Far beyond nutrition

Understanding the chemical composition of foods and how it influences their sensory quality and biological effects is one of the goals of the Food Research Center, supported by FAPESP.

By Karina Toledo

Agência FAPESP – Although they are not digestible by the human organism, some types of polysaccharides such as pectin found in food appear to have the capacity to modulate the functioning of immune system cells.

Identifying compounds with this property is the goal of a project led by João Roberto Oliveira do Nascimento, a professor at the University of São Paulo’s School of Pharmaceutical Sciences (FCF-USP) in Brazil. The project is being conducted by the Food Research Center (FoRC), one of the Research, Innovation and Dissemination Centers (RIDCs) supported by FAPESP.

“We’re screening for hydrosoluble polysaccharides in bananas, guavas, chayote, and some mushroom species,” Nascimento said. “Based on the composition of the molecules found and on data from the scientific literature, it’s possible to speculate whether the molecules have immunomodulatory potential. The most promising molecules will be purified and tested in immune system cell cultures.”

Depending on the results of the in vitro experiments, and at a later stage on the in vivo results, Nascimento said the group may think about extracting the compound to use it as a food supplement or an ingredient in various formulations.

A progress report was presented at the First FoRC Symposium, Advances in Food Science and Nutrition, held on September 2-3 at FCF-USP. The event was attended by researchers involved in several ongoing projects in the sub-areas into which FoRC is divided: Biological Systems in Foods; Food, Nutrition & Health; Food Safety & Quality; and New Technology & Innovation.

Nascimento and Adriana Mercadante from the University of Campinas’s Food Engineering School (FEA-UNICAMP) are coordinators of the first pillar (Biological Systems in Foods), which focuses on studying the chemical composition of fruits, vegetables and fungi.

“Chemical composition is directly linked to both sensory quality – color, texture and flavor – and physiological effects in the organism,” Nascimento said. “The idea is to study not only the components present in food crops while they’re growing but also the changes they undergo while maturing, as well as during storage and processing.”

In the project led by Mercadante, the goal is to identify carotenoids, naturally occurring pigments that give a red, orange or yellow hue to the fruits present in Brazilian biodiversity, and to discover whether they are beneficial to human health. Mercadante is developing new methodologies to facilitate this type of analysis.

The aim of the project led by Eduardo Purgatto from FCF-USP is to compare three varieties of Surinam cherry (Eugenia uniflora), one of which is yellow due to beta-carotene, another purple due to anthocyanin, and a third red due to lycopene, the latter being the most common.

“These three pigments have different biological actions, although they’re all antioxidants,” Purgatto said.” Anthocyanin has been studied for its anti-inflammatory action. The consumption of lycopene has been associated in previous studies with a reduction in the risk of prostate and lung cancer. Beta-carotene appears to be effective against liver cancer.”

With the aid of transcriptomics and techniques for the large-scale analysis of gene expression as well as metabolomics to screen for the metabolites produced by plants, the researchers are trying to understand how the metabolic pathways relating to pigment synthesis are regulated.

“We want to find out whether plants are influenced by soil or climate or whether natural mutations have occurred,” Purgatto said. “Once we understand what influences pigment metabolism, we can interfere in the process and enhance the plant’s quality attributes. We also want to understand what happens to these pigments when fruit is stored or processed, for example, in the manufacturing of juice.”

Impact on health

Investigating how bioactive compounds in food, especially polyphenols, act in the organism from the cellular level outward and how they are absorbed and metabolized is the focus for the second pillar (Food, Nutrition & Health), coordinated by Franco Lajolo and Thomas Ong, who are both professors at FCF-USP.

“Essentially we’re studying why it’s important to eat fruit and vegetables,” Lajolo joked. “There are epidemiological studies that associate the consumption of vegetables with a lower risk of disease, but few people have performed clinical or intervention trials in which volunteers are given certain types of food to observe the effect on their health and to study the mechanisms involved in this biological action.”

Several varieties of orange have been studied by the group. According to Lajolo, oranges are the leading source of polyphenols in the typical Brazilian’s diet. Other fruits studied include jabuticaba (Plinia cauliflora), grumichama (Eugenia brasiliensis), and a variety of purple corn developed in partnership with the University of São Paulo’s Luiz de Queiroz College of Agriculture (ESALQ-USP).

“We isolate a certain component, feed it to rodents and study its effect on urine, blood plasma and organs, as well as any metabolic changes, all at the same time,” Lajolo said. “We also study action mechanisms in cultured cells.”

Once the biological effect has been shown in clinical trials, Lajolo explained, this knowledge can be applied in various ways. One is selecting plant varieties that produce relatively large amounts of the bioactive compound of interest. Another is developing technology to process food without impairing its functional properties. A third is calculating the amount that needs to be consumed to obtain health benefits.

“All of these developments lead toward biomedical agriculture,” he said.

More quality and less risk

Assuring the innocuousness and microbiological quality of food throughout the production chain is one of the goals of the FoRC’s third pillar (Food Safety & Quality), coordinated by Mariza Landgraf and Bernadette Dora Gombossy de Melo Franco, who are also professors at FCF-USP.

Among the ongoing research in this sub-area is a project to detect pathogenic bacteria in organic vegetables such as Shiga toxin-producing Escherichia coli (STEC) and Salmonella, both of which cause acute diarrhea.

“We chose organic vegetables because growers typically use animal dung as manure,” Landgraf explained. “No STEC was found in any of the samples, and the occurrence of Salmonella was low. We believe this is because organic farmers sterilize manure by composting, which entails the fermentation of organic matter for two to three months to acidify its pH. Any pathogenic microorganisms present in the manure will be eliminated in this process.”

Another project involves predictive microbiology, which uses mathematical models to establish the control measures required to prevent health hazards due to cross-contamination during the handling of ready-to-eat food.

Here, the main focus is Listeria monocytogenes, a bacterium that can cause meningitis and encephalitis, as well as miscarriage in at-risk women, and that is often present in food processing environments.

The researchers simulate procedures deployed in places that sell food such as the slicing of cheese or cold cuts in supermarkets and bakeries. “The results are used to predict the behavior of microorganisms in food products and to determine which control measures are most effective,” Landgraf said.

“We found that a slicer contaminated with this bacterium, which is common in cheese, can be contaminate up to 200 ham slices if the hygienic conditions and ambient temperature aren’t appropriate,” Melo Franco added.

Other projects in the third pillar aim to evaluate natural substances with antimicrobial action that could be used as food additives or could be included in packaging to prevent the proliferation of microorganisms. Examples include limonene, found in lemon essential oil, and eugenol from cloves.

The researchers are also studying antimicrobial compounds produced by bacteria that are naturally present in food, such as bacteriocins, which can be active against other undesirable microorganisms.

Innovation

The fourth pillar (New Technology & Innovation), which is closely linked to the other three, develops technological processes for the industrial-scale production of functional ingredients and ways of converting the knowledge generated in the RIDC’s various projects into products. This pillar is coordinated by Carmen Tadini from the University of São Paulo’s Engineering School (POLI-USP) and Paulo José Sobral from its Animal Science & Food Engineering School (FZEA-USP).

One of the projects, which has reached an advanced stage and is being conducted in partnership with a company based in Ribeirão Preto, aims to develop an industrial-scale process to produce green banana flour with high resistant-starch content.

“We’ve developed a prototype hybrid dryer,” Tadini said. “The prototype is currently being tested, and we’re determining the optimal parameters for the production of banana flour. This flour contains a relatively high proportion of resistant starch, which isn’t digested by the small intestine but is digested only by the colon so that it isn’t rapidly converted into sugar.”

Studies coordinated by Elizabete Wenzel de Menezes, a researcher at FCF-USP, showed that green banana flour promotes satiety, improves bowel motility, and favors the growth of gut flora that are beneficial to human health.

“We used green banana flour in cereal bars, soup and other formulations and observed that it prevented food intake from causing blood sugar spikes, which represent one of the factors that can favor the development of diseases like diabetes,” Tadini said.

According to Sobral, another research line is geared toward developing bioactive packaging materials based on natural substances such as gelatin and polysaccharide, which increase the shelf life and reduce the risk of contamination.

“The main problem is how to make bioactive packaging economically feasible,” he said. “It won’t be like plastic, which can be used with any type of food. It will be specific to each product, with the advantage of being biodegradable. And we know there’s a demand for this type of material.”

Challenges

During the opening session of the symposium, FAPESP’s Scientific Director Carlos Henrique de Brito Cruz said that the institution expects the research conducted by the FoRC to have a major scientific, economic and social impact.

“Our expectation is that the researchers develop connections with industry and government agencies that are responsible for food supply and safety,” he said. “The four pillars of the RIDC’s research must be well articulated to ensure that the results add up.”

According to Melo Franco, FoRC’s Principal Investigator, transferring the knowledge created by the research to society, especially to the food industry, is the main challenge faced by the group.

“Brazil has few food companies with the wherewithal to invest in research, development and innovation,” she said. “The large multinational corporations market products developed by R&D centers located in their countries of origin. Brazilian companies have tight profit margins. However, we now have some promising negotiations under way.”

The symposium was also attended by members of the FoRC’s International Advisory Board, who delivered presentations on the research conducted by the institutions to which they are affiliated. They included Didier Attaix from France’s National Institute for Agricultural Research, K.P. Sandeep from North Carolina State University (USA), Paul Kroon from the UK’s Institute of Food Research, Donald Schaffner from Rutgers University (USA), and Robert Buchanan from the University of Maryland’s Center for Food Safety & Security Systems (USA).