The work was supported through the project UIDB/50006/2020, funded by FCT/MCTES through national

funds and by the AgriFood XXI I&D&I project (NORTE-01-0145-FEDER-000041 co-financed by European

Regional Development Fund (ERDF), through the NORTE 2020. N Teixeira and Hiléia Souza thanks FCT

for CEECIND/00025/2018/CP1545/CT0009 and PTDC/OCE-ETA/31250/2017 contracts, respectively.

Acknowledgements

Extraction of polyphenolic compounds

Film production – Casting method

Films with NADES and NADES/GT extracts (10%, 20% and 30% w/w).

Two systems: CH films with and without addition of NADES or

NADES/GT.

Film characterization

Scanning Electron Microscopy (SEM)

Experiments were carried out at

CEMUP, Porto, Portugal.

Water Vapour Permeability (WVP)

Optical properties (colour and opacity)

Swelling Index (SI)

Results and discussion

CH biofilms (with and without binary and ternary NADESs), produced by

casting method, present compact, homogenous and transparent structure.

Ternary NADES (ChCl/lactic acid/glycerol) exhibit great potential to be

used as a plasticizer for polysaccharides biofilms.

The results obtained suggest that, by varying the composition/structure of

these potentially biodegradable films, the morphology as well the water

resistance proprieties of the films can be altered.

Conclusions

References[1]Queiroz,Q.U.B; Collares-Queiroz, F. P. Polymer Reviews 49 (2009) 65-78.

[2] Galvis-Sánchez,A.C., Sousa,A.M.M., Hilliou,L., Gonçalves, M.P. and Souza,H.K.S. . Green Chemistry, 18 (2016), 1571-1580.

[3]Trouillas, P. Sancho-García, J. C., De Dreitas, V., Gierschner, J., Otyepka, M. and Dangles, D. Chemical Reviews, 116 (2016) 4937-4982.

[4]Papuc, C., Goran, G. V., Predescu, C. N., Nicorescu, V. and Stefan, G. Comprehensive Reviews in Food Science and Food Safety 16 (2017) 1243-1268.

Swelling Index (SI)

Similar increase of water retention

capacity evolution was observed.

Despite the process being very fast for

all the samples, it depends on the type of

NADESs used.

Scanning Electron Microscopy (SEM)

Chit

Compact and homogenous microstructures were

observed for chitosan film without plasticizers.

Outer surface of all films show no cracks or pores.

Surface morphologies depending on NADESs type

used.

The presence of GT polyphenols leads to different

surface structures, and so, the surface of the film

becomes rough with the increase of GT content.

NADES1_10% NADES2_10% NADES3_10%

NADES1_GT_10%

5000 X

NADES1_GT_20% NADES1_GT_30%

Water Vapour Permeability (WVP) and Thickness

Films d (mm)WVP

(g-1·s-1Pa-1)x10-10

Chit 0.085±0.006 3.12±0.03

Chit-NADES1-20% 0.077±0.003 3.37±0.15

Chit-NADES2-20% 0.080±0.004 3.90±0.04

Chit -NADES3-20% 0.076±0.007 3.29±0.07

Chit-NADES1-GT 20% 0.078±0.007 3.67±0.01

Chit-NADES2-GT 20% 0.071±0.002 3.79±0.02

Chit-NADES3-GT 20% 0.079±0.004 3.33±0.05

Films prepared with Chit

show higher thickness values

than plasticizer films.

Films with NADES showed

different WVP from the

unplasticized film.

Within films containing

NADES/GT extraction (Ta-

ble 1), the lowest value was

displayed by Chit-NADES3-

GT.

Table 1 - WVP and thickness, d, values of investigated films with 20% of plasticizer.

Optical properties

Addition of NADES had a noticeable impact on biofilm’s colour.

Graphic 2 - Colour parameters for CH films in presence

and absence of NADES or NADES/GT extraction.

Graphic 3 – Opacity parameter for CH films, with and

without addition of NADES or NADES/GT extraction.

Graphic 1 –Swelling Index for CH films in presence and absence of NADES or NADES/GT extraction

Introduction

It is expected that every aspect of industrial manufacturing can shift to

develop environmentally friendly processes in order to obtain functional

materials from biodegradable and naturally abundant resources.

Concerning the bioplastic industry, chitosan (CH) is a very promising

candidate for production of bio-based materials since it is renewable, non-

toxic and biodegradable. CH has been used to develop packaging

applications.[1,2]

Green technologies, such as the use of natural deep eutectic solvents

(NADES), have been recently used as an environmentally friendly media

for plasticizer biofilm and as an extraction medium of bioactive

products.[3,4]

In this work, we report the successful use of binary and ternary NADES as

a multi-functional medium for the extraction of polyphenolic compounds

from green tea (GT). The polyphenols extracted were used for the

production of CH bio-films. Transparent films were obtained and evaluated

in terms of water resistance, optical and microstructural properties and

thermal proprieties. Significant differences were verified in the biofilm's

microstructural properties, hygroscopic and thermal behaviour for the

NASDES type and content considered.

Tiago Filipe P. Alves*, Natércia Teixeira, Victor de Freitas and Hiléia K. S. Souza

Green tea extract and green ionic liquids used as

functional additives for chitosan filmsREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto,

Rua do Campo Alegre s/n, 4169-007 Porto, Portugal. *Email: up201704456@edu.fc.up.pt

Concurso para Projetos de I C&DT

em Todos os Dom ínios Cient íficos

Guia de Apoio ao Preenchim ento do

Form ulár io de Candidatura

2 8 de janeiro de 2 02 1

The films tended to be green (-a*) and yellow (+b*).

NADES-1 films and NADES-2/GT were the most transparent’s biofilms.

NADES:

NADES1 - ChCl/latic acid (LA) 1:2

NADES2 - ChCl/glycerol (Gly) 1:2

NADES3 - ChCl/LA/Gly 1:1:1

CH (3% w/w)

(DD=78%)

pH=5.70

Adjusted with acetic acid

NADES (1,2,3)-GT

extraction