A plant-based food preservative discovered by scientists from Nanyang Technological University, Singapore (NTU Singapore) is more effective than synthetic preservatives.
This organic preservative contains flavonoids—a naturally-occurring substance and a varied group of phytonutrients present in nearly all fruits and vegetables. NTU scientists created the flavonoids that have strong antioxidant and antimicrobial properties—two major features of preservatives that prevent the growth of bacteria and keep food fresher for a longer period of time.
Tests performed on samples of meat and fruit juice showed that the organic preservative maintained its samples fresh for a couple of days without refrigeration, as opposed to commercial-grade artificial food preservatives. The other food samples containing artificial preservatives succumbed to bacteria contamination within a period of six hours during the experiment performed at room temperature (approximately 23 °C).
Professor William Chen, Director of NTU’s Food Science & Technology program headed the NTU research team, which is already in discussion with multinational companies to further advance the novel food preservative.
The researchers’ discoveries appeared last month in the scientific journal Food Chemistry – one among the top three research-based food science publications.
Prof Chen stated, “This organic food preservative is derived from plants and produced from food grade microbes, which means that it is 100 per cent natural. It is also more effective than artificial preservatives and does not require any further processing to keep food fresh.
“This may open new doors in food preservation technologies, providing a low-cost solution for industries, which could in turn encourage a sustainable food production system that produces healthier food that stays fresh longer.”
Harnessing nature’s gifts
Flavonoids are chemicals that occur naturally in plants and they are responsible for protecting plants against herbivores, pests, pathogens, and even environmental stress like strong ultraviolet rays from extended hours of sunshine. It is found in almost all fruits and vegetables and is responsible for causing bright colors in them. These include grapes, kale, strawberries, tea, and onions.
Although the antimicrobial potential of flavonoids has been reported, they are yet to be utilized as a food preservative because they have to be further processed before they can reduce bacteria. This is referred to as ‘prenylation’ – a process in which hydrophobic molecules are added to a protein to enable cell attachment – which is neither sustainable nor cost-effective.
Now, the NTU team has identified a new way to grow flavonoids in a natural and sustainable manner. These flavonoids also have high antioxidant and antimicrobial properties. The researchers accomplished this feat by implanting the plants’ flavonoid-producing mechanism into baker’s yeast (a species called Saccharomyces cerevisiae).
Just like how vaccines are produced using yeast, the team discovered that the flavonoids produced by the yeast contain high antimicrobial properties, which are not found in samples of pure flavonoid obtained directly from plants.
Prof Chen stated, “Anti-microbial and anti-oxidant properties are key elements in food preservation. Flavonoids extracted directly from plants need to be further processed to be anti-microbial whereas our flavonoids produced from yeast do not require this. Secondly, there have been no reports on anti-oxidant properties in flavonoids while our yeast-based flavonoids naturally come with it.”
Growing international concern on artificial preservatives
The study comes at a time when there is an increasing body of scientific proof on how synthetic preservatives impact the long-term growth and development of the body.
On 23 July 2018, the American Academy of Pediatrics representing about 67,000 pediatricians in the U.S, made an announcement expressing concerns regarding the chemicals utilized in food preservatives particularly in meat products. These chemicals include nitrites and nitrates, which can obstruct with the production of thyroid hormones that are important for the regulation of key metabolic processes, and have also been associated with nervous and gastrointestinal system cancers.
Sharing an independent outlook on the study, Dr. Gabriel Oon Chong Jin, a Consultant Medical Oncologist at Mount Elizabeth Medical Centre, stated, “The new source of natural food preservatives from flavonoids safely produced from yeast by NTU is brilliant, as this species of yeast has been used in brewing beer and in the manufacture of Hepatitis B vaccines.
Dr Oon, a pioneer in implementing the universal vaccination program in Singapore and a former consultant and adviser to the World Health Organization, stated, “Flavonoids are important natural food supplements with vitamins, but also used as food additives, without causing harm to the human system. This is unlike currently available artificial preservatives used in most processed foods such as aspartame and nitrates, which may cause cancer among other adverse health effects.”
The aim of NTU researchers is to further advance their findings with the food industry and improve its safety and efficacy so that it can be utilized in all packaged food products.