By Grace Samuel
Scientists in the United States say they have discovered a water plant that could boost agriculture and lead to food security in the country.
Thr new study led by Penn State researchers suggests that the water plant, Carolina azolla, which is often overlooked can double its biomass in two days, capture nitrogen from the air, making it a valuable green fertilizer and be fed to poultry and livestock could serve as life-saving food for humans in the event of a catastrophe or disaster,
Carolina azoll,sometimes referred to as mosquito fern, fairy moss and water fern—holds excellent potential for use as a fast-growing, short-season crop that requires minimal inputs, upkeep and processing, Winstead noted, adding that the plant could be used to increase the food supply.
Native to the eastern U.S., the plant, azolla caroliniana Willd, could ease food insecurity in the near future. According to the findings recently published in Food Science & Nutrition, the researchers found that the Carolina strain of azolla is more digestible and nutritious for humans than azolla varieties that grow in the wild and also are cultivated in Asia and Africa for livestock feed.
The study, which was led by Daniel Winstead, a research assistant in the labs of Michael Jacobson, professor of ecosystem science and management, and Francesco Di Gioia, assistant professor of vegetable crop science, is part of a larger interdisciplinary research project called Food Resilience in the Face of Catastrophic Global Events conducted in the College of Agricultural Sciences.
“Other species of azolla have been used across the world for several thousand years as a livestock feed and as ‘green manure’ to fertilize crops because of the plant’s ability to fix nitrogen,” Jacobson said.
“The use of azolla for human consumption was thought to be limited by its high total polyphenolic content, which interferes with its digestibility. But this research demonstrates that the phenolic content of the Carolina strain is much lower, and cooking the plant diminishes it further.”
Polyphenols, which are naturally abundant compounds found in plants, at lower concentrations are beneficial to human health because of 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 to determine phenol content in food.
In the study, Carolina azolla, which has been described as having a crisp texture and a neutral taste—was grown in a greenhouse located at Penn State’s University Park campus.
The researchers determined that Carolina azolla has a total phenolic content of about 4.26 grams, gallic acid equivalents per kilogram dry weight.
This measurement compares with fruits, Winstead pointed out, which generally are between 1.4 and 6.2; beans at 1.2 to 6.6; and nuts, ranging from 0.5 to 19.
By comparison, he added, other species of azolla that grow in Asia and Africa are between 20 and 69 grams, gallic acid equivalents per kilogram dry weight—too high for humans to digest comfortably.
The researchers tested three cooking methods, boiling, pressure cooking and natural fermentation that multiple studies have shown can decrease polyphenolic content in foods, with the aim of reducing antinutritional factors potentially restricting consumption of azolla by both humans and livestock.
Tests showed total phenol content was reduced by 88%, 92% and 62% with boiling, pressure cooking and natural fermentation, respectively, compared to the raw plant.