Around the world, researchers in nutrition-health, taste, food safety and technologies are providing us with exciting advances.
Bioactive compounds of citrus fruits may be effective in combatting age-related cognitive decline. Research programs are investigating the origins of increasing food allergies. Sensory science is shedding new light on the sensation of astringency. A research group is studying the use of insect flour adapted for human food applications, such as bread. Another group of scientists is developing modified starch-based hydrogels that can be used as the “ink” in 3D printers. Finally, Canadian scientists have demonstrated that gamma rays are more effective against insects than X-rays.
Read the June 2021 edition of VitaWatch, our scientific intelligence bulletin for the agri-food sector.
Diet and health
The role of citrus in brain health: polyphenols play a role in fighting cognitive decline
A study published in Frontiers in Neuroscience indicates that citrus polyphenols have anti-inflammatory and antioxidant properties. “Having examined the evidence available, we are most confident in the finding that citrus bioactive compounds (i.e. nutrients and polyphenols) improve general cognition, both in health populations and people with age-related cognitive decline”, declares Dr David Vauzoura Senior Research Fellow Norwich Medical School.
This study, lead by a team from the University of East Anglia (United Kingdom), determined that the absorption of polyphenols was optimised when consumed as citrus juice rather than as whole fruit, probably due to the fibre content of the fruit that acted as a barrier in the gut.
According to Dr Carrie Ruxton, of the Fruit Juice Science Center, it is important that food manufacturers show the advantages of their products using clinical research. With ageing populations, prevention of cognitive decline is an important public health challenge and consumers should have access to information on how their diet can impact their health.
Are excessively strict food safety control systems to blame for food allergies?
Faced with an increase in food allergies, a number of studies are seeking to understand the causes. One hypothesis is that these allergies are caused by the absence of natural pathogens, such as parasites, in our modern environments.
Immunobiologists from Yale University are advancing another theory. According to their research, il would appear that the hypersensitivity of our immune systeme to certain food-borne allergens is due in part to an increased use of hygiene products and antibiotics, as well as an increased consumption of processed foods, that reduces our exposure to raw foods. Finally, our intake of food preservatives and chemicals (such as dish detergent) may be new elements that our immune system is not able to handle.
Collectively, these changes in the environment effectively trigger food quality control responses making the immune system react to food proteins the way it would react to toxic substances, explains the team immunobiology researchers at Howard Hugues Medical Institute.
Formulation / process
Getting to the bottom of astringency
Astringency, the sensation of dryness or roughness in the mouth, for example when consuming a square of dark chocolate or a glass of red wine, can represent a barrier to the acceptability of plant-based foods that generate this sensation.
In a report published in the Journal of Agricultural and Food Chemistry, scientists from INRAE, CNRS and the University of Burgundy (CSGA) studied the mechanisms of astringency in order to identify the causes. According to their research, it appears that the protein MUC1, present on the surface of oral mucosa, plays a role in this sensation. By provoking the aggregation of oral mucosa proteins, tannins cause MUC1 to separate into two parts, leading to the detection of the sensation of astringency.
This discovery could lead to new areas of research aiming to further understand these mechanisms, and perhaps lead to the development of plant-based foods that are better accepted by consumers.
Scientists improve the cooking properties of insect flour
The ‘Biopolymer research group’ lead by Dr Azad Emin of the Chair of food process engineering (LVT) at Karlsruhe Institute of Technology (KIT, Germany) are studying the use of insect flours adapted for human food applications, such as bread.
While many consumers are still hesitant to eat whole insects in an unprocessed state, the acceptability of “invisible” insect ingredients is higher. In order to achieve a better acceptability with consumers, insect flours must appear as similar as possible to traditional flours.
These researchers used extrusion to process the insects. The LVT team analysed their physical and functional properties, such as their dissolution capacity, water retention capacity or elasticity. The research aims to improve these properties so that they correspond to the characteristics of classical bread flours.
The effects of extrusion on the digestibility and bioavailability of the nutrients in the insect flours are being studied in cooperation with the Max Rubner Institute. “Another advantage of the method is the deactivation of enzymes and the reduction of microbial contaminants. In addition, digestibility may be improved,” says Dr Emin.
“Future research will concentrate on the applicability of the flours produced in the baking sector. External bread checks are to cover not only the shape and appearance, but also the texture of the bread,” he reports, highlighting that the results will be of significant interest for the production of more sustainable foods incorporating insects.
Researchers create ingredients for producing 3D printed foods
3D printed food is currently undergoing a boom and is opening the possibility of foods that are personalised to consumer preferences in terms of taste, texture, usage and nutritional characteristics.
Brazilian researchers from the Luiz de Queiroz Agricultural College of the University of Sao Paulo (ESALQ-USP), in partnership with French researchers of Oniris and INRAE, are developing hydrogels based on modified starch that can be used as the “ink” in 3D food printers.
Published in Food Research International, their research studies the various technologies tested over the last years to obtain gels with the ideal characteristics for use in 3D food printing.
The two most effective methods for producing gel from wheat and cassava starch use ozone or try heating. For the first method, the researchers produced ozone by applying an electric charge to oxygen. The gas produced was mixed with water with the cassava starch in suspension. The water was then eliminated from the mixture, in order to obtain a gel whose properties varied according to the production conditions (temperature, concentration of ozone etc.). The second, more recently developed, method used dry heat on the cassava and wheat starch.
"We've demonstrated the feasibility of food production by 3D printing and fabrication of tailor-made ingredients. Now we plan to extend the applications and test other raw materials," said Pedro Esteves Duarte Augusto, a professor at ESALQ-USP and principal investigator for the project. The gels based on modified cassava and wheat starch can also be used in printing other things than food, such as biomedical products (capsules, nutraceuticals etc.).
Food safety / packaging
Food safety: irradiation and essential oil vapour for treating grains
In a report published by Radiation Physics and Chemistry, the team of Professor Monique Lacroix of INRS (national institute of scientific research - Canada), has demonstrated that a treatment combining irradiation and essential oil vapour effectively eliminated insects, bacteria and mould from stored grains. Irradiation of foods consists of exposing them to ionising radiation, such as gamma or X-rays.
The research team showed that gamma radiation is more effective against insects that X-rays. A higher flow rate with gamma rays was more effective than a low flow rate. The addition of essential oils of eucalyptus and tea-tree oil significantly improved the efficiency.
While more resistant to radiation than insects, bacteria and mould were similarly destroyed by the treatment. After carrying out several experiments, in particular on 5kg sacks of rice, the team now intends to test the process in an industrial setting, in partnership with agrifood businesses.
Fermented food waste can improve crops
Scientists at UC Riverside (California) have published results in Frontiers in Sustainable Food Systems indicating that fermented food by-products and beer mash (a by-product of brewing) could stimulate beneficial bacteria for crop growing, and make plants more resistant to pathogens. “Beneficial microbes increased dramatically when we added fermented food waste to plant growing systems,” said UCR microbiologist Deborah Pagliaccia, who led the research.
In this experiment, plants were cultivated in a greenhouse, meaning that the benefits of the waste products were maintained within a closed irrigation system. The roots of the plants received a dose of the treatment with each watering.
“This is one of the main points of this research,” Dr Pagliaccia said. “To create a sustainable cycle where we save water by recycling it in a closed irrigation system and at the same time add a product from food waste that helps the crops with each watering cycle.”
Samantha Ying, an environment specialist at UCR, also noted an increase in the quantity of carbon in the soil after each application of the food waste derivative, then reaching a plateau, suggesting that beneficial bacteria used the available carbon to reproduce. “If waste byproducts can improve the carbon to nitrogen ratio in crops, we can leverage this information to optimize production systems,” said Dr Pagliaccia .
An important note : the food waste and the beer mash underwent safety checks so as not to transmit bacterial pathogens onto the crops.
Similar experiments using by-products of almond shells are currently underway.