Onion, one of the most cultivated and consumed vegetables on the planet, contains some components that have antioxidant and antimicrobial properties, making it possible to use it to preserve food, says a new study.
The study has been conducted by researchers from the Polytechnic University of Cataluna (UPC) and the University of Barcelona (UB),
"The antioxidant and antimicrobial properties of the flavonoids of the raw onion make it a good candidate for use in food preservation", said researcher Jonathan Santas from the department of nutrition and bromatology at the University of Barcelona (UB).
The study has shown that the flavonoids of onion, in addition to having beneficial properties for health, increase the life of foods, and so "they are a natural alternative to artificial additives used in the food industry".
Flavonoids are phenolic compounds (with the phenol group), which are synthesized by plants.
The results confirm that, especially the yellow variety, is "a good source of these types of substances, and there is a positive correlation between the presence of flavonoids and their antioxidant capacity".
"The onion can be effective for delaying lipid oxidation in emulsions of oil and water -a model system of foods like margarines and mayonnaises-, and it also inhibits the growth of microorganisms that alter foods", Santas said.
The scientific team analysed onions of the White varieties "Fuentes de Ebro" and "Calgot de Valls" and the yellow variety "Grano de Oro".
Using them the researchers demonstrated that phenolic compounds in the onion prevent the development of bacteria such as Bacillus cereus, Staphylococcus aureus, Micrococcus luteus and Listeria monocytogenes, microorganisms typically associated with the deterioration of foods.
Previous studies indicate that flavonoids have beneficial effects for health due to their antioxidant, anti-inflammatory, cardioprotective, vasodilatory and anti-carcinogenic properties, making it of special interest in the prevention of chronic illnesses, such as cardiovascular illnesses, and some types of cancer.
The study has been published in the International Journal of Food Science and Technology.