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Bovi, G. G., Caleb, O. J., Ilte, K., Rauh, C., & Mahajan, P. V. (2018). Impact of modified atmosphere and
humidity packaging on the quality, off-odour development and volatiles of ‘Elsanta’ strawberries. Food
Packaging and Shelf Life, 16, 204–210. https://doi.org/10.1016/j.fpsl.2018.04.002
Graziele G. Bovi, Oluwafemi J. Caleb, Kathrin Ilte, Cornelia Rauh,
Pramod V. Mahajan
Impact of modified atmosphere and
humidity packaging on the quality, off-
odour development and volatiles of
‘

Elsanta’ strawberries
Accepted manuscript (Postprint) Journal article |

Impact o f modified atmosphere and hum idity pack ag ing on the quality, off -
odour de velopment and vo l atiles of ‘Elsanta’ stra wberries

In: Food Packaging and Shelf L ife, 16, 204 -210.

Cite as: Bovi, G. G., Caleb, O. J., I lte, K., Rauh, C., & Mahajan, P. V. (2018). Impact of
modified atmosphere a nd humidit y packaging on the quality, off -odour development and
volatiles of ‘Elsanta’ strawberries. Food Pac k aging and Shelf Life, 16, 204 -210.
doi: https://doi.org/10.1016/j.fpsl.2018.04.002

Impact of m odif ied atmosphere and h umidity packaging on the quality, off-odour
development and volatiles of ‘Elsanta’ strawberries
Graziele G. Bovi a, b ,* , Oluwafe mi J . Caleb a , c , Kathr in Ilte a , Cornelia Rauh b , Pramod V.
Mahajan a
a Department of Horticultural Enginee ring, Leibniz Institut e for Agricultural Engineering and
Bioeconomy (ATB), Potsdam, Ge rmany
b Department of Food Bi otechnology and Food Process Engineering, Technical University of
Berlin, Germany
c Post-harvest and Agro-processing Tec hnologies, Agricultural Research Council ( ARC )
Infruitec-Nietvoorbij, Stellenbosch 7599, South Africa
* Corresponding author : Phone: +49(0)3315699628 ; E-mail: [email protected]
(Graziele G. Bovi)

Abstract
Development of of f-odours, as well as visual qualit y of packa ged fresh produce pla ys a
crucial role in consumer ’s choice . In this contex t, this work investi gated the odour profile ,
condensation, gas composition, and postharvest quality attributes of str awberries stor ed under
modified atmosphere and humidit y packagin g at 5 °C for 14 day s. The packages were fitted
with fixed area (69, 126.5, and 195.5 cm 2 ) of diff erent permeable membranes (NatureFlex,
Xtend, and Propafilm). No significant changes were detected on the measured
physicochemica l qualit y attributes of strawberries and mass loss was below 1.5% across the
differe nt packaging systems. Package modification/desig n had an influence on in -package
water v apour condensation, gas composition, and accumulation of second ary volatil e organic
compounds (acetaldehyde, acetone, ethanol and ethyl acetate).
Keywords: pac k aging, strawberry, off-odour, qualit y

1. Introduction
Fresh produce remains metabolica ll y active even after ha rvest and continues to respire and
lose water (Bovi, Caleb, Linke, Rauh, & Mahajan, 2016). This repre sents a challenge for the
development of c ontrolled atmosphere (CA) and modified atmosphere pa ckaging (MAP)
systems, since it leads to changes in th e package atmosphere ove r time. Jo, Kim, An, Lee, and
Lee (2013) developed a fresh produce container that comb ines the principles of MAP
(atmosphere modific ation based on produc e res piration) and CA (pe rio dic adjustment of
atmosphere composition) . Their approach consists of a controlled container system fitted with
a gas diffusion tube re sp onding to rea l -time measure d O 2 and CO 2 concentra tion. Howe ver,
this approach add resses only to optimum g as eous composition and do es n ot take into account
the ac cumulation of water vapour. Water va pou r evolution inside fresh produce p ackages
often limits product´s shelf life due to the form ation of condensation (Bovi & Mahajan, 2017).
Condensation represents a risk to the product qua lit y as water ma y accumulate on packaging
system and/or product surface leading to defects i n external appearance and promoting growth
of spoilag e microorganisms (B ovi et al., 2018; Linke & Geyer, 2013) . Thus, the concept of a
modified atmosphere and humi dit y pa ckaging ( MAHP) equipped with a humidit y control
window might represe nt an innovative approach to avoid or lessen the risk of condensation.
Besides conde nsation, vi sual quality , freshness aroma , and dev elopment of cha racteristi c off-
odour volatiles play a c rucial role in consumer’s choice , and this influences future decisions to
purchase the product. Thus, the identific ation of chara ct eristic of f -odou r volatiles during
storage life of packaged fresh produce c an s erve as an indicator of prod uct quality. Around
360 volatile compounds have been identified in the aroma of strawberry ( Fragari a x ananassa
Duch.), however, only a small portion (15-25) of these volatiles are important contributors to
the aroma (Jouquand, Chandler, Plotto, & Goodner, 2008; Nielsen & Leufvén, 2008;
Za b etakis & Holden, 1 997). Some of these c o mpounds include methyl and ethy l esters,
furanone s, C 6 aldeh yde s and other C 6 derivative compounds. I n addition, strawberries ma y
produce secondary volatile organic compound (VOCs), such as acetaldehyde, ethanol and
ethyl acetate during storage. W hen these secondar y volatiles ar e present in concentrations
above their threshold limi t they can have a negative effect on the flavo ur (Pela yo, Ebeler, &
Kader, 2003).
Postharvest life of strawberr y is short due to phy sical dama ge during ha ndling , water loss,
physiologica l disorders, high susceptibility to spo ilage microorganisms (Caleb, Wegner, et al.,
2016; Chandra, Choi, Lee, Lee, & Kim, 2015; Lara, García, & Vendrell, 2006) , and hi gh

respiration rate (RR) of 50 to 100 mL CO 2 kg -1 h -1 at 20 °C (Ozka y a, Dündar, Scovazzo, &
Volpe, 2009). Nevertheless, refrigeration in combination with MA sy stems has been
extensively used to exte nd shelf-life of strawberr y. Results have shown that MAP c an slow
strawberry respiration rate b y keeping CO 2 conc entration between 10 an d 30% (Lara et al.,
2006; Nielsen & Leufvén, 2008). I n this context, the a im of the study w as to design, develop
and investi gate the effects of modified atmosphere and humidity packaging on : a) its
performance in terms o f headspace ga s composition and moisture co ndensation; b) the
physicochemica l quality attributes of strawbe rri es ; and c ) the shift in VOCs prof iles of
packaged strawberries during storage.
2. Mater ials an d me tho ds
2.1. Plant mater ials
Fresh strawberr y (cv. Elsanta) was obtained from the commercial grower (F ru chthof Hens en
Er dbeerkulturen GmbH & Co. KG, Swisttal-Mömerzheim, German y ), a nd transported in
cooled conditions to the Freshness L aborator y , Department of Horticultural Eng ineerin g,
Le ibniz Institute for Agricultural Engineering and Bioeconom y , Potsda m, German y . The
strawberries were carefull y so rted and the dama ged, ov erripe, and poor quality fruit were
discarded in order to obtain uniform samples. The strawberries were precooled to the study
temperature of 5 °C for 3 hours.
2.2. Design of modified atmosphere and humidity packaging
Pol y prop ylene packages (total 10) o f siz e 13 x 20 x 9 cm (total volum e 2.3 L) w ere used as
the base storage container. The lid of each pac kage was modified b y cutt ing window s of
differe nt sizes of 33, 66, and 100% of total lid area which is equivalent to absolute area of 69,
126.5, and 195.5 cm 2 , respectively. These open windows were h ermeticall y sealed (using
double sided hermetic tapes) with different pac kaging films: i) Xtend (XT) film (StePac,
Tefen, Israel), ii ) Pol y p rop y len e based Propa film (PP) (I nnovia Films, Cumbria, UK), and iii)
cellulose-base d Na tur eFlex (N F) pol ymer i c film ( Innovia Films, Cumbria, UK). Each
packaging film covering the window was perforated with 2 holes of 0.7 mm diameter in order
to achieve equilibrium modified atmosphere. Table 1 shows the description of the different
packaging window design us ed in this stud y. Different window sizes and packa ging films
were used in or d er to crea t e different modified humidit y conditions. The wa ter vapour
transmission rate (WVT R) is 42.79, 19.34, and 0.8 g m − 2 d − 1 for NatureFlex, Xtend, and
Propafilm, respec tivel y and at 5 °C.

2.3. Pac kag e design performance
The packages were filled with strawbe rries (700 ± 5 g), closed tightly with the designed lids
and stored at 5 °C for 14 da ys. Headspace gas composition (O 2 and C O 2 concentra tions )
inside each package was moni tored dail y b y using a CheckMate 3 ga s anal y ser (PB I
Dansensor, Ringst ed, Denmark). A visual documentation of moisture condensation on the lid
and window film was recorded after 14 day s of storage. In addition, condensation
(free/conde ns ed water) and total mass loss (mass loss of strawberr y ), was q uantified at the e nd
of storage on da y 14. The amount of water va pour condensed insi de the package (g) was
quantified b y wei ghing the empt y p ackages befor e and after the removal of condensed water
on the package w alls, windows and the lids. The water loss through the film, due to
permeability , was also calculated from the difference in the amount o f water lost b y the
strawberry and the amount of water conde nsed inside the package. One replicate was carried
out totalizing 10 packages.
2.4. Physico-chemical quality changes
Fresh strawberr y juice was used to measure total soluble soli ds (TSS), pH and titratable
acidity (TA). A digital refractometer (DR301 -95, Krüss Optronic, Hambu rg, German y ) was
used to measure TSS and expressed as %. The TA concentration of the juice sample was
measured potentiometricall y b y titration with 0.1 mol L − 1 NaOH, to an endpoint of pH 7.0
using an automated T50 M Titra-tor with Rondo 20 sample changer (Mettler Toledo,
Switzerland). The T A concentration w as expressed as g L − 1 of citric acid b ased on fr esh mass.
The pH was m easured with a pH m eter (ino La b pH720, WTW Series, W eilheim, Germany)
after calibrating with pH buff ers 4 a nd 7. The measurements we r e done in triplicate on da y 0
and on day 14.
2.5. Visual and ortho -nasal quality evaluation
Twelve untrained panelists who are regular consu mers and f amiliar with the quality attributes
of strawberr y carried out visual and ortho -nas al qualit y evaluation. Strawberr y qu a lit y
attributes such as texture, odour, and decay were eva luated on a scale of 1 to 5 (Table 2). I n
addition, visual observation of water vapo ur cond ens ed on the lid window was also scored on
a scale of 1 to 5.
2.6. Evolution of volatile organic compounds
Volatile compounds wer e extracted b y static he adspace sampling (SHS). Strawberries f rom
each pa ckage were c rush ed into puree and 5 g of aliquot was placed in 20 mL glass vial with

100 μ L of 3 -octanol (dil uted in absolute methanol to a concentration of 0.1 g L -1 ) as inte rnal
standard. The vials were tig htl y capped and equili b rated at 80 °C fo r 20 mi n in the headspace
auto-sampler incubator. Gas sample (1 m L) was automatically withdr awn from the headspace
of e ach vial (HS-20 automated-sampler, Shimadzu Europa GmbH, Duisburg, German y).
Sampling condition for HS -20 auto-sampler w as maintained as follows: the oven, sampling
line and transfe r line temperature was 80 °C, 150 °C and 150 °C, respectively ; pressurizing
pressure and time was 7 6 kPa a nd 2 min, respectively . To increase the sensitivit y of the SHS
sampling method on the GC – MS, vial shaking level of 3, load time of 0.5 min and injection
time of 1 min with single injection parameters were used.
Gas samples were transferr ed from HS-20 sampler into the GCMS -QP2010 (Shi madzu
Europa GmbH, Duis -burg, Germa n y) for separation of volatile compounds. Due to the
volatilit y , nonpolar character and r eactivit y of vol atile sulph ur compounds a mid- polar 1.4 μ m
film thickness Zebr onT M capillar y column, with 30 m length and 0.25 mm inner diameter
was used (ZB-624, Phenomenex, Aschaff enbu rg, Ge rman y). Anal y ses were carried out using
helium as carrier gas with a total flow of 16.4 mL min -1 and a column flow of 1.22 m L min -1 .
The GC temperature was held at 50 °C for 1 min, then ramped to 110 °C at 5 °C mi n -1 , then to
180 °C at 20 °C min -1 , held for 3 min and finall y to 200 °C at 5 °C mi n -1 , and held at thi s
temperature for 1.5 min in tot al run time of 25 min and split ratio (1:10). The mass selective
detector (MSD) was operated in full scan mode and mass spectra in the 35 – 350 m/z range
were recorded. The ion source and interface temperature were maintained at 200 °C and 230
°C, respectively. Individual volatile compound were id entified b y their retention time (RT)
and calculated Kovats r etention index (RI) usi ng n - alkane group. The compounds were
compared to those registered on the N ational Institute for Standards and T echnolog y (NIST)
mass spectra l librari es (NIST v. 08 and 08s, Gaithersbug, MD, USA) and other literature.
Only compounds with the square of the c orrelation c oefficient (R 2 ) above 90% between
experimental spectra an d NI ST MS library were considered. S emi -qu antification of the
identified compounds was estimated according to Bugaud and Alter (2016) using Eq. (6):
RA = 𝐴𝑖 𝑐
𝐴 𝑖𝑡𝑠
𝐶 𝑖𝑡𝑠
where RA is the relative abundances of the identif ied compound (g L -1 ), Ai c is the peak area of
the identified compound, A its is the peak area of the int ernal standard, and C its is the final
concentration of interna l standard in the sample (0.1 m g m L -1 ).
2.7. Statistical analysis

The da ta obtained were submitted to a nal y sis of variance (ANOVA) and T ukey’s test with
significa n ce set at p < 0.05 using the Statistica software (v ersion 10.0, StatSoft Inc., Tulsa,
USA). I n addition, Dun can multiple range test was used to anal y se the vol atile or ga nic
compounds of strawberries in order to determine t he difference between m ean values at p <
0.05. Results were presented as mean ± standard deviation.
3. Results and discussions
3.1. Modified atmosphere and moisture condensation
Gas composition inside the pa ckages va ried between 5-14% for O 2 and 8-19% for CO 2
(Figure 1), with exception of the control package. The gas composition of the control package
was not shown is Figure 1, neve rthel ess, it wa s measured. It reached 1.29% of O 2 alread y on
day 3 of stora ge and 0% on the remaining da ys. For CO 2 the concentration reac h ed 23.27% on
day 5 and 45 % b y th e end of stora ge. The PP33, P P66, and NF66 pa ckages had the lowest O 2
steady state conditions (around 6%). However, it was sti ll withi n the re commended M A
conditions for stra wb erries of 5 – 10% O 2 and 15 – 20% CO 2 (Brecht et al., 2003). A d ecline o f
O 2 below c ritical limits (5%) should be avoid ed as this mi ght le ad to in -package anox ia;
which in turn re sults in ferme ntation and of f-odour development (Luca, Mahajan, &
Edelenbos, 2016). Overall, the values obtained show similar tre nds with ex perimental micro-
perforated wild strawberries packed in containers (8 -14% O 2 ) cove red with polyethylene
terephthalate/polypr op y l ene (PET/PP ) multilaye r films with three micro - perforations stored
for 4 d a y s at 10 °C (Almenar, Catala, He rnandez -Muñoz , & Gavar a, 2009) . F urthermore, thi s
study showed that the u se of fixed window with 2 mi cro-perf o rations h as the capabilit y of
preventing anoxic conditions on packaged strawberries.
Package s fitted with N atureF l ex and Xtend windows, independent of the thei r siz es,
effectively prevented water vapou r condensation (free/condensed water) in comparison to
those fitted with Propafilm and the control package (Figure 2 and 3). This is di rectl y related to
the WVTR of the films. Natureflex and Xtend films have ver y high WVTR, 42.79 and 19.34
g m − 2 d − 1 measure d at 5 °C, respec tivel y when compared to Propafilm, 0.8 g m − 2 d − 1 (Sousa-
Gallagher, Mahajan, & Mezdad, 2013). However, the prevention of water vapour
accumulation on the package film led to higher mass loss of strawberries. R esults show that
the t y p e of film and its siz e ha d an influ ence on the ra t e of mass loss stra wberries ( Figure 3).
The highest product mass loss was observ ed in th e pack ages covered with NatureFlex (0.57 -
1.46%), while samples i n Propafilm (0.20 -0.27%) had the lowest mass loss. The bigger the
window size the higher was the mass loss recorded, with the exception of samples PP 33 and

P66 that presented similar mass loss indep endent of the window size, pr obably, due to the
very low permeabilit y o f PP film to water vapour. Nevertheless, the overall mass lost b y
strawberries in this study did not exceed 1.5 %, and therefore was significantly b elow the
recommende d maxim um acce ptabl e loss of 6% (C. N. Nunes & Emond, 2007). Sim ilarly ,
Caleb, Ilte, Fröhling, Gey e r, and Mahajan (20 16) investigated the effects of appropriate
design o f modified atmosphere and humidit y packaging (MAHP) s ystems , with NatureFlex
film window on poly prop ylene film on the postharvest qualit y of m inimall y processed
broccoli branchlets. Results also showed that the use of the window effectivel y prev ented
water vapour condensat ion on the film surfac e when compared to bi-axiall y oriented
polypropylene and cling-wrapped commercial co ntrol, however, at the ex pense of a higher
product mass loss compared to the control pack age. Nevertheless, the u se of lid window
covere d with high WVTR films has the capacity of reducing water vapour from the package
headspace and ther efore, might retard mic robial spoilage and increase shelf life. Furthermore,
the use of such films as humidit y windows is innovative and efficie nt as these containe rs a re
re -usable and there is only the n eed to change the window film.
3.2. Physico-chemical quality changes
The traditional ph y sical and chemical quality attributes detected no significant (p ≤ 0.05)
changes by the Tukey test in packag ed strawberries after 14 da y s of stora ge at 5 °C. The range
of total soluble soli ds (TSS ), total acidity (TA), a nd pH obtained in this stud y was 4.0 - 5.2 %,
0.9 - 1.2 g L -1 , and 3.9 - 4.1, respectivel y. TSS an d TA are important parameters to d etermine
the fruit qualit y as the y have a direct effect on t he flavo u r. The y v ar y si gnificantly amon g
differe nt stra wberr y v arieties (Kallio, Hakala, P elkkikangas, & La pv eteläinen, 2000). The
authors investigated the sugar and acid composition of six strawberr y varieties. The y reported
that the major acids in stra wberries are citric (7.3 -15.8 g L -1 ) and malic (2.2 - 6.9 g L - 1 ) and
total sugar content varied from 5.35 to 10.96%. Nev ertheless, both t he TSS and the T A
obtained in this stud y were lower than th at repor ted b y Kallio et al. (2000), which indicated
that the strawberries contained less sugar and were v er y acid. On the other hand, the pH
obtained in this stud y for cv. Elsanta strawberries wa s within the range reported for `Sonata`
strawberry b y Caleb, Wegner, et al. (2016), which was in the range of 3.9 to 4.7. Furthermore,
the size and t y p e of film did not affect the physi co-chemical qualit y attri butes as there were
no significa nt changes from t he initial to the end of storage .
3.3. Visual and ortho -nasal quality evaluation

All sensory attributes received scores below 3 which indicated that all the packages presented
compromised quality, especiall y the control p ackage as it had th e lowest s core fo r most of the
evaluated attributes (F i gure 4). Low scores for the strawberr y texture can be associated with
mass loss as this leads t o shriveling and wiltin g of the p roduct. Furthermore, o ur s ensorial
analy sis scor es were in accordance with Figure 2 and 3, containers fitted with NatureFlex and
Xtend films as lid windows reduced condensation when compared to o ther pa ckages. This
reduction was ver y important as in-package condensation led to poor qualit y. Moreover,
condensation was quantified as zero, however in the sensory evaluation it was v isible.
Possibl y the films NatureFlex and Xtend absorbed water and formed d r oplets; therefor e, it
was visible but could not be quantified. This was due to the fact th at the fil ms were not coated
with anti-mist and therefore show ed d roplets adhered to the film as conde nsed water. On the
other hand, P ropafilm is a standard material coated with anti-mist; nevertheless, due to the
low W VTR the moi sture condensation was sti ll visible. I t is worth mentio ning that anti-mist
are chemica ls th at a bsorb water and spread it throughout the coated surf ace. This keeps water
droplets from bec omin g big enough to be visible as condensation.
3.4. Evolution of volatile organic compounds
A total of 8 secondar y VOCs were detected at the end of storage da y 14 in the different
packaging conditions (Table 4). Th e development of acetaldehyde, a cetone, and ethy l acetate
are well known to be a result of fermentative metabolism (N ielsen and L euf v én, 2008).
Ethanol was below detection limit on day 0. T he other fermentative volatil es were detected a t
low concentrations already on da y 0, but further a ccumulated during the storage of th e
strawberries. Strawberries ke pt on the control pa c kage had the highest tissue a ccumulation of
ethanol, which indic ated that anaerobic respiration was tri ggered. Th e i ncrease in ethanol
concentration can be ass ociated with the critical gas composition of 45% CO 2 measured on
day 14 of storage. High CO 2 conce ntration could result in the disruption o f enzyme a ctivities
such as the li pox yge n ase pathwa y (Giuggioli, Briano, Baudino, & Peano, 2015). The
production of ethanol and esters v aried according to the different modified atmosphere
conditions. The influence of headspace ga s composition on the ac cumulation of alcohols and
further s y nthesis of esters was reported b y Giu ggioli et al. (2015) and Bela y , C aleb, and
Opara (2017).
Moreover, the str awberries reacted in a different manner to the packaging s y stem conditions.
Similar results were found by Nielsen and Leufvén, (2008). Authors pointed out that there can
be large differences between stra wberr y cultivars, espe ciall y with regard to the aroma

development. Their stud y indicated that storage in a modified atmosphere a ffected negatively
the aroma dev elopment in Korona strawberries; however, the aroma production in Honeoye
was not affected in a sim ilar manner. Furthermore , what can be observed fr om these r esults is
that the traditional ph y sico and chemical properties from strawberries had very little changes
within the 14 days of storage comp ared to the e missi on of VOCs and the development of off -
odour. Thus, this stud y indicates that the investigation of off-odour durin g storage can serv e
as a better indicator of pr oduct quality.
4. Conclusion
The overall results indi cated that th e modified atmosphere and humid it y conditions were
capable o f preventing condensation when the window was cov ered w ith films with high
permeability to water vapour . Therefore, the conc ept of such packaging s ystem equipped with
a control window represents an innovative approach to minimiz e the risk of moisture
condensation. Mor eover, this study sho wed that the fixed window with micro-perforations
was capable of preventing anoxic conditions. Furthermore, the tr aditional qualit y p arameter
detected no significant changes in packaged strawberries, how ever, the e volution of volatile
organic compounds in the package headspace s howed significant changes during stora ge.
Therefore, the inv estigation o f off-odour by GC- MS served as a better e arl y indi cator of the
product quality during storage wh en compared to the traditional qualit y parameters (pH, TA,
and TSS). Further studie s are needed to elu cidate the per formance of such packaging s ystem
under fluctuating temperature conditions, which normall y occurs during the lon g distance
supply chain of fresh produce. M easuring actual relative humidit y inside the package
headspace will also be helpful to understand the d y namics of mois ture evolution an d
condensation on differe nt parts of the package.
Acknowledgement
This work was supported b y Conselho Nacional de Desenvolvimento Científico e
Tecnológico (CNPq) thr ough a PhD grant (201623/2015 -3). The Georg Forster Postdoctoral
Researc h Fellowship (H ERMES ) programme from the Alex ander von Humbol dt Founda tion
(Ref. ZAF – 1160635 – GFHERMES – P ) is also apprec iated.

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Figure 1. Chang es in heads pace gas composition f or packaged strawberri es seale d with fixed window
of (a) Polypropyl ene based Pro pafil m (PP), (b) NatureF lex (NF), and (c) Xt end fil ms (XT).
0 2 4 6 8 10 12 14
0
3
6
9
12
15
18
21 PP33 O2 PP66 O2 PP100 O2
PP33 CO2 PP66 CO2 PP100 CO2

0 2 4 6 8 10 12 14
0
3
6
9
12
15
18
21
Gas composition (kPa)

NF33 O2

NF66 O2

NF100 O2

NF33 CO2

NF66 CO2

NF100 CO2

0 2 4 6 8 10 12 14
0
3
6
9
12
15
18
21

XT33 O2

XT66 O2

XT100 O2

XT33 CO2

XT66 CO2

XT100 CO2

(a)

(b)

(c)

Figure 2. Visual do cumenta tio n of lid and film condens ation after 14 days of storag e.

Figure 3. Mass l oss of stra wberry and in-package con densation during the storage period of 14 days
at 5 °C. *The v alues in bracket r epresent the perc entage strawberry mass loss.

02468 10 12
Control
PP33
PP66
PP100
XT33
XT66
XT100
NF33
NF66
NF100
Mass loss, g
Mass loss of strawberries Free wat er/condensed water Water l oss over film

(1.46 %)
(1.04 %)
(0.57 %)
(0.27 %)
(0.20 %)
(0.23 %)
(0.26 %)
(0.23 %)
(0.41 %)
(0.20 %)

Figure 4. Changes in visua l q uality attributes of p ack aged strawberries and observed water
vapour condensation on the humid ity window after 14 days of storag e at 5 °C .

1
2
3
4
5
PP33
PP66
PP100
NF33
NF66
NF100
XT33
XT66
XT100
Contr ol
Decay Odor Texture Humidity wi ndow conde nsation

Table 1. Packaging f ilms used and window sizes designe d for the stora ge containers.
Sample

Packaging film

Window size

% of lid
area

Area of
window (cm 2 )

Control

Pol y prop y lene lid
without perfora tion

-

-

PP33

Propafilm *

33

69

PP66

Propafilm *

66

126.5

PP100

Propafilm *

100

195.5

XT33

Xtend *

33

69

XT66

Xtend *

66

126.5

XT100

Xtend *

100

195.5

NF33

NatureFlex *

33

69

NF66

NatureFlex *

66

126.5

NF100

NatureFlex *

100

195.5

* With 2 micro-perf or ations of 0.7 mm

Table 2. Qualit y scores and descriptors for strawberr y
1

Descriptors

Scores and des cription

Reference

1

2

3

4

5

*Humidity
windo w
condensation

Hum idit y window i s
extensively cov ered
with wate r vapour

Hum idit y window i s
partially cov ered with
water v apour ≥ 50 %

Hum idit y window i s
partially cov ered with
water v apour ≤ 50 %

Hum idit y window is
partially cov ered with
water v apour ≤ 25 %

Hum idit y window i s
completely free of water
vapour condensa tion

Rux, Caleb,
Geyer, and
Mahajan
(2017)

Texture

Very poor ( fr ui t are
extrem ely soft)

Poor (frui t are very soft)

Fair (fru it exhibi t minor
signs of sof tness)

Good (fruit a re firm)

Very g ood (fruit are
firm and turg id)

(M. C. N.
Nunes,
Em ond, &
Brecht,
2003)

Odour

Dislike v ery much

Dislike m oderately

Neither lik e nor dislike

Like m oderately

Like v ery much

-

Decay

76- 100 %
decay(extr eme
decay/com pletely
rotten)

51- 75 % decay (moderate
to severe decay )

26- 50% decay (spots with
dec ay )

1- 25 % decay
(probable de cay)

0 % decay (no d ecay)

(Rux et al.,
2017)

* Adapted from other studi es

2

3

4

5

6

7

8

9

10

11

12

13

14

Table 3. Volatile organic compounds of stra wb erries stored for 14 days at 5 °C (mean values ( n = 3) ± standard deviation).
15

Volatiles (m g/mL)

RT

K-RI
Est.

K-RI
Lit.

Day 0

Day 14

Control

PP33

PP66

PP100

XT33

XT66

XT100

NF33

NF66

NF100

Acetaldehyd e

4.28

540

518

0.03 d

0.25 ± 0.01 a

0.1 ± 0.01 b

0.09 ± 0.06 b

0.03 ± 0.01 d

0.06 ± 0.001 c

0.12 ± 0.03 b

0.04 ± 0.00 d

0.04 ± 0.02 cd

0.07 ± 0.00 c

0.10 ± 0.01 b

Ethanol

5.41

602

668

nd

1.98 ± 0.08 a

0.29 ± 0.03 b

0.06 ± 0.004 c

0.05 ± 0.00 c

0.02 ± 0.00 d

0.02 ± 0.00 d

0.03 ± 0.00 d

0.18 ± 0.06 b

0.07 ± 0.01 c

0.02 ± 0.00 d

Acetone

6.03

660

455

0.66 a

0.02 ± 0.01 c

0.09 ± 0.002 b

0.10 ± 0.03 b

0.08 ± 0.003 b

0.10 ± 0.02 b

0.09 ± 0.02 b

0.04 ± 0.00 c

0.08 ± 0.01 b

0.09 ± 0.01 b

0.09 ± 0.00 b

Acetic acid, methyl
ester

6.48

554

487

0.001 e

0.06 ± 0.002 c

0.10 ± 0.04 a

0.02 ± 0.00 d

0.17 ± 0.06 a

0.10 ± 0.04 a

0.16 ± 0.08 a

0.18 ± 0.04 a

0.09 ± 0.05 a bc

0.12 ± 0.004 b

0.18 ± 0.01 a

Ethyl Aceta te

8.76

632

628

0.002 f

1.60 ± 0.07 a

1.52 ± 0.50 a

0.33 ± 0.03 b

0.97 ± 0.06 a

0.13 ± 0.02 d

0.17 ± 0.00 c

0.06 ± 0.00 e

1.12 ± 0.54 a

0.04 ± 0.01 e

0.33 ± 0.05 b

Butanoic acid, ethyl
ester

15.15

836

785

nd

0.06 ± 0.01

nd

nd

nd

nd

nd

nd

nd

nd

nd

Butanoic acid, 2 -
methyl-, ethyl ester

16.35

919

820

nd

0.03 ± 0.002

nd

nd

nd

nd

nd

nd

nd

nd

nd

Hexanoic a ci d, ethyl
ester

19.47

1157

984

nd

0.03 ± 0.02

nd

nd

nd

nd

nd

nd

nd

nd

nd

Mean value ± standard dev iat ion in th e same row with different lower ca se superscripts are significan tl y di ff erent bas ed on Duncan (Pos t - hoc test) at p ≤ 0.05.
16

nd: implies that volatile wa s below detection limit/ not dete cted; K -RI : kovats retention ind ex Est. (estimated ) and Lit. (based on literature)
17

18

19

20

21

22

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