An often overlooked aquatic plant, capable of doubling its biomass in two days, capturing nitrogen from the air making it a valuable green manure, and feeding poultry and livestock, could serve as a vital food for humans in the event of a disaster. or disaster, suggests a new study by Penn State researchers.
Native to the eastern United States, the Azolla caroliniana Willd plant, commonly known as Carolina azolla, may also alleviate food insecurity in the near future, according to findings recently published in Food science and nutrition. Researchers have found that the Carolina strain of azolla is more digestible and nutritious for humans than azolla varieties that grow wild and are also cultivated in Asia and Africa for livestock feed.
The study, led by Daniel Winstead, research assistant in the laboratories of Michael Jacobson, professor of ecosystem science and management, and Francesco Di Gioia, assistant professor of vegetable science, is part of an interdisciplinary research project broader framework called Food Resilience. in the face of global catastrophic events led in the College of Agricultural Sciences.
“Other azolla species have been used around the world for several thousand years as livestock feed and as ‘green manure’ to fertilize crops due to the plant’s ability to fix nitrogen,” he said. Jacobson said. “Azolla’s use for human consumption was thought to be limited by its high total polyphenol content, which interferes with its digestibility. But this research demonstrates that the phenol content of the Carolina strain is much lower and that cooking the plant diminishes it further.”
Polyphenols, which are naturally abundant compounds found in plants, at lower concentrations are beneficial to human health due to their antioxidant activity. However, high concentrations of polyphenols can limit nutrient absorption in the body and act as antinutritional factors, Jacobson explained. Gallic acid is a stable phenol and has become a standard measurement for determining the phenol content of foods.
In the study, Carolina azolla, which was described as having a crisp texture and neutral taste, was grown in a greenhouse located on Penn State’s University Park campus. Researchers determined that Carolina azolla has a total phenolic content of approximately 4.26 grams, gallic acid equivalents per kilogram of dry weight.
That measurement compares to fruit, Winstead pointed out, which typically ranges between 1.4 and 6.2; beans between 1.2 and 6.6; and nuts, ranging from 0.5 to 19. In comparison, he added, other azolla species that grow in Asia and Africa weigh between 20 and 69 grams, gallic acid equivalents per kilogram of dry weight, too high for humans to digest comfortably.
The researchers tested three cooking methods – boiling, pressure cooking and natural fermentation – which several studies have shown can decrease the polyphenol content of foods, with the aim of reducing anti-nutritional factors potentially limiting food intake. ‘azolla by humans and livestock. Tests showed that the total phenol content was reduced by 88%, 92% and 62% with boiling, pressure cooking and natural fermentation respectively, compared to the raw plant.
Carolina azolla, sometimes called mosquito fern, fairy moss and water fern, has excellent potential for use as a fast-growing, short-season crop that requires minimal inputs, maintenance and processing, Winstead noted, adding that the plant could be used. to increase the food supply.
“Our study highlights the nutritional value and moderate protein content of Carolina azolla and demonstrates that cooking methods readily and significantly reduce total phenolic content,” he said. “Azolla’s moderate protein and mineral yields make this species desirable for cultivation.”
The easy and quick nature of growing azolla makes it an ideal resource in times of disasters, as well as for regular use by small farms and low-income areas, the researchers said. It is a versatile edible wild plant that has great potential in terms of economic, agricultural, nutritional and resilience benefits, but requires further development, they said.
“Whether as a ‘quick fix’ in disaster scenarios or a long-term resilience plan, Carolina azolla has the potential to provide large amounts of protein and calories to people and livestock,” he said, noting that the plant has even been considered for inclusion in the U.S. space program. “If azolla cultivation and preparation systems can be made more efficient, growing it indoors or outdoors after natural disasters could provide additional climate-resilient nutrient production.”
This study is linked to other ongoing systematic reviews by the same Penn State researchers examining regional, resilient, drought-tolerant food crops and increased agrobiodiversity in the face of increasingly frequent and often disruptive disasters. of the food system. For example, an article published in Frontiers of sustainable food systemsexamines the plethora of edible wild plants currently rarely used in North America, which were once used extensively by Native Americans.
“Currently we are conducting reviews in the African regions,” Jacobson said. “Hopefully, exposing the viability of lesser-used plants can help society be better prepared to ensure a resilient food system.” »
More information:
Daniel Winstead et al, Nutritional properties of Azolla caroliniana Willd., a raw and cooked edible wild aquatic plant, Food science and nutrition (2024). DOI: 10.1002/fsn3.3904
Provided by Pennsylvania State University
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