Sveučilište u Zagrebu Agronomski fakultet

Obrana doktorskog rada :: Slaven Jurić, mag.nutr.

Datum održavanja:

Bioencapsulation as a sustainable delivery of active agents for plant nutrition/protection and production of functional foods
09.10.2020., 11:00 sati, vijećnica (Prehrambeno-biotehnološki fakultet)

Obrana doktorskog rada u okviru doktorskog studija Biotehnologija i bioprocesno inženjerstvo, prehrambena tehnologija i nutricionizam, znanstvenog polja interdisciplinarnih biotehničkih znanosti.

Mentori doktorskog rada:

  • izv. prof. dr. sc. Marko Vinceković
  • prof. dr. sc. Anet Režek Jambrak

Povjerenstvo za obranu doktorskog rada:

  • Prof. dr. sc. Verica Dragović-Uzelac, Sveučilište u Zagrebu Prehrambeno-biotehnološki fakultet
  • Prof. dr. sc. Ksenija Durgo, Sveučilište u Zagrebu Prehrambeno-biotehnološki fakultet
  • Doc. dr. sc. Luna Maslov Bandić, Sveučilište u Zagrebu Agronomski fakultet

Abstract

Encapsulation into biopolymer microparticles ensures the protection and targeted delivery of active agents, it offers controlled release with higher efficiency and environmental safety for ecological and sustainable plant production. This work includes the preparation and application of microparticles loaded with chemical (Cu2+, Ca2+, Mg2+) and biological (Trichoderma viride spores) agents. Desirable microparticles in terms of physicochemical characteristics, cost efficiency, and sustainability, were further applied in the production of the vine (Vitis vinifera L.) and lettuce (Lactuca sativa L.). The application of microparticles presents an innovative way to stimulate plant metabolites synthesis. This would enhance plants' defense against pests and pathogens and would result in the production of higher quality food. Results reveal complex intermolecular interactions between used components for encapsulation. T. viride germination inside the matrix and germ tubes penetration out of the microspheres revealed an environment supportive of T. viride growth. Kinetics and mechanisms of agents released from uncoated and chitosan-coated alginate microparticles were investigated. Increased cation concentration promoted, but the presence of the chitosan layer reduced the rate of active agents release. The release mechanism was Fickian diffusion or a combination of diffusion and erosion mechanisms. T. viride spores release mechanism from Ca-alginate microspheres was detected as anomalous transport kinetics whereas from Ca-alginate microcapsules is controlled by Type II transport. Microparticles were tailored to supply plants (vine and lettuce) throughout the growth period. Treatments of the vine resulted in a significant increase in almost all measured parameters (total polyphenols, antioxidant capacity, total carotenoids, and total chlorophylls) of vine leaves compared to the control. The treatments enhanced vine leaves in terms of bioactive potential and can be further used as a functional food or serve as a source of functional compounds. All treatments with microparticles had a positive effect on the enhancement of plant metabolites content in lettuce. The highest increase of chlorophylls, antioxidant activity, and total polyphenolic compounds was obtained with calcium-based microparticles treatments in both, conventionally and hydroponically grown lettuces. Non-encapsulated fungus T. viride enhanced the synthesis of plant secondary metabolites only in hydroponics cultivation signifying the importance of its encapsulation. Bioencapsulation was revealed to be a promising method for the efficient delivery of active agents for plant nutrition/protection and the production of functional foods.

Keywords: ionic gelation, sodium alginate, chitosan, plant secondary metabolites, functional foods, sustainability