Miguel Franco Londono | ALES Graduate Seminar

Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.

This is an ALES MSc Final Exam Seminar by Miguel Franco Londono. This seminar is open to the general public to attend.

MSc with Dr. Marleny Aranda Saldana.

Thesis Topic: Extraction of Dill Seed Oil/Essential Oil and Cranberry Pomace Anthocyanins using Green Technologies and In Vitro Evaluation of their Antifungal Activity

Abstract: 

Climate change has altered weather patterns that favor the growth of fungi on crops. Therefore interest in natural alternatives such as essential oils and phenolic compounds has increased due to concerns on the effects of chemical fungicides on the environment and human health. This study evaluated the use of supercritical CO2 (SC-CO2) technology to extract essential oil from dill seeds (Anethum graveolens) and high-intensity ultrasound (HIUS) with natural deep eutectic solvents (NADES) to extract anthocyanins from cranberry pomace (Vaccinium macrocarpon). The extraction was conducted at temperatures ranging from 40 to 60 °C, pressures from 150 to 350 bar, and scaled up 3- and 10-fold. Three kinetic models were used to fit the data. Then, commercial dill essential oil and SC-CO2 extracts were encapsulated via HIUS emulsification, using pea and lentil protein isolates, to test their antifungal activity against Fusarium graminearum and Pyrenophora tritici-repentis, two wheat pathogens. Pea protein isolate demonstrated stability comparable to synthetic emulsifiers. Extracts with higher carvone and limonene concentrations showed greater antifungal efficacy, with F. graminearum exhibiting a minimum inhibitory concentration (MIC) of 1.00 µL/mL, while P. tritici-repentis had MIC of 0.25 µL/mL.

On the other hand, cranberry pomace, rich in anthocyanins and phenolics, was investigated for its potential antimicrobial effects. The research optimized extraction by varying HIUS power levels and extraction times. Results revealed that a mixture of choline chloride + glycerol resulted in total anthocyanin content of 0.77 mg Cy3GE/g, comparable to ethanol (0.86 mg Cy3GE/g). The extract of anthocyanins using choline chloride + glycerol was evaluated as an antifungal agent against F. graminearum and P. tritici-repentis. The mycelial appearance suggested that choline chloride + glycerol may inhibit the production of fungal metabolites involved in F. graminearum pathogenicity. Furthermore, anthocyanins powder from bilberries (Vaccinium myrtillus) were assessed. At a concentration of 4.0 mg/mL of anthocyanin, F. graminearum and P. tritici-repentis showed inhibition rates of 23% and 55%, respectively. This research highlights the potential of essential oils and anthocyanins obtained with green solvents and extraction technologies, and the use of natural emulsifiers for encapsulation of these extracts to create sustainable, effective antifungal agents for cereals and to contribute to sustainable agriculture.