New research could unlock the economic potential of pineapple scraps

Pineapple processing generates a large amount of waste, but with fermentation and microencapsulation technology, researchers at the Universidad del Valle (Univalle) are looking to take advantage of the bioactive compounds contained within these scraps.

The department of Valle de Cauca accounted for a production of 161,198 tonnes of pineapple in 2019, 14% of Colombia's total, according to figures from the Colombian Ministry of Agriculture and Rural Development, but in recent years, production costs and difficulties with the supply chain have contributed to a decline in pineapple exports.

Professor Anna Maria Polanía, a lecturer at the Tuluá regional headquarters and a PhD in engineering with an emphasis on food engineering, explained that the peel, core and crown of the pineapple, which are usually discarded, contain bioactive compounds from pineapple waste, such as phenolic compounds, flavonoids and phenolic acids.

"Pineapple by-products could be converted into antioxidant capsules to be used as food additives, using agricultural by-products to open up the possibility of a secondary market," said Prof Polanía.

Image: A montage of the different stages of solid-state fermentation of pineapple. Photo: Credit: Anna Polanía.

The Research 

Professor Polanía explained that the pineapple peel, core and crown, which are usually discarded, contain bioactive compounds from pineapple waste, such as phenolic compounds, flavonoids and phenolic acids.

To release these compounds from pineapple waste, the researchers developed a solid-state fermentation process using a fungus called Rhizopus oryzae.

In the scientific paper entitled "Encapsulation of Pineapple Peel Extracts by Ionotropic Gelation Using Corn Starch, Weissella confusa Exopolysaccharide, and Sodium Alginate as Wall Materials" published in the scientific journal Foods, researchers isolated the compounds and found a way to encapsulate them.

Cristina Ramírez Toro, senior lecturer of the GIPAB group of the School of Food Engineering of Univalle, and of the MIBIA group; director of the project and a co-author of the scientific paper explained that the research group has extensive experience in microencapsulation, i.e. this technology forms a protective layer that protects bioactive compounds from high temperatures and allows for adequate bioavailability.

"It would be a great complement to a food that does not have the bioactive compounds in the recommended daily intake concentrations, and it could be added to any type of food without generating problems in its stability," Ramírez said. 

Professor Ramirez explained that the role of transdisciplinarity was very important in the development of the project. 

"This research has involved biologists, engineers, and we have even worked with groups outside the country, such as the Bioprocesses and Bioproducts Research Group (BBG-DIA) at the Autonomous University of Coahuila in Mexico," Ramírez said.

Professor Polania won an Orquídeas grant from the Ministry of Science and Technology (MinCiencias), whose main objective is to develop innovative and sustainable fermentation methods for the production of high-quality speciality coffees for small-scale producers. 

In the implementation of the project, the skills and knowledge acquired during the experimentation carried out for the valorisation of pineapple residues will be of great use.

"The fermentation process currently used by coffee growers consumes large amounts of water, so we hope to implement coffee fermentation processes by dry milling, preserving the taste and quality of the coffee," Professor Polanía said.

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Photo: A fungus growing on dried fermented pineapple. Photo: Credit: Anna Polanía.

International collaboration and regional education

To do this project, Prof. Polania needed to learn more about high-performance liquid chromatography (HPLC) and did an internship in Mexico.

Cristóbal Noé Aguilar González, a senior lecturer and director of research at the Autonomous University of Coahuila (UAdeC) in northern Mexico trained Professor Polania in HPLC when she did her doctoral thesis, under the framework of international cooperation between the Microbiology and Applied Biotechnology group (MIBIA) of the Universidad del Valle and the Bioprocesses and Bioproducts Research group (BBG) of the UAdeC. 

"The working model between Colombia and Mexico and in particular between Univalle and UAdeC has allowed mobility in both directions not only of students, but also of researchers and the organisation of events of global quality," said Professor Aguilar, adding that international scientific cooperation is key to strengthening the education and training of researchers.

Professor Polanía currently teaches at Univalle's Tuluá regional campus, located in a key intermediate city in the agricultural and service-intensive industry in the centre of the department of Valle del Cauca.

Founded in 1987 during Univalle's regionalisation push, the branch offers Electronics Technology, Software Development, Food, Construction; and degrees in Food Engineering and Systems Engineering, Nutrition and Dietetics, among others.

Professor Polanía explained that today, she is the director of four student research projects at the campus, among which are: the development of a snack whose main ingredients are the peel and core of pineapple; and an energy bar with dehydrated orellanas.

If you are interested in contacting the researcher or learning more about the project, please write to the Communications Office Faculty of Engineering: comunicaingenieria(at)correounivalle.edu.co

Cover photo: Professor Anna Polania. Credit: Anna Polania