κ-Carrageenan composite film and its application to oil packaging

Journal Pre-proof Formation mechanism of egg white protein/κ-Carrageenan composite film and its application to oil packaging

Xiang Huang, Xin Luo, Lan Liu, Kai Dong, Ran Yang, Chao Lin, Hongbo Song, Shugang Li, Qun Huang PII:

S0268-005X(19)32801-2

DOI:

https://doi.org/10.1016/j.foodhyd.2020.105780

Reference:

FOOHYD 105780

To appear in:

Food Hydrocolloids

Received Date:

04 December 2019

Accepted Date:

17 February 2020

Please cite this article as: Xiang Huang, Xin Luo, Lan Liu, Kai Dong, Ran Yang, Chao Lin, Hongbo Song, Shugang Li, Qun Huang, Formation mechanism of egg white protein/κ-Carrageenan composite film and its application to oil packaging, Food Hydrocolloids (2020), https://doi.org/10. 1016/j.foodhyd.2020.105780

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.

Journal Pre-proof

Formation mechanism of egg white protein/κ-Carrageenan composite film and its application to oil packaging

Xiang Huanga, Xin Luoa, Lan Liua, Kai Donga, Ran Yanga, Chao Linc, Hongbo Songa, Shugang Lib,*, Qun Huanga,*

aFujian

Provincial Key Laboratory of Quality Science and Processing Technology in

Special Starch, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China

bKey

Laboratory of Fermentation Engineering (Ministry of Education), Hubei

University of Technology, Wuhan, 430068 Hubei, China

cEngineering

Research Centre of Fujian-Taiwan Special Marine Food Processing and

Nutrition, Ministry of Education, Fuzhou, Fujian 350002, China

*Corresponding author: Qun Huang, Tel.: + 86 591 83789348 Shugang Li, Tel.: + 86 27 59750467

E-mail address: [email protected]; [email protected]

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Author

E-mail

addresses:

[email protected];

[email protected]; [email protected];

[email protected]; [email protected];

[email protected]

Postal address: No 15 Shangxiadian Road, Fuzhou City in Fujian Province, 350002, PR China.

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Abstract

2

Natural biopolymers have the potential to be used as modern green food

3

packaging materials because of their excellent biocompatibility and biodegradability.

4

In this manuscript, egg white protein (EWP) and κ-Carrageenan (κ-C) were mixed to

5

prepare a composite film. The effects of EWP contents on the mechanical, physical,

6

barrier and microstructural properties of the composite film were investigated.

7

Scanning electron microscopy (SEM) images showed that the disorder degree of the

8

composite film was enhanced as the mass ratio of EWP increased. In addition, the

9

elongation at break (EAB) and light transmission of the composite film were

10

improved to 10.85% and 53.3%, respectively. However, the oxygen permeability,

11

water vapor permeability (WVP) and water soluble time were notably reduced to 4.17

12

meq/kg, 1.59 g·mm/m2·s·Pa and 29.9 s, respectively. Fourier transform infrared

13

spectroscopy (FT-IR) and chemical interaction analyses indicated that the increase of

14

mass ratio of EWP reduced the hydrogen bond interactions of the composite film,

15

resulting in a decline in the tensile strength (TS), while increase of the degree of

16

nonspecific crosslinking and the electrostatic interactions. The composite film was

17

used as food packaging material in edible oil packaging. It was found that the

18

composite film could effectively delay the rancidity of oil during storage compared to

19

unpackaged and brand film. Moreover, the TS and water soluble time of the film

20

improved to 23.31 MPa and 64 s, respectively, while the EAB reduced to 16.64%.

21

Our study enriched the preparation of the edible film, the EWP and κ-C composite

22

films would have extensive applications in the food packaging industry.

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Keywords: Egg white protein; κ-Carrageenan; Composite film; Formation

24

mechanism; Oil packaging

25 26

1. Introduction

27 28

In the past 20 years, the production and use of plastics in the worldwide have

29

grown enormously (Nazmi, Isa, & Sarbon, 2017), and petroleum-based synthetic

30

polymer packaging materials are widely used in food packaging. However, these

31

materials caused a series of problems such as environmental pollution, resource

32

depletion, and food contamination (Salmieri & Lacroix, 2006), because they were

33

synthesized from nonrenewable energy sources and could not be biodegraded (Avella

34

et al., 2005; Bucci, Tavares, & Sell, 2005). In recent years, the development of

35

biodegradable food packaging materials with excellent performance is a hot research

36

topic in the world (Kanmani & Rhim, 2014).

37

Currently, biodegradable materials, such as proteins and polysaccharides

38

extracted from animal or microbial sources, are gradually being used as substitutes in

39

film production (Ghanbarzadeh, Almasi, & Entezami, 2010; González & Igarzabal,

40

2013). Various types of biopolymers have been used as raw materials for the

41

production of biodegradable films and coatings (Belgacem & Gandini, 2008; Moradi,

42

Tajik, Razavi Rohani, & Mahmoudian, 2016), these products help to prolong the shelf

43

life of foods and reduce the use of food plastic packaging (Saberi et al., 2016).

44

Therefore, the development of edible films has been highly valued by researchers.

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Edible films with porous network structure and specific functions are made by

46

different processes using edible biopolymers (e.g. proteins, polysaccharides, and

47

lipids) as the main matrix (Han, 2014). Proteins are typical natural food polymers

48

deriving from a wide range of sources including grains and beans. It has been widely

49

used in the preparation of edible film materials (Azeredo & Waldron, 2016; Jiang &

50

Tang, 2013; Song, Zhou, Fu, Chen, & Wu, 2013). Compared to films prepared by

51

lipids and polysaccharides, protein-based edible films generally have excellent barrier

52

properties (Gennadios & Weller, 1990; Bourtoom, 2009; Wittaya, 2012), and are

53

more versatile in structure and biological applications.

54

In recent years, research on edible films has gradually shifted from a single

55

component, single-layer films to multicomponent, multilayer films and film

56

modifications. A composite edible film is advantageous for improving the defects of

57

each component, can effectively improve the comprehensive performance and

58

processing utilization of the film (Debeaufort, Quezada-Gallo, & Voilley, 2000). A

59

previous study reported that synthetic biopolymer edible films have better properties

60

than single-component films (Nazmi et al., 2017). Mehdizadeh et al. (2012)

61

formulated various composite films using thyme essential oil (EO), starch and

62

chitosan as substrates and investigated their physiochemical and biological properties.

63

They found that the antibacterial and antioxidant properties were significantly

64

enhanced as the EO content increased. Guo et al. (2012) studied the effects of the

65

mass ratio of zein and wheat gluten on the physical properties of the composite film.

66

It was reported that the tensile strength (TS) of the edible film was the highest (10.01

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MPa) when the zein/wheat gluten mass ratio was 80:20, and the elongation at break

68

(EAB) was the maximum (57%) when the mass ratio was 20:80.

69

As an ideal film and coating material, protein can be extracted from whey,

70

soybean, gluten and gelatin. Egg white protein (EWP) is a kind of high nutritional

71

protein (Clark, Kiss, Wilde, & Wilson, 1992), which contains eight essential amino

72

acids required by the human body. The digestibility and absorptivity of EWP in the

73

human body can reach 98%. In addition, EWP contains abundant disulfide bonds and

74

sulfhydryl groups and has excellent film forming properties (Peng et al., 2017). Due

75

to the multilevel structure of protein, protein-based edible films are usually of

76

superior flexibility and biocompatibility, which can be used in food packaging to

77

improve the nutritional value of edible films. However, there are obvious weaknesses

78

of protein-based edible films, such as low mechanical properties, poor heat-sealing

79

performance (Yayli, Turhan, & Saricaoglu, 2017). κ-Carrageenan (κ-C) is a typical

80

water soluble anionic polysaccharide, derived from red algae, which can be widely

81

used in the pharmaceutical, cosmetic and food industries due to its excellent

82

biocompatibility (Kassab, Aziz, Hannache, Ben Youcef, & El Achaby, 2019; Xie et

83

al., 2019). It has well film forming properties due to κ-C has only one negative group

84

and a considerable amount of sulphonic groups in its structure that allows the

85

formation of the film through the self-aggregation of its helical structures (Carneiro et

86

al., 2013; Pasini Cabello et al., 2014). κ-C has the advantages of high mechanical

87

strength and excellent barrier properties (Fabra, Talens, & Chiralt, 2008; Farhan &

88

Hani, 2017), and has been well studied in the preparation of edible films and coatings

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(Hanani, 2017; Kanmani & Rhim, 2014). By applying κ-C to food packaging, the

90

prepared film is not only edible but also biodegradable under natural conditions.

91

However, the structure of κ-C is excessively neat, and the formed film has the

92

disadvantage of being brittle, which limits its application in food packing (Nouri,

93

Yaraki, Ghorbanpour, & Wang, 2018). To improve the mechanical properties of κ-C

94

biopolymer, it is often necessary to mix it with other biopolymers (Nouri et al., 2018).

95

Therefore, a mix of EWP and κ-C to develop a new edible film can broaden their

96

application.

97

The objective of this study was to prepare EWP/κ-C composite film, and the

98

effects of EWP content on the properties of the composite film were investigated. The

99

structural changes were characterized by FT-IR, scanning electron microscope (SEM)

100

and chemical interactions. The film forming mechanism was proposed and the sealing

101

process of the film was optimized. In addition, the formed films were used in oil

102

packaging. The oil quality and packaging film properties were measured during oil

103

storage. This study broadens the research direction of edible films and provides a

104

theoretical reference for the production and application of EWP/κ-C edible packaging

105

materials.

106 107

2. Materials and methods

108 109

2.1. Materials and reagents

110

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The eggs were purchased from Fujian Guangyang Egg Industry Co., Ltd. (Fujian,

112

China). The κ-Carrageenan was purchased from Lvxin Food Co., Ltd. (Fujian, China).

113

The soluble starch and soybean oil were purchased from Fujian Xinweicheng Test

114

Instrument Co., Ltd. (Fujian, China). The chemical reagents used were analytical

115

grade, and deionized water was used in all experiments.

116 117

2.2. Methods

118 119

2.2.1. Preparation of egg white powder

120 121

Here insert Fig. 1

122 123

2.2.2. Preparation of EWP/κ-C composite film

124

The solid mass of the film forming liquid was fixed at 2.19 g. The film forming

125

liquid blends with different mass ratios, i.e., 0:100, 20:80, 40:60, 60:40, 80:20, and

126

100:0, were prepared by adding the EWP to the κ-C solutions. The names of the films

127

formed were Egg-0, Egg-20, Egg-40, Egg-60, Egg-80, and Egg-100, respectively.

128

The κ-C was added to 40 ℃ water and stirred until no air bubbles, followed by

129

the addition of EWP powder and 0.50 ml/g glycerol, and the volume of the film

130

forming solution was adjusted to 60 mL with deionized water. The pH of the film

131

forming solution was adjusted to 10.5, and the solution was then heated at 60 ℃ for

132

30 min with magnetic stirring, and degassed by ultrasound for 10 min. A total of 13

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mL of the film forming solution was poured into a plastic petri dish and cooled for 1 h

134

at room temperature, and then, the film was dried at 40 ℃ in an oven until reaching

135

constant weight. The film was equilibrated at 25 ℃, 53% relative humidity (RH) for

136

24 h before further examination.

137 138

2.3. Determination of properties of EWP/κ-C composite films

139 140

2.3.1 Tensile strength (TS) and elongation at break (EAB)

141

TS and EAB of the film were measured by texture analyzer (TA.TX Plus, STable

142

Micro System, UK). The specific steps of the method were as follows: a complete,

143

smooth and homogeneous film was selected, the films were cut into a uniformly sized

144

dumbbell-shaped film 4 mm × 50 mm by using a dumbbell cutting blade, and

145

thickness of the film was measured. The film was fixed on the texture analyzer probe,

146

and the initial gap of the probe was set to 23 mm. The film strip was stretched moving

147

the headspace of 2 mm/s until broken. The measurements were conducted for each

148

film at least three times. TS (MPa) and EAB (%) were calculated according to

149

equations (1) and (2).

150 151

TS MPa  

F S

EAB%   ( L1  L 0) / L 0  100%

9

（1） （2）

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where F is the maximum tensile force (N), S is the cross-sectional area (mm2) of the

153

film sample, L1 is the length of the film from stretching to fracture (mm), and L0 is the

154

initial length of the film (mm).

155 156

2.3.2. Film light transmission

157

The UV-2200 ultraviolet-visible spectrophotometer (Shimadzu, Kyoto, Japan)

158

was used to determine light barrier properties of the composite films. The specific

159

steps were as follows: the films were attached to the outside of the spectrophotometer

160

colorimetric cell and scanned at 430 nm. The absorbance of the film was measured,

161

and the blank colorimetric cell was used as the blank control. Measurements were

162

carried out in triplicate.

163 164

2.3.3. Color measurement

165

The color of the EWP/κ-C composite film was determined with the ADCI-60-C

166

automatic colorimeter (Chen Taike Instruments Co. Ltd., Beijing, China) according to

167

a reported method (Yu et al., 2018). A white color plate was used as a standard for

168

calibration and as a background for color measurements of the films. The

169

measurements were repeated five times for each film. The color difference △E was

170

calculated by equation (3).

171

△E  (a*) 2  (b*) 2  ( L*) 2

（3）

172

where L* is the lightness, chromaticity parameters -a* is the greenness, +a* is the

173

redness, and -b* is the blueness, +b* is the yellowness.

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2.3.4. Water soluble time

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The edible films were cut into square shapes (2 cm × 2 cm) and placed in a

177

conical flask. A total of 100 mL of hot distilled water (80 ℃) was added and stirred at

178

200 rpm until the film was totally dissolved. The time was recorded, and the

179

measurements were carried out in triplicate.

180 181

2.3.5. Water vapor permeability (WVP)

182

The WVP of the film was determined by using the “cup method” (Jahit, Nazmi,

183

Isa, & Sarbon, 2016). According to this method, a cup with a uniform mouth size (40

184

mm in height and 50 mm in diameter) was selected, and calcium chloride was placed

185

in the cup. A non-porous, un-cracked edible film with homogeneous thickness was

186

selected and cut into 60 mm in diameter. The films were used to cover the cups and

187

sealed with paraffin, and the cups with films were weighted to record the initial

188

weight. The cup was placed in a constant temperature and humidity chamber (25℃,

189

73% RH), and the cup was weighed at 1 h intervals over 10 h of period. Three

190

replicates were obtained for each sample. WVP of the film was calculated by equation

191

(4).

192

WVP( g  mm m 2  s  Pa ) 

wd A  t  ΔP

（4）

193

where w is the increased weight of the beaker (g), d is the thickness of the film (m), A

194

is the test area of the film (m2), t is the testing time (s), and △P is the water vapor

195

pressure difference across the film (Pa).

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2.3.6. Oxygen barrier properties

198

A total of 20.0 g of soybean oil was weighed into a conical flask, a complete film

199

was selected to seal the mouth of the flask, and the soybean oil directly in contact

200

with the air as the control. Place the beaker in an oven at 60 ℃ for 10 days. A 3.0 g oil

201

sample was weighed, and its peroxide value was measured. The peroxide value was

202

determined by following the method of Nowzari, Shabanpour, and Ojagh (2013). The

203

oxygen barrier properties were calculated by equation (5). The results are expressed in

204

meq peroxide/1000 g lipid.

POV (meq kg ) 

205

V  N  1000 W

(5)

206

where V is the volume of thiosulphate for titration (mL), N is the normality of

207

thiosulphate, and W is the weight of the lipid (g).

208 209

2.3.7. Film thickness

210

A film with a complete and homogeneous appearance was selected, and the

211

thickness of the film was measured by a Micromar 40 EWR digital micrometer

212

thickness gauge (Mahr, Göttingen, Germany). Nine measurements at different

213

positions were taken on each sample.

214 215

2.4. Structure and characterization of the composite film

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2.4.1. Scanning electron microscopy (SEM)

218

The cross-section of the films was visualized following the method described

219

by El-Shabasy et al. (2019), using an SEM (Nova Nano SEM 230, FEI, USA) at a

220

magnification of 5000 × and an accelerating voltage of 10.0 kV. The sample was

221

pasted with a double-sided adhesive, mounted on stainless steel, and coated with a

222

gold layer using a sputter coater before observation.

223 224

2.4.2. Fourier transform infrared spectroscopy (FT-IR)

225

The FT-IR spectra of the films were determined as reported by Xie et al. (2020).

226

The films were recorded at wavelength between 4000 and 600 cm−1 using a Spectrum

227

100 Fourier transform spectrophotometer (Nicolet iS5, ThermoFisher, USA). Dried

228

films were prepared as translucent potassium bromide (KBr) pellets.

229 230

2.4.3. Chemical interactions

231

The chemical interactions of the film were measured according to the method

232

described by Gómez-Guillén et al. (1997). The film samples were each dissolved in 5

233

different solutions: 0.05 mol/L NaCl (S1), 0.6 mol/L NaCl (S2), 0.6 mol/L NaCl + 1.5

234

mol/L urea (S3), 0.6 mol/L NaCl + 8 mol/L urea (S4) and 0.6 mol/L NaCl + 8 mol/L

235

urea + 0.5 mol/L 2-β-mercaptoethanol (S5), and the protein content in the solutions

236

was determined. The solubility of proteins in these solutions can represent different

237

chemical interactions: the nonspecific associations (protein solubilized in S1), ionic

238

bonds (difference between protein solubilized in S2 and protein solubilized in S1),

239

hydrogen bonds (difference between protein solubilized in S3 and protein solubilized 13

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in S2), hydrophobic interactions (difference between protein solubilized in S4 and

241

protein solubilized in S3) and disulfide bonds (difference between protein solubilized

242

in S5 and protein solubilized in S4).

243 244

2.4.4. Differential scanning calorimetry (DSC)

245

The measurement of thermal stability of film was conducted using DSC (DSC

246

Q2000 Modulated, TA Instrument, USA) following a method according to Guerrero

247

et al. (2010). The calorimeter cell was flushed with 10 ml/min nitrogen. The run was

248

performed from 0 to 250 °C, at the heating rate of 10 °C/min. The mass was close to 3

249

mg of sample.

250 251

2.5. Application of EWP/κ-C composite film in oil package

252 253

2.5.1 Effect of different sealing processes on sealing strength of composite films

254

A composite film with a thickness of 50 ± 5 μm was selected and the sealing site

255

of the composite film was wetted with wet filter paper, and the blank control was

256

performed with the dried composite film. The effects of the sealing time and sealing

257

temperature on the sealing strength were investigated. The sealing strength of the film

258

was determined using a texture analyzer. The films were cut into strips of 100 mm

259

length × 150 mm width, and both ends were fixed on the probe of the texture analyzer.

260

The initial gap was set to 30 mm, the rising speed of the probe was 2 mm/s, and the

261

sealing strength was the maximum tensile load in N/m. The test was repeated three

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times.

263 264 265 266

2.5.2. Peroxide value (POV) The peroxide value (POV) was determined by following the same method in 2.3.6.

267 268

2.5.3. Acid value (AV)

269

The acid value (AV) of the oil was determined using titrimetric analysis

270

according to BS EN ISO 660 (National Standard of the People’s Republic of China.

271

GB 5009.229-2016) with slight modification (Zhang et al., 2015). The AV of the oil

272

was determined by using isopropanol and calculated according to equation (8).

273

AV mgKOH g  

(V  V 0)  c  56.11 m

(7)

274

where V is the volume of potassium hydroxide (KOH) consumed in sample

275

measurement, V0 is the volume of KOH consumed in blank control measurement, c is

276

the KOH concentration (mol/L), and m is the sample quality (g).

277 278

2.5.4. Properties determination of composite film during storage

279

The oil bag was placed in an instant noodle box, and the box was sealed and

280

stored for 0 d, 10 d, 20 d, 30 d, and 40 d, respectively. Subsequently, the mechanical

281

(TS, EAB) properties and water soluble time of the packaging films were determined.

282

The measurements followed the same method in 1.4.4.

283

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2.6. Statistical analysis

285 286

All the experiments were repeated three times. The data were plotted using

287

Origin 2017 (OriginLab Corp., Northampton, MA, USA), subjected to analysis of

288

variance (ANOVA) using SPSS version 24.0.0 (SPSS Inc., Chicago, IL, USA). All

289

data were expressed as mean ± standard deviation. A level of P < 0.05 was considered

290

significant.

291 292

3. Results and discussion

293 294

3.1. Effects of EWP content on physiochemical properties of EWP/κ-C composite film

295 296

The effects of EWP on the TS, EAB, oxygen permeability, WVP, light

297

transmittance, water soluble time and color of the composite films are summarized in

298

Table 1.

299 300

Here insert Table 1

301 302

As the mass ratio of EWP increased, the TS significantly decreased (P < 0.05)

303

(Table 1), this could be due to that the EWP reduced the hydrogen bond interactions

304

in the composite film, therefore led to the decline of TS (Pan, Jiang, Chen, & Jin,

305

2014). On the other hand, over crosslinking causes difficulty in polymer orientation,

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which is detrimental to the mechanical properties of the film. This finding was similar

307

with a study performed by Sun et al. (2011).

308

With the increase of EWP mass ratio, the EAB increased first and then declined

309

with Egg-40 had the largest value of EAB (10.85 ± 0.44%). The addition of EWP

310

should have changed the spatial structure and diversified the structure of the

311

composite film, thus enhancing the EAB (Kassab et al., 2019). Moreover, the EWP

312

reduced the intermolecular hydrogen bond interactions. When the intermolecular

313

interactions are weak, the composite film is prone to fracture, resulting in a decrease

314

in the EAB of the composite film (Zhang & Jiang, 2012). The films EAB values

315

found in this work was higher than the values reported for other κ-C composite films

316

by other authors (Farhan et al., 2017; Rodriguez-Canto et al., 2020).

317

As the mass ratio of EWP increased, the oxygen permeability significantly

318

enhanced (P < 0.05) (Table 1). This is because the addition of EWP caused a decline

319

in the polymerization ability of the composite system (Pan et al., 2014), resulting in a

320

loose of structure and big pore diameter of the composite film, therefore led to an

321

increase in oxygen permeability of the film.

322

The WVP values of the films are essential measures for the applications of

323

packaging materials. WVP reflects the water exchange capacity between food and

324

atmosphere, and the lower the WVP, the better the food preservation (Gontard,

325

Guilbert, & CUQ, 1992). With the increase of EWP mass ratio, the WVP significantly

326

reduced (P < 0.05) (Table 1). The κ-C molecules in the composite film could combine

327

with water, which increased the intermolecular distance, and the overall water

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absorption and expansion of the composite film improved the fluidity of water

329

molecules in the film (Jiménez, Sánchez-González, Desobry, Chiralt, & Tehrany,

330

2014). However, the degree of water absorption and swelling of the composite films

331

reduced as the mass ratio of EWP increased, resulting in a decline in the WVP of the

332

films.

333

Film materials used in food packaging not only hinder the gas exchange (such as

334

O2, CO2 or water vapor) but also block the absorption of light. The light transmittance

335

of food packaging materials directly affects the appearance of the packaged food and

336

is one of the important quality factors of film materials (Pereda, Dufresne, Aranguren,

337

& Marcovich, 2014). As seen, with the increase of EWP mass ratio, the light

338

transmittance significantly decreased (P < 0.05) (Table 1). The addition of EWP

339

destroyed the ordered structure of κ-C molecules, at the same time, the aggregation of

340

molecules between EWPs led to the increase of the degree of disorder in the film,

341

thereby reducing the light transmittance (Fang, Tung, Britt, Yada, & Dalgleish, 2010).

342

Thus, it can be concluded that the addition of EWP improved the light barrier ability

343

of the composite film, which is more conducive to the preservation of photosensitive

344

food.

345

The effect of the EWP mass ratio on the water soluble time of the composite film

346

is shown in Table 1. As the mass ratio of EWP increased, the water soluble time

347

firstly increased and then reduced. When the proportion of EWP is 40%, the water

348

soluble time is the longest. The κ-C interacted with the EWP to form a

349

three-dimensional (3D) reticular structure (Iwata, Ishizaki, Handa, & Tanaka, 2011).

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When the EWP content is relatively small, the tight 3D structure in the film delays the

351

water penetration rate, thereby prolonging the water soluble time. As the EWP mass

352

ratio increased, the internal structure of the composite film became loose and porous,

353

and the water soluble time was extended. Therefore, the increase of EWP resulted in a

354

significant declined (P < 0.05) (Table 1) in water soluble time of the composite film.

355

The color of the edible film affects the appearance of the product and the

356

acceptance of the consumers (Etxabide, Uranga, Guerrero, & de la Caba, 2015). As

357

the mass ratio of EWP increased, the change of L* values in the composite film was

358

not significant (P > 0.05) (Table 1); a* values firstly increased and then decreased, in

359

contrast, b* values firstly reduced and then increased. The results suggested that the

360

addition of EWP caused a red and yellow color of the EWP/κ-C composite film,

361

which was significantly different from that of the single κ-C film (P < 0.05).

362

The mechanical properties of ideal packaging materials should satisfy the EAB

363

greater than 10% and the TS greater than 10 MPa (Chapman, Potter, Chapman, &

364

Potter, 2004). In summary, Egg-40 film has the best physiochemical properties, with

365

the largest EAB, excellent TS, and low oxygen permeability and WVP. Therefore, the

366

optimal mixing ratio EWP and κ-C is 40:60, and subsequent experiments are

367

conducted with the optimal ratio.

368 369

3.2. Scanning electron microscopy (SEM)

370

The SEM of the composite films is depicted in Fig. 2. The cross-section of Egg-0

371

film is flat, dense and structurally intact. κ-C is a copolymer of α-(1-3)-d-galactose

19

Journal Pre-proof 372

and β-(1-4)-3,6-anhydro-d-galactose. In the process of film formation, carrageenan

373

molecules can form a homogeneous, dense and continuous network structure (Paula et

374

al., 2015). Therefore, this film has better airtightness and high light transmittance.

375

As shown in Fig. 2(B), the cross-section of Egg-40 film shows some wrinkles.

376

The interactions between EWP and κ-C resulted in the stretch structure of EWP and

377

formed a 3D network structure. The stretching of EWP structure led to the exposure

378

of its internal hydrophobic groups, resulting in the degradation of composite film

379

solubility, which is consistent with the results in Table 1. Furthermore, EWP is a kind

380

of biological macromolecular and has low compatibility with κ-C. A certain amount

381

addition of EWP disturbed the dense network structure of κ-C, resulting in an increase

382

in the intermolecular gap and a decrease in the rigidity and tightness of the composite

383

film, thus leading to the improvement of the EAB and a reduction in the oxygen

384

barrier properties (Tulamandi et al., 2016). Additionally, the rise of EWP content

385

enhanced the degree of disorder inside the composite film, which led to a decline in

386

the film light transmittance.

387

Fig. 2(C) shows the Egg-80 film, in which the cross-section is rough, wrinkles,

388

and has a large gap (Tulamandi et al., 2016). Moreover, an increase in the mass ratio

389

of EWP led to a further improvement in the degree of disorder of the composite film,

390

resulting in a large gap in the cross-section of the Egg-80 film. Due to the enlarging of

391

the internal gap of the composite film, the contact area between the composite film

392

and water increased, thereby reduced the water soluble time of the composite film.

393

This is consistent with the results in Table 1.

20

Journal Pre-proof 394

Here insert Fig. 2

395 396 397

3.3. Analysis of the formation mechanism of composite films

398 399

3.3.1. FT-IR analysis

400

The aligned and compared FT-IR spectrum of the composite films with different

401

mixing ratios is shown in Fig. 3(A). In detail, a strong band at 3332 cm−1 related to

402

the O−H stretching vibration of hydroxyl group (El Miri et al., 2015). Moreover,

403

stretching frequencies at 2935 cm−1 and 2870 cm−1 were attributed to the symmetric

404

C−H vibrations (Lam, Chollakup, Smitthipong, Nimchua, & Sukyai, 2017). The band

405

in 1500–1800 cm−1 corresponded to the carbonyl (C=O) region in the κ-C monomer

406

D-galactose (Balqis, Khaizura, Russly, & Hanani, 2017). The region of 800−1500

407

cm−1 is the fingerprint region containing the two characteristic peaks of κ-C at 1161

408

cm−1 and 1037 cm−1 (Xie et al., 2019). In addition, the peak around 1228 cm−1 was

409

due to the S=O vibration (El Achaby, Kassab, Barakat, & Aboulkas, 2018), which

410

corresponded to the sulfate ester (O=S=O). Peaks at 925 cm−1 and 846 cm−1

411

corresponded to the 3,6-dehydrated galactose (C−O−C) and galactose-4-sulfate

412

(C−O−S), respectively.

413

In the original spectra of κ-C film, the characteristic peaks of hydrogen bonds are

414

at 3332 cm-1. As the EWP content increased, the O−H stretching bands at 3000 - 3500

415

cm-1 are obviously shifted to a lower frequency in the spectra of the composite film.

21

Journal Pre-proof 416

Furthermore, by comparing the FT-IR spectra of Egg-80 film and Egg-0 film, it is

417

noted that the latter shows a wider range. The absorption peak of the O-H bonds at

418

3286 cm-1 is narrower than that of the single κ-C film, illustrating that the increase of

419

EWP content weakens the hydrogen bond interactions of composite film (Ye,

420

Kennedy, Li, & Xie, 2006). κ-C belongs to polyhydroxy polysaccharide, which has

421

strong intermolecular strong hydrogen bond interactions. With the addition of EWP,

422

the intermolecular distance increased and the intermolecular hydrogen bond

423

interactions reduced, resulting in a decline in the TS of the composite film.

424 425

3.3.2. Chemical interactions

426

The solubility of composite films with different EWP mass ratios in five

427

solutions is shown in Fig. 3(B). There is no protein in Egg-0 film, so it has low

428

chemical interactions. As the mass ratio of EWP increased, the nonspecific

429

crosslinking and electrostatic interactions trend upward, while the hydrophobic

430

interactions trend downward. The hydrogen bond interactions reduced firstly and then

431

increased, while the disulfide bonds were almost unchanged.

432

The increase of EWP mass ratio led to a more disorder of the composite film,

433

resulting in improving the degree of nonspecific crosslinking of the composite film. In

434

addition, an increase in the mass ratio of EWP also caused a higher molecular density

435

and charge density per unit volume, resulting in improving electrostatic interactions in

436

the composite film. Hydrogen bonds in proteins maintain the stability of the α-helix

437

structure. However, the interactions between κ-C and EWP will cause the hydrogen

22

Journal Pre-proof 438

bonds that maintain the ordered structure in EWP to be broken, reducing the hydrogen

439

bonding interactions of the composite film. Therefore, the interactions between EWP

440

and κ-C weakened, and the degree of hydrogen bond destruction in the composite film

441

reduced as the EWP mass ratio increased, thereby enhancing the hydrogen bonding

442

interactions. Hydrophobic interaction refers to the phenomenon that hydrophobic

443

groups in proteins are close to each other and aggregate to avoid water. Hydrophobic

444

interactions are the primary interaction that affects the tertiary structure of EWP,

445

which plays an important role in stabilizing of protein film structure and its functional

446

properties. The interactions of EWP with κ-C caused the stretching of protein

447

structure, thereby resulting in the exposure of the hydrophobic groups inside the

448

protein, which is conducive to the formation of hydrophobic interactions (Tang &

449

Jiang, 2007). However, as the mass ratio of egg white protein increased, the

450

interactions between EWP and κ-C decreased, and the hydrophilicity increased. In

451

addition, the structure of the composite film also becomes loose and water molecules

452

are easy to pass through, resulting in reduced hydrophobic interactions. Therefore, an

453

increase in EWP content reduced the hydrophobic interaction. Furthermore, the

454

hydrophobic properties of the film surface are not only related to the number of

455

hydrophobic groups in the film, but also the structure of the film. Therefore, the

456

surface hydrophobicity of the film can be indirectly reflected by measuring the

457

hydrophobic interactions of the film. Owing to the preparation of the composite film

458

was carried out at 60 ℃, the conditions are relatively mild, and the exposure of

459

sulfhydryl groups was limited, which reduced the hydrophobic interactions and the

23

Journal Pre-proof 460

formation of intermolecular disulfide bonds (McHugh & Krochta, 1994), thus little

461

change in the disulfide bonds.

462

Here insert Fig. 3.

463 464 465

3.4 DSC analysis

466 467

The effect of EWP on the thermal properties of κ-C film can be obtained by

468

characterizing the thermal properties of the composite film, and the glass transition

469

temperature is helpful to determine the sealing temperature (Anker, Stading, &

470

Hermansson, 1999). The DSC results of Egg-0, Egg-40 and Egg-100 are shown in Fig.

471

4. In the DSC curve of Egg-0, the absorption peaks appearing around 92.9 ℃ and 164.9

472

℃ respectively, which correspond to the internal dehydration of κ-C film and the

473

thermal decomposition of κ-C structure (Balasubramanian, Kim, & Lee, 2018). In the

474

DSC curve of Egg-40, the first peak appeared at 96.8 ℃, and the second peak appeared

475

at 122.60 ℃. However, the absorption peak of Egg-100 began to show at 126 ℃. By

476

comparing the DSC curves of the three films, it is found that the initial temperature of

477

the endothermic peak in the DSC curve of the mixed film (Egg-40) is higher than that of

478

the single film (Egg-0 and Egg-100). These data show that EWP decreased the onset

479

temperature so that it was close to the heat-sealing temperature, which improved the

480

sealing process (Abdorreza, Cheng, & Karim, 2011). It also shows that the thermal

481

stability of the film is enhanced by mixing EWP with κ-C, which improves the

24

Journal Pre-proof 482

processability of the film.

483 484

Here insert Fig. 4.

485 486

3.5. Application of composite film in oil packaging

487 488

3.5.1. Determination of sealing properties

489

The effect of the sealing temperature on the sealing strength was studied by

490

fixing the sealing time, as shown in Fig. 5(A). Heat sealing of a polymer is a

491

combination of mass and heat transfer process (Farhan et al., 2017). The seal strengths

492

of the films were primarily affected by the heat sealing temperature. Specifically,

493

when the sealing temperature of the dipped-water film increased from 60 ℃ to 90 ℃,

494

the sealing strength gradually enhanced and reached a maximum value (236 N/m) at

495

the sealing temperature of 90 ℃. When the sealing temperature further raised from 90

496

℃ to 120 ℃, the sealing strength gradually decreased, while the sealing strength of

497

the dipped-water film at any sealing temperature was higher than that of the dry film.

498

This is because the increase of temperature can accelerate the fusion speed of the

499

composite film and improve the fusion degree of the seal, thereby enhancing the

500

sealing strength. However, the decreased strength of seals formed above 90 ℃ was

501

due to EWP denatured in the case of excessive heat treatment, resulting in the

502

formation of stomata at the seals, which led to a decline in the sealing strength (Kim

503

& Ustunol, 2001). This finding was similar with a study by Cho et al. (2010).

504

Therefore, 90 ℃ was the optimum temperature for sealing the composite film. 25

Journal Pre-proof 505

The effect of the sealing time on the sealing strength was studied by fixing the

506

sealing temperature, as shown in Fig. 5(B). As the sealing time for the dipped-water

507

film increased from 1 s to 2.5 s, the sealing strength gradually enhanced and reached a

508

maximum value (236 N/m) at a sealing time of 2.5 s. As the sealing time continues to

509

increase, the sealing strength trends downward, while the sealing strength of the

510

dipped-water film at any sealing time was higher than that of the dry film. With

511

increasing sealing time, the degree of fusion at the sealing site gradually increased,

512

which improved the sealing strength. However, when the sealing was over time, the

513

denaturation of EWP in the film led to the formation of stomata at the sealing site,

514

which caused the decline of the sealing strength. Therefore, 2.5 s was selected as the

515

optimal sealing time.

516

In general, the high value of seal strength is desirable during the packaging

517

process of food products. The highest seal strength values obtained in the present

518

study were 236 N/m. This value is higher than that the semi-refined

519

kappa-carrageenan (SRC)-30G and SRC-30S films (181 and 174 N/m) (Farhan et al.,

520

2017), but much lower than that for heat-sealed synthetic polymers (≥ 730 N/m)

521

(Abdorreza et al., 2011).

522

Here insert Fig. 5.

523 524 525 526

3.5.2. POV The results for the changes of POV during storage are shown in Fig. 6(A). Under

26

Journal Pre-proof 527

the storage environment of 60 ℃, the POV of unpacked edible vegetable oil increased

528

significantly (P < 0.05). It could be mainly due to the high content of unsaturated fatty

529

acids in the oil and directly exposed to external oxygen, which facilitates oxidization.

530

Meanwhile, the higher temperature accelerated the reaction. The use of a brand film

531

packaging oil, the oxidation of oil can be alleviated to a certain extent, but the POV is

532

still high, which suggests that this packaging film can slightly insulate oxygen, thus

533

decelerating the oxidation of oil. However, the POV of the oils packaged with

534

EWP/κ-C edible film was not significantly increased (P > 0.05). Protein films are

535

generally good barriers against oxygen at intermediate RH (Javanmard, 2008),

536

indicating that the edible film can effectively barrier oxygen and have higher oxygen

537

barrier property, which led to reduce the degree of oil oxidative rancidity. After 10

538

days of accelerated oxidation, the POV of the edible vegetable oil packaged with the

539

EWP/κ-C edible film is still less than 0.25 meq/kg, which demonstrates that the edible

540

film can effectively reduce the formation of lipid peroxides.

541 542

3.5.3. AV

543

The results for the changes in the AV during storage are shown in Fig. 6(B).

544

Under the storage environment of 60 ℃, the AV of the unpackaged edible vegetable

545

oil increased significantly (P < 0.05), mainly because of the direct contact between oil

546

and air, resulting in the oil oxidation. With the progress of oxidation, the oxide

547

gradually forms acid substances, and higher temperature accelerates this reaction. The

548

oil packed with a brand packaging film that has a higher AV, principally due to the

27

Journal Pre-proof 549

increase in the AV of the oil caused by bacteria and/or oxygen in the packaging bag,

550

while the AV of the oil packed with EWP/κ-C edible film slightly increases. After 10

551

days of accelerated oxidation, the AV of the edible vegetable oil packed with

552

EWP/κ-C edible film was lower than 3 mg KOH/g, demonstrating that the edible film

553

can effectively reduce the formation of free fatty acids.

554

Here insert Fig.6.

555 556 557

3.6. Changes in film properties during oil storage

558 559

3.6.1. TS and EAB

560

The mechanical properties of the films are vital for the food packaging

561

application during shipping, handling and storage. The effect of storage time on the

562

mechanical properties of EWP/κ-C composite film is shown in Fig. 7(A). With the

563

increase of storage time, the TS of the composite film enhanced significantly and the

564

EAB decreased significantly (P < 0.05). This could be ascribed to the oil penetrate the

565

film during the storage. As a non-polar substance, the oil affects the transfer of water

566

molecules in the film, while water molecules play a plasticizing role in the film,

567

which leads to a decline in the water content in the film. Simultaneously, during the

568

storage period, the molecules aggregated in the film rearrange, and the degree of

569

freedom in the film decreases, resulting in a decline of EAB but an increase of TS

570

(Artharn, Prodpran, & Benjakul, 2009).

28

Journal Pre-proof 571 572

3.6.2. Water solubility (WS)

573

The WS of a film is used as a measure of resistance of the film against water.

574

The changes in water soluble time of the edible film oil bag during storage are shown

575

in Fig. 7(B). It is clear to note that the water soluble time of the EWP/κ-C edible film

576

gradually increased as the storage time increased. The oil penetrates the interior of the

577

edible film, which reduces the contact area between water and film, and hinders the

578

permeation of water molecules, thereby reducing the water soluble speed of the film

579

and prolonging the water soluble time (Shojaee-Aliabadi et al., 2014). Besides, during

580

the storage of the oil package, the degree of crosslinking and tightness between the

581

molecules gradually enhanced (Schmid, Merzbacher, & Müller, 2018), which led to

582

the increase of the water soluble time. The water soluble time of the EWP/κ-C edible

583

film used in the present study was much lower than the previously reported water

584

soluble time of SPI film (150-180 s) (Cho et al., 2010; Su, Huang, Yang, & Yuan,

585

2008). Therefore, the EWP/κ-C edible film can be used as a hot water soluble

586

packaging film in oil packaging.

587

Here insert Fig. 7.

588 589 590

4. Conclusions

591 592

In conclusion, EWP content significantly affected the physiochemical properties

29

Journal Pre-proof 593

of the EWP /κ-C composite film. Microstructure and FT-IR analyses indicated that

594

the increase of EWP content enhanced the disorder degree of the composite film,

595

improved the EAB and light barrier properties, and notably declined the TS, oxygen

596

barrier properties, and WVP of the film. Chemical interactions analysis indicated that

597

an increase in EWP content enhanced the degree of nonspecific crosslinking and

598

electrostatic interactions of the composite film. Furthermore, the composite film was

599

used as a packaging material to storage the oil, compared with the commercial film,

600

the composite film could effectively delay the rancidity of oil during storage.

601

Consequently, the film can make an application for food packaging as a natural,

602

environmentally friendly and renewable resource instead of synthetic plastics. The

603

applications of EWP/κ-C composite films offer new opportunities to develop novel

604

food biodegradable packaging. This can improve the practical value of EWP/κ-C film

605

and provide a new avenue for further development of edible packaging films.

606 607

Acknowledgements

608

This study was financially supported through grants from the National Key

609

Research and Development Program of China (2018YFD0400302) and the National

610

Natural Science Foundation of China (No. 31871732).

611 612

References

613

30

Journal Pre-proof 614 615

Abdorreza, M. N., Cheng, L. H., & Karim, A. A. (2011). Effects of plasticizers on thermal properties and heat sealability of sago starch films. Food Hydrocolloids, 25(1), 56-60.

616

Anker, M., Stading, M., & Hermansson, A. M. (1999). Effects of pH and the gel state on the

617

mechanical properties, moisture contents, and glass transition temperatures of whey

618

protein films. Journal of Agricultural and Food Chemistry, 47(5), 1878-1886.

619

Artharn, A., Prodpran, T., & Benjakul, S. (2009). Round scad protein-based film: storage stability

620

and its effectiveness for shelf-life extension of dried fish powder. LWT-Food Science and

621

Technology, 42(7), 1238-1244.

622

Avella, M., De Vlieger, J. J., Errico, M. E., Fischer, S., Vacca, P., & Volpe, M. G. (2005).

623

Biodegradable starch/clay nanocomposite films for food packaging applications. Food

624

Chemistry, 93(3), 467-474.

625 626

Azeredo, H. M., & Waldron, K. W. (2016). Crosslinking in polysaccharide and protein films and coatings for food contact–A review. Trends in Food Science & Technology, 52, 109-122.

627

Balasubramanian, R., Kim, S. S., & Lee, J. (2018). Novel synergistic transparent

628

k-Carrageenan/Xanthan gum/Gellan gum hydrogel film: Mechanical, thermal and water

629

barrier properties. International Journal of Biological Macromolecules, 118, 561-568.

630

Balqis, A. M. I., Khaizura, M. A. R. N., Russly, A. R., & Hanani, Z. A. N. (2017). Effects of

631

plasticizers on the physicochemical properties of kappa-carrageenan films extracted from

632

Eucheuma cottonii. International Journal of Biological Macromolecules, 103, 721-732.

633

Belgacem, M. N., & Gandini, A. (2008). Chapter 3 - Materials from Vegetable Oils: Major

634

Sources, Properties and Applications. In M. N. Belgacem & A. Gandini (Eds.),

31

Journal Pre-proof 635

Monomers, Polymers and Composites from Renewable Resources (pp. 39-66).

636

Amsterdam: Elsevier.

637 638 639 640

Bourtoom, T. (2009). Edible protein films: properties enhancement. International Food Research Journal, 16(1), 1-9. Bucci, D., Tavares, L., & Sell, I. (2005). PHB packaging for the storage of food products. Polymer Testing, 24(5), 564-571.

641

Carneiro, T. N., Novaes, D. S., Rabelo, R. B., Celebi, B., Chevallier, P., Mantovani, D., Beppu, M.

642

M., & Vieira, R. S. (2013). BSA and Fibrinogen Adsorption on Chitosan/κ‐C arrageenan

643

Polyelectrolyte Complexes. Macromolecular Bioscience, 13(8), 1072-1083.

644 645

Chapman, S., Potter, L., Chapman, S., & Potter, L. (2004). Edible films and coatings: a review. Edible Films & Coatings A Review.

646

Cho, S. Y., Lee, S. Y., & Rhee, C. (2010). Edible oxygen barrier bilayer film pouches from corn

647

zein and soy protein isolate for olive oil packaging. LWT - Food Science and Technology,

648

43(8), 1234-1239.

649 650 651 652

Clark, D., Kiss, I., Wilde, P., & Wilson, D. (1992). The effect of irradiation on the functional properties of spray-dried egg white protein. Food Hydrocolloids, 5(6), 541-548. Debeaufort, F., Quezada-Gallo, J. A., & Voilley, A. (2000). Edible Barriers: A Solution to Control Water Migration in Foods. ACS Symposium Series, 753, 9-16.

653

El-Shabasy, R., Yosri, N., El-Seedi, H., Shoueir, K., & El-Kemary, M. (2019). A green synthetic

654

approach using chili plant supported Ag/Ag2O@P25 heterostructure with enhanced

655

photocatalytic properties under solar irradiation. Optik, 192, 162943.

32

Journal Pre-proof 656

El Achaby, M., Kassab, Z., Barakat, A., & Aboulkas, A. (2018). Alfa fibers as viable sustainable

657

source for cellulose nanocrystals extraction: Application for improving the tensile

658

properties of biopolymer nanocomposite films. Industrial Crops and Products, 112,

659

499-510.

660

El Miri, N., Abdelouahdi, K., Zahouily, M., Fihri, A., Barakat, A., Solhy, A., & El Achaby, M.

661

(2015). Bio-nanocomposite films based on cellulose nanocrystals filled polyvinyl

662

alcohol/chitosan polymer blend. Journal of Applied Polymer Science, 132(22).

663

Etxabide, A., Uranga, J., Guerrero, P., & de la Caba, K. (2015). Improvement of barrier properties

664

of fish gelatin films promoted by gelatin glycation with lactose at high temperatures.

665

LWT-Food Science and Technology, 63(1), 315-321.

666

Fabra, M. J., Talens, P., & Chiralt, A. (2008). Effect of alginate and λ-carrageenan on tensile

667

properties and water vapour permeability of sodium caseinate–lipid based films.

668

Carbohydrate Polymers, 74(3), 419-426.

669

Fang, Y., Tung, M. A., Britt, I. J., Yada, S., & Dalgleish, D. G. (2010). Tensile and Barrier

670

Properties of Edible Films Made from Whey Proteins. Journal of Food Science, 67(1),

671

188-193.

672

Farhan, A., & Hani, N. M. (2017). Characterization of edible packaging films based on

673

semi-refined

674

Hydrocolloids, 64, 48-58.

675 676

kappa-carrageenan

plasticized

with

glycerol

and

sorbitol.

Food

Gennadios, A., & Weller, C. L. (1990). Edible films and coatings from wheat and corn proteins. Food Technology.

33

Journal Pre-proof 677

Ghanbarzadeh, B., Almasi, H., & Entezami, A. A. (2010). Physical properties of edible modified

678

starch/carboxymethyl cellulose films. Innovative Food Science & Emerging Technologies,

679

11(4), 697-702.

680

Gómez-Guillén, M. C., Borderı́as, A. J., & Montero, P. (1997). Chemical Interactions of

681

Nonmuscle Proteins in the Network of Sardine (Sardina pilchardus) Muscle Gels. LWT -

682

Food Science and Technology, 30(6), 602-608.

683

Gontard, N., Guilbert, S., & CUQ, J. L. (1992). Edible wheat gluten films: influence of the main

684

process variables on film properties using response surface methodology. Journal of Food

685

Science, 57(1), 190-195.

686 687

González, A., & Igarzabal, C. I. A. (2013). Soy protein–Poly (lactic acid) bilayer films as biodegradable material for active food packaging. Food Hydrocolloids, 33(2), 289-296.

688

Guerrero, P., Retegi, A., Gabilondo, N., & de la Caba, K. (2010). Mechanical and thermal

689

properties of soy protein films processed by casting and compression. Journal of Food

690

Engineering, 100(1), 145-151.

691

Guo, X., Lu, Y., Cui, H., Jia, X., Bai, H., & Ma, Y. (2012). Factors affecting the physical

692

properties of edible composite film prepared from zein and wheat gluten. Molecules,

693

17(4), 3794-3804.

694

Han, J. H. (2014). Chapter 9 - Edible Films and Coatings: A Review. In J. H. Han (Ed.),

695

Innovations in Food Packaging (Second Edition) (pp. 213-255). San Diego: Academic

696

Press.

34

Journal Pre-proof 697

Hanani, Z. N. (2017). Physicochemical characterization of kappa-carrageenan (Euchema cottoni)

698

based films incorporated with various plant oils. Carbohydrate Polymers, 157,

699

1479-1487.

700 701

Iwata, K., Ishizaki, S., Handa, A., & Tanaka, M. (2011). Preparation and characterization of edible films from fish water-soluble proteins. Fisheries Science, 66(2), 372-378.

702

Jahit, I. S., Nazmi, N. N. M., Isa, M. I. N., & Sarbon, N. M. (2016). Preparation and physical

703

properties of gelatin/CMC/chitosan composite films as affected by drying temperature.

704

International Food Research Journal, 23(3), 1068-1074.

705 706

Javanmard, M. (2008). Effect of whey protein edible film packaging on the quality and moisture uptake of dried peanuts. Journal of Food Process Engineering, 31(4), 503-516.

707

Jiang, Y., & Tang, C. H. (2013). Effects of transglutaminase on sorption, mechanical and

708

moisture-related properties of gelatin films. Food Science and Technology International,

709

19(2), 99-108.

710

Jiménez, A., Sánchez-González, L., Desobry, S., Chiralt, A., & Tehrany, E. A. (2014). Influence

711

of nanoliposomes incorporation on properties of film forming dispersions and films based

712

on corn starch and sodium caseinate. Food Hydrocolloids, 35, 159-169.

713

Kanmani, P., & Rhim, J.-W. (2014). Development and characterization of carrageenan/grapefruit

714

seed extract composite films for active packaging. International Journal of Biological

715

Macromolecules, 68, 258-266.

716

Kassab, Z., Aziz, F., Hannache, H., Youcef, H. B., & El Achaby, M. (2019). Improved mechanical

717

properties of k-carrageenan-based nanocomposite films reinforced with cellulose

718

nanocrystals. International Journal of Biological Macromolecules, 123, 1248-1256.

35

Journal Pre-proof 719

Kim, S. J., & Ustunol, Z. (2001). Thermal Properties, Heat Sealability and Seal Attributes of

720

Whey Protein Isolate/ Lipid Emulsion Edible Films. Journal of Food Science, 66,

721

985-990.

722

Lam, N. T., Chollakup, R., Smitthipong, W., Nimchua, T., & Sukyai, P. (2017). Characterization

723

of Cellulose Nanocrystals Extracted from Sugarcane Bagasse for Potential Biomedical

724

Materials. Sugar Tech, 19(5), 539-552.

725

McHugh, T. H., & Krochta, J. M. (1994). Water vapor permeability properties of edible whey

726

protein-lipid emulsion films. Journal of the American Oil Chemists’ Society, 71(3),

727

307-312.

728

Mehdizadeh, T., Tajik, H., Razavi Rohani, S. M., & Oromiehie, A. R. (2012). Antibacterial,

729

antioxidant and optical properties of edible starch-chitosan composite film containing

730

Thymus kotschyanus essential oil. Veterinary Research Forum: an international

731

quarterly journal, 3(3), 167-173.

732

Moradi, M., Tajik, H., Razavi Rohani, S. M., & Mahmoudian, A. (2016). Antioxidant and

733

antimicrobial effects of zein edible film impregnated with Zataria multiflora Boiss.

734

essential oil and monolaurin. LWT - Food Science and Technology, 72, 37-43.

735

Nazmi, N. N., Isa, M. I. N., & Sarbon, N. M. (2017). Preparation and characterization of chicken

736

skin gelatin/CMC composite film as compared to bovine gelatin film. Food Bioscience,

737

19, 149-155.

738

Nouri, A., Yaraki, M. T., Ghorbanpour, M., & Wang, S. (2018). Biodegradable

739

κ-carrageenan/nanoclay nanocomposite films containing Rosmarinus officinalis L. extract

36

Journal Pre-proof 740

for improved strength and antibacterial performance. International Journal of Biological

741

Macromolecules, 115, 227-235.

742

Nowzari, F., Shábanpour, B., & Ojagh, S. M. (2013). Comparison of chitosan–gelatin composite

743

and bilayer coating and film effect on the quality of refrigerated rainbow trout. Food

744

Chemistry, 141(3), 1667-1672.

745 746

Pan, H., Jiang, B., Chen, J., & Jin, Z. (2014). Blend-modification of soy protein/lauric acid edible films using polysaccharides. Food Chemistry, 151, 1-6.

747

Pasini Cabello, S. D., Molla, S., Ochoa, N. A., Marchese, J., Gimenez, E., & Compan, V. (2014).

748

New bio-polymeric membranes composed of alginate-carrageenan to be applied as

749

polymer electrolyte membranes for DMFC. Journal of Power Sources, 265, 345-355.

750

Paula, G. A., Benevides, N. M. B., Cunha, A. P., Oliveira, A. V. D., Pinto, A. M. B., Morais, J. P.

751

S., & Azeredo, H. M. C. (2015). Development and characterization of edible films from

752

mixtures ofκ-carrageenan, ι-carrageenan, and alginate. Food Hydrocolloids, 47, 140-145.

753

Peng, N., Gu, L., Li, J., Chang, C., Li, X., Su, Y., & Yang, Y. (2017). Films based on egg white

754

protein and succinylated casein cross-linked with transglutaminase. Food and Bioprocess

755

Technology, 10(8), 1422-1430.

756

Pereda, M., Dufresne, A., Aranguren, M. I., & Marcovich, N. E. (2014). Polyelectrolyte films

757

based on chitosan/olive oil and reinforced with cellulose nanocrystals. Carbohydrate

758

Polymers, 101, 1018-1026.

759

Rodriguez-Canto, W., Cerqueira, M. A., Chel-Guerrero, L., Pastrana, L. M., & Aguilar-Vega, M.

760

(2020). Delonix regia galactomannan-based edible films: Effect of molecular weight and

761

k-carrageenan on physicochemical properties. Food Hydrocolloids, 103, 105632.

37

Journal Pre-proof 762

Saberi, B., Thakur, R., Vuong, Q. V., Chockchaisawasdee, S., Golding, J. B., Scarlett, C. J., &

763

Stathopoulos, C. E. (2016). Optimization of physical and optical properties of

764

biodegradable edible films based on pea starch and guar gum. Industrial Crops and

765

Products, 86, 342-352.

766

Salmieri, S., & Lacroix, M. (2006). Physicochemical properties of alginate/polycaprolactone-based

767

films containing essential oils. Journal of Agricultural and Food Chemistry, 54(26),

768

10205-10214.

769 770

Schmid, M., Merzbacher, S., & Müller, K. (2018). Time-dependent crosslinking of whey protein based films during storage. Materials Letters, 215, 8-10.

771

Shojaee-Aliabadi, S., Mohammadifar, M. A., Hosseini, H., Mohammadi, A., Ghasemlou, M.,

772

Hosseini, S. M., Haghshenas, M., & Khaksar, R. (2014). Characterization of

773

nanobiocomposite kappa-carrageenan film with Zataria multiflora essential oil and

774

nanoclay. International Journal of Biological Macromolecules, 69(8), 282-289.

775

Song, X., Zhou, C., Fu, F., Chen, Z., & Wu, Q. (2013). Effect of high-pressure homogenization on

776

particle size and film properties of soy protein isolate. Industrial Crops and Products, 43,

777

538-544.

778

Su, J. F., Huang, Z., Yang, C. M., & Yuan, X. Y. (2008). Properties of soy protein isolate/poly

779

(vinyl alcohol) blend “green” films: compatibility, mechanical properties, and thermal

780

stability. Journal of Applied Polymer Science, 110(6), 3706-3716.

781

Sun, W. W., Yu, S. J., Yang, X. Q., Wang, J. M., Zhang, J. B., Zhang, Y., & Zheng, E. L. (2011).

782

Study on the rheological properties of heat-induced whey protein isolate–dextran

783

conjugate gel. Food Research International, 44(10), 3259-3263.

38

Journal Pre-proof 784

Tang, C. H., & Jiang, Y. (2007). Modulation of mechanical and surface hydrophobic properties of

785

food protein films by transglutaminase treatment. Food Research International, 40(4),

786

504-509.

787

Tulamandi, S., Rangarajan, V., Rizvi, S. S. H., Singhal, R. S., Chattopadhyay, S. K., & Saha, N. C.

788

(2016). A biodegradable and edible packaging film based on papaya puree, gelatin, and

789

defatted soy protein. Food Packaging & Shelf Life, 10, 60-71.

790 791

Wittaya, T. (2012). Protein-based edible films: Characteristics and improvement of properties. Structure and Function of Food Engineering, 43-70.

792

Xie, H., Xiang, C., Li, Y., Wang, L., Zhang, Y., Song, Z., Ma, X., Lu, X., Lei, Q., & Fang, W.

793

(2019). Fabrication of ovalbumin/κ-carrageenan complex nanoparticles as a novel carrier

794

for curcumin delivery. Food Hydrocolloids, 89, 111-121.

795

Xie, Y., Wang, J., Wang, Y., Wu, D., Liang, D., Ye, H., Cai, Z., Ma, M., & Geng, F. (2020).

796

Effects of high-intensity ultrasonic (HIU) treatment on the functional properties and

797

assemblage structure of egg yolk. Ultrasonics Sonochemistry, 60, 104767.

798

Yayli, D., Turhan, S., & Saricaoglu, F. T. (2017). Edible Packaging Film Derived from

799

Mechanically Deboned Chicken Meat Proteins: Effect of Transglutaminase on

800

Physicochemical Properties. Korean Journal for Food Science of Animal Resources,

801

37(5), 635-645.

802

Ye, X., Kennedy, J. F., Li, B., & Xie, B. J. (2006). Condensed state structure and biocompatibility

803

of the konjac glucomannan/chitosan blend films. Carbohydrate Polymers, 64(4),

804

532-538.

39

Journal Pre-proof 805

Yu, Z., Sun, L., Wang, W., Zeng, W., Mustapha, A., & Lin, M. (2018). Soy protein-based films

806

incorporated with cellulose nanocrystals and pine needle extract for active packaging.

807

Industrial Crops and Products, 112, 412-419.

808

Zhang, M., Sun, A., Meng, Y., Wang, L., Jiang, H., & Li, G. (2015). High activity ordered

809

mesoporous carbon-based solid acid catalyst for the esterification of free fatty acids.

810

Microporous and Mesoporous Materials, 204, 210-217.

811 812

Zhang, Y. B., & Jiang, J. (2012). Preparation and Performance Characterization of Soy Protein Isolate Edible Film. Food Science, 33(6), 100-104.

813

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Journal Pre-proof Conflicts of interest The authors declared that they have no conflicts of interest to this work. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.

Journal Pre-proof Author statement The author states that they have no missing file types to this work.

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Abbreviation: Egg white protein (EWP)

κ-Carrageenan (κ-C)

Scanning electron microscopy

Fourier transform infrared

(SEM)

spectroscopy (FT-IR)

Water vapor permeability (WVP)

Elongation at break (EAB)

Tensile strength (TS)

Relative humidity (RH)

Differential scanning calorimetry Three-dimensional (3D) (DSC) Peroxide value (POV)

Acid value (AV)

Potassium hydroxide (KOH)

Water solubility (WS)

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Figure Captions

Fig. 1. Schematic representation of the overall experiment.

Fig. 2. Scanning electron microscope images of the cross-section of EWP/κ-C composite film samples with different EWP content; EWP content from left to right: Egg-0: The mass ratio of κ-C and EWP was 100:0; Egg-40: The mass ratio of κ-C and EWP was 60:40; Egg-80: The mass ratio of κ-C and EWP was 20:80.

Fig. 3. Formation mechanism of composite film under different contents of EWP. (A): FTIR spectra of EWP/κ-C composite film with different EWP content. (B): Chemical interactions of EWP/κ-C composite film under different EWP content. Egg-0: The mass ratio of κ-C and EWP was 100:0; Egg-20: The mass ratio of κ-C and EWP was 80:20; Egg-40: The mass ratio of κ-C and EWP was 60:40; Egg-60: The mass ratio of κ-C and EWP was 40:60; Egg-80: The mass ratio of κ-C and EWP was 20:80.

Fig. 4. Heating-up DSC curves of Egg-0 film, Egg-40 fim, Egg-100 film.

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Fig. 5. Effect of the sealing process on the sealing strength: (A) Effect of different sealing temperature on sealing strength. (B) Effect of different sealing time on sealing strength.

Fig. 6. Changes of oil quality during storage: (A) Effect of each packing material on the POV of oil under different storage time. (B) Effect of each packing material on the AV of oil under different storage time.

Fig. 7. Changes in film properties during oil storage: (A) Changes in mechanical properties (TS and EAB) of oil package under different storage times. (B) Changes in Water solubility of oil package under different storage times. The bars with different letters indicate a significant difference at P < 0.05.

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Journal Pre-proof Highlights 

Egg white protein (EWP) and κ-Carrageenan (κ-C) were used to prepare a composite film.



EWP content significantly affect the physiochemical properties of EWP/κ-C composite film.



The formation mechanism of EWP/κ-C film is analyzed.



EWP/κ-C composite film can be used as edible food packaging material for oil packaging.

Table 1 Effects of EWP content on physiochemical properties of EWP/κ-C composite film Film samples Properties Egg-0

Egg-20

Egg-40

Egg-60

Egg-80

TS（MPa）

36.67±1.91a

33.27±1.10ab

29.98±1.42c

15.49±0.97d

7.45±0.98e

EAB(%)

9.34±0.25ab

10.43±0.68a

10.85±0.44a

9.86±0.54ab

8.56±0.52b

POV（meq/kg）

2.93±0.21b

2.87±0.14b

3.11±0.17b

3.76±0.34a

4.17±0.29a

WVP（g·mm/m2·s·Pa）

2.55±0.07a

2.17±0.17a

2.12±0.16ab

1.72±0.10bc

1.59±0.07c

Light transmittance(%)

83.6±1.2a

81.7±0.8ab

77.3±1.2c

64.5±2.2d

53.3±1.7e

L*

61.83±1.49a

63.58±0.66a

64.69±0.82a

64.01±0.53a

65.28±0.41a

a*

-11.23±1.69c

-2.84±0.48a

-2.86±0.54a

-6.88±0.25b

-7.67±0.36b

b*

-38.56±2.82a

-50.93±0.59b

-53.51±0.92b

-49.14±0.67b

-49.68±0.59b

E*

73.84±2.30b

81.53±0.76a

84.02±1.16a

80.99±0.79a

82.32±0.52a

Water soluble time（s）

65.3±0.9b

68.9±0.4b

73.2±1.0a

41.8±1.1c

29.9±0.9d

Data are expressed as the mean ± SD from triplicate determinations. Different letters in the same column indicate significant differences (P < 0.05).