View
213
Download
0
Category
Preview:
Citation preview
7/21/2019 Development of Antioxidant Packaging Material
1/7
E:Food
Engineering
&
Development of Antioxidant Packaging Materialby Applying Corn-Zein to LLDPE Filmin Combination with Phenolic CompoundsHye-YeonPark, Sung-Jin Kim, Ki Myong Kim, Young-Sun You, So Yeon Kim, and Jaejoon Han
Abstract: Functional active packaging materials were successfully developed by incorporating antioxidant agents into
corn-zein-laminated linear low-density polyethylene (LLDPE) film. The minimum effective concentrations of the active
compounds (for example, thymol, carvacrol, eugenol) were determined and these compounds were then laminated into
LLDPE films to develop corn-zein-laminated films with antioxidant agents. The release rate of antioxidant agents in
gas and liquid media were determined along with the mechanical and water barrier properties of the films containing
these compounds. Tensile strength and percentage elongation at break were reduced in the corn-zein-laminated LLDPE
films when compared to typical LLDPE film. Furthermore, the ability of the corn-zein-laminated films to repel moisture
decreased by approximately 12.2%, but was improved by incorporating hydrophobic antioxidant compounds in the corn-
zein layer. Examination of release kinetics in the gas and liquid phases verified that antioxidants were effectively released
from the films and inhibited oxidation during testing. Finally, the films were used for fresh ground beef packaging,
and effectively inhibited lipid oxidation and had a positive effect on the color stability of beef patties during storage.
These results indicate that the developed antioxidant films are a novel active packaging material that can be effectively
implemented by the food industry to improve the quality and safety of foods.
Keywords: antioxidant film, corn-zein, diffusion test, ground beef, mechanical property
Practical Application: Zein protein, a by-product of corn processing industry, was laminated into plastic films in combi-
nation with natural phenolic compounds to develop antioxidant packaging films. The films demonstrated their efficient
release patterns of antioxidant compounds, which are suitable for packaging applications and food protection.
IntroductionThe main purpose of food packaging is to maintain the qual-
ity and safety of food during distribution and storage. In recent
years, there have been increasing concerns about food quality and
safety, which have motivated the development of active packaging
(Dallyn and Shorten 1988). Active packaging is an innovative type
of packaging that prevents or slows deterioration in food quality
(Buonocore and others 2003). Oxygen scavengers, carbon diox-
ide scavengers/emitters, moisture absorbers and ethanol generators
are some examples of active packaging. Active packaging also in-
volves the release of antioxidants and/or antimicrobial substances
onto the food surface. Due to environmental and health concerns,
active packaging has been made from eco-friendly and biodegrad-
able food packaging materials combined with natural preservatives
(Appendini and Hotchikiss 2002; Suppakul and others 2003).Polyethylene (PE), the most common and least expensive syn-
thetic polymer, is a widely used plastic material in food packaging.
MS 20120474 Submitted 3/28/2012, Accepted 7/10/2012. Authors Park,S.-J. Kim, and Han are with Dept. of Food Science and Biotec hnology, SungkyunkwanUniv., Suwon 440-746, Republic of Korea. Author K. M. Kim is with Dept. of Foodand Nutrition, Honam Univ., Gwangju 506-714, Republic of Korea. Author Youis with Bio Polymer R&D Center, Korea Bio Material Packaging Assn., Bucheon421-742, Republic of Korea. Author S. Y. Kim is with Boimedical Research Institute,Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea. Directinquiries to author Han (E-mail: han2009@skku.edu).
PE is the family name for resins such as low-density polyethy-
lene (LDPE), high-density polyethylene (HDPE), and linear low-
density polyethylene (LLDPE) (Robertson 1993). However, de-
spite the physical and economic advantages of PE films, they cause
environmental problems due to their nondegradability and diffi-
culty in recycling. Therefore, researchers have begun to use nat-
ural polymers as substitutions for synthetic polymers to develop
biodegradable food packaging materials (Peppas 2004).
Biopolymers are biodegradable, nontoxic, recyclable polymers
that are frequently applied as edible coatings or films (Cuq and
others 1998). They are made from natural sources such as polysac-
charides, proteins, and lipids. Zein is the major storage protein of
corn (Zea mays L.) and comprises 45% to 50% of corn protein.
It is a widely used biopolymer for producing biodegradable pack-aging materials. The advantage of corn-zein is its ability to form
tough, relatively hydrophobic, and grease-proof films with excel-
lent flexibility and compressibility (Lai and others 1997). However,
corn-zein film has problems relating to its brittleness under dry
conditions, which restricts its use as a free-standing film or a coat-
ing material (Pomes 1971; Shukla and Cheryan 2001). To over-
come this problem, biopolymers are often coated on conventional
synthetic plastic films to develop a multilayered film structure (Atik
and others 2008).
For over 50 y, antioxidants have been added to the food-making
process to delay auto-oxidation (Cuvelier and others 1994). In ac-
tive antioxidant packaging, this consists of introducing antioxidants
C 2012Institute of FoodTechnologists R
doi: 10.1111/j.1750-3841.2012.02906.x Vol. 00, Nr. 0, 2012 Journal of Food Science E1Further reproductionwithout permission is prohibited
7/21/2019 Development of Antioxidant Packaging Material
2/7
E:Food
Engi neeri ng
&
Antioxidant packaging film . . .
into food packaging material instead of adding them directly to
the food (Tovar and others 2005). A wide range of compounds,
most of them synthetic molecules, have been used as antioxidant
agents in packaging (Padgett and others 1998). Currently, the most
frequently and widely used synthetic antioxidants in active food
packaging are butylated hydroxyanisole (BHA) and butylated hy-
droxytoluene (BHT), which are highly stable and efficient, and are
also cost-effective. Although these antioxidants can effectively in-
hibit the lipid oxidation of foods, the use of synthetic antioxidants
is strictly regulated as they are known to cause health risks (Branen1975) and is becoming increasingly unacceptable to consumers be-
cause of their potential toxicity (Chan and others 2007; Yen and
others 2008). Due to safety concerns in the active food packaging
sector, natural compounds have been deemed more appropriate.
Essential oils, extracted from herbs or spices, are regarded as
natural alternatives to synthetic preservatives and the use of these
oils in food meets consumer demands for safe food products (Burt
2004). Many essential oils exhibit antioxidant activity, which is
attributable to their high phenolic compound content. Phenolic
compounds are free radical scavengers, metal chelators, reducing
agents, hydrogen donors, and singlet oxygen quenchers (Proestos
and others 2006). In particular, thymol, carvacrol, and eugenol are
some of the most active phenolic antioxidants found in essentialoils. They are the major phenolic compounds present in thyme,
oregano (thymol and carvacrol), and clove (eugenol) essential oils.
Roberto and Baratta (2000) reported that thymol, eugenol, and
carvacrol exhibited the highest antioxidant activity in a study of
100 pure components of essential oils. In recent reports, eugenol,
menthol, and thymol maintained the quality and safety of sweet
cherries under modified atmospheric conditions (Serrano and
others 2005).
Active packaging acts as an inert barrier between food products
and the external environment, and the incorporation of antiox-
idant agents into polymeric packaging materials is an exciting
development in food packaging (Nern and others 2006). Antiox-
idants are released from packaging films by diffusion, and directlyinhibit lipid rancidity on the food surface, especially in oxidation-
sensitive foods. Antioxidant packaging also has the potential to
extend the shelf life of foods (Anklam and others 1997; Morales-
Aizpuruaand and Tenuta-Filho 2005).
The objective of the present study was to develop multilayer
films based on corn-zein and LLDPE films incorporated with an-
tioxidant agents (thymol, carvacrol, and eugenol). The mechanical
properties and hydrophobic qualities of developed films and the
release rate of antioxidant agents from the film matrix into model
systems were measured. In addition, the effectiveness of the de-
veloped packaging films on color stability and lipid oxidation for
the storage of fresh ground beef was evaluated.
Materials and Methods
Chemicals and reagentsCorn-zein, antioxidant agents (thymol, carvacrol, and eugenol),
and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were purchased from
Sigma-Aldrich Chemicals Co. (St. Louis, Mo., U.S.A.). Polyethy-
lene glycol 400 (PEG 400), a plasticizer of corn-zein film, was
obtained from Junsei Chemicals Co. Ltd. (Tokyo, Japan). LLDPE
film was obtained from Hanjin P&C Co. Ltd. (Seoul, Korea), while
propyl gallate (PG) and ethylenediaminetetraacetic acid (EDTA)
were obtained from DAEJUNG (Siheung, Korea). Thiobarbituric
acid (TBA) was purchased from Alfa Aesar (St. Ward Hill, Mass.,
U.S.A.).
Film preparationCorn-zein coating solutions were prepared according to the
methods described by Mastromatteo and others (2009) with some
modifications. Corn-zein was dissolved in 95% ethanol at 20 g/
100 mL. As a plasticizer, PEG 400 was added to corn-zein solu-
tion at 4 g/100 mL and the solution was then heated at 70 C for
15 min. After cooling, thymol, carvacrol, and eugenol were in-
dividually added to the corn-zein solutions at a designated con-
centration (1.5, 3, or 5%, v/v) and stirred for 15 min. Corn-zein
solutions containing different concentrations of each antioxidantagent were coated onto corona-treated LLDPE films (surface ten-
sion 45 5 dyne/min; thickness 40 0.4 m) using a Nr. 28
coating rod (RDS, Webster, N.Y., U.S.A.) and dried for 15 min
at room temperature. The coated side of the double-layered film
was laminated with another LLDPE film using a heat laminat-
ing machine (GMP Co., Paju, Korea). The final multilayered film
(thickness 95 2.2m) structure is shown in Figure 1.
Measurement of film propertiesFilm thickness. Laminated film thickness was measured with
a digital micrometer (ID-C112X, Mitutoyo, Kawasaki, Japan) at
5 random positions on the film. The mean of the 5 measure-
ments was used to calculate tensile strength (TS) and water vaporpermeability (WVP).
Mechanical properties. Mechanical properties of the films
were determined by ASTM standard method D882-91 (1995)
using an Instron universal testing machine (Model 5566, Instron
Engineering Co., Canton, Mass., U.S.A.). Films were cut into
strips with a test dimension of 25.4 mm 100 mm. Before testing,
all of the films were conditioned for 48 h in a thermo-hygrostat
(LAM-MADE011, Sejong Scientific Co., Bucheon, Korea) held
at 25 C and 50% RH. The equilibrated strip was placed between
grip heads of the machine. The initial grip separation and cross
head speed were set at 50 mm and 500 mm/min, respectively. TS
was expressed in MPa and was calculated by dividing the maximum
load (N) by the initial cross sectional area (m
2
) of the specimen.The percentage elongation at break (%E) was calculated as theratio of the final length at the point of break to the initial length
of a specimen (50 mm) and expressed as a percentage. TS and %Ewere replicated 5 times for each type of film.
Water vapor permeability. WVP was determined gravimet-
rically, based on ASTM standard method E96-95 (1997). Each film
sample was mechanically sealed onto a polymethylmethacrylate
cup containing 30 g of anhydrous calcium chloride. The weights
of the sealed cups were measured using an electronic scale with a
precision of 0.001 g and cups were left in a controlled humidity
chamber adjusted to 30 C and 90% RH. After 24 h, they were
reweighed and WVP was calculated according to the following
Figure 1Structure of zein-laminated LLDPE film with antioxidant agent.
E2 Journal of Food Science Vol. 00, Nr. 0, 2012
7/21/2019 Development of Antioxidant Packaging Material
3/7
E:Food
Engineering
&
Antioxidant packaging film . . .
formula:
WVP
g mn/m2 d kPa= W x/A T(P2 P1) ,
where W is the increase in weight of the cup (g) after 1 d, x isthe average thickness of the film (mm), A is the exposed area ofthe film (1.66 103 m2), and (P2 P1) is the differential vaporpressure across the films (P2 P1 = 1.70 kPa at 30
C). WVP
measurements of each film sample were carried out in triplicate.
Release characteristics in different mediaRelease of antioxidant agent into the atmosphere. The
release test was carried out according to the methods described
in Gamege and others (2009), with some modifications. Corn-
zein-laminated LLDPE films with antioxidant agent were put into
a plastic tube (500 mL volume) and carefully adhered to the in-
ner wall to avoid gaps. The tube was tightly sealed with a cap
and stored at room temperature. Air samples (1 mL) were peri-
odically withdrawn through a rubber septum on the tube using
a syringe to determine the release of antioxidant agent from the
films into the inner atmosphere. The amount of antioxidant in the
gaseous medium was analyzed using the 6890A gas chromatog-
raphy (GC) system (Agilent Technologies, Santa Clara, Calif.,
U.S.A.) equipped with an FID detector and HP5 MS capillary
column (30 m 0.25 mm 0.25 m). Gaseous samples (1 mL)
were injected manually, and the split ratio was 1:60. Helium was
used as the carrier gas at a flow rate of 1 mL/min. The split/splitless
injector temperature and detector temperature were set at 200 C
and 350 C, respectively. The initial column temperature was set
at 60 C and increased to 200 C at a rate of 10 C/min. The
antioxidant compound was identified by comparing its mass spec-
tra with those of authentic compounds in the computer library.
The concentration of the identified compound in the atmosphere
was quantified according to the peak area integrated by the data
analysis program. Tests were conducted 4 times each.
Release of antioxidant agent into the liquid state. The
release of antioxidant agent from the films into liquid medium
was measured by 2,2-DPPH radical scavenging assay according
to methods described in Shimada and others (1992), with some
modifications. The films were tightly adhered to the inner wall of
a 30 mL glass vial filled with 25 mL of 0.1 mM DPPH solution.
The vial was wrapped with aluminum foil thoroughly to avoid
light, and then stored in a shaking incubator (Vision Scientific Co.
Ltd., Korea) at 25 C and 70 r pm. The absorbance was measured
with an Ultrospec 3100 Pro UV spectrophotometer (Pharmacia
Biotech Inc., Little Chalfont, U.K.) at 517 nm every 3 h. The test
directly measured the antioxidant activities of the released agent
into solution. DPPH radical scavenging activity was expressed as
milligrams of ascorbic acid equivalents (AAE) per grams of filmsample. Tests were replicated 4 times.
Effects of antioxidant packaging on ground beef pattiesBeef samples and storage conditions. Fresh ground beef
(top round roast) was obtained from a local butcher shop in
Suwon, Korea, and stored under refrigerated conditions (4
1 C). On the day of purchase, the roasts were trimmed of all
separable fat and connective tissue, ground twice, and then ana-
lyzed for fat content according to the methods described in Folch
and others (1957). Beef patties (30 g, 3.8% fat) were prepared us-
ing Petri dishes (6 cm dia, 1.2 cm height) in the laboratory for
each experiment. The raw beef patties were then packaged in 1
of 3 different ways, as follows: (i) over-wrapping with oxygen-
permeable polyvinyl chloride (PVC) film (O2transmission rate =
91.54 cm3/m/m2/24 h at 25 C), (ii) vacuum packaging with
LLDPE film, or (iii) vacuum packaging with developed antioxi-
dant films (0.3% or 3% antioxidant concentration). Samples were
stored at 4 C and the degree of lipid oxidation and the colors of
the patties in each packaging group were measured every 2 d.
Evaluation of lipid oxidation. Lipid oxidation of beef patties
was determined by analysis of 2-thiobarbiutric acid reactive sub-
stances (TBARS) according to the modified distillation methoddescribed in Rhee (1978). To prevent further oxidation, a mixed
solution of PG and EDTA was added to each beef patty before
distillation. After adding 4N HCl solution and distilled water, the
mixture was distilled in a Kjeldahl flask and the distillate was col-
lected in a 50 mL Falcon tube. Then, the distillate was reacted
with 2-TBA in a water bath at 100 C for 35 min to induce color
change. The optical density of the sample was read at 530 nm
with an Ultrospec 3100 pro UV spectrophotometer (Pharmacia
Biotech Inc.). The results of TBARS content were expressed as
milligrams of malondialdehyde equivalents (MDA) per kilogram
of meat sample. Tests were replicated 4 times.
Color changes in beef patty. Color changes were measured
with a CR-400 colorimeter (Minolta Co., Japan). The pattieswere exposed to oxygen for 10 min before color evaluation. The
colorimeter was calibrated using a standard white plate. Measure-
ments were taken 5 times for each sample, and the mean values
were used to determine the color coordinates L (lightness), a
(redness), andb (yellowness). In order to monitor meat browningduring storage, hue angle (H= arctan b/ a; higher values aremore brown) was calculated. Tests were conducted 4 times.
Statistical analysisData analysis was performed using Statistical Analysis System
(SAS) software, version 8.1 (SAS Inst., Cary, N.C., USA). The
General Linear Models Procedure was used for analysis of variance,
with main effect means separated by Student-Newman-Keuls test.Significance was defined asP 0.05.
Results and Discussion
Mechanical properties of filmThe mechanical properties of the corn-zein laminated LLDPE
films were measured by uniaxial tensile tests. The TS and %Eoflaminated films were determined from the attained stressstrain
curves (Table 1).
The TS of simple LLDPE film was 31.33 MPa, which was
the highest value among all tested films. When comparing to
the simple LLDPE film, the TS of the corn-zein-laminated film
(LLDPE/zein/LLDPE) decreased (P 0.05) by 28.6% (22.38MPa). The lower TS of the LLDPE/zein/LLDPE film was prob-
ably due to the physical weakness of the zein film layer. Rhim and
others (1997) reported that the TS of simple zein film was 5.52
MPa, which is much lower than LLDPE film. In zein-laminated
film groups, laminated films containing antioxidants had TS values
ranging from 22.28 to 24.27 MPa. Thus, the addition of an an-
tioxidant agent up to 5% (v/v) in the zein layer resulted in a slight
but insignificant increase in TS (P> 0.05). Generally, the TS oflaminated films is dependent on the substrate or base film rather
than the coating or laminated layer (Hong and others 2004). In
this study, zein film was applied to LLDPE film as a coating mate-
rial; LLDPE film was the substrate or base film in these laminated
films. In this study, the TS of zein-laminated LLDPE film was
Vol. 00, Nr. 0, 2012 Journal of Food Science E3
7/21/2019 Development of Antioxidant Packaging Material
4/7
E:Food
Engi neeri ng
&
Antioxidant packaging film . . .
22.38 MPa. Earlier studies reported that zein-coated polypropy-
lene film had a TS of 45 MPa (Lee and others 2008), and the TS
of zein-coated carrageenan films ranged from 26.38 to 37.73 MPa
according to the concentration of zein-coating solutions (Rhim
and others 1997). This difference may be attributed to the different
substrate materials of the films.
The value of %E is associated with the elasticity and flex-ibility of the film. Values of %E for simple LLDPE andLLDPE/zein/LLDPE films were estimated to be 776.60% and
667.30%, respectively. Values of %Efor LLDPE/zein/LLDPE filmdecreased by 14% in comparison to LLDPE film, but slightly in-
creased when antioxidant agents were added. Gamage and oth-
ers (2009) reported that the %E values of various essential oil-incorporated films were significantly higher compared to those
of nonessential oil-incorporated films. These results indicate that
antioxidant agents act as adhesives in the protein polymer matrix,
similar to plasticizer. Therefore, the addition of essential oil im-
proved the flexibility and %Eof the films. Based on these results,antioxidants may be considered as potential replacements for plas-
ticizers in protein biopolymer films. In addition, antioxidants can
contribute positively to the mechanical properties of packaging
materials composed of biopolymer.
Water barrier properties of filmsWVP is determined by the chemical arrangement of film-
forming polymers and the morphology of the film (Siripatrawan
and Harte 2010). WVP was calculated according to the aforemen-
tioned formula, and the results are depicted in Table 2. Simple
Table 1 Mechanical properties of zein-laminated LLDPE films
with different antioxidant compounds and concentrations.
Film Tensile Elongationconstruction strength (MPa) at break (%)
LLDPE 31.33 0.98a 776.60 36.19a
LLDPE/zein/LLDPE 22.38 1.80b 667.30 50.88b
LLDPE/zein with thymol1.5%/LLDPE
22.78 2.90b 767.54 63.66a
LLDPE/zein with carvacrol1.5%/LLDPE
24.21 2.29b 746.03 54.78a
LLDPE/zein with eugenol1.5%/LLDPE
23.88 1.81b 786.13 61.11a
LLDPE/zein with thymol 3%/LLDPE 23.02 1.73b 802.20 35.17a
LLDPE/zein with carvacrol3%/LLDPE
23.14 2.05b 744.47 85.85a
LLDPE/zein with eugenol3%/LLDPE
23.58 2.01b 763.87 82.10a
LLDPE/zein with thymol 5%/LLDPE 22.83 1.09b 786.27 74.44a
LLDPE/zein with carvacrol5%/LLDPE
24.27 1.95b 784.73 55.54a
LLDPE/zein with eugenol
5%/LLDPE
22.28 2.54b 784.33 68.44a
a,bWithin a column, different superscripts indicate significant differences ( P 0.05).
Table 2 Water vapor permeability of zein-laminated LLDPE
films with different antioxidant compounds.
Film Water vapor permeabilityconstruction (gmm/m2dkPa)
LLDPE 1.778 0.045a
LLDPE/zein/LLDPE 2.033 0.112b
LLDPE/zein with thymol 3%/LLDPE 1.958 0.105ab
LLDPE/zein with carvacrol 3%/LLDPE 1.913 0.045ab
LLDPE/zei n with eugenol 3%/LLDPE 1.920 0.112ab
a,b Within a column, different superscripts indicate significant differences ( P 0.05).
LLDPE film had a lower WVP (1.778 gmm/m2dkPa) than any
other laminated film, indicating that LLDPE film provides a good
barrier for moisture. In contrast, LLDPE/zein/LLDPE film had
the highest WVP at 2.033 gmm/m2dkPa, and thus performed
the most poorly as a moisture barrier among the film samples
tested in this study. Results showed that simple zein-laminated
films had relatively high WVP compared to LLDPE film, which
was probably due to the hydrophilic groups in zein molecules.
These hydrophilic groups are formed from the amino acids that
compose corn-zein protein, and that they weakened the water bar-rier properties of corn-zein-laminated film. The WVP of other
laminated films containing phenolic antioxidant agents were es-
timated between 1.913 and 1.958 gmm/m2dkPa. Regardless
of the type of antioxidant agent used at 3% concentration (v/v),
films containing antioxidants had improved water barrier prop-
erties when compared to simple zein-laminated film due to the
strong hydrophobicity of the added antioxidant agents, which in-
terrupts the penetration of water molecules. Thymol, carvacrol,
and eugenol, which were used as antioxidant agents in this study,
are hydrophobic and are major compounds of naturally occurring
essential oils in thyme, oregano, and cloves. According to Sanchez-
Gonzalez and others (2011), the same behavior was observed when
essential oils (bergamot, lemon, or tea tree oil) were incorporatedinto chitosan/hydropropylmethylcellulose composite films. They
reported that WVP values of composite films showed a decrease
in line with the increase in the concentration of hydrophobic an-
tioxidant agent. The results of this study were in accordance with
these observations.
Release into the atmosphereGC analysis was used to measure changes in the concentration
of antioxidants released from the developed films into the atmo-
sphere (Figure 2). Overall, the maximum concentration of antiox-
idants in the headspace was correlated with the concentrations ofantioxidants added to corn-zein film solution, and the released
concentrations of antioxidants reached a maximum within 2 d in
all experimental groups. Films containing higher concentrations
of antioxidants also had faster diffusion rates of antioxidants into
the air yet still maintaining higher concentrations of antioxidants
than films with lower concentrations.
GC analyses of headspace gas composition revealed that the
concentrations of diffused antioxidants in the container reached
saturation after approximately 1 to 2 d, after which the amount
of antioxidants was reduced or maintained. Groups containing
thymol and carvacrol displayed a similar quantitative trend. There
were no significant changes in the concentration of antioxidants
in these groups after day 2, indicating that all antioxidants escaped
from these films within 2 d.
The diffused antioxidants of zein-5% eugenol-laminated film
displayed the highest concentration and the longest holding time
in the gas state. In this film, concentration of eugenol remained at
a high level for approximately 3 d and decreased over the following
2 d. From day 5 to day 7, eugenol levels inside the headspace re-
mained constant. The maximum value of this group was observed
up to day 3, and then it gradually reduced over last time pe-
riod. This might suggest that eugenol leaked out of the container
through the lid or septum of the container, even though the con-
tainer was sealed carefully. However, LLDPE/zein/LLDPE films
containing 1.5% and 3% eugenol showed a similar pattern, even
though they contained different initial amounts of antioxidants.
E4 Journal of Food Science Vol. 00, Nr. 0, 2012
7/21/2019 Development of Antioxidant Packaging Material
5/7
E:Food
Engineering
&
Antioxidant packaging film . . .
Release into the liquid stateDPPH radical assays were performed with some modifications,
to evaluate the effectiveness of the antioxidant agents released
from the films into the liquid medium. DPPH radical scavenging
activities of the samples consistently increased with storage time
in all of the experimental groups, suggesting that there was a
continuous release of antioxidant agents (Figure 3).
There were slight changes in the radical scavenging effects of
LLDPE film and zein-laminated film even though they did not
contain any antioxidant agent. These changes might have been
Figure 2Concentration changes of thymol (A), carvacrol (B), and eugenol(C) released by antioxidant films into the atmosphere over 1 wk.
caused by the instability of DPPH radicals resulting in a grad-
ual extinction of radicals over time. By contrast, zein-laminated
films containing antioxidant (thymol, carvacrol, or eugenol) dis-
played considerable changes in the activity of released antioxidants.
Antioxidant film with eugenol had the maximum DPPH radical
scavenging activity of all the tested films. In addition, the reac-
tion mechanism of DPPH radicals and eugenol molecules released
from the film was terminated much sooner than thymol and car-
vacrol, at a concentration one-tenth that of the others. After 21 h,
absorbance at 517 nm of eugenol-containing film dropped below0.1, which is a value that was too small to be measured correctly
by a UV spectrophotometer with the optimum measurable ab-
sorbance range of 0.1 to 2.0. Therefore absorbance of this film
was not evaluated after 21 h. The DPPH radical scavenging activi-
ties of thymol and carvacrol were similar, although thymol activity
was not significantly higher than that of carvacrol, perhaps because
they are isomers with the same molecular formula and a similar
chemical nature.
Generally, the release of an active compound from the swelled
polymeric network occurs in 2 steps. First, water molecules pene-
trate into the polymeric matrix, causing the matrix to swell. Then,
active compounds diffuse through the widened mesh of the poly-
meric network (Del Nobile and others 2008). Therefore, releaseof an active compound is affected by the structural properties of
the polymer or polymeric network and the diffusion rate of the
active compound. However, in this study, the structural proper-
ties of the films were likely not factors because the antioxidant
active films had the same structure as the LLDPE/zein/LLDPE
film. Moreover, the 3 antioxidant compounds added to the de-
veloped films have similar molecular weights and water solubility,
and therefore differences in diffusion rates were also negligible.
Consequently, the factor that influenced DPPH radical scaveng-
ing activities the most was the antioxidant ability of the antioxidant
agent. Yanishilieva and others (1999) reported that thymol is a bet-
ter antioxidant than carvacrol due to the greater steric hindrance
of the phenolic g roup in thymol. According to Mastelic and others(2008), eugenol exhibited outstanding DPPH radical scavenging
activity, followed by thymol and carvacrol. This study reported
similar results.
TBA valuesIn the diffusion test of antioxidants in a liquid state, zein-
laminated film with 0.3% eugenol showed the greatest antioxidant
Figure3Diffusionofantioxidantcompoundsfromthefilmtoliquidmediumover 30 h.
Vol. 00, Nr. 0, 2012 Journal of Food Science E5
7/21/2019 Development of Antioxidant Packaging Material
6/7
E:Food
Engi neeri ng
&
Antioxidant packaging film . . .
properties. Therefore, this film formulation was used for raw beef
patty packaging in this study. TBA value was measured in or-
der to examine the preventive effects of antioxidant-containing
films on lipid oxidation of meat during storage (Figure 4). In
all experimental groups, TBARS contents increased consistently
throughout storage. The control group, over-wrapped with the
oxygen-permeable PVC film, had a higher TBA value (P 0.05)than all of the vacuum-packaged g roups. In contrast, vacuum
packaging effectively protected beef patties from the beginning of
storage, with a TBA value lower than 2 mg MDA/kg over thecourse of 14 d. There were few differences in TBA values among
the vacuum-packaged groups, and vacuum-packaged patties with
zein-laminated film with 3.0% eugenol had the lowest TBA val-
ues. Even though vacuum packaging alone inhibited lipid oxida-
tion effectively, the developed antioxidant films demonstrated a
synergistic effect in combination with vacuum treatment against
lipid oxidation, and completely suppressed lipid oxidation during
the 14 d. Specifically, TBA value of vacuum only packaging
increased 86.1% after 14 d, but TBA values of vacuum packaging
with 0.3% eugenol-containing film and vacuum packaging with
3% eugenol-containing film increased 40.9% and 27.7%, respec-
tively, after 14 d. This result implied that the antioxidant films
Figure4Effects of packaging material on theTBARSvalues of beef pattiesafter 14 d.
improved the efficacy of vacuum packaging and stabilized raw
beef patties against oxidation. The antioxidant property of pre-
pared film containing 3% eugenol was similar to that of the film
containing 0.3% eugenol, which suggests that eugenol is a strong
antioxidant and 0.3% concentration was sufficient to completely
retard lipid oxidation in beef patties.
The inhibitory effect of eugenol on lipid oxidation is induced
by the phenolic g roup, which contains an electron-repelling group
in the ortho-position. This phenolic group is capable of reducing
both lipid radicals and ferric ion (Dorman and others 2000). Ogataand others (1997) suggested that eugenol prevents lipid oxidation
by trapping active oxygen species, such as O2 or hydroxyl radicals.
Lipid oxidation has been associated with off-flavors and off-
taste in meat and meat products. According to Insausti and others
(2001), humans detect off-flavors or off-taste in meat when TBA
values are greater than or equal to 5 mg MDA/kg. In this study,
TBA values above 5 mg MDA/kg meat were only observed in
the PVC-wrapped control group. In the other vacuum-packaged
groups, TBA values remained below 2 mg MDA/kg at all times
during storage.
Color changes
Color values including L (lightness), a (redness), and b(yellowness) of the oxygen-permeable control group and the
vacuum-packaged groups using antioxidant active films were mea-
sured and used to calculate the hue index. The color of meat is
one of the most important factors in customer selection because
color is an indicator of freshness (Mancini and Hunt 2005). Color
changes during storage at 4 C are presented in Table 3.
Treatment and storage time had no significant effects onL andb values of beef patties. In the control group, beef patty samplessuffered considerable decreases ina values, in contrast to the othergroups which exhibited relatively higha values. Vacuum packag-ing and the addition of eugenol made it possible to maintain initial
a levels over time. Allen and Conforth (2010) also observed that
after 14 d, the a
value of beef patties mixed with 0.05% eugenolwas significantly more reddish, and therefore more desirable to
consumers, than the control group. Control samples had signif-
icantly higher (P 0.05) hue angle values (more reddish andless yellow) in comparison with the hue angle values of vacuum-
packaged samples, regardless of eugenol existence within films.
A significant increase in the hue angle value of a control sample
Table 3Color value of beef patties packaged with the developed film.
Time of storage (d)
Color value Type of packaging 0 4 7 14
L PVC wrap 36.44 2.57Aa 36.01 1.93Aa 36.77 2.22Aa 36.88 1.52Aa
vacuum packaging only 38.09 3.10ABa 36.81 3.31ABa 35.77 2.34Aa 36.19 2.44ABa
vacuum packaging with antioxidant film (0.3% eugenol) 36.77 3.71ABa
34.59 2.27Ba
36.00 2.25Aa
34.75 2.00Ba
vacuum packaging with antioxidant film (3% eugenol) 34.96 1.87Ba 34.06 1.87Ba 34.76 1.37Aa 35.36 1.60ABa
a PVC wrap 13.57 2.07Aa 9.60 1.36Ab 10.05 1.94Ab 9.35 1.17Ab
vacuum packaging only 12.19 0.97Ba 12.99 1.06Bab 13.94 1.10Bb 12.86 1.94Bab
vacuum packaging with antioxidant film (0.3% eugenol) 12.01 1.01Ba 13.80 1.80Bb 13.64 1.42Bb 12.94 1.40Bab
vacuum packaging with antioxidant film (3% eugenol) 12.63 1.19ABa 13.52 0.69Ba 13.68 1.23Ba 11.26 2.08Cb
b PVC wrap 4.49 1.17Aa 4.62 0.75Aa 3.43 0.82Ab 3.32 0.78Ab
vacuum packaging only 3.61 1.50Ba 3.73 1.22Ba 3.52 0.57Aa 3.85 1.68Aa
vacuum packaging with antioxidant film (0.3% eugenol) 2.80 0.81Ba 3.25 0.72Bab 3.12 0.65Aab 3.81 1.13Ab
vacuum packaging with antioxidant film (3% eugenol) 2.98 0.60Ba 3.00 0.67Ba 3.36 0.90Aa 2.79 1.01Aa
Hue angle PVC wrap 18.09 2.05Aa 24.30 2.85Ab 25.27 3.14Abc 27.20 2.78Ac
vacuum packaging only 14.54 2.66Ba 15.23 1.70Ba 14.58 1.19Ba 16.19 2.55Ba
vacuum packaging with antioxidant film (0.3% eugenol) 13.06 1.66Ba 13.39 1.57Ca 12.83 1.67Ba 15.42 2.03Bb
vacuum packaging with antioxidant film (3% eugenol) 13.24 2.14Ba 13.52 1.62Ca 13.40 1.69Ba 14.33 2.52Ba
AtoC: Within a column, different letters indicate significant differences (P 0.05).a,b : Within a row, different letters indicate significant differences (P 0.05).
E6 Journal of Food Science Vol. 00, Nr. 0, 2012
7/21/2019 Development of Antioxidant Packaging Material
7/7
E:Food
Engineering
&
Antioxidant packaging film . . .
indicated discoloration. The control group became brownish (de-
creased redness and increased yellowness) with an increase in stor-
age time. Color change in the control group might be associated
with lipid oxidation and the formation of metmyoglobin (Djenane
and others 2002; Nern and others 2006). Beef patties vacuum-
packaged with antioxidant films showed lower changes in hue
angle values. In these groups, the films acted as an oxygen gas bar-
rier preventing the direct contact of meat with oxygen. Moreover,
the strong antioxidant property of eugenol released from the films
contributed to protection of the beef patties from lipid oxidation.These data suggest that diffusion of eugenol from the packaging
delays oxidation of beef color pigments.
ConclusionWe developed zein-laminated LLDPE films with natural an-
tioxidants and measured their physical and functional properties.
In addition, diffusion modes of antioxidants in the gas and liquid
states were estimated. Zein-laminated films with antioxidants had
reduced TS and %Evalues compared to LLDPE films. These filmsalso had higher WVP than LLDPE film. The antioxidant film was
tested in fresh beef patty packaging. Antioxidant films effectively
retarded lipid oxidation and inhibited color change in beef during
storage. These results suggest that zein-laminated films contain-ing antioxidants are suitable for packaging applications and food
protection.
AcknowledgmentThis work was supported by the Natl. Research Foundation
of Korea (NRF) grant funded by the Korea government (MEST)
(Nr. 2011-0014710).
ReferencesAllen K, Cornforth D. 2010. Comparison of spice-derived antioxidants and metal chelators on
fresh beef color stability. Meat Sci 85(4):6139.Anklam E, Gaglione S, Muller A. 1997. Oxidation behavior of vanillin in dairy products. Food
Chem 60(1):4351.Appendini P, Hotchkiss JH. 2002. Review of antimicrobial food packaging. Innov Food Sci
Emerg Technol 3(2):11326.American Society for Testing and Materials (ASTM). 1995. Standard test method for tensile
properties of thin plastic sheeting. Philadelphia, Pa.: ASTM. D88291.American Society for Testing and Materials (ASTM). 1997. Standard test method for water vapor
transmission of materials. Philadelphia, Pa.: ASTM. E9695.Atik ID, Ozen B, Tihminlioglu F. 2008. Water vapor barrier performance of corn-zein coated
polypropylene (PP) packaging films. J Therm Anal Cal 94(3):68793.Branen AL. 1975. Toxicology and biochemistry of butylated hydroxyanisole and butylated hy-
droxytoluene. J Am Oil Chem Soc 52(2):5963.Buonocore GG, Del Nobile MA, Panizza A, Corbo MR, Nicolais L. 2003. A general approach
to describe the antimicrobial agent release from highly swellable films intended for foodpackaging applications. J Control Release 90(1):97107.
Burt S. 2004. Essential oils: their antimicrobial properties and potential applications in foodsareview. Int J Food Microbiol 94(3):22353.
Chan EWC, Lim YY, Chew YL. 2007. Antioxidant activity ofCamellia sinensis leaves and teafrom a lowland plantation in Malaysia. Food Chem 102(4):121422.
Cuq B, Gontard N, Cuq JL, Guilbert S. 1998. Packaging films based on myofibrillar proteins:fabrication, properties and applications. Mol Nutr Food Res 42(34):2603.
Cuvelier ME, Berset C, Richard H. 1994. Antioxidant constituents in sage ( Salvia officinalis). J
Agric Food Chem 42(3):6659.
Dallyn H, Shorten D. 1988. Hygiene aspects of packaging in the food industry. Int Biodeterio-ration 24(45):38792.
Del Nobile MA, Conte A, Incoronato AL, Panza O. 2008. Antimicrobial efficacy and release ofthymol from zein films. J Food Eng 89(1):5763.
Djenane D, Sanchez-Escalante A, Beltran JA, Roncales P. 2002. Ability of-tocopherol, taurineand rosemary, in combination with vitamin C, to increase the oxidative stability of beef steakspackaged in modified atmosphere. Food Chem 76(4): 40715.
Dorman HJD, Surai P, Deans SG. 2000. In vitro evaluation of antioxidant activity of essentialoils and their components. Flav Frag J 15(1):126.
Folch J, Lees M, Sloane-Stanley GH. 1957. A simple method for isolation and purification oftotal lipids from animal tissues. J Biol Chem 226:497509.
Gamage GR, Park HJ, Kim KM. 2009. Effectiveness of antimicrobial coated oriented polypropy-lene/polyethylene films in sprout packaging. Food Res Int 42(7):8329.
Hong SI, Han JH, Krochta JM. 2004. Optical and surface properties of whey protein isolatecoatings on plastic films as influenced by substrate, protein concentration, and plasticizer type.J Appl Polym Sci 92(1):33543.
Insausti K, Beriain MJ, Purroy A, Alberti P, Gorraiz C, Alzueta MJ. 2001. Shelf life of beef fromlocal Spanish cattle breeds stored under modified atmosphere. Meat Sci 57(3):27381.
Lai H, Padua G, Wei L. 1997. Properties and microstructure of zein sheets plasticized withpalmitic and stearic acids. Cereal Chem 74(1):8390.
Lee JW, Son SM, Hong SI. 2008. Characterization of protein-coated polypropylene films as anovel composite structure for active food packaging application. J Food Eng 86(4):48493.
Mancini RA, Hunt MC. 2005. Current research in meat colour. Meat Sci 71(1):10021.Mastelic J, Jerkovic I, Blazevic I, Poljak-Blazi M, Borobic S, Ivancic-Bace I, Smercki V, Zarkovic
N, Brcic-Kostic K, Vikic-Topic D, Muller N. 2008. Comparative study on the antioxidantand biological activities of carvacrol, thymol, and eugenol derivatives. J Agric Food Chem56(11):398996.
Mastromatteo M, Barbuzzi G, Conte A, Del Nobile MA. 2009. Controlled release of thymolfrom zein based film. Innov Food Sci Emerg Technol 10(2):2227.
Morales-Aizpurua IC, Tenuta-Filho A. 2005. Oxidation of cholesterol in mayonnaise duringstorage. Food Chem 89(4):6115.
Nern C, Tovar L, Djenane D, Camo K, Salafranca J, Beltran JA, Roncales P. 2006. Stabilization
of beef meat by a new active packaging containing natural antioxidants. J Agric Food Chem54(20):78406.Ogata M, Hoshi M, Shimotohno K, Urano S, Endo T. 1997. Antioxidant activity of magnolol,
honokiol, and related phenolic compounds. J Am Oil Chem Soc 74(5):55762.Padgett TR, Han IY, Dawson PL. 1998. Incorporation of food-grade antimicrobial compounds
into biodegradable packaging films. J Food Protect 61(10):13305.Peppas NA. 2004. Devices based on intelligent biopolymers for oral protein delivery. Int J Pharm
277(12):117.Pomes AF. 1971. Zein. In encyclopedia of polymer science and technology: plastics, resins,
rubbers, fibers. Vol. 15. New York: Interscience Publishers. p 123125.Proestos C, Boziaris IS, Nychas GJE, Komitis M. 2006. Analysis of flavonoids and phenolic acids
in Greek aromatic plants: investigation of their antioxidant capacity and antimicrobial activity.Food Chem 95(4):66471.
Rhim JW, Park JW, Jung ST, Park HJ. 1997. Formation and properties of corn zein coatedK-carrageenan films. Korean J Food Sci Technol 29(6):118490.
Rhee KS. 1978. Minimization of further lipid peroxidation in the distillation 2-Thiobarbituricacid test of fish and meat. Food Sci 43(6):17768.
Robertson GL. 1993. Food packaging: principles and practice. New York: Marcel Dekker, Inc.Ruberto G, Baratta MT. 2000. Antioxidant activity of selected essential oil components in tow
lipid model systems. Food Chem 69(2):16774.
Sanchez-Gonzalez L, Chiralt A, Gonzalez-Martnez C, Chafer. 2011. Effect of essential oils onproperties of film forming emulsions and films based on hydroxypropyl methylcellulose andchitosan. J Food Eng 105(2):24653.
Serrano M, Martnez-Romero D, Castillo S, Guillen F, Valero D. 2005. The use of naturalantifungal compounds improves the beneficial effect of MAP in sweet cherry storage. InnovFood Sci Emerg Technol 6(1):11523.
Shimada K, Fujikawa K, Yahara K, Nakamura T.1992. Antioxidative properties of xanthan onthe autoxidation of soybean oil in cyclodextrin emulsion. J Agric Food Chem 40(6):9458.
Shukla R, Cheryan M. 2001. Zein: the industrial protein from corn. Ind Crop Prod 13(3):7192.Siripatrawan U, Harte BR. 2010. Physical properties and antioxidant activity of an active film
from chitosan incorporated with green tea extract. Food Hydrocol 24(8):7705.Suppakul P, Miltz J, Sonneveld K, Bigger SW. 2003 Active packaging technologies with an
emphasis on antimicrobial packaging and its applications. Food Sci 68(2):40821.Tovar L, Salafranca J, Sanchez C, Nern C. 2005. Migration studies to assess the safety in use of
a new antioxidant active packaging. J Agric Food Chem 53(13):52705.Yanishlieva NV, Marinova EM, Golden MH, Raneva VG. 1999. Antioxidant activity and mech-
anism of action of thymol and carvacrol in two lipid systems. Food Chem 64(1):5966.Yen M, Yang J, Mau J. 2008. Antioxidant properties of chitosan from crab shells. Carbo Polym
74(4):8404.
Vol. 00, Nr. 0, 2012 Journal of Food Science E7
Recommended