The scientists of Nanyang Technological University, Singapore (NTU Singapore) have discovered a plant-based food preservative which is more effective than artificial preservatives.

The organic preservative contains a naturally-occurring substance named 'flavonoids', a diverse range of phytonutrients found in almost all fruits and vegetables. The flavonoids produced by the NTU scientists have strong anti-microbial and anti-oxidant qualities; these two key attributes of preservatives can inhibit bacterial growth and keep food fresher for longer.

In the tests performed on samples of meat and fruit juice, the organic preservative maintained the freshness of its samples for two days without refrigeration, in comparison to commercial-grade artificial food preservatives.

The experiment was performed at room temperature (about 23 degrees Celsius). At this temperature, the other food samples that had artificial preservatives were affected by bacteria contamination within six hours.

Flavonoids are chemicals that naturally occur in plants and are responsible for safeguarding plants against pathogens, herbivores, pests, and even environmental challenges such as the powerful ultraviolet rays from prolonged exposure to sunshine.

They are found in almost all fruits and vegetables and are responsible for imparting vivid colors to them. Some of the fruits and vegetables containing flavonoids are onions, tea, strawberries, kale, and grapes.

Even though the anti-microbial potential of flavonoids has been noted, they have not been employed as a food preservative as they need to be further processed to counter bacteria. This process, known as 'prenylation', involves adding hydrophobic molecules to a protein to promote cell attachment. However, this process is neither cost-effective nor sustainable.

NTU researchers have not only found a way to cultivate flavonoids with significant anti-microbial and antioxidant qualities but also in a natural and sustainable fashion.

Like the way vaccines are produced using yeast, the researchers noticed that the flavonoids produced by yeast had high anti-microbial qualities, which were not even to be found in pure flavonoid samples directly taken from plants.

Professor Chen commented, "Anti-microbial and anti-oxidant properties are key factors in food preservation.

 Flavonoids directly extracted from plants must be further processed to become antimicrobial, but our flavonoids produced from yeast don't require such processing. Also, there have been no reports on anti-oxidance properties in flavonoids, whereas our yeast-based flavonoids come with this property naturally."

This research comes at a time when there is a growing amount of scientific evidence demonstrating how artificial preservatives impact the body's long-term growth and development.

The NTU research team endeavors to further develop their findings in conjunction with the food industry to improve its effectiveness and safety so that it can be used in all packaged food products.