Subscriber access provided by TULANE UNIVERSITY
Biofuels and Biobased Materials
Electrospun gelatin nanofibers encapsulated with peppermint and chamomile essential oils as potential edible packaging Yadong Tang, Ying Zhou, Xingzi Lan, Dongchao Huang, Tingting Luo, Junjie Ji, Zihui Mafang, Xiaomin Miao, Han Wang, and Wenlong Wang J. Agric. Food Chem., Just Accepted Manuscript • Publication Date (Web): 04 Feb 2019 Downloaded from http://pubs.acs.org on February 4, 2019
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 34
Journal of Agricultural and Food Chemistry
1
Electrospun gelatin nanofibers encapsulated with peppermint and chamomile
2
essential oils as potential edible packaging
3 4
Yadong Tang a,b*, Ying Zhou a, Xingzi Lan a, Dongchao Huang a, Tingting Luo a,
5
Junjie Ji a, Zihui Mafang a, Xiaomin Miao a, Han Wang c, and Wenlong Wang d*
6 7
a
Department of Pharmaceutical Engineering, Guangdong University of Technology, Guangzhou, 510006, China
8 b
9
School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529020, China
10 c
11
Guangdong Provincial Key Laboratory of Micro-nano Manufacturing Technology
12
and Equipment, School of Electromechanical Engineering, Guangdong University of
13
Technology, Guangzhou, 510006, China
14 15
d
School of Mechanical and Electric Engineering, Guangzhou University, Guangzhou, 510006, China
16 17
E-mail:
[email protected];
[email protected] 18 19 20
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
21
Abstract
22
Natural and edible materials have attracted increasing attentions in food
23
packaging, which could overcome the serious environmental issues caused by
24
conventional non-biodegradable synthetic packaging. In this work, gelatin nanofibers
25
incorporated with two kinds of essential oil (EO), peppermint essential oil (PO) and
26
chamomile essential oil (CO), were fabricated by electrospinning for potential edible
27
packaging application. Electron microscopy showed that smooth and uniform
28
morphology of the gelatin/EOs was obtained, and the diameter of nanofibers was
29
mostly enlarged with the increase of EO content. 1HMR spectrum confirmed the
30
existence of PO and CO in nanofibers after electrospinning. The addition of EOs led
31
to an enhancement of the water contact angle of nanofibers. The antioxidant activity
32
was significantly improved for the nanofibers loaded with CO, while the anti-bacteria
33
activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was
34
better for the fibers with PO addition. The combination of half PO and half CO in
35
nanofibers compensated their respective limitations and exhibited optimum
36
bioactivities. Finally, the MTT assay with NIH-3T3 fibroblasts demonstrated the
37
absence of cytotoxicity of the gelatin/EOs nanofibers. Thus, our studies suggest that
38
the developed gelatin/PO/CO nanofiber could be a promising candidate for edible
39
packaging.
40 41
Keywords:
Electrospinning, Gelatin, Essential oils, Edible packaging
42
ACS Paragon Plus Environment
Page 2 of 34
Page 3 of 34
Journal of Agricultural and Food Chemistry
43
1. Introduction
44
Food packaging is essential for protecting food from surrounding environment
45
and extending the shelf-life of food products 1. However, materials currently used for
46
food packaging are mostly non-biodegradable petrochemical-based plastics, which is
47
one of the main causes of environmental issues
48
materials are drawing more and more attentions in food packaging field due to their
49
environment-friendly and biodegradable characteristics, as well as the effective
50
controlling of the surface microbial by applying directly on the surface of food 6.
2-5.
Nowadays, natural and edible
51
The materials used for edible must be chosen carefully. Gelatin, one of the
52
versatile biomaterials, has been widely used in edible packaging, wound dressing and
53
tissue engineering, and it can be formed by hydrolysing collagen, the most abundant
54
biopolymer in animals
55
bioactivities, such as the protective effects against microbial and oxidative damage,
56
which are the main factors of food spoilage 7-9. Especially for many refrigerated food
57
products, such as fresh meat, in addition to isolating them from the outside bacteria,
58
controlling the surface microbial growth on food is also crucial since it is the main
59
source of contamination 9, 10. Besides, the high hydrophilic nature is another weakness
60
of gelatin as food packaging, due to its sensitivity to moisture
61
have been studying blending gelatin with other materials possessing bioactivities or
62
hydrophobicity to alleviate these drawbacks in food packaging applications 12, 13.
2, 7.
However, sole gelatin packaging does not have enough
11.
Thus, researchers
63
Essential oils (EOs) are extracted from plants and exhibit natural bioactivities,
64
which have been categorized as GRAS (Generally Recognized as Safe) by the Food
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
14-17.
Page 4 of 34
65
and Drug Administration (FDA)
Thus, EOs are eligible to be added in edible
66
food packaging and have been proved to improve the bioactivities as well as the
67
hydrophilicity of gelatin-based packaging
68
essential oil ( PO ) possesses outstanding antimicrobial activity, which has been
69
well-studied and applied in food preservation, pharmaceutical and wound dressing
70
18-20.
71
medicinal tea, cosmetics perfume and food industry due to its calming and
72
anti-bacteria properties, and in particular, the excellent antioxidant activity, which has
73
been widely studied 21-24.
1.
Among many others, peppermint
On the other hand, chamomile essential oil (CO), has been largely used in
74
In this study, PO and CO were chosen as bioactive agents to be added in gelatin
75
edible packaging to improve the antibacterial, antioxidant and hydrophobic properties.
76
Particularly, different from most previous reports 1, 2, 25, electrospinning technique was
77
used in this work, but not the commonly used casting method for film formation of
78
gelatin, to avoid the heating process resulted rapid evaporation loss of volatile EOs.
79
Electrospinning is a simple and versatile technique used to form homogeneous and
80
porous nanofibers
81
of electrospun nanofibers, have been proved to be beneficial for the sustained release
82
of bioactive agents from nanofibers to food surface, and amplify the bioactive effects
83
29, 30.
84
well as their controllable tensile modulus and strength by morphology and diameter of
85
nanofibers, make them promising food packaging materials
86
electrospinning of EOs has been reported mostly for wound dressing 32, 33, Han et al 30
26-28.
The high surface area to volume ratio and the nano-structure
Besides, the excellent mechanically flexibility of electrospun nanofiber mats, as
ACS Paragon Plus Environment
31.
Although the
Page 5 of 34
Journal of Agricultural and Food Chemistry
34
87
and Lin et al
have also reported the electrospun nanofibers of essential oils and
88
synthetic polymers for active food packaging. However, electrospun nanofibers with
89
EOs and natural polymers for edible packaging and the joint effect of different EOs in
90
nanofibers were rarely studied.
91
In this work, gelatin nanofibers incorporated with PO and CO for potential edible
92
packaging were fabricated via electrospinning, and characterized by scanning electron
93
microscopy (SEM), 1NMR and water contact angle (WCA) measurement. The
94
antibacterial property and the barrier function of nanofibers against Escherichia coli
95
(E. coli) and Staphylococcus aureus (S. aureus) were investigated by dynamic contact
96
method and microbial penetration test, respectively. DPPH radical scavenging assay
97
and MTT assay were performed to evaluate the antioxidant activities and cytotoxicity
98
of the gelatin/EO nanofibers, respectively.
99 100
2. Materials and methods
101
2.1 Materials
102
EOs of peppermint and chamomile were purchased from Jiangxi Cedar Natural
103
Medicinal Oil Co., Ltd. Gelatin (G2625), 2,2-diphenyl-1-picrylhydrazyl hydrate
104
(DPPH), 3-[4,5-dimethylthiazol-2-yl]-diphenyltetrazolium bromide (MTT) and
105
dimethyl sulfoxide (DMSO) were obtained from Sigma-Aldrich. High glucose
106
Dulbecco’s modified Eagle medium (DMEM), fetal bovine serum (FBS), phosphate
107
buffer solution (PBS), Trypsin-ethylenediaminetetraacetic acid (EDTA) solution and
108
Penicillin-Streptomycin were purchased from Gibco. Nutrient agar and mueller hinton
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
109
broth (MH) were obtained from Guangdong Huankai Microbiology Technology Co.
110
Ltd.
111 112
2.2 Preparation of electrospinning solutions
113
The process of electrospinning solution preparation was illustrated in Fig. 1(a).
114
Gelatin solution (12% w/v) was prepared by dissolving gelatin powder in a solvent
115
mixture of acetic acid and distilled water with a volume ratio of 22:3. Then a certain
116
percentage (0, 3%, 6%, 9% v/v) of essential oils (peppermint oil (PO) or chamomile
117
(CO) or 50% v/v PO and 50% v/v CO (PO/CO)) was added into the mixture
118
mentioned above and stirred at room temperature for 3 h using a magnetic stirrer
119
(C-MAG HS7 digital) to get homogeneous solutions used for electrospinning.
120 121
2.3 Fabrication of nanofibers
122
Gelatin/EOs nanofibers were fabricated via electrospinning, as shown in Fig.
123
1(b). In brief, the above electrospinning solution was filled into a 1 ml syringe with an
124
18-G needle and mounted on a syringe pump with a preset flow rate of 0.3 ml/h. The
125
needle was connected to the anode of high potential power supply with a bias voltage
126
of 15 kV. The cathode was connected to a grounded roller covered with a piece of
127
aluminum foil for nanofiber collection. The distance between needle and aluminum
128
foil was 10 cm. After electrospinning, the collected fibers were placed in a vacuum
129
dryer overnight to completely remove residual solvent and set aside for experiment.
130
ACS Paragon Plus Environment
Page 6 of 34
Page 7 of 34
131
Journal of Agricultural and Food Chemistry
2.4 Scanning electron microscopy (SEM) observation
132
The morphology of nanofibers was characterized by SEM (TM3030, Hitachi,
133
Tokyo, Japan) at an accelerating voltage of 5 kV. Nanofiber’s diameter was calculated
134
directly from the SEM images using Image Pro Plus 6.0 soft imaging system, and
135
each sample was measured by randomly selecting 150 fibers from the SEM image.
136
Then, the diameter of sample was presented by average diameter (AD) ± standard
137
deviation (SD).
138 139 140
2.5 Chemical characterization 1H
NMR (DPX-400, Bruker) spectra was recorded at 400 MHz by dissolving 20
141
mg nanofiber into 500 μL of DMSO-d6 to prove the existence of essential oils in
142
nanofibers 35. The chemical shifts were reported in parts per million (ppm) relative to
143
residual DMSO-d6 (δ=2.50, 1H).
144 145
2.6 Water contact angle measurement
146
The hydrophilicity of nanofibers was evaluated by water contact angle
147
measurement with an automatic contact angle system (OCA100, Dataphysics,
148
Germany) 2. 2 μL of distilled water was dropped on the surface of each nanofiber
149
sample and photographed immediately (t = 0). In this manner, each sample was
150
measured at least three times at different locations for average.
151 152
2.7 Antioxidant activity study
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 8 of 34
153
The antioxidant activity of nanofibers was analyzed in terms of DPPH radical
154
scavenging activity 36. In brief, nanofiber samples were placed in a six-well plate and
155
soaked with 3 ml DPPH solution (0.1 mmol/L) prepared by dissolving DPPH powder
156
in alcohol. After 30 min of incubation at room temperature in dark, the absorbance of
157
the solution was recorded at 517 nm by using an UV-Vis spectroscopy (Lambda 25,
158
PerkinElmer, America). Then, the efficiency of scavenging free radicals was
159
calculated by the following formula:
160
Radical scavenging activity (%) =
𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑂𝐷 ― 𝑆𝑎𝑚𝑝𝑙𝑒𝑂𝐷 𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑂𝐷
× 100
161
Where, ControlOD is the absorbance of the DPPH aqueous solution without fiber,
162
while, SampleOD is the absorbance of the DPPH aqueous solution with nanofiber
163
sample.
164
The ultraviolet (UV) light transmittance (%) of gelatin/EOs nanofibers was
165
determined by quantifying the transmittance of light at selected wavelengths between
166
200 nm and 400 nm and using an UV-Vis spectrophotometer (Lambda 25,
167
PerkinElmer, America) 1. Gelatin film prepared by casting was regarded as control.
168
Firstly, gelatin solution (12% (w/v)) was prepared by dissolving gelatin powder in
169
distilled water, then the mixture was heated at 70 ℃ for 30 min with continuous
170
stirring to obtain completely solubilize gelatin. Next, the gelatin solution was casted
171
on a plastic plate and placed in a laboratory fume hood at room temperature for
172
gelation 2. During experiment, the thickness of gelatin films was controlled to 0.2 mm
173
by controlling the casting volume of gelatin solution.
174
ACS Paragon Plus Environment
Page 9 of 34
175
Journal of Agricultural and Food Chemistry
2.8 Antibacterial assay
176
The antimicrobial activity of nanofibers against E. coli and S. aureus was
177
evaluated by dynamic contact method 37.The frozen strains were removed from - 80℃
178
and incubated overnight at 37 ℃ on nutrient agar plate to obtain viable strains. Then,
179
a certain amount of bacteria was extracted from the plate with an inoculating ring and
180
diluted to a density of 105 CFU/ml in physiological saline. Secondly, 100 μL of the
181
diluted bacterial solution was added into MH to obtain a bacteria solution of 104
182
CFU/ml. Subsequently, UV sterilized nanofibers were added into the solution and
183
incubated for 6 h at 37 ℃ in a shaker with an oscillation frequency of 200 r/min. For
184
comparison, the group without nanofiber was regarded as control. Then, 100 μL of the
185
bacterial solution after incubation was serially diluted 10-fold in saline, and 20 μl of
186
diluent was spread on nutrient agar plate. After overnight incubation at 37 ℃,
187
surviving colonies on each plate were counted. Three parallel experiments were
188
performed for each sample, and the average value of CFU was recorded.
189 190
2.9 Microbial penetration assay
191
To evaluate the barrier function of nanofibers against microbial penetration, 5 ml
192
of sterile nutrient broth was added into each test tube, then the test tubes were capped
193
with nanofiber samples
194
regarded as control group. After 14 days, the growth of microbial in each test tube
195
was revealed by the absorbance value of the nutrient broth, measured with a
196
microplate reader (Multiskan FC, Thermo, USA) at 620 nm.
38.
During experiment, the test tubes without any cap was
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 10 of 34
197 198 199
2.10 Cytotoxicity test The cytotoxicity of nanofibers was measured by MTT assay
35.
NIH-3T3 cells
200
were cultured in DMEM supplemented with 10% (v/v) FBS and 1% (v/v)
201
penicillin/streptomycin at 37 ℃ and 5% CO2. 10 mg of each sample was sterilized for
202
2 h under UV, then soaked in 2 ml of DMEM and incubated for 24 h at 37 ℃. Then
203
the extract solutions of samples were filtered via sterile disposable filter (0.22 μm,
204
Merck, Darmstadt, Germany). NIH-3T3 cells were seeded in 96-well plates at a cell
205
density of 5×103 per well and incubated for 24 h, then the culture medium was
206
exchanged with 100 μL of the extract solution. After 48 h of culture, the extract
207
solution was removed and 100 μL of MTT solution was added. After 4 h of
208
incubation in dark, 100 μL of DMSO was added to change the MTT solution and
209
dissolve the dark blue formazan crystals. Finally, the absorbance of formazan solution
210
was measured by a microplate reader at a wavelength of 570 nm.
211 212
2.11 Statistical analysis
213
The statistical analysis of the data was carried out using one-way analysis of
214
variance (ANOVA) with GraphPad Prism (V.7). To evaluate the statistically
215
significance difference between groups, Tukey’s post-hoc test was applied, and p
348
0.05). The result demonstrates that the gelatin/EOs nanofibers are not cytotoxic which
349
is eligible for edible packaging application.
350
ACS Paragon Plus Environment
Page 17 of 34
Journal of Agricultural and Food Chemistry
351
In conclusion, gelatin nanofibers encapsulated with PO and CO were
352
successfully fabricated via electrospinning with homogeneous and smooth
353
morphology. The incorporation of EOs was confirmed by 1H-NMR. The surface
354
hydrophobicity of nanofibers was enhanced with the addition of EOs. All the gelatin
355
nanofibers
356
concentration-dependent antibacterial property against E. coli and S. aureus, as well
357
as certain antioxidant property. Especially, the addition of PO resulted into better
358
antibacterial activity, while that of CO showed better antioxidant property. The joint
359
of PO and CO in gelatin nanofiber showed overall optimum bioactivities compared
360
with single PO or CO. Finally, the MTT assay indicated the non-cytotoxicity of
361
gelatin nanofibers incorporated with PO and CO, demonstrated the qualification of the
362
gelatin/EOs nanofibers as potential edible packaging. Furthermore, the addition of EO
363
has been reported to strengthen the films by inducing the rearrangement of protein
364
network, and some compounds in EO might also cross-link polymer chains to
365
enhance the tensile property of film 5. Therefore, the impact of EO on nanofiber’s
366
mechanical property in food packaging application would be of concern in our future
367
research.
containing
PO,
CO
or
PO/CO
exhibited
improved
EO
368 369
Acknowledgement
370
This work was financially supported by National Natural Science Foundation of
371
China (Grant No. 81801830), and Project of Innovative Research Teams of Jiangmen
372
(2017TD02).
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
373
References
374
1.
375
properties of gelatin film from the skin of unicorn leatherjacket incorporated with essential oils. Food
376
Hydrocolloids 2012, 28, 189-199.
377
2.
378
M. Antibacterial and Barrier Properties of Gelatin Coated by Electrospun Polycaprolactone Ultrathin
379
Fibers Containing Black Pepper Oleoresin of Interest in Active Food Biopackaging Applications.
380
Nanomaterials (Basel) 2018, 8.
381
3.
382
bilayer films based on fish gelatin and poly(lactic acid). Food Hydrocolloids 2018, 77, 248-256.
383
4.
384
and co-antimicrobial agents in polylactic acid /chitosan composite film for food packaging. Carbohydr.
385
Polym. 2018, 183, 102-109.
386
5.
387
food packaging. Trends in Food Science & Technology 2016, 48, 51-62.
388
6.
389
2014, 2014, 1-13.
390
7.
391
Nanofibers Containing Zinc Oxide Nanoparticles for Antimicrobial Packaging. J. Agric. Food Chem.
392
2018, 66, 9498-9506.
Ahmad, M.; Benjakul, S.; Prodpran, T.; Agustini, T. W. Physico-mechanical and antimicrobial
Figueroa-Lopez, K. J.; Castro-Mayorga, J. L.; Andrade-Mahecha, M. M.; Cabedo, L.; Lagaron, J.
Nilsuwan, K.; Benjakul, S.; Prodpran, T. Physical/thermal properties and heat seal ability of
Niu, X.; Liu, Y.; Song, Y.; Han, J.; Pan, H. Rosin modified cellulose nanofiber as a reinforcing
Atarés, L.; Chiralt, A. Essential oils as additives in biodegradable films and coatings for active
Shit, S. C.; Shah, P. M. Edible Polymers: Challenges and Opportunities. Journal of Polymers
Liu, Y.; Li, Y.; Deng, L.; Zou, L.; Feng, F.; Zhang, H. Hydrophobic Ethylcellulose/Gelatin
ACS Paragon Plus Environment
Page 18 of 34
Page 19 of 34
Journal of Agricultural and Food Chemistry
393
8.
394
antibacterial quince seed mucilage films containing thyme essential oil. Carbohydr. Polym. 2014, 99,
395
537-546.
396
9.
397
complex encapsulated in electrospun polymeric nanofibers. J. Agric. Food Chem. 2013, 61, 8156-65.
398
10. Falguera, V.; Quintero, J. P.; Jiménez, A.; Muñoz, J. A.; Ibarz, A. Edible films and coatings:
399
Structures, active functions and trends in their use. Trends in Food Science & Technology 2011, 22,
400
292-303.
401
11. Nur Hanani, Z. A.; Roos, Y. H.; Kerry, J. P. Use and application of gelatin as potential
402
biodegradable packaging materials for food products. Int. J. Biol. Macromol. 2014, 71, 94-102.
403
12. Fakhouri, F. M.; Costa, D.; Yamashita, F.; Martelli, S. M.; Jesus, R. C.; Alganer, K.;
404
Collares-Queiroz, F. P.; Innocentini-Mei, L. H. Comparative study of processing methods for
405
starch/gelatin films. Carbohydr. Polym. 2013, 95, 681-9.
406
13. Hosseini, S. F.; Rezaei, M.; Zandi, M.; Farahmandghavi, F. Bio-based composite edible films
407
containing Origanum vulgare L. essential oil. Industrial Crops and Products 2015, 67, 403-413.
408
14. Manso, S.; Becerril, R.; Nerín, C.; Gómez-Lus, R. Influence of pH and temperature variations on
409
vapor phase action of an antifungal food packaging against five mold strains. Food Control 2015, 47,
410
20-26.
411
15. Biddeci, G.; Cavallaro, G.; Di Blasi, F.; Lazzara, G.; Massaro, M.; Milioto, S.; Parisi, F.; Riela,
412
S.; Spinelli, G. Halloysite nanotubes loaded with peppermint essential oil as filler for functional
413
biopolymer film. Carbohydr. Polym. 2016, 152, 548-557.
Jouki, M.; Mortazavi, S. A.; Yazdi, F. T.; Koocheki, A. Characterization of antioxidant–
Kayaci, F.; Ertas, Y.; Uyar, T. Enhanced thermal stability of eugenol by cyclodextrin inclusion
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
414
16. Bakry, A. M.; Abbas, S.; Ali, B.; Majeed, H.; Abouelwafa, M. Y.; Mousa, A.; Liang, L.
415
Microencapsulation of Oils: A Comprehensive Review of Benefits, Techniques, and Applications.
416
Comprehensive Reviews in Food Science and Food Safety 2016, 15, 143-182.
417
17. Krepker, M.; Shemesh, R.; Danin Poleg, Y.; Kashi, Y.; Vaxman, A.; Segal, E. Active food
418
packaging films with synergistic antimicrobial activity. Food Control 2017, 76, 117-126.
419
18. Liang, R.; Xu, S.; Shoemaker, C. F.; Li, Y.; Zhong, F.; Huang, Q. Physical and antimicrobial
420
properties of peppermint oil nanoemulsions. J. Agric. Food Chem. 2012, 60, 7548-55.
421
19. Liakos, I.; Rizzello, L.; Hajiali, H.; Brunetti, V.; Carzino, R.; Pompa, P. P.; Athanassiou, A.;
422
Mele, E. Fibrous wound dressings encapsulating essential oils as natural antimicrobial agents. Journal
423
of Materials Chemistry B 2015, 3, 1583-1589.
424
20. Chumpitazi, B. P.; Kearns, G. L.; Shulman, R. J. Review article: the physiological effects and
425
safety of peppermint oil and its efficacy in irritable bowel syndrome and other functional disorders.
426
Aliment. Pharmacol. Ther. 2018, 47, 738-752.
427
21. Roby, M. H. H.; Sarhan, M. A.; Selim, K. A.-H.; Khalel, K. I. Antioxidant and antimicrobial
428
activities of essential oil and extracts of fennel (Foeniculum vulgare L.) and chamomile (Matricaria
429
chamomilla L.). Industrial Crops and Products 2013, 44, 437-445.
430
22. Agatonovic-Kustrin, S.; Babazadeh Ortakand, D.; Morton, D. W.; Yusof, A. P. Rapid evaluation
431
and comparison of natural products and antioxidant activity in calendula, feverfew, and German
432
chamomile extracts. J. Chromatogr. A 2015, 1385, 103-10.
433
23. Duman, F.; Ocsoy, I.; Kup, F. O. Chamomile flower extract-directed CuO nanoparticle formation
434
for its antioxidant and DNA cleavage properties. Mater. Sci. Eng. C Mater. Biol. Appl. 2016, 60,
435
333-338.
ACS Paragon Plus Environment
Page 20 of 34
Page 21 of 34
Journal of Agricultural and Food Chemistry
436
24. Cvetanović, A.; Švarc-Gajić, J.; Mašković, P.; Savić, S.; Nikolić, L. Antioxidant and biological
437
activity of chamomile extracts obtained by different techniques: perspective of using superheated water
438
for isolation of biologically active compounds. Industrial Crops and Products 2015, 65, 582-591.
439
25. Pérez-Mateos, M.; Montero, P.; Gómez-Guillén, M. C. Formulation and stability of biodegradable
440
films made from cod gelatin and sunflower oil blends. Food Hydrocolloids 2009, 23, 53-61.
441
26. Wongsasulak, S.; Patapeejumruswong, M.; Weiss, J.; Supaphol, P.; Yoovidhya, T.
442
Electrospinning of food-grade nanofibers from cellulose acetate and egg albumen blends. J. Food Eng.
443
2010, 98, 370-376.
444
27. Anu Bhushani, J.; Anandharamakrishnan, C. Electrospinning and electrospraying techniques:
445
Potential food based applications. Trends in Food Science & Technology 2014, 38, 21-33.
446
28. Liu, Y.; Deng, L.; Zhang, C.; Feng, F.; Zhang, H. Tunable Physical Properties of
447
Ethylcellulose/Gelatin Composite Nanofibers by Electrospinning. J. Agric. Food Chem. 2018, 66,
448
1907-1915.
449
29. Neo, Y. P.; Swift, S.; Ray, S.; Gizdavic-Nikolaidis, M.; Jin, J.; Perera, C. O. Evaluation of gallic
450
acid loaded zein sub-micron electrospun fibre mats as novel active packaging materials. Food Chem.
451
2013, 141, 3192-3200.
452
30. Wen, P.; Zhu, D.-H.; Wu, H.; Zong, M.-H.; Jing, Y.-R.; Han, S.-Y. Encapsulation of cinnamon
453
essential oil in electrospun nanofibrous film for active food packaging. Food Control 2016, 59,
454
366-376.
455
31. Huang, Z.-M.; Zhang, Y. Z.; Ramakrishna, S.; Lim, C. T. Electrospinning and mechanical
456
characterization of gelatin nanofibers. Polymer 2004, 45, 5361-5368.
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
457
32. Deldar, Y.; Pilehvar-Soltanahmadi, Y.; Dadashpour, M.; Montazer Saheb, S.; Rahmati-Yamchi,
458
M.; Zarghami, N. An in vitro examination of the antioxidant, cytoprotective and anti-inflammatory
459
properties of chrysin-loaded nanofibrous mats for potential wound healing applications. Artif Cells
460
Nanomed Biotechnol 2018, 46, 706-716.
461
33. Dadras Chomachayi, M.; Solouk, A.; Akbari, S.; Sadeghi, D.; Mirahmadi, F.; Mirzadeh, H.
462
Electrospun nanofibers comprising of silk fibroin/gelatin for drug delivery applications: Thyme
463
essential oil and doxycycline monohydrate release study. J Biomed Mater Res A 2018, 106, 1092-1103.
464
34. Cui, H.; Bai, M.; Lin, L. Plasma-treated poly(ethylene oxide) nanofibers containing tea tree
465
oil/beta-cyclodextrin inclusion complex for antibacterial packaging. Carbohydr. Polym. 2018, 179,
466
360-369.
467
35. Rieger, K. A.; Schiffman, J. D. Electrospinning an essential oil: cinnamaldehyde enhances the
468
antimicrobial efficacy of chitosan/poly(ethylene oxide) nanofibers. Carbohydr. Polym. 2014, 113,
469
561-8.
470
36. Yuan, Y.; Zhang, J.; Fan, J.; Clark, J.; Shen, P.; Li, Y.; Zhang, C. Microwave assisted extraction
471
of phenolic compounds from four economic brown macroalgae species and evaluation of their
472
antioxidant activities and inhibitory effects on alpha-amylase, alpha-glucosidase, pancreatic lipase and
473
tyrosinase. Food Res Int 2018, 113, 288-297.
474
37. Park, J.-A.; Kim, S.-B. Preparation and characterization of antimicrobial electrospun poly(vinyl
475
alcohol) nanofibers containing benzyl triethylammonium chloride. React. Funct. Polym. 2015, 93,
476
30-37.
ACS Paragon Plus Environment
Page 22 of 34
Page 23 of 34
Journal of Agricultural and Food Chemistry
477
38. Gilotra, S.; Chouhan, D.; Bhardwaj, N.; Nandi, S. K.; Mandal, B. B. Potential of silk sericin based
478
nanofibrous mats for wound dressing applications. Mater. Sci. Eng. C Mater. Biol. Appl. 2018, 90,
479
420-432.
480
39. Celebioglu, A.; Yildiz, Z. I.; Uyar, T. Thymol/cyclodextrin inclusion complex nanofibrous webs:
481
Enhanced water solubility, high thermal stability and antioxidant property of thymol. Food Res Int
482
2018, 106, 280-290.
483
40. Luchese, C. L.; Pavoni, J. M. F.; Dos Santos, N. Z.; Quines, L. K.; Pollo, L. D.; Spada, J. C.;
484
Tessaro, I. C. Effect of chitosan addition on the properties of films prepared with corn and cassava
485
starches. Journal of food science and technology 2018, 55, 2963-2973.
486
41. Khazaei, N.; Esmaiili, M.; Djomeh, Z. E.; Ghasemlou, M.; Jouki, M. Characterization of new
487
biodegradable edible film made from basil seed (Ocimum basilicum L.) gum. Carbohydr. Polym. 2014,
488
102, 199-206.
489
42. Sánchez Aldana, D.; Andrade-Ochoa, S.; Aguilar, C. N.; Contreras-Esquivel, J. C.;
490
Nevárez-Moorillón, G. V. Antibacterial activity of pectic-based edible films incorporated with
491
Mexican lime essential oil. Food Control 2015, 50, 907-912.
492
43. Nazzaro, F.; Fratianni, F.; De Martino, L.; Coppola, R.; De Feo, V. Effect of Essential Oils on
493
Pathogenic Bacteria. Pharmaceuticals 2013, 6, 1451-1474.
494
44. Higueras, L.; López-Carballo, G.; Gavara, R.; Hernández-Muñoz, P. Reversible Covalent
495
Immobilization of Cinnamaldehyde on Chitosan Films via Schiff Base Formation and Their
496
Application in Active Food Packaging. Food and Bioprocess Technology 2014, 8, 526-538.
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
497
45. Ohtsu, N.; Kohari, Y.; Gotoh, M.; Yamada, R.; Nagata, Y.; Murata, M. Utilization of the Japanese
498
Peppermint Herbal Water Byproduct of Steam Distillation as an Antimicrobial Agent. J Oleo Sci 2018,
499
67, 1227-1233.
500
46. Dhumal, C. V.; Sarkar, P. Composite edible films and coatings from food-grade biopolymers.
501
Journal of Food Science and Technology-Mysore 2018, 55, 4369-4383.
502
47. López-de-Dicastillo, C.; Gómez-Estaca, J.; Catalá, R.; Gavara, R.; Hernández-Muñoz, P. Active
503
antioxidant packaging films: Development and effect on lipid stability of brined sardines. Food Chem.
504
2012, 131, 1376-1384.
505
48. Mohammad Al-Ismail, K.; Aburjai, T. Antioxidant activity of water and alcohol extracts of
506
chamomile flowers, anise seeds and dill seeds. J. Sci. Food Agric. 2004, 84, 173-178.
507
49. Sanchez-Garcia, M. D.; Lopez-Rubio, A.; Lagaron, J. M. Natural micro and nanobiocomposites
508
with enhanced barrier properties and novel functionalities for food biopackaging applications. Trends
509
in Food Science & Technology 2010, 21, 528-536.
510
ACS Paragon Plus Environment
Page 24 of 34
Page 25 of 34
Journal of Agricultural and Food Chemistry
512
Figure captions
513
Figure 1. Schematic illustration for preparation of gelatin/EOs nanofibers. (a)
514
Preparation of gelatin/EOs solutions for electrospinning; (b) Electrospinning process
515
for gelatin/EOs nanofiber fabrication; (c) Photograph of gelatin/EOs nanofibrous mat;
516
(d) SEM image of gelatin/EOs nanofibers.
517 518
Figure 2. SEM images and fiber diameter distribution of gelation/EOs nanofibers: (a)
519
gelatin nanofibers; (b-d) gelatin/PO nanofibers with PO ratio at 3%, 6%, 9% (v/v),
520
respectively; (e-g) gelatin/CO nanofibers with CO ratio at 3%, 6%, 9% (v/v),
521
respectively; and (h- j) gelatin/PO/CO nanofiber with PO/CO ratio at 3%, 6%, 9%
522
(v/v), respectively. AD and SD refer to average diameter and standard deviation,
523
respectively.
524 525
Figure 3. 1H NMR spectra of (a) peppermint essential oil; (b) chamomile essential oil;
526
(c) gelatin nanofiber; and (d−f) gelatin/EOs nanofibers containing PO, CO and
527
PO/CO respectively with EOs ratio at 9% (v/v) dissolved in DMSO-d6. Protons used
528
to prove the existence of gelatin, PO, and CO are shown by star sign; purple and blue,
529
PO; orange and black, CO; green and red, gelatin.
530 531
Figure 4. (a-d) Images of water droplets in contact angle measurements on the surface
532
of (a) gelatin nanofibers, (b) gelatin/PO nanofibers, (c) gelatin/CO nanofibers, and (d)
533
gelatin/PO/CO nanofibers; (e) Water contact angles of nanofibers contained different
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
534
EOs (black, PO; blue, CO; red, PO/CO).
535 536
Figure 5. Antimicrobial activity of gelatin/EOs nanofibers against E. coli (a) and S.
537
aureus (b). *p < 0.05 versus the control group. Results are mean ± SD (n=3).
538 539
Figure 6. DPPH radical scavenging activity of nanofiber incorporated with different
540
concentration (0%, 3%, 6%, 9%) of EOs (PO, CO, PO/CO) and the corresponding
541
photographs of DPPH solution containing different nanofibers. *p < 0.05 versus the
542
control group. Results are mean ± SD (n=3).
543 544
Figure 7. Cytotoxicity of gelatin/EOs nanofibers. NIH-3T3 cells were cultured in the
545
extract solutions of different nanofibers for 48 hours, and cell viability was quantified
546
by MTT assay. The content of EOs has little effect on the biocompatibility of
547
nanofibers (p > 0.05 between groups). Results are mean ± SD (n=4).
548
ACS Paragon Plus Environment
Page 26 of 34
Page 27 of 34
549
Journal of Agricultural and Food Chemistry
Figure 1
550 551
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
552
Figure 2
553 554
ACS Paragon Plus Environment
Page 28 of 34
Page 29 of 34
555
Journal of Agricultural and Food Chemistry
Figure 3
556 557 558
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
559
Figure 4
560 561
ACS Paragon Plus Environment
Page 30 of 34
Page 31 of 34
562
Journal of Agricultural and Food Chemistry
Figure 5
563 564
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
565
Figure 6
566 567
ACS Paragon Plus Environment
Page 32 of 34
Page 33 of 34
568
Journal of Agricultural and Food Chemistry
Figure 7
569 570
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
571
TOC graphic:
572
ACS Paragon Plus Environment
Page 34 of 34