic content of foods is necessary to assess the effects of their intake on various biological parameters. Therefore, by demonstrating that some bioactives of cocoa and its processing byproducts have largely been underestimated, this study provides crucial information that would contribute to better understanding of the chemistry of cocoa products and their potential health benefits.”

Costa de Camargo said: “Our data and current knowledge demonstrates that a lot has to be done to achieve circularity in zero waste in terms of recovering bioactive compounds from plant foods and byproducts thereof.”

Principles of circular economy: The 9R framework

The principles of circular economy, according to the Food and Agriculture Organization (FAO) of the United Nations, are efficient use of primary sources; eco design; reuse; and recycling. However, those working in the food industry may find the 9R framework more useful, which outlines the following strategies: refuse, rethink, reduce, reuse, repair, refurbish, remanufacture, repurpose, recycle, and recover. This economic model starts from the beginning of a product's lifecycle, with the main goal being to circulate products, competence, and materials in the most efficient way possible.

The reintroduction of waste into the production chain is one of the most important fields of action within the circular economy. One of the main benefits from an economic point of view is the low cost of waste or by-products compared with other raw materials. Costa de Camargo outlined two scenarios: downcycling and upcycling.

He also discussed the 2030 Agenda for Sustainable Development, adopted by all UN member states in 2015, which “provides a shared blueprint for peace and prosperity for people and the planet, now and into the future”. It outlines 17 Sustainable Development Goals (SDGs) in what the UN describes as “an urgent call for action”. SDG number 12 – responsible consumption and production – is divided into two components: food loss index and food waste index.

However, without a reliable phenolics database to work from, much work remains to be done if we are to move closer towards a circular model, Costa de Camargo argued.

“In general, our studies have shown that the contents of some bioactive compounds in foods and their processing by province has been largely underestimated,” he said.