Progress in Organic Coatings 161 (2021) 106550

Contents lists available at ScienceDirect

Progress in Organic Coatings

journal homepage: www.elsevier.com/locate/porgcoat

Fabrication of Cleistocalyx operculatus extracts/chitosan/gum arabic

composite as an edible coating for preservation of banana
Khoa Hai Le a, b, D. Duong La c, *, Phuong Thi Mai Nguyen a, d, Minh Dac-Binh Nguyen e,
Anh Thi Kieu Vo a, b, Minh Thi Hong Nguyen f, D. Lam Tran a, b, S. Woong Chang g,
X. Hoan Nguyen i, *, D. Duc Nguyen g, h
a
Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
b
Institute for Tropical Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
c
Institute of Chemistry and Materials, Hanoi, Vietnam
d
Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
e
Institute of Regional Research and Development, Ministry of Science and Technology, Hanoi, Vietnam
f
University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
g
Department of Environmental Energy Engineering, Kyonggi University, Republic of Korea
h
Faculty of Environmental and Food Engineering, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, District 4, Ho Chi Minh City, 755414, Vietnam
i
Faculty of Environment Natural Resources and Climate Change, Ho Chi Minh City University of Food Industry, Ho Chi Minh City, Vietnam

A R T I C L E I N F O A B S T R A C T

Keywords: The phenolic compounds from natural plant extracts, which have strong antioxidant properties as inhibitors for
Banana browning retardants of fruits, have been extensively investigate in the last few decades. In this study, the
Cleistocalyx operculatus polyphenols in Cleistocalyx operculatus (Roxb.), a distinct plant in tropical region, was successfully extracted and
Antioxidants
determined. The obtained Roxb. extract (CE) as an antioxidant additive was employed in Chitosan/Gum Arabic
Chitosan
Gum Arabic
(CH/GA) edible coating for the fruit preservation. The resultant CE/CH/GA coating revealed the high effec­
tiveness in improving the freshness of banana at ambient storage conditions. The properties of bananas before
and after coated by CE/CH/GA were investigated and assessed. The surface structure of banana was examined by
using scanning electron microscopy, showed wrinkle and crack structure for uncoated banana and smooth
surface for banana coated with CE/CH/GA coating. The freshness of banana treated with CH/GA/CE edible
coating could last for 21 days of storage at room conditions. Thus, it is promising for good potential practical
application to preserve fruits.

1. Introduction postharvest losses including low-temperature storage [42,43] and

controlled atmosphere and hypobaric storage [5,6]. However, using
It has been well-known that banana is one of the most widely growth these approaches damage physical properties of fruits causing chilling
and consumed fruit in the world, especially in the tropical/subtropical injury, being expensive to operate. Thus, it is necessary to find alter­
regions [1]. Bananas contain all the essential nutrients with valuable native cost-effective methods to extent the shelf life of postharvest ba­
nutrition and calories such as vitamins and minerals [2]. However, ba­ nanas [7]. One of the cost-effective methods for improving the bananas’
nana is a climacteric fruit, which is highly biodegradable and facilely shelf-life is to apply the safe coatings on the surface of banana [8]. The
infected by diseases leading to shorten the shelf life of fruit [3]. There­ mechanism of protecting perishable fruits from deterioration by edible
fore, the control of postharvest losses of bananas fruit will reduce the coatings is to suppress respiration, enhance textural quality, maintain
cost of cultivation and distribution, as a result, lowering price for con­ volatile of the flavour, minimize the microbial growth and retard
sumers and increasing income for the farmers. Thus, prolonging the dehydration [9]. Many edible coating systems have been developed to
shelf life of postharvest bananas are received extensive attention [45]. remain the quality as well as prolong the freshness of fruits including,
Many techniques have been employed to effectively minimize the but not limited to, lipid-based coatings (oils, waxes, fatty acid and

* Corresponding authors.
E-mail addresses: duc.duong.la@gmail.com (D.D. La), hoannx@hufi.edu.vn (X.H. Nguyen).

https://doi.org/10.1016/j.porgcoat.2021.106550
Received 2 June 2021; Accepted 22 September 2021
Available online 6 October 2021
0300-9440/© 2021 Elsevier B.V. All rights reserved.
K.H. Le et al. Progress in Organic Coatings 161 (2021) 106550

Fig. 1. Phytochemical screening of CE by TLC. The sample was run on TLC using a suitable solvent system (TEAF - toluene:ethyl acetate:acetone:formic acid 5:3:1:1)
(A) and then stained with a specific reagent to detect the presence of the compounds of interest (B).

monoglycerides and resins), protein-based coatings (casein, whey pro­ daily life. Unlike green tea extracts, roxb. extracts (CE) haven’t yet been
tein, wheat gluten, corn zein, collagen and gelatin, and surimi), studied for such applications because of local characteristics, especially
carbonhydrate-based coatings (cellulose, pectin, sucrose ester, chitin/ for enzymatic browning inhibiting application in food and fruits.
CH, starch, aloe vera, alginate and carrageenan) [10–12]. The edible Herein, we report the fabrication of the edible coatings containing
coatings could be formulated with singe or combination of two or three chitosan, gum arabic, and CE extract for postharvest banana fruits. The
coating materials along with addition of antioxidant and antimicrobial effect of CE contents on the physiological and biochemical properties of
additives [13–15, 44]. banana is studied in detail. The protective efficiency of the prepared CH/
Gum Arabic, a complex polysaccharide, commonly consists of valu­ GA/CE composite coating is compared with control and the optimized
able mineral for human health such as magnesium, calcium, and po­ CH/GA composite coating.
tassium, which is extracted from part of Acacia plants [16]. The gum
arabic (GA) is a safe compound and commonly employed as a food ad­ 2. Experimental section
ditive in many industrial sectors as well as is utilized as an emulsifier
thank to the better solubility in comparison to other hydrocolloids 2.1. Materials collection and extraction
[17,18]. Chitosan (CH) is one of polysaccharides obtained from the
shells of crabs, shrimps with chemical structure similar to the cellulose. Leaves of C. operculatus were collected in Ha Tay province, Vietnam
With good inhibiting properties of reducing dehydration and respira­ and identified. The CE leaves was dried and ground in powder form
tion, the CH could be extensively used as a coating to maintain the food before extracted with water for 2 days. The extraction was repeated
quality by preventing the deterioration of many types of foods [19]. twice and dried using rotary vacuum.
Additionally, the CH has remarkable biochemical and film forming
properties, which is commonly employed as an additive for food in­ 2.2. Phytochemical screening of CE
dustry as well as in the coating composition to prolong the shelf life of
fruits and vegetables. It has been reported in the literature that, A solvent mixture of formic acid, acetone, ethyl acetate, and toluene
chitosan-based coatings has been extensively studied to prevent the with volume ratio of 5/3/1/1, respectively was used to separate the
deterioration of postharvest fruits and vegetables including, but not extract using thin-layer chromatography (TLC) plates. The specific re­
limited to banana, mango, avocado, strawberry, papaya, and tomato agents (polyethylene glycol, anisaldehyde–sulfuric acid, Dragendorff’s
[20–22]. Maqbool, Ali, Alderson, Zahid and Siddiqui [1] successfully reagent, 5% KOH, and vanillin‑sulfuric acid) were then sprayed on the
fabricated the GA and CH edible coating and studied the biochemical TLC plates to determine the organic compounds such as flavonoids, al­
and physiological properties of banana fruits after covered with the kaloids, terpenes/steroids, and others in the CE extract [27].
resultant coating. The banana protected by GA/CH composite coating
lasted for 28 days at at 13 ◦ C and 80% relative humidity, and 5 days at
25 ◦ C, 60% RH. The results showed that the composite with 10% GA and 2.3. Total polyphenol and flavonoid determination of CE
1.0% CH could prolong the storage life of bananas up to 33 days at the
temperature of around 5 ◦ C. The reagent of Folin Ciocalteu reported by Singleton and Rossi was
Recently, many works have been devoted to find alternative phenolic utilized to determine the total phenolic contents in the ethanolic CE
compounds from natural plant extracts, which have strong antioxidant extracts [28]. Gallic acid was used as standard. Typically, 5 ml of Folin
properties as inhibitors for browning retardants of fruits and food Ciocalteu reagent was mixed with 4 ml sodium carbonate solution (75 g/
[23,24]. These extracted with high phenolic contents play a significant l) with addition of 1 ml CE extract solution, the mixed solution was kept
role as inhibitors for enzyme polyphenol oxidase [25]. Cleistocalyx stirring for 30 min. The mixed solution was then measured the absor­
operculatus (roxb.) is widely distributed tropical countries (India, Viet­ bance at the wavelength of 765 nm using garlic acid as standard to
nam, China) which has been well-known as a good source of poly­ determine the total phenolic content. The polyphenol content was
phenolic compounds with strong antioxidant properties [26]. In these calculated as mg phenolic/g of gallic acid.
countries, C. operculatus has been commonly used as drinking tea in The spectrophotometry was employed to determine the total flavo­
noid content in the extract [29]. The quercetin solution was used as

2
K.H. Le et al. Progress in Organic Coatings 161 (2021) 106550

standard. Typically, 1 ml CE extracts was dissolved in 1 ml aluminum Table 1

chloride methanolic solution 2%, followed by incubating for 15 min at Polyphenolic and flavonoid contents of the extract.
room temperature. The mixed solution was then measured the absor­ Plant extract Content (%)
bance at the wavelength of 430 nm using Milton Roy 601 UV–Vis
Polyphenol 12.4 ± 1.48
spectrophotometer. The flavonoid content was calculated by mg flavo­ Flavonoid 0.62 ± 0.15
noid/g of quercetin.

2.8. Colors
2.4. Phytochemical screening and flavonoid content of CE
7-Stage point ladder was employed to measure the color of bananas’
The phytochemical screening on the TLC plates revealed the pres­ peel, which determine the ripening degree of the bananas. The ripening
ence of terpenes and flavonoids in the extract with the flavonoids con­ of bananas are recognized as following: point 1 when 0–10% of peel is
tent of up to 6.8 mg/g dried CE leaves. The antibacterial properties of yellow; point 2 is from 10 to 30% yellow; point 3 is 30 to 50% yellow;
the polar compounds in the CE extracts against S. aureus and S. mutans point 4 is from 50 to 70% yellow; point 5 is from 70 to 90% yellow; point
pathogenic bacteria was observed by bioautography, which is indicated 6 is from 90 to 100% yellow; and point 7 meant the banana is rotten.
by the low Rf value in TLC plates (Fig. 1).
2.9. Weight loss

2.5. Antioxidant activity of CE The weight loss of each tested banana was calculated by mass dif­
ferences of banana weighted on the basic of 1 day during the storage
The capability of removing the free 1, 1- diphenyl-2-picryl hydrazyl period.
(DPPH) radicals was employed to determine the antioxidant property of
the extract. When the extract was added to the DPPH solution, the
2.10. Banana firmness
radicals was scavenged and the color of the DPPH solution was changed
This from purple to yellow. The color changing degree determines the
The banana firmness was estimated by the force amount (N) applied
strength of the antioxidant property of the extract. In the typical
to leave a hole on the banana’s surface. The Instron Universal Testing
experiment, 1 ml DPPH 0.1 mM solution in ethanol was added to 3 ml of
Machine with a 8 mm-diameter tip connected to a desktop and the
the extracts with various concentration ranging from 5 to 30 μg/ml. The
compression speed of 20 mm/min. Each banana was measured the
mixture was vigorously shaken and measured the absorbance at the
firmness for three times to obtain the average firmness data.
wavelength of 517 nm after 30 min of stand at room temperature. The
experiment was repeated for three times with ascorbic acid as standard.
2.11. Acidity of bananas
The log dose inhibition curve was utilized to determine the IC50 value of
the mixture. The following equation: DPPH scavenging effect (%) = (A0 -
Titratable acidity of bananas was determined using the titration
A0)/A0 × 100 (where, A0 was the absorption intensity of initial DPPH
approach. In a typical experiment, certain tested bananas were removed
solution and A1 was the absorption intensity of the DPPH solution in
the peel and blended with 40 ml water. The resultant mixture was
presence of the extract), was used to determine the DPPH radicals
filtered by centrifugation at 7000 rpm for 15 min followed by filter
scavenging capability of the extract [30].
paper. 03 drops of 0.1% phenolphthalein indicator were added to the 5
ml filtered sample. 0.1 M NaOH solution was then drop-wised to the
2.6. Fabrication of CH/GA/CE edible coatings solution until the color of the solution changed to pink, which indicated
the reaction between base and acids in the bananas. The malic acid
The optimized CH and GA contents of 1% and 10% w/w, respec­ percentage in the banana pulp is the acidity of bananas.
tively, were adopted from previous study [1]. In this work, edible
coatings containing CH 1% and GA 10% were prepared upon addition of 2.12. Reducing sugar in bananas
various CE contents. Typically, the solution A was prepared by dis­
solving 20 g gum arabic in 100 ml with vigorous stirring for 2 h at 40 ◦ C. Tested bananas were blended with the distilled water using a blender
In order to prepare solution B, 2 g chitosan was dissolved in 100 ml to obtained a homogeneous solution. The obtained solution was cen­
water with addition of 0.5 ml acetic acid for 2 h at room temperature. trifugated 7000 rpm for 15 min and filtered through a filter paper. 1 ml
The diluted NaOH or H2SO4 solution was utilized to adjust the pH so­ of the filtrate solution was introduced to the glass tube with addition of
lution to around 5.5. The solution A was then mixed with solution B with 2 ml dinitrosalicylic acid (DNS) as a standard agent to determine the
addition of various CE extract concentrations to obtain the edible reducing sugar. The mixed solution was then heated at temperature of
coatings for the preservation of the bananas. 100 ◦ C for 5 min and naturally cooled down to room temperature. The
absorbance of the resultant solution was studied at wavelength of 540
nm using a UV-Spectrophotometer.
2.7. Covering bananas with edible coatings
3. Results and discussion
The 0.01% NaClO solution was employed to clean the post-harvest
bananas for 5 min. The treated bananas were immersed in the various 3.1. Phytochemical screening on the TLC plates of the extract
prepared edible coatings solution of 1%CH + 10%GA, 1%CH + 10%GA
with addition of various CE extract concentration ranging from 0.05% to Phytochemical screening was carried out to investigate the presence
0.5% CE, until form the uniform film on the surface of bananas. The of the main group of secondary metabolites in the CE. Our data indicated
bananas with coating were used as controlled samples. 90 bananas were the presence of the flavonoid, triterpenes and coumarin groups in this
divided into 6 groups (15 bananas/group) for different treatments and extract, while alkaloid was not found.
each experiment was repeated for 3 cycles. The edible coating-treated
bananas were natural dried at 25 ◦ C and 70% for 21 days. After inter­ 3.2. Polyphenol and flavonoid contents
val of 4 days, the one banana of each treatment was taken out to
determine the physicochemical properties of the bananas. It was known that CE has high polyphenol content and flavonoids

3
K.H. Le et al. Progress in Organic Coatings 161 (2021) 106550

Fig. 2. Free radical scavenging activity of CE.

Fig. 3. Physical appearance of bananas with and without coatings (uncoated, coated with CH 1% + GA 10%, and CH 1% + GA 10% + 0.25 CE%) before and after 21
days of storage at 25 ◦ C and 70% relative humidity.

were the major constituents of the extract [31]. The data in Table 1 assay even at low concentrations. Above 60% of activity was found at
indicated that the polyphenol content in the test extract here is 12.4% concentration of 50 μg/ml.
and flavonoid concentration is 0.62% of dry material.

3.4. Color investigation

3.3. Anti-oxidant activity of the extract
The bananas aging was primarily studied based on the color chang­
Illustrated in Fig. 2 is the antioxidant property of the CE extract, ing of bananas appearance from green to yellow, experienced ripening
which was presented in a dose-dependent manner. It can be clearly seen processes before rotten in brown color at the end of the banana’s life.
that CE extract exhibited a high free radical scavenging in the DPPH The change of bananas colors upon application of various edible coating

4
K.H. Le et al. Progress in Organic Coatings 161 (2021) 106550

Table 2
Colors of uncoated bananas (control) and bananas coated with various coating composites at different days of
storage at 25 ◦ C and 70% relative humidity.

Control CH 1%/CA 10% CH 1%/CA 10%/SE 0.05%

CH 1%/CA 10%/SE 0.15% CH 1%/CA 10%/SE 0.25% CH 1%/CA 10%/SE 0.5%

80
30
Fruit firmness (N)
Weight loss (%)

60
20
40

10
20

(a) (b)
0 0
0 5 10 15 20 25 0 5 10 15 20 25
Storage time (days) Storage time (days)

Fig. 4. (a) weight loss and (b) firmness of bananas with and without coatings (uncoated, coated with CH 1% + GA 10%, and CH 1% + GA 10% + CE various
concentrations) before and after 21 days of storage at 25 ◦ C and 70% relative humidity.

after preservation for 30 days at 21 days at ambient condition of 25 ◦ C life of bananas. This is ascribed to the capability of the edible coating
and 70% relative humidity (RH) was investigated. It is well-perceived against the moisture escaping and slower the respiration rate of the
that the yellowing of the fruits is ascribed to the chlorophyll biodegra­ bananas, as a result, the degradation rate of chlorophyll is decreased,
dation by the chlorophyllase enzyme to form yellow pigments such as indicating a decrease in the banana aging. These results indicate the
xanthophyll and carotene [32]. The brown appearance is due to the CH1% + GA10% + 0.25%CE edible coating can effectively prolong the
formation of the brown pigment by the polymerization of small mole­ freshness of bananas by more than 21 days stored at the ambient
cules to macromolecules as well as the reaction between phenol and conditions.
polyphenol oxidase (PPO) [33]. It can be seen from the Fig. 3 that the The change in different color stages of bananas during storage was
color of uncoated banana is extremely changed to brown, even rotten. evaluated visually by numerical rating scale of 1 to 7 illustrated in
The banana coated with CH 1% and GA 10% composite shows the Table 2. The color of uncoated banana stored at 25 ◦ C and 70% RH starts
changes from green to totally yellow color after 21 days of storage. to change after 6 days and totally ripen after 18 days of storage. With
Interestingly, when coated banana with CH1% + GA10% + 0.25%CE CH1% + GA10% coating system, the banana changes color after 9 days
edible composite only partial yellow appearance of banana was of storage and rotten after 21 days. Interestingly, the bananas coated
observed after 21 days. These results indicate that the used of CH1% + with CH1% + GA10% + CE significantly slower the decay of the banana
GA10% + 0.25%CE composite coating significantly prolongs the storage as bananas only start to change the color after 12 days and not be rotten

5
K.H. Le et al. Progress in Organic Coatings 161 (2021) 106550

Control CH 1%/CA 10% CH 1%/CA 10%/CE 0.05%

CH 1%/CA 10%/CE 0.15% CH 1%/CA 10%/CE 0.25% CH 1%/CA 10%/CE 0.5%

50 0.4

Reducing sugar (mg/g)

Titratable acidity (%)

40
0.3
30

20
0.2

10

(a) (b)
0 0.1
0 5 10 15 20 25 0 5 10 15 20 25
Storage time (days) Storage time (days)

Fig. 5. (a) Reducing sugars and (b) Titratable acid with and without coatings (uncoated, coated with CH 1% + GA 10%, and CH 1% + GA 10% + CE various
concentrations) before and after 21 days of storage at 25 ◦ C and 70% relative humidity.

after 21 days. The most effective composite coating was observed with structure, cell wall, and intracellular materials are responsible for the
0.25% CE as the coated banana with this coating system after 21 days softening of the fruit [36]. The decay of fruit causes the shorten of the
was only at stage 3 of ripening process. length of pectin compounds in banana leading to enhance the activities
Illustrated in Fig. 4a is the weight loss of banana before and after of two enzymes: pectinesterase and polygalacturonase [37]. The appli­
coated with various edible coating formulas in ambient conditions. One cation of coatings on the banana plays a significant role in hindering the
of the most affecting factors for the effectiveness of a coating for storage penetration of the oxygen and carbon dioxide, which lower the activities
life and quality of banana is the weight loss. It can be seen from the of these enzymes, as a result, the firmness of bananas is improved. This is
Fig. 4a that the use of coating significantly reduces the weight loss of the explained why the retention of the fruit firmness when bananas were
banana. With uncoated banana, the mass loss was calculated to be treated with CH/GA/CE coating systems.
around 34% after 21 storing days. The calculated weight loss of banana The ripening process of banana fruit is further evaluated by moni­
coated with CH/GA coating system to be approximately 28%. Upon toring the change in sugars of fruit. It has been well-known that during
addition of CE, the weight loss of banana reduces significantly with a the first stage of ripening process the starch content in banana are
minimal loss of 20% observed at the CE content of 0.25%. This dem­ constantly reduced [38], leading to generation of sugar, and this sugar
onstrates that the addition of CE improves the effectiveness of CH/GA content in later stage of ripening process will be consumed by the
coating system for postharvest bananas. It has been demonstrated that respiration process, which reduce the sugar content [39]. The amounts
the vapor pressure through the peel of fresh fruit and vegetables is of RS in uncoated and coated bananas over storage time were deter­
responsible for the weight loss and this weight loss caused metabolic mined and the results are showed in Fig. 5a. In the controlled banana,
reactions in the fruit, as a result, the fruit was soften and ripen [34]. the RS value increased steadily until 15 days of storage before suddenly
Furthermore, the respiration phenomenon in the fruit involving the decreased and continued until the end of tested storage time. Similar
losing process of carbon atom in each cycle could also trigger the weight trend was observed with the bananas preserved with 0.05% CE/CH/GA
loss. The utilization of coating on the banana fruit could serve as barrier and CH/GA coating systems, which the RS reached a maximal after 18
against penetration of moisture, carbon dioxide and oxygen, as a result, days of storage. On the other hand, the bananas treated with 0.15% CE/
decreasing the water loss, metabolic reaction and respiration process CH/GA, 0.25% CE/CH/GA, and 0.5% CE/CH/GA reveal a steady in­
[35]. The CE is of high content of polyphenols (~13%) as free radical crease in RS until the end of storage period. These results demonstrate
scavenging agents for reducing the oxidative species in contact with that the ripening process of banana are significantly improved by utili­
banana, which cause the metabolic reactions in fruits. It was observed zation of CH/GA/CE edible coatings.
that the increase of CE content reduces the weight loss of banana treated The major organic acid in the banana is the malic acid, thus the value
with the CH/GA/CE coatings and reach a weight loss minimal at the CE of malic acid could be used as an indicator for evaluating the effec­
content of 0.25%. Further increase of CE content of higher than 0.25% tiveness of coatings for bananas preservation. The change in acidity is
demonstrated a negligible reduce of weight loss. Thus, 0.25% can be also involved to the aging of bananas, which change the color of banana.
considered as optimized concentration of CE extract in the CE/CH/GA The Fig. 5b shows the titratable acid (TA) values in bananas with un­
edible coating for minimizing the mass loss of banana. coated and coated by CH/GA and CH/GA/CE coating systems. It is
Another decisive parameter to determine the effectiveness of an obvious that without coatings, the TA values decrease significantly over
edible coating for the freshness and quality of fruit is the firmness. storage time and the value recorded after 21 days of storage is approx­
Fig. 4b shows the firmness of banana before and after coated with imately 0.15% in comparison with initial TA value before storage of
various edible coatings experiment at 25 ◦ C and relative humidity of 0.4%. The decrease of TA values slows remarkably upon the use of
approximately 70%, which indicates that firmness of uncoated banana coatings, which is demonstrated that after 21 days the calculated TA
significantly decreases from 86 N to less than 10 N after 15 storing days. values remain around 0.23% and 0.26% for CH/GA and CH/GA/0.25%
The banana firmness is significantly improved when coated with CH/GA CE coatings, respectively. This is because the coatings restrict the
coating, which is 22 N after 15 days and still remains about 12 N after 12 ripening process of banana fruit by introducing a protective coating
days of storage. Especially, when CE as an antioxidant was introduced to around the banana, thus the levels of TA in coated bananas are higher
the CH/GA system, the firmness of bananas is further increased with a than that of controlled banana over storage time. The primary signs of
firmness retention of approximately 38 N after 21 days of storage with respiration process in banana is to consume the malic acid in banana,
0.25% added CE. It has been demonstrated that the deterioration of cell therefore, the more decrease in the values of acidity causes the higher

6
K.H. Le et al. Progress in Organic Coatings 161 (2021) 106550

Fig. 6. SEM images of banana peels of (a) uncoated, (b) coated with CH/GA, and (c) coated with CH/GA/CE edible coatings.

respiring fruit [40]. RS and fruit firmness. This CH/GA/CE edible coating could be employed
It has demonstrated that the cuticle surface of banana fruit acceler­ as an effective pathway to prolong the shelf-life of banana.
ated the loss of water leading the high speed of respiration, which where the control is uncoated, and treated bananas are coated with
eventually caused the invasion of fungus. Thus, the application of CH 1% + GA 10%, and CH 1% + GA 10% + CE at various
coatings on the banana’s surface would block the pores of the cuticle, concentrations).
which minimize the water loss of banana [41]. Furthermore, the coating
also prevents the contact between external and internal environment of Declaration of competing interest
banana, which reduce the effect of outside atmospheres on the ripening
process of banana. The authors declare that they have no known competing financial
The surface structure of the banana’s skin with uncoated and coated interests or personal relationships that could have appeared to influence
with edible coatings were observed using scanning electron microscopy the work reported in this paper.
as shown in Fig. 6. The surface structure of uncoated banana shows the
wrinkle and cracks on the epidermal cells of the skin (Fig. 6a). When Acknowledgements
banana was coated with CH/GA coatings, the skin’s surface is much
smoother than controlled banana with significantly reduce of cracks on This work was funded by the Vietnam Ministry of Science and
the pericarp surface (Fig. 6b). The smooth surface with no cracks on the Technology under Grant No. 01/2021/HĐ-ĐT/VPTV. The research
banana’s skin is observed when banana was treated with CH/GA/CE collaboration among the groups, institutions, and universities of the
coating system (Fig. 6c). This enhanced smoothness of banana surface by authors is grateful.
these edible coatings could significantly slow down the respiration rate,
improving internal environment, and suppressing transpiration losses, References
as a result, maintaining the freshness of bananas.
[1] M. Maqbool, A. Ali, P. Alderson, N. Zahid, Y. Siddiqui, Effect of a novel edible
composite coating based on gum arabic and chitosan on biochemical and
4. Conclusion physiological responses of banana fruits during cold storage, J. Agric. Food Chem.
59 (2011) 5474–5482.
[2] M. Islam, A. Kabir, Effect of postharvest treatments with some coating materials on
The natural polyphenols were successfully extracted from the shelf life and quality of banana, Pak. J. Biol. Sci. 4 (2001) 1149–1152.
C. operculatus plants in water. The total polyphenol in CE was 12.4 ± [3] M. Mehdi, A. Asgar, P.G. Alderson, Effect of cinnamon oil on incidence of
1.48 mg/ml. This extract was employed as antioxidant additive in anthracnose disease and postharvest quality of bananas during storage, Int. J.
Agric. Biol. 12 (2010) 516–520.
fabrication of newly edible coatings of CH/GA/CE. The resultant edible
[5] A. Kader, D. Zagory, E. Kerbel, C. Wang, Modified atmosphere packaging of fruits
coatings with CE exhibited a significant improvement of banana shelf- and vegetables, Crit. Rev. Food Sci. Nutr. 28 (1989) 1–30.
life in comparison with control and banana treated with CH/GA edible [6] N. Bessemans, P. Verboven, B.E. Verlinden, M. Janssens, M.L.A.T.M. Hertog, B.
M. Nicolaï, Apparent respiratory quotient observed in headspace of static
coating. The CH1% + GA10% + 0.25%CE composite coating could
respirometers underestimates cellular respiratory quotient of pear fruit,
effectively prolong the freshness of bananas up to 21 storing days at the Postharvest Biol. Technol. 162 (2020), 111104.
ambient conditions. After coated with CH/GA/CE systems, the banana
showed smooth surface and maintained the necessary nutrients such as

7
K.H. Le et al. Progress in Organic Coatings 161 (2021) 106550

[7] R. Thakur, P. Pristijono, M. Bowyer, S.P. Singh, C.J. Scarlett, C.E. Stathopoulos, Q. [26] P.T.M. Nguyen, N. Schultze, C. Boger, Z. Alresley, A. Bolhuis, U. Lindequist,
V. Vuong, A starch edible surface coating delays banana fruit ripening, LWT 100 Anticaries and antimicrobial activities of methanolic extract from leaves of
(2019) 341–347. Cleistocalyx operculatus L, Asian Pac. J. Trop. Biomed. 7 (2017) 43–48.
[8] R. Ghasemzadeh, A. Karbassi, H.B. Ghoddousi, Application of edible coating for [27] H. Wagner, S. Bladt, Plant Drug Analysis: A Thin Layer Chromatography Atlas,
improvement of quality and shelf-life of raisins, World Appl. Sci. J. 3 (2008) 82–87. Springer Science & Business Media, 1996.
[9] F. Debeaufort, J.-A. Quezada-Gallo, A. Voilley, Edible films and coatings: [28] V.L. Singleton, J.A. Rossi, Colorimetry of total phenolics with phosphomolybdic-
tomorrow’s packagings: a review, Crit. Rev. Food Sci. 38 (1998) 299–313. phosphotungstic acid reagents, American J. Enol. Viticult. 16 (1965) 144–158.
[10] R. Dhall, Application of edible coatings on fruits and vegetables, Biobased [29] L. Subedi, S. Timalsena, P. Duwadi, R. Thapa, A. Paudel, K. Parajuli, Antioxidant
Environ. Benign Coat. (2016) 87–119. activity and phenol and flavonoid contents of eight medicinal plants from Western
[11] M.L. Zambrano-Zaragoza, R. González-Reza, N. Mendoza-Muñoz, V. Miranda- Nepal, J. Trad. Chinese Med. 34 (2014) 584–590.
Linares, T.F. Bernal-Couoh, S. Mendoza-Elvira, D. Quintanar-Guerrero, [30] L. Leaves, Antioxidant activity by DPPH radical scavenging method of ageratum
Nanosystems in edible coatings: a novel strategy for food preservation, Int. J. Mol. conyzoides, Am. J. Ethnomed. 1 (2014) 244–249.
Sci. 19 (2018) 705. [31] N.T. Dung, V.K. Bajpai, J.I. Yoon, S.C. Kang, Anti-inflammatory effects of essential
[12] A. Prakash, R. Baskaran, V. Vadivel, Citral nanoemulsion incorporated edible oil isolated from the buds of Cleistocalyx operculatus (Roxb.) Merr and Perry, Food
coating to extend the shelf life of fresh cut pineapples, LWT 118 (2020), 108851. Chem. Toxicol. 47 (2009) 449–453.
[13] M. Maqbool, A. Ali, P. Alderson, A combination of gum arabic and chitosan can [32] T. Prabha, N. Bhagyalakshmi, Carbohydrate metabolism in ripening banana fruit,
control anthracnose caused by Colletotrichum musae and enhance the shelf-life of Phytochemistry 48 (1998) 915–919.
banana fruit, J. Hortic. Sci. Biotechnol. 85 (2010) 432–436. [33] J.K. Brecht, Physiology of lightly processed fruits and vegetables, Hortic. Sci. 30
[14] M. Maqbool, A. Ali, P. Alderson, M.T.M. Mohamed, Y. Siddiqui, N. Zahid, (1995) 18–22.
Postharvest application of gum arabic and essential oils for controlling anthracnose [34] J. Bai, V. Alleyne, R.D. Hagenmaier, J.P. Mattheis, E.A. Baldwin, Formulation of
and quality of banana and papaya during cold storage, Postharvest Biol. Technol. zein coatings for apples (Malus domestica Borkh), Postharvest Biol. Technol. 28
62 (2011) 71–76. (2003) 259–268.
[15] H. Eom, Y. Chang, E.S. Lee, H.D. Choi, J.J. Han, Development of a starch/gum- [35] E. Baldwin, J. Burns, W. Kazokas, J. Brecht, R. Hagenmaier, R. Bender, E. Pesis,
based edible coating for rice cakes to retard retrogradation during storage, LWT 97 Effect of two edible coatings with different permeability characteristics on mango
(2018) 516–522. (Mangifera indica L.) ripening during storage, Postharvest Biol. Technol. 17 (1999)
[16] A. Prakash, M. Joseph, M. Mangino, The effects of added proteins on the 215–226.
functionality of gum arabic in soft drink emulsion systems, Food Hydrocoll. 4 [36] G. Seymour, J. Taylor, G. Tucker, Biochemistry of Fruit Ripening, Chapman & Hall,
(1990) 177–184. London, England, 1993, pp. 327–341.
[17] S. Motlagh, P. Ravines, K. Karamallah, Q. Ma, The analysis of Acacia gums using [37] Ö. Yaman, L. Bayoιndιrlι, Effects of an edible coating and cold storage on shelf-life
electrophoresis, Food Hydrocoll. 20 (2006) 848–854. and quality of cherries, LWT-Food Sci. Technol. 35 (2002) 146–150.
[18] E.M. Çanga, F.C. Dudak, Characterization of cellulose acetate/gum Arabic fibers [38] C. Trakulnaleumsai, S. Ketsa, W.G. van Doorn, Temperature effects on peel spotting
loaded with extract of Viburnum opulus L. fruit, LWT 110 (2019) 247–254. in ‘Sucrier’ banana fruit, Postharvest Biol. Technol. 39 (2006) 285–290.
[19] G. Martínez H., M.L. Amodio, G. Colelli, Carvacrol-loaded chitosan nanoparticles [39] A. Ali, M.T.M. Muhammad, K. Sijam, Y. Siddiqui, Effect of chitosan coatings on the
maintain quality of fresh-cut carrots, Innov, Food Sci. Emerg. 41 (2017) 56–63. physicochemical characteristics of Eksotika II papaya (Carica papaya L.) fruit
[20] J. Wang, B. Wang, W. Jiang, Y. Zhao, Quality and shelf life of mango (Mangifera during cold storage, Food Chem. 124 (2011) 620–626.
Indica L. cv.Tainong’) coated by using chitosan and polyphenols, Food Sci. [40] A. El-Anany, G. Hassan, F.R. Ali, Effects of edible coatings on the shelf-life and
Technol. Int. 13 (2007) 317–322. quality of Anna apple (Malus domestica Borkh) during cold storage, J. Food
[21] C. Han, C. Lederer, M. McDaniel, Y. Zhao, Sensory evaluation of fresh strawberries Technol. 7 (2009) 5–11.
(Fragaria ananassa) coated with chitosan-based edible coatings, J. Food Sci. 70 [41] C. Amarante, N.H. Banks, S. Ganesh, Characterising ripening behaviour of coated
(2005) S172–S178. pears in relation to fruit internal atmosphere, Postharvest Biol. Technol. 23 (2001)
[22] H. Vatankhah, A.R. Taherian, H.S. Ramaswamy, High-pressure induced thermo- 51–59.
viscoelasticity and dynamic rheology of gum Arabic and chitosan aqueous [42] H. Zhang, et al., Physiology and quality response of harvested banana fruit to cold
dispersions, LWT 89 (2018) 291–298. shock, Postharvest Biol. Technol. 55 (3) (2010) 154–159, https://doi.org/10.1016/
[23] A. Silva-Weiss, M. Ihl, P. Sobral, M. Gómez-Guillén, V. Bifani, Natural additives in j.postharvbio.2009.11.006.
bioactive edible films and coatings: functionality and applications in foods, Food [43] C.I. Mata, et al., Omics analysis of the ethylene signal transduction in tomato as a
Eng. Rev. 5 (2013) 200–216. function of storage temperature, Postharvest Biol. Technol. 155 (2019) 1–10,
[24] C.D. Goldsmith, Q.V. Vuong, C.E. Stathopoulos, P.D. Roach, C.J. Scarlett, https://doi.org/10.1016/j.postharvbio.2019.04.016.
Ultrasound increases the aqueous extraction of phenolic compounds with high [44] K.H. Le, et al., A novel antimicrobial ZnO nanoparticles-added polysaccharide
antioxidant activity from olive pomace, LWT 89 (2018) 284–290. edible coating for the preservation of postharvest avocado under ambient
[25] D. Su, Z. Wang, L. Dong, F. Huang, R. Zhang, X. Jia, G. Wu, M. Zhang, Impact of conditions, Progress in Organic Coatings 158 (2021), 106339, https://doi.org/
thermal processing and storage temperature on the phenolic profile and 10.1016/j.porgcoat.2021.106339.
antioxidant activity of different varieties of lychee juice, LWT 116 (2019), 108578. [45] D.D. La, et al., Effects of antibacterial ZnO nanoparticles on the performance of a
chitosan/gum arabic edible coating for post-harvest banana preservation, Prog.
Org. Coat. 151 (2021), 106057, https://doi.org/10.1016/j.porgcoat.2020.106057.