Received: 8 October 2017 Revised: 14 December 2017 Accepted article published: 22 December 2017 Published online in Wiley Online Library: 22 January 2018
(wileyonlinelibrary.com) DOI 10.1002/pi.5518
Bio-nanocomposites for food packaging
applications: eﬀect of cellulose nanoﬁbers on
morphological, mechanical, optical and barrier
Raissa Alvarenga Carvalho, Taline Amorim Santos,
Viviane Machado de Azevedo, Pedro Henrique Campelo Felix,
Marali Vilela Dias and Soraia Vilela Borges
The eﬀect of the addition of various concentrations of cellulose nanoﬁbers (CNF) on the thickness, solubility, morphology,
mechanics, water vapor permeability and optical properties of biopolymers isolated from whey protein produced by the casting
method was studied.The results show that the addition of CNF did not cause signiﬁcant variation in the thickness of the ﬁlms and
resulted in nanocomposites with lower solubility and water vapor permeability. Scanning electron microscopy analysis showed
that the ﬁlms obtained with up to 4% of CNF showed good dispersion of the nanoﬁbers in the whey protein matrix. The results
of mechanical tests showed that the nanoﬁbers acted as reinforcing material resulting in more resistant and less ﬂexible ﬁlms.
© 2017 Society of Chemical Industry
Keywords: whey protein isolate; nanoparticles; solubility; SEM; elastic modulus
Packaging materials made from synthetic plastics are becoming a
growing problem for the environment due to their resistance to
natural degradation, improper disposal and use of non-renewable
resources as raw materials for their production. The use of
biodegradable polymers for the production of packaging is an
attractive alternative to aid in the reduction of the problem,
since these materials, when discarded in the environment, will be
decomposable and are also derived from renewable sources.
Whey protein isolate (WPI) has been studied for the produc-
tion of food ﬁlm-type packaging, and has sparked great interest
since, besides being a biodegradable material, it is obtained as a
by-product of cheese manufacturing, and is an edible product.
Films produced from WPI as polymer base have an excellent bar-
rier to oxygen, an important feature, because when in contact
with food, oxygen can cause degradation and loss of sensory and
nutritional characteristics through the oxidation process. More-
over, these biopolymer ﬁlms also exhibit a good barrier to aro-
mas, high transparency and ﬁlm-forming ability and can be used
as active packaging for transporting food additives, antioxidants,
antimicrobial agents and nutrients, among others.
However, due to the amino acid chains present in the pro-
tein base, these biopolymers have a hydrophilic nature, a feature
which directly inﬂuences their water vapor barrier and solubility
Solubility may be desirable or not, depending on the
purpose of the material to be used. For water vapor permeabil-
ity values, biopolymers intended for use in food packaging should
have reduced permeability values, in order to minimize moisture
exchange between the environment and the packaged product.
Moreover, ﬁlms produced from WPI are fragile and not very mal-
leable, requiring the addition of other reinforcing materials which
are able to improve the mechanical properties.
A widely used method to obtain improved biopolymer per-
formance is the addition of nanoscale materials to the biopoly-
These materials have a larger contact sur-
face area per weight of material when compared with those on a
macroscale, allowing greater interaction with the polymer matrix
of the ﬁlm and leading to better performance of the material.
Among nanoscale materials, cellulose-derived nanoﬁbers (CNF)
have a great potential for application as a reinforcing material in
polymeric matrices. Cellulose is widely distributed in nature as
a component of plant ﬁber. It is derived mainly from industrial
by-products and may be obtained from various sources such as
cotton, eucalyptus, wood, ﬂax, sugarcane bagasse and sugar beet,
among others, which makes its use even more advantageous
from an environmental and economic point of view.
It has a
hydrophilic nature, leading to high aﬃnity with protein-based
polymer formulations and also with most natural polymers.
When added to packaging CNF are capable of imparting high
rigidity, vapor permeability and water solubility reduction.
Correspondence to: TA Santos, Food Science Department, Federal University of
Lavras, 37200-000, Lavras, MG, Brazil.
Food Science Department, Federal University of Lavras, Lavras, MG, Brazil
Polym Int 2018; 67: 386–392 www.soci.org © 2017 Society of Chemical Industry