Fruit peel is the armor of fruits, acting as a barrier against outer damage, pathogen invasion, and preventing water loss. The cuticle is the outermost part of the fruit peel and is mainly comprised of cutin. This polymer (a network of molecules), highly abundant in nature, provides antimicrobial properties to the peel. Due to its easily removable cuticle, the tomato is a key model for studies on cutin.
Portugal is the third biggest processor of tomatoes in Europe, and the resulting pomace is usually destined for animal feeding. In this article, a team of scientists led by ITQB NOVA’s PI Cristina Silva Pereira focused on further exploring the potential of tomato pomace as a source of antimicrobial mixtures extracted from cutin through a fast, simple, and sustainable method.
Depending on the processing and cultivation methods, pomaces’ composition can vary significantly (different amounts of seeds, peels, and stems). The team studied the extraction process from two tomato pomaces produced in two different countries. They used a liquid extractant, which allows the recovery of cutin with minor alterations and washes out the remaining components. In addition, this extractant is biodegradable, biocompatible, and can be recycled and reused.
The researchers showed that the extracts could be processed to obtain mixtures with antimicrobial activity against pathogenic bacteria. Both mixtures showed effectiveness against Staphylococcus aureus and Escherichia coli. However, there were some differences in effectiveness against E. coli, depending on the composition of the pomace.
“Many studies have explored the potential of tomato peels as a source of cutin,” says Rita Escórcio, who has been studying the process during her PhD. “However, they rely on long processes with multiple steps. We have just provided proof of concept that it is possible to use tomato pomace to extract cutin in a fast, simple, and green method. The extracts can then be processed to obtain mixtures with antimicrobial properties.” In the future, these mixtures can be used to provide antimicrobial properties to biomaterials.
Read the complete article at www.itqb.unl.pt.
ACS Sustainable Chemistry and Engineering. Finding a Needle in a Haystack: Producing Antimicrobial Cutin - Derived Oligomers from Tomato Pomace, Rita Escórcio, Artur Bento, Ana S. Tomé, Vanessa G. Correia, Rúben Rodrigues, Carlos J. S. Moreira, Didier Marion, Bénédicte Bakan, and Cristina Silva Pereira, DOI: 10.1021/acssuschemeng.2c03437