Process that reduces sugar by “fishing” sucrose by magnetic nanoparticles is an option for low-calorie foods
Brazil has the goal of reducing sugar consumption in processed foods by around 144 thousand tons by the end of 2022. The agreement between the government and industry is a means of combating obesity, which is the cause of serious diseases such as diabetes.
Natural juices did not make the list, but they become even healthier by reducing their caloric value, and with a competitive advantage for the industry. Hence the importance of a technology developed at Unicamp, with a protection strategy made by Agência Inova Unicamp and a patent application already filed with INPI.
The process reduces the sucrose content in natural juices using nanotechnology, and could be an option to increase the supply of low-calorie foods. Sucrose represents approximately 60% of the sugar molecules in the juice. “Orange juice contains fructose, glucose, sucrose, flavones, water, vitamin C, various fibers and other compounds. We developed a way to obtain sucrose without interfering with the composition or organoleptic properties of the juice, as if it were fishing”, says Ljubica Tasic, professor and researcher at the Institute of Chemistry (IQ) from Unicamp.
The research was motivated by the significant production of the fruit in the country. Brazil is the world's largest orange producer and one of the main juice exporters. The country accounts for 35% of global fruit production and produces three of every five glasses of the drink consumed on the planet, according to the Citrus Defense Fund (Fundecitrus).
Bait to attract sucrose
The method for producing hypocaloric juices includes the preparation of a “bait” that removes sucrose by modifying the surface of a magnet. The research team - made up entirely of women - synthesized magnetite nanoparticles, a nanostructured iron oxide, which was then coated with an inert material, and functionalized with the invertase enzyme, responsible for accelerating the chemical reaction to break down sugar molecules. . “Invertase is isolated from biological yeast and has a highly specific interaction, perfect for isolating target molecules. Unlike other methods of obtaining low-calorie juices, which use columns and filtration, it does not interact with the other components present in a suspension as complex as orange juice”, he explains.
In this way, it was possible to isolate sucrose without altering the properties so appreciated in orange juice, such as aroma, color, texture and flavor, in addition to reducing industrial steps that could eliminate desirable nutritional and sensory aspects in juices, such as fiber and lumps. of the fruit. To separate the nanoparticles from the sucrose after the “fishing” process, a magnet was used.
Magnetic separation is used in other sectors of the food and beverage industry. In wine production, it helps remove proteins that cause turbidity. Other examples are the clarification of fruit juices and the removal of whey. The use of nanoparticles - smaller than the generally applied microspheres - is seen as promising due to the greater contact area in relation to volume.
Iron oxide nanoparticles are already permitted as dyes and food additives and have been approved for use in living beings by the FDA (North American Food and Drug Administration). In the pharmaceutical industry they are also applied in PCR tests, to purify samples and detect viral RNA.
Reusing orange sugar
The process developed “offers enormous potential from a scientific and economic point of view”, says the text sent by Inova Unicamp with the request for protection of the technology. In tests carried out in the IQ Biological Chemistry, the nanomaterial was reused for ten consecutive rounds without loss of sucrose capture capacity and invertase activity.
The capture also occurred without the occurrence of hydrolysis (a reaction that promotes the breaking of the sucrose bond into smaller units). “We discovered that invertase, at the low pH of orange juice, is inactive for other molecules and does not lead to catalysis, which allows sugar to be recovered in two ways”, says Tasic. The study was published in Royal Society Chemistry.
The sucrose removed from orange juice can be used as traditional table sugar or inverted sugar (also known as sugar honey), adding value to production and enabling the reduction of cultivated areas. The next phase is to scale the tests to an industrial plant. To achieve this, Inova Unicamp seeks partnerships with companies.
