From farm to fork via the analytical road: the case of Passiflora waste on the integration of chemistry, circular economy and a sustainable future
How analytical chemistry can collaborate into the development of novel processes to extract valuable goods from what was once considered a residue
According to The United Nations Food and Agriculture Organization (FAO), one third of the food produced worldwide is lost or discarded per year  and, in a world with more than 800 million people going hungry, it is increasingly necessary to rethink the way we produce and deal with food. Especially in an integrated (or globalized) system, with agriculture production in massive scales, local problems related to crops and food systems have increased significantly and impacted not only local ecosystems, but also globally. The recent fires in the Amazon and Pantanal biomes in Brazil, often related to the expansion of low-efficiency crops and meat production – that are shipped all over the world –, are examples of how there is a world-wide responsibility over local issues, which may also have global impacts and accelerate the climate crisis.
New movements towards a more sustainable relationship of mankind with food have been created recently, such as Field & Food Tech Hub-UFSCar launched in November 2019 and, this year the EU’s “From Farm to Fork” strategy, focusing on the prevention of food waste and greener food production, logistics and consumption, as one of the main actions of the European New Green Deal. In this way, new opportunities arise for agriculture-based countries through sustainable agriculture and food production, on which regional solutions can be promoted to create new markets and help boosting weaker economies towards economical emancipation, as long as it ensures a fair distribution of wealth and land.
The article “Development and application of green and sustainable analytical methods for flavonoid extraction from Passiflora waste” comes from a place of study and several lessons learned from the Brazilian agro-industrial scenario, as well as it shows the integration of the local problems related to food waste with green and sustainable chemistry and circular economy . This work aimed at developing, applying and comparing three different methodologies to evaluate the best conditions of flavonoids extraction from the processing residue of Passion fruit, one of the most important fruits in the Brazilian agriculture. Flavonoids are naturally occurring compounds that are often related to defense mechanisms in plants, possessing several bioactivities (e.g. fungicide, bactericide and pesticidal activity in general) and antioxidant properties. They are considered a valuable chemical product that, isolated or incorporated in crude extracts, could return to the food supply chain as a nutritional enhancement or conservative food ingredient.
The extraction of flavonoids isoorientin, orientin and isovitexin, from the peels of the Passiflora edulis Sims f. flavicarpa Deg (yellow or sour passion fruit), was evaluated with homogenizer-assisted (HAE), ultrasound-assisted (UAE) and microwave-assisted (MAE) solid-liquid extraction techniques in ethanolic solutions, with the aid of a full factorial design to reach optimal parameters concerning sample mass, energy and solvent efficiencies. Therefore, it was possible analyze efficiency and sustainability aspects and compare the three extraction techniques, being a more simple and holistic approach to lab scale extraction methodologies when compared to other green metrics available in the literature .
According to the results, we have observed that the sustainable factors could assist to distinguish efficiency in terms of mass yield and energy and solvent consumption, helping us to better understand true sustainability for each technique and to make a fairer comparison between green technologies. As extraction results, the procedure based on HAE presented best conditions for the extraction of selected flavonoids (1.07, 0.90 and 0.33 mg g-1 of isoorientin, orientin and isovitexin, respectively) and it was considered the best method according to the green and sustainable factors. In this case, we concluded that two extraction techniques (MAE and UAE) that are usually listed as green and/or sustainable methods, had lower energy and solvent efficiencies than HAE, which is usually neglected as a sustainable technology.
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