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| Proffesor and researcher Andrés Felipe Caballero Tovar, author of the investigation. Credit: Édgar Bejarano, Communications Office, Faculty of Engineering. |
Current trends in the consumption of healthier foods have brought with them challenges in terms of production and the search for ingredients that meet these needs. Cocoa, being the basis for the preparation of chocolates and their derivatives, represents a case of special interest. Research aims to use new ingredients that contribute to improve the nutritional characteristics of chocolates, while offering new experiences for the consumer's palate.
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The search for healthier products
The path to this research, whose results were published in the specialized journal "Journal of Food Engineering", began years ago, when professor and researcher Andrés Felipe Caballero Tovar formed his own company in the area of chocolate, thanks to resources from the Emprender Fund. To successfully carry out his bet, he made an alliance with a cocoa producer in the municipality of Rivera, Huila, which allowed him to establish a chocolate factory where he processed from the fruit of the cocoa tree to fine chocolates. In this place, tests were carried out, which included fillings with different fruit pulps. This experimentation was the basis for the research project he later carried out, when he sought to evaluate the effect of the incorporation of sugars and citric acid in cocoa butter from an emulsification process, as part of his doctoral studies in Engineering with emphasis in Food Engineering, at the Universidad del Valle, with the support of the "Call for the Training of High Level Human Capital for the Department of Tolima", of the Ministry of Science, Technology and Innovation (MinCiencias). These doctoral studies were supported and directed by professors and researchers Angélica Piedad Sandoval Aldana, from the Department of Plant Production and Health of the Faculty of Agronomic Engineering of the University of Tolima; and Alejandro Fernández Quintero, from the School of Food Engineering at the Universidad del Valle.
"The research arose from people's current trends to consume healthy foods, and we see that every day. You can already find warning labels on product labels. If it has higher saturated fat content you have to report it, if it has excess sugar you have to report it. And everything leads both the industry and the scientific community to start formulating products to replace these exaggerated amounts, so that they comply with the requirements and regulations", says professor and researcher Andrés Felipe Caballero Tovar.
For his research, the starting point was to recognize the high caloric level of chocolates, mainly due to the fat and sugar content, which, according to the researcher, can range between 40% and 50% in traditionally manufactured chocolates. "The main problem is not the cocoa fat in fine chocolates, because it has an important content of unsaturated fatty acids that are beneficial to health," he explains, adding that the difficulty comes from the high cost of this raw material, which forces producers to substitute it with other cheaper sources of fat, whose effects on consumers' bodies can be harmful. These are ingredients with high concentrations of saturated fats, the consumption of which is associated with diseases related to the cardiovascular system.
In view of this scenario, several researches have indicated that it is possible to reduce the high content of these fats by incorporating microscopic water droplets in the oily phase of these chocolates, by means of an emulsification process. "By incorporating water, in the form of microscopic droplets in the structure, it is possible to achieve a considerable reduction in the lipid content of traditional products," says professor and researcher Andrés Felipe Caballero Tovar.
His research also proposed an innovative approach: experimentation took advantage of the opportunity to incorporate substances of interest inside the water droplets, for which a study model was used, taking passion fruit juice as a reference.
The bet: drops of water with passion fruit inside
Emulsions, the basis of the experiment, are the union of two immiscible liquids, whose characteristics make their integration very difficult. For this to happen, the components of these liquids must be distributed, considering their bases: on the one hand, there is the oily phase, composed of fats, and, on the other hand, the aqueous phase, composed of water. The process consists of the addition of one phase to the other, dispersed in tiny droplets, technically called the "dispersed phase". Some of the products which use this method are found in mayonnaises, salad dressings, cosmetic creams and sunscreens. In this case, the "dispersed phase" of water was incorporated into the oily phase represented by the cocoa fat. This "dispersed phase" included the main components of passion fruit juice.
"Passion fruit was taken as a reference because it has been used a lot in chocolates. It is a fruit that mixes very well for preparations, sensorially," explains professor and researcher Andrés Felipe Caballero Tovar. Because the juices of this fruit contain a large number of substances and properties, including vitamins, aromas, antioxidants and compounds such as beta-carotene, the study focused only on its main components: glucose, fructose, sucrose and the most predominant acid in this juice, citric acid. Based on this decision, a model was created based on these properties, and their effect on the structuring of a stable emulsion was studied.
Promising results
Cocoa fat is complex when it comes to this type of procedure, since its structure changes according to the temperature differences to which it is subjected. Depending on the temperature, up to six types of structures can be formed, scientifically called "polymorphs". These structures are responsible for the chocolate's gloss and hardness, and depending on which ones they are, they have greater or lesser stability.
Alpha 1 and 2 "polymorphs" have a high level of instability, and melt at a relatively low temperature. Beta "polymorphs" 3 and 4, called transition polymorphs, have a higher level of stability. And "polymorphs" 5 and 6 have the highest level of stability, as they require a temperature above 37°C to melt.
In addition, two surfactants were used for the research, which had a high affinity with both water and cocoa fat, in order to obtain a hydrophilic and lipophilic balance to stabilize the emulsion.
One of the surfactants chosen is typically used in the manufacture of chocolates, called polyglycerol polyricinoleate; the other is used for the manufacture of margarines, since the similarities between this type of emulsion and that of margarines were high. "It was found that the mixture of surfactants does favor the formation of these polymorphic structures around the dispersed phase. It forms as a barrier. When that barrier forms, it prevents those droplets from coalescing and destabilizing. It was a very interesting result," recalls professor and researcher Andrés Felipe Caballero Tovar, adding that another of the findings of this research was the contribution of citric acid to the stability of the emulsion.
"One of the factors that are of interest for the stabilization of these emulsions is that the droplets are very small. The smaller they are, the more suspended they will be and the more difficult it will be for the dispersed phase to separate from the oily phase, which will make the emulsion more stable. By incorporating citric acid and passion fruit sugars into these drops, the surfactants that are around them will adhere more", are his words.
The place of this type of product in the industry of the future
Thanks to his proximity to the chocolate industry, and despite the fact that he is no longer in charge of the company where it all began, professor and researcher Andrés Felipe Caballero Tovar assures that the results obtained in this doctoral research, beyond the publication of a scientific article, are being applied. "Not only the results directly, but also the selection of emulsifiers, so that they are more effective and comply with current regulations, which are more demanding," he says.
In addition, he believes that this is the right time to create products with added value and greater relevance at the functional level, which respond to the demands of contemporary consumers. "We have to think about developing chocolates which have a more interesting functional profile. This could be an interesting option to start including them," he says.
If interested in being in touch with the researcher or any further information about the investigation, please write the Faculty of Engineering Communications Office: comunicaingenieria@correounivalle.edu.co
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