Presentation Title

A study on the formation of e-polylysine and zein nanoparticles to be used as coatings to extend the shelf-life of Hass avocados (Persea americana)

Faculty Mentor

Gabriel Davidov-Pardo PhD

Start Date

23-11-2019 12:45 PM

End Date

23-11-2019 1:00 PM

Location

Markstein 213

Session

oral 3

Type of Presentation

Oral Talk

Subject Area

biological_agricultural_sciences

Abstract

Avocados (Persea americana) are a fruit, whose shelf-life is jeopardized by rapid loss of firmness and moisture. Fungal prevalence of Colletotrichum spp. in avocados heightens the need for post-harvest treatments to extend the fruit shelf-life. The application of biopolymeric coatings to produce has resulted in reduction of microbial decay, water and firmness loss. e-Polylysine (e-PL) has been successfully utilized as a natural antimicrobial against different bacterial and fungal species; the corn prolamine zein, has effectively reduced moisture loss. The objective of this project is to coat avocados with coatings made of e-PL and zein to prolong shelf-life. In this part of the study, in-vitro tests were conducted to assess the ability of e-PL to taper the incidence of Colletotrichum spp. and determine the optimal conditions to create the e-PL and zein suspension to coat the avocados. Mycelial disks of 7-day old cultures were placed on PDA plates with varying e-PL concentrations and incubated to determine minimal inhibitory concentration. Concentration of 1000 ppm showed significant reduction of fungal growth (2.88±0.16cm) after 7 days when compared to the control (5.8±0.92cm). Zein nanoparticles that will be used to create the coating for avocados were produced by antisolvent precipitation by adding 3% zein dissolved in 85% ethanol to buffer at pH 3 and 7. Bare zein nanoparticles at pH 7 had a mean diameter and zeta-potential of 186.9±8.92 nm and -25.9±0.87 mV, while at pH 3, 79.75 ±8.06 nm and 34.47±8.02 mV respectively. The addition of e-PL in the antisolvent at pH 7 caused precipitation at all tested concentration, while at pH 3 it was possible to add up to 0.65% (w/v) and form zein nanoparticles with a mean diameter and zeta-potential of 221.9± 16.19 nm and 49.6 ± 4.06 mV, respectively. Future research includes coating avocados with nanoparticles and conducting a shelf-life study.

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Nov 23rd, 12:45 PM Nov 23rd, 1:00 PM

A study on the formation of e-polylysine and zein nanoparticles to be used as coatings to extend the shelf-life of Hass avocados (Persea americana)

Markstein 213

Avocados (Persea americana) are a fruit, whose shelf-life is jeopardized by rapid loss of firmness and moisture. Fungal prevalence of Colletotrichum spp. in avocados heightens the need for post-harvest treatments to extend the fruit shelf-life. The application of biopolymeric coatings to produce has resulted in reduction of microbial decay, water and firmness loss. e-Polylysine (e-PL) has been successfully utilized as a natural antimicrobial against different bacterial and fungal species; the corn prolamine zein, has effectively reduced moisture loss. The objective of this project is to coat avocados with coatings made of e-PL and zein to prolong shelf-life. In this part of the study, in-vitro tests were conducted to assess the ability of e-PL to taper the incidence of Colletotrichum spp. and determine the optimal conditions to create the e-PL and zein suspension to coat the avocados. Mycelial disks of 7-day old cultures were placed on PDA plates with varying e-PL concentrations and incubated to determine minimal inhibitory concentration. Concentration of 1000 ppm showed significant reduction of fungal growth (2.88±0.16cm) after 7 days when compared to the control (5.8±0.92cm). Zein nanoparticles that will be used to create the coating for avocados were produced by antisolvent precipitation by adding 3% zein dissolved in 85% ethanol to buffer at pH 3 and 7. Bare zein nanoparticles at pH 7 had a mean diameter and zeta-potential of 186.9±8.92 nm and -25.9±0.87 mV, while at pH 3, 79.75 ±8.06 nm and 34.47±8.02 mV respectively. The addition of e-PL in the antisolvent at pH 7 caused precipitation at all tested concentration, while at pH 3 it was possible to add up to 0.65% (w/v) and form zein nanoparticles with a mean diameter and zeta-potential of 221.9± 16.19 nm and 49.6 ± 4.06 mV, respectively. Future research includes coating avocados with nanoparticles and conducting a shelf-life study.