Milk chocolate wins option antirust

Nutritionist uses discarded green coffee beans to enrich the dessert with polyphenols.

To achieve the creaminess and caramel flavor that attracts so many consumers, milk chocolate needs a reduced proportion of cocoa in its formula and the addition of milk. While this makes it more palatable than dark chocolate, it reduces its content of phenolic compounds – substances that give cocoa and dark chocolate their bioactive antioxidant properties. Seeking to solve this equation, nutritionist Julia Millena Silva developed a functional milk chocolate in her doctoral research at the Faculty of Food Engineering (FEA) of Unicamp, whose bioactive potential surpasses that of dark chocolates available on the Brazilian market. The study was conducted in partnership with the Institute of Food Technology (Ital).

The production of functional milk chocolate is the result of a project by the Integrated Biotechnology Platform for Healthy Ingredients (PBIS). This is an initiative of the São Paulo Research Foundation (FAPESP), spearheaded by its first Science for Development Center (CCD) focused on the food sector, located at ITAL. The program brings together professionals from the public sector, private industries, and the third sector, as well as scientists. It also has the sponsorship of nine partner companies that have first-hand access to discoveries, among other benefits.

One of the priority themes for the PBIS (Brazilian Program for the Promotion of Sustainable Agriculture) that served as a starting point for the research is the need to develop higher value-added alternatives for defective green coffee beans that end up being produced alongside specialty coffees. “We are giving an outlet to an agro-industrial co-product in which we are world leaders. This means providing an opportunity to add value to the coffee chain, which is extremely important in Brazil and involves producers of various sizes,” comments Juliana Alves Macedo, a professor at FEA (Faculty of Economics and Administration) who supervised the doctoral thesis along with Gisele Camargo, a researcher at Ital (Institute of Technological Innovation). “For small producers, disposing of these surpluses and finding a high value-added use is a problem,” she states.

Silva reveals that his main objective was to produce a functional ingredient that could be applied to different food matrices and make the final product more nutritionally interesting. Found naturally in various vegetables, such as cocoa, phenolic compounds have antioxidant action, combating the action of free radicals — atoms and molecules responsible for cellular degradation, associated with chronic non-communicable diseases such as permanent inflammatory processes and cancer. In Brazil, one of the main sources of these compounds is coffee.

“We have access to extremely rich sources, which have great potential to improve overall health or to contribute to the supply of antioxidants for the prevention of chronic diseases. Green coffee is one of them: it is a raw material of the highest quality,” emphasizes Macedo, who coordinates a research line at PBIS on the use of phenolic compounds for the production of healthy foods.

Another priority for the researcher was to develop a milk chocolate that was as antioxidant as a chocolate with a pronounced bitterness, but accessible, palatable, and well-accepted by the general public. "The idea was that the milk chocolate would have a higher final content of phenolic compounds and add more health benefits [for the consumer]," explains Silva, noting the growing interest of the population in foods enriched with bioactive substances, that is, those that guarantee some benefit to the body.

Hands-on

Part of the research was undertaken at the Bioactive Compounds Laboratory of FEA, and another part at the Cereal and Chocolate Technology Center (Chocotec) of Ital. Responsible for the complete development of the product, from the first to the last stage, Silva worked with fruits donated by the Minas Sul Cooperative as raw material. After extracting the phenolic compounds from the coffee, using clean solvents, the nutritionist moved on to scaling up the production of the extract—from the bench to the pilot plant—ensuring a similar phenolic profile and antioxidant capacity in this process.

Before obtaining the encapsulated polyphenol extracts, she conducted a study to define the appropriate encapsulating agent to coat and protect the extract. “Often, these compounds are sensitive to light, heat, and various other factors,” says the researcher. “Encapsulation has a dual function. The first is to stabilize the phenolics and allow for longer-term use. The second is to protect our mouths from the phenolic compound. In other words, by encapsulating, we can minimize the impact of taste and astringency,” explains the supervisor.

Silva studied the levels of phenolic compounds in dark chocolate available on the Brazilian market, aiming to define the quantities to be used. She clarifies that preserving the sensory characteristics that make milk chocolate palatable was fundamental. “Green coffee naturally has a bitterness. It was important to mask this flavor so that it wouldn't be noticeable in the final product.”

Finally, the nutritionist conducted an in vitro digestion simulation to examine whether the antioxidants added to the chocolate would be available for absorption as expected. Following standardized methodology, Silva simulated the processes of oral, gastric, and intestinal digestion. The experiment revealed that, compared to standard dark chocolate, her product managed to increase the amount of phenolic compounds absorbed. “We also managed to preserve them: when you look at the concentration of phenolics in the intestine, you can see that it is similar to what was initially present [in the capsule].”

“Julia conducted a study with different encapsulating materials and managed to arrive at a stable product [the phenolic compound extract], which is easily dispersed and imperceptibly transferred to the chocolate mass. It is also not noticeable in the texture and does not impart a strong flavor. In the highest doses we tested, its flavor is extremely mild,” explains Macedo, highlighting that the extract made by the nutritionist has the potential to be a 100% Brazilian functional ingredient.