Volume 8 - 2024 | https://doi.org/10.3389/fsufs.2024.1334030
a globally recognized fruit esteemed for its nutritional content and bioactive compounds
faces the critical challenge of post-harvest shelf life impacting its marketability and appeal to consumers
This study aims to assess the efficacy of edible coatings in preserving “Tardivo di Ciaculli” mandarin (Citrus reticulata Blanco cv
and distilled water) and EC2 (comprising gellan gum
were subjected to comparative analysis against control samples (CTR)
mandarin fruits were immersed in the respective edible coating solutions for approximately 5 min and promptly stored at 6 ± 1°C
and sensory analyses were conducted throughout the cold storage period (7
Chemical analysis of the oregano essential oil in EC2 revealed the presence of 27 compounds
with carvacrol being the predominant chemical
The findings indicate that the application of edible coatings effectively preserved the quality parameters of mandarin fruits
exhibited the capability to diminish the viability of molds throughout the entire study duration
thereby extending the shelf life of mandarin fruits
The most crucial factor leading to citrus fruit not-marketability is post-harvest decay
As the industry moves toward sustainable practices and environmentally friendly solutions with minimal impact
this study aims to evaluate the application of natural gellan-gum products enriched with oregano EO on the pomological
and microbial aspects of “Tardivo di Ciaculli” mandarins
The hybrid plants between “Origanum vulgare ssp. viridulum × Origanum vulgare ssp. hirtum” were collected grown in a farm located in Grotte (Agrigento, Italy; Figure 1). This area represents a model of Sicilian environmentally friendly multifunctionality for soil protection (Mammano et al., 2023)
The cultivation of oregano plants was carried out according to traditionally used management methods
Propagating materials were obtained from a local wild genotype previously classified as Origanum vulgare L.
and transplanted in the field in winter 2020
with plant distances of 2.0 × 0.3 m
thereby achieving a plant density of 16,660 plants ha−1
Location of oregano field (37.381621 N
The essential oil was extracted from dried oregano leaves and flowers as described by Garofalo et al. (2023)
EOs were extracted from flowers and leaves using a 12 L volume steam distiller (Spring Extractor
the EO were collected in 25 mL amber glass bottles with screw caps (Laboindustria
The analysis of volatile organic components (VOC) of OEO was conducted using the solid-phase microextraction (SPME) GC–MS technique
following a dilution with hexane at a ratio of 1:100
Supelco) was exposed to the diluted oils while stirring at a temperature of 60°C
the fiber was inserted into a GC spitless injector
and the volatile organic components were desorbed for 1 min at 250°C
A DB-624 capillary column (Agilent Technologies
and coated with a 1.40 μm film) was utilized for chromatographic separation
The oven temperature program was set with a 5-min isotherm at 40°C
followed by a linear temperature increase of 5°C per minute up to 200°C
The temperature was held at 200°C for 2 min
was maintained at a flow rate of 1 mL/min
The interface temperature was set at 230°C
and mass spectra were recorded in the range of m/z 40–400 amu using the full-scan acquisition mode
Identification of individual volatile organic compounds was performed by comparing each mass spectrum with the NIST05 commercial library
and the reported values are expressed as percentages relative to the significant peak
Citrus reticulata Blanco “Tardivo di Ciaculli,” collected from a commercial orchard in Palermo (38° 40‘N
were moved to the laboratory immediately after picking
Mandarins were hand-picked at ripe fruit stage (RF) and placed in boxes before being taken to the laboratory
sanitized by immersion in 200 mg kg−1 of sodium hypochlorite for 5 min
and left to dry at room temperature (~15°C)
fruit quality parameters were analyzed on 30 fruits
Only mandarin fruits with no external injuries were used for the following research and fruit processing operations were performed in sanitary conditions at 15 ± 1°C
The edible coating was prepared in the laboratory of the Department of Agricultural
Two different edible coatings were tested and compared with the untreated sample
• EC1: fruits treated with edible coating based on gellan gum (special ingredients
The edible coating solution was placed in a 1 L beaker: 935 mL distilled water; 5 g gellan gum; 30 g CaCl2; 30 mL glycerol
The solution was subjected to magnetic stirring (30°C) for 2 h and immediately afterwards was applied to the fruits
• EC2: fruits treated with edible coating based on gellan gum specialin gredients
and high-carvacrol oregano essential oil (EC2)
The edible coating solution was placed in a 1 L beaker: 933 mL distilled water; 5 g gellan gum; 30 g CaCl2; 30 mL glycerol; and 2 mL of OEO
This composition imparts specific characteristics to EC2
including potential antimicrobial and antioxidant properties attributed to the oregano essential oil
The thorough mixing and application of EC2 contribute to its potential in safeguarding the fruits and maintaining their freshness during storage
The mandarin fruits were immersed in the two different edible coating solutions (EC1 and EC2) for approximately 5 min to ensure uniform coverage of the entire fruit surface
both the samples treated with edible coatings and the control samples were placed in plastic commercial boxes and stored
Quality evaluations were conducted at various stages
and 24 days at 6 ± 1°C)
and distinct shelf-life phases (I: 7 days at 6 ± 1°C plus 7 days at 15 ± 1°C; II: 14 days at 6 ± 1°C plus 7 days at 15 ± 1°C; III: 24 days at 6 ± 1°C plus 7 days at 15 ± 1°C)
a comprehensive analysis was performed on 15 mandarin fruits for each treatment
The examinations included both destructive and non-destructive analyses:
• Texture: Evaluated using a “Fruit Texture Analyzer” (GS-15 Qa Supplies United States) equipped with a pipette tip
• Total Soluble Solids (TSS) Content: Determined using a digital refractometer (Atago
• Titratable Acidity (TA): Measured by titrating 10 mL of mandarin juice with a 0.01 M NaOH solution and expressed as a percentage of citric acid
• pH: Assessed with a digital pH meter (model HI8453
• Weight Loss: Verified by weighing the samples during storage with a digital scale (Beurer Italia Srl
The percentage reduction in weight for each treatment (CTR
EC2) was determined based on measurements taken during cold storage on days 0
and 30 at 6 ± 1°C
The formula used for % Weight Loss calculation was:
• Color: Measured by assessing the parameters L*
and b* with a colorimeter (Minolta chroma-meter CR-400) at two opposite points of the equatorial zone of the fruits
and yellowish or bluish color (b*)
The instrument was calibrated using a manufacturer’s plate
For each sampling date and experimental treatment (CTR
three samples were randomly chosen and analyzed
Mandarin fruit samples were frozen at −80°C pending extract preparation. Upon thawing, the samples underwent chopping, and the seeds were separated from the pulp. The pulp was homogenized, and fruit extracts were prepared following a previously described procedure with minor modifications (Kanner et al., 2001)
10 g of the whole homogenate were weighed and then extracted using 80% (v/v) methanol containing 2% formic acid
The samples were vortex-mixed for 5 min and sonicated at room temperature for 15 min (~25°C)
The mixtures were allowed to stand for 2 h at room temperature
Following centrifugation (10 min at 8000× g
The extraction procedure was iterated to obtain three distinct technical replicates
Total phenolic content (TPC) of extracts from treated and untreated fruits was determined by the reduction of phosphotungstic–phosphomolybdic acid (Folin–Ciocalteu’s reagent) to blue pigments, in alkaline solution according to Folin–Ciocalteu’s method (Singleton and Rossi, 1965)
Total phenolic content was expressed as mg gallic acid (GA) equivalent (GAE)
The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging analysis was performed on 2 g of frozen tissue with 5 mL 50% (v/v) ethanol according to Wang et al. (2020)
The homogenate was centrifuged at 12,000× g for 20 min at 4°C
The reaction mixture consisted of 0.1 mL supernatant and 1.9 mL 120 μmol L − 1 DPPH
Results were calculated using the following formula: DPPH radical scavenging activity (%) = [(A0 − A1)/A0] × 100
with A0 referring to absorbance of the control
DPPH radical scavenging was expressed as a percentage
Ascorbic acid in CTR, EC1 and EC2 samples was determined by extracting 10 g of blended fruit sample in 100 mL metaphosphoric acid (HPO3), then filtered through Whatman no 1 filter paper. A volume of 10 mL from filtered solution was determined volumetrically with the 2–6 dichlorophenol-indophenol reagent until a slightly pink coloration was observed and persisted for 15 s (Allegra et al., 2017)
The reading of ascorbic acid content was expressed in mg/100 g FW
except those for members of Enterobacteriaceae family
which were counted by pour plating on double-layered agar media to determine the microanaerobiosis conditions
Microbiological analyses of mandarin fruit samples were performed in triplicate
Sensorial analysis and visual score were evaluated at each sampling date
Sensory analysis was carried out at the Department (SAAF) and three sections per fruit were used for each treatment
An experimental randomization scheme was adopted for statistical analysis complete with 3 replications per treatment and for sampling date
The data were analyzed using one-way analysis of variance (ANOVA)
and pairwise comparisons between the samples of control and treated fruits were evaluated using Tukey’s test
The differences were considered significant for p < 0.05
The statistical analysis was carried out using Systat (Systat
The collected biomass was intended for the distillation of essential oils
so it was necessary to identify the time of complete flowering
The harvested plants belonged to local ecotypes characterized by considerable genotypic variability and non-uniform flowering
The harvest time of oregano depends on the commercial use of the product:
• at maximum blooming (higher than 50%) and plant coverage (leaves and flowers), for food use (Comparetti et al., 2022)
The NDVI index is sensitive toward crop biophysical properties like nitrogen, chlorophyll, vigor, and biomass etc. The oregano was harvested when the NDVI values of most of the plants were equal to 0.58 and high flowering was evident from visual checks (Figure 3)
The volatile profile of OEO is graphically represented in Figure 4
A comprehensive analysis identified 27 volatile compounds belonging to six phytochemical groups: monoterpenes
Volatile composition of oregano essential oil
Results indicate the mean percentage values of three measurements and are expressed as relative peak areas (peak area of each compound/total area of the significant peaks in all samples) x l00
The effect of edible coatings implemented with oregano essential oil should be positive, particularly regarding microbial growth, as demonstrated by Barreto et al. (2016)
One of the most important mandarin fruits quality parameters is peel color, because it determines consumers’ visual perception, and influences their decision in purchases. The color of mandarin peel and pulp is principally governed by the content and composition of its carotenoid and apocarotenoid pigments (Rodrigo et al., 2013)
Changes in weight loss (%) in mandarin fruits control samples (CTR)
treated mandarin fruit samples (EC1; EC2) during the cold storage at 6 ± 1°C Different lowercase letters indicate significant differences at p ≤ 0.05 between the treatments on each sampling date
Uppercase letters indicate significant differences at p ≤ 0.05 between the different survey on the same treatment on each sampling treatment
Data are the mean ± S.D
during the period from day 0 to day 14 at 6 ± 1°C + 7 days at 15 ± 1°C
the total phenolic content decreased by 37.8% in the control sample
it decreased by 15.2% (EC1) and 8.79% (EC2)
Total phenolic content during harvest (day 0) and during the shelf-life I shelf-life: harvest plus 7 days at 15 ± 1°C; II shelf-life: 14 days at 6°C plus 7 days at 15 ± 1°C and III shelf-life: 24 days at 6°C plus 7 days at 15 ± 1°C
Different lowercase letters indicate significant differences at p ≤ 0.05 between the treatments on each sampling date
Uppercase letters indicate significant differences at p ≤ 0.05 between the different storage period on each sampling treatment
Essential oils inherently contain natural antioxidant compounds, and their incorporation into coatings has the potential to enhance their functional properties, making them more effective in protecting fruits and vegetables. Numerous studies have explored the impact of edible coatings enriched with antioxidants, including essential oils, on the quality and preservation of both fresh and fresh-cut fruits and vegetables (Yousuf et al., 2021)
has also shown the capability to augment the antioxidant capacity of food
DPPH radical scavenging rate during harvest (day 0) and during the shelf-life I shelf-life: 7 days ±1°C; at 6 plus 7 days at 15 ± 1°C; II shelf-life: 14 days at 6°C plus 7 days at 15 ± 1°C and III shelf-life: 24 days at 6°C plus 7 days at 15 ± 1°C
The ascorbic acid content (AAC) in mandarin fruits underwent notable variations influenced by the applied treatments
At day 7 ± 1°C plus 7 days at 15 ± 1°C
a substantial increase of approximately 15% in ascorbic acid content was observed in both treated and untreated fruits
initiating a subsequent decline from day 14 at 6°C plus 7 days at 15 ± 1°C
By day 14 at 6°C plus 7 days at 15 ± 1°C
the ascorbic acid content decreased by 2.08% in the control samples compared to day 0
the treated samples exhibited an increase of 11.56% in EC1 and 9.12% in EC2 compared to day 0
On day 24 at 6°C plus 7 days at 15 ± 1°C
the increase in ascorbic acid in EC2 was 5.77%
whereas a decrease of 10.4% was noted in CTR
Ascorbic acid rate during harvest (day 0) and during the shelf-life I shelf-life: harvest plus 7 days at 15 ± 1°C; II shelf-life: 14 days at 6°C plus 7 days at 15 ± 1°C and III shelf-life: 24 days at 6°C plus 7 days at 15 ± 1°C
Cell densities of molds on control and treated mandarins fruit samples
Histograms followed by different lowercase letters are significantly different according to Tukey’s test (p < 0.05)
The “sweet” parameter was evaluated positively by the panelists; in fact
the sweetness of the fruits remained constant in all samples
and at the last shelf-life EC1 samples had one point more than the CTR and EC2 ones
The juiciness parameter remained similar in all three theses during the storage periods; as well as for chewiness
The parameter “typical tangerine flavor “had the higher score in EC2 at 24 days at 6 ± 1°C plus 7 days at 15 ± 1°C
the treated samples were preferred by the panelists showing 2 points more in EC2 on 24 days at 6 ± 1°C plus 7 days at 15 ± 1°C than the CTR samples
Bitter and sour parameters were similarly evaluated during the storage periods by the panelists
(A) Sensorial analysis of mandarin fruits control samples (CTR-A)
treated mandarin fruit samples (EC1-B; EC2-C) at I shelf-life: 7 days at 6°C plus 7 days at 15°C; (B) Sensorial analysis of mandarin fruits control samples (CTR-A)
treated mandarin fruit samples (EC1-B; EC2-C) at II shelf-life: 14 days at 6°C plus 7 days at 15°C; (C) Sensorial analysis of mandarin fruits control samples (CTR-A)
treated mandarin fruit samples (EC1-B; EC2-C) at III shelf-life: 24 days at 6°C plus 7 days at 15 ± 1°C
“Oregano odor,” “Oregano flavor” and “herbaceous smell” remained persistent until 3rd day of the second storage period (II shelf-life), following a slight increase in these descriptors between 3rd day and 7th day of the first storage period (Figure 10C)
There was a similar evaluation at harvest (0 days) and 3rd day of the second storage period (II shelf-life) until these descriptors were not detected from 7th day of the second storage period (II shelf-life)
These descriptors were completely absent during the third storage period (III shelf-life 24 days at 6 ± 1°C + 7 days at 15 ± 1°C) (Figure 10C)
During the three storage periods, all treatments samples showed scores above the marketability threshold (Figure 11)
Only treated samples maintained a score above 4 during the three storage periods
Visual score of mandarin fruits control samples (CTR)
treated mandarin fruit samples (EC1; EC2) at the harvest
during the shelf-life (I shelf-life: harvest plus 7 days at 15 ± 1°C; II shelf-life: 14 days at 6°C plus 7 days at 15 ± 1°C and III shelf-life: 24 days at 6°C plus 7 days at 15 ± 1°C)
The analysis of multispectral images acquired through UAVs offers the potential to identify the optimal collection time
for harvested oregano intended for essential oil extraction
the balsamic time was determined when the NDVI values of most plants reached 0.58
This study marks the first evaluation of the impact of a coating composed of gellan
and calcium chloride enriched with essential oils of oregano featuring high carvacrol content on the shelf life of mandarin fruits
Our findings suggest that the application of edible coatings maintained the quality parameters of the fruits without inducing quality decay
the edible coating resulted in reduced weight loss of the treated fruits
a crucial aspect for preserving product quality
the edible coatings demonstrated the ability to better preserve nutritional and nutraceutical attributes throughout the storage periods
carvacrol exhibited inhibitory effects for 24 days at 6 ± 1°C plus 7 days at 15 ± 1°C
preventing the occurrence of green and blue mold
which are responsible for rendering the product unsuitable for commercialization
This underscores the significant value of the treatments in safeguarding the quality parameters of mandarin fruits and mitigating food waste arising from non-marketability
The raw data supporting the conclusions of this article will be made available by the authors
The author(s) declare financial support was received for the research
- Validazione di protocolli innovativi per la produzione di piante officinali di interesse nutraceutico coltivate in Sicilia.” Bando PSR Sicilia 2014/2022 – Sottomisura 16.1
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations
Any product that may be evaluated in this article
or claim that may be made by its manufacturer
is not guaranteed or endorsed by the publisher
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Fascella G and Mammano MM (2024) Effect of the gellan-based edible coating enriched with oregano essential oil on the preservation of the ‘Tardivo di Ciaculli’ mandarin (Citrus reticulata Blanco cv
Received: 06 November 2023; Accepted: 22 January 2024; Published: 07 February 2024
Copyright © 2024 Liguori, Greco, Salsi, Garofalo, Gaglio, Barbera, Greco, Orlando, Fascella and Mammano. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)
distribution or reproduction in other forums is permitted
provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited
in accordance with accepted academic practice
distribution or reproduction is permitted which does not comply with these terms
*Correspondence: Giuseppe Greco, Z2l1c2VwcGUuZ3JlY28wM0B1bmlwYS5pdA==; Giancarlo Fascella, Z2lhbmNhcmxvLmZhc2NlbGxhQGNyZWEuZ292Lml0
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Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher
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the photographer and member of a punk band
who had cut his teeth by covering the underground scene in Palermo
found himself thrust into the heart of mafia crimes
From 1986 he worked for the local newspaper
He recounts these three years in his life in his recent book
Chronicles of the Newspaper L’Ora: Palermo 1985–1988
I started working for the newspaper L’Ora because I wanted to be a photographer, and above all I wanted to escape my city
and having plenty of different experiences
There was no “business as usual” at L’Ora: Sometimes we had only routine news to cover; other times there could be three or more murders within the span of a few hours
L’Ora came out in the early afternoon; it was a left-wing paper with a team of excellent journalists who conducted delicate investigations
but it was the editorial staff that made the final decision
we were just witnessing of the rise of the Corleonesi
unlike what was published in the newspaper
you can see sequences that illustrate my way of working
Black-and-white was the only film used by the newspaper
but black and white fits better my way of seeing things: it allows me to play with the notions of time and space
I don’t really remember if I arrived before the others
But what I do know is that once I got there
I would try to get into position quickly and concentrate on framing the scene as best I could
away from other photographers or TV networks
and I had to get the picture back to the newspaper
you had to call the editorial office to find out what had happened and rush to the scene
I had already come across a dead body on my way to school on the bus
Palermo was a violent city that was going through tough times
especially with the escalation of hard drugs like heroin and cocaine
Those were the times I lived through.
it is certain that the mafia was watching me”
it is certain that the mafia was watching me
I remember one event in particular: late at night
A Fiat Panda with four men inside pulled up alongside us
He pulled out a gun and rested it on his arm
turned my head to the street in front of me
were in a dedicated section up high (newspapers from all over the world were covering the trial)
or next to the family members of the detainees
I remember the strange feeling of seeing these people who had lost their charisma
this was especially true of Tommaso Buscetta
throwing the victim’s naked body into the sea after a night of torture
This was one of the first victims I ever photographed
There is a whole series in the book about this scene
You could feel the cruelty and the sense of helplessness that was felt on both sides of this war
“The mafia never stops mutating and its legacy is passed on from generation to generation”
The idea came from a meeting with Giandomenico Carpentieri (Yard Press and Union Editions)
My approach was a little different from that of other photographers
The city has changed, it has lost its ghoulish aura. It has evolved, become more European, open to mass tourism
Collective well-being has come to replace the malaise we experienced in the 1980s
But Palermo has put on a pretty coat and shows it off in broad daylight
even while dirty business is conducted in the shadows
and its legacy is passed on from generation to generation.
Fabio Sgroi, Chronicles of the Newspaper L’Ora. Palermo 1985–1988
Read More: Letizia Battaglia, Who Photographed the Italian Mafia, Dies at 87
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Five killed in Sicilian wildfires and Milan storm of 110kph gales, Greece battling devastating wildfires driven by intense heat on the islands of Evia
Greece has been battling devastating wildfires driven by intense heat on the islands of Evia