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Abstract

Use of fresh-cut vegetables has increased and new technologies have been applied to preserve the quality during transportation and storage. The aim was to investigate the colour changes during storage of fresh-cut rocket, chicory and Swiss chard leafy vegetables during storage at 4-5°C with or without light (150 µmol m -2 s -1 light intensity per 12 h). Moreover, the effect of wash treatments (water or 150 mg L -1 citric acid, applied at the harvesting time) on colour changes was evaluated. During the experimental period of 12 days the colour changes were monitored by the variations of total chlorophyll, carotenoids and anthocyanins. The potential browning development was assessed by polyphenol measurements. Rocket and chicory stored in light conditions showed leaf yellowing after 4 days, while Swiss chard was affected after 8 days of light storage. On the contrary, dark storage preserved better the visual appearance of the minimally processed leafy vegetables tested. The carotenoids declined after 8 days of storage in all treatments and species used. At the end of the experiment the carotenoids reduction was in average 37-47% respect the initial value. Anthocyanins declined in light stored rocket but did not change in other species or treatments. Total polyphenols did not change during storage in all species tested.
40 Journal of Food, Agriculture & Environment, Vol.2 (3&4), August&December 2004
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Journal of Food, Agriculture & Environment Vol.2 (3&4) : 40-44. 2004
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Science and Technology
Colour changes of fresh-cut leafy vegetables during storage
A. Ferrante1*, L. Incrocci2, R. Maggini2, G. Serra3 and F.Tognoni2
1Dipartimento Produzione Vegetale, University of Milan, Via Celoria, 2 CAP 20133 , Milan, Italy,2Dipartimento Biologia delle
Piante Agrarie, University of Pisa, Pisa, Italy. 3Scuola Superiore S. Anna – Pisa, Italy. * e-mail: antonio.ferrante@unimi.it
Received 12 July 2004, accepted 11 October 2004.
Abstract
Use of fresh-cut vegetables has increased and new technologies have been applied to preserve the quality during transportation and storage. The aim
was to investigate the colour changes during storage of fresh-cut rocket, chicory and Swiss chard leafy vegetables during storage at 4-5°C with or
without light (150 µmol m-2 s-1 light intensity per 12 h). Moreover, the effect of wash treatments (water or 150 mg L-1 citric acid, applied at the
harvesting time) on colour changes was evaluated. During the experimental period of 12 days the colour changes were monitored by the variations of
total chlorophyll, carotenoids and anthocyanins. The potential browning development was assessed by polyphenol measurements. Rocket and
chicory stored in light conditions showed leaf yellowing after 4 days, while Swiss chard was affected after 8 days of light storage. On the contrary,
dark storage preserved better the visual appearance of the minimally processed leafy vegetables tested. The carotenoids declined after 8 days of
storage in all treatments and species used. At the end of the experiment the carotenoids reduction was in average 37-47% respect the initial value.
Anthocyanins declined in light stored rocket but did not change in other species or treatments. Total polyphenols did not change during storage in all
species tested.
Key words: Colour change, chicory, chlorophyll, carotenoids, rocket, Swiss chard, visual appearance.
Introduction
The market of fresh-cut minimally processed or “ready to eat”
leafy vegetables has been exponentially increasing in the recent
years. The processes involved to prepare minimally processed
leafy vegetables, such as grading, chopping and packaging lead
to many postharvest disorders1. These disorders affect internal
and external quality, mainly the appearance of vegetables. The
visual appearance of leafy vegetables is very important to be
attractive for consumers and also for wholesalers and retailers.
The visual appearance of fresh-cut vegetables may include colour,
size of chopped leaves and absence of damages, defects or
microbial contaminations2-4. However the visual appearance
should be correlated with the taste and aroma, otherwise the
consumer is not satisfied and will not purchase that product again.
The colour is an important quality index and should be preserved
until the vegetable is sold.
The green colour of leafy vegetables depends on many factors
and when it is lost the browning and chlorophyll and carotenoids
degradation takes place. Browning of chopped surfaces is
aesthetically unattractive and is due to oxidative reactions of
phenolic compounds by polyphenol oxidase, which produces
ο-quinones to various polymerized products 5. The catabolism of
leaf pigments is tightly connected with storage conditions. Low
temperatures usually slow down all leaf metabolisms preserving
the quality. Colour changes might be due to senescence
processes. The senescence usually leads to leaf yellowing as
observed in Asian leafy vegetables 6. The presence of light may
influence the storage in promoting or preserving the chlorophyll
degradation. Ascorbic and citric acid (CA) have been used to
inhibit enzymatic browning in apples 7.
The colour may be also considered an index for estimating the
antioxidant proprieties of the leafy vegetables. In fact, many
pigments such as carotenoids, anthocyanins and polyphenols
that are involved in the leaf coloration, have been proven to have
antioxidant activity. Our work was focused on the variation of
colour during storage of three fresh-cut vegetables. The colour
change was studied under different storage conditions (light or
darkness) and wash treatments with antioxidant agent (citric acid)
or water. The colour changes during cold storage were determined
by measuring anthocyanins, chlorophyll carotenoids content and
total phenolic compounds.
Materials and Methods
Plant material and growing system: Rocket (Eruca sativa Mill.),
Swiss chard (Beta vulgaris L.) and chicory (Cichorium intybus
L.) were grown in floating hydroponic system. Seeds were directly
sown in trays containing perlite. After emergence all the trays
containing seedlings were placed in floating tanks containing
nutrient solution. Rocket plants were grown in floating systems
with the following nutrient solution (concentrations are expressed
in mM) 13 N-NO3, 1.5 P, 8 K, 3.5 Ca, 1.7 Mg, 9.5 Na, 8.0 Cl, 2.7 S, 0.04
Fe and Hoagland’s concentration for micronutrients.
Treatments: Fresh-cut rocket and Swiss chard were washed with
de-ionized water or 100 mg L-1 citric acid (CA, Sigma) and slightly
dried prior storage. Fresh-cut rocket and Swiss chard were stored
at 5°C in darkness or under 150 µmol m-2 s-1 light intensity with 12
h photoperiod.
Measurements: During storage chlorophyll, carotenoids,
anthocyanins and phenolic compounds were measured. Sampling
was performed at 0, 4, 8 and 12 days. Chlorophyll and carotenoids
were extracted using methanol 99.9% as solvent. Samples were
Journal of Food, Agriculture & Environment, Vol.2 (3&4), August&December 2004 41
kept in dark cold room at 4°C for 24 hours. Quantitative chlorophyll
determinations were carried out immediately after extraction.
Absorbance readings were measured at 665.2 and 652.4 nm for
chlorophyll pigments and 470 nm for total carotenoids. Chlorophyll
and carotenoid concentrations were calculated by Lichtenthaler’s
formula 8.
Anthocyanins content were determined spectrophotometrically.
Samples of the frozen tissue (100 mg) were ground in pre-chilled
mortar and were extracted into methanolic HCl (1%).
Samples were incubated overnight at 4°C in darkness. The
concentration of cyanidin-3-glucoside equivalents was determined
spectrophotometrically at 535 nm 9. The sampling was carried out
at 0, 4, 8 and 12 days. Visual appearance was determined by daily
observation of chopped leafy vegetables during storage.
Polyphenols in leaf tissue were determined
spectrophotometrically following two different approaches: the
direct measurement of the leaf extract absorbance at 320 nm and
the Folin-Ciocalteu method 10. Analyses have been performed
immediately after sampling or within three days. In the latter case,
the samples have been stored at –18°C. Treatment of samples and
absorbance measurements were carried out at room temperature.
About 0.1 g of leaf tissue (3 replicates for each treatment) was
weighed and homogenized with 10 mL methanol. The homogenate
was centrifuged at 3000 g for 15 minutes. The supernatant
(methanol and polyphenols) was collected without further
treatment and its absorbance at 320 nm was measured at room
temperature immediately after centrifugation using pure methanol
as reference solution. The absorbance value was steady since
less than 1% change was observed after keeping the extract at
+4°C overnight. Using Folin-Ciocalteu method the supernatant,
200 µL methanol extract, was added to 800 µL buffer containing
7.5% (w/v) Na2CO3 and 1.0 mL Folin-Ciocalteu reagent. Absorbance
readings were taken half an hour later at 765 nm. The solution
used as reference was the buffer with 200 µL deionised water
instead of plant extract.
Statistical analysis: The data were subjected to two-way analysis
of variance and the differences among treatments were analyzed
by Bonferroni post-test (P < 0.05). The data are reported in figures
and tables as means with standard errors. Each treatment
composed of 3 replicate storage boxes and three samples for each
box were used for measurements.
Results
Chlorophyll, carotenoids and anthocyanins: The fresh-cut rocket
was stored in dark and light conditions for 12 days. Rocket leaves
stored at 4-5°C for 4 days did not show any significant differences
in colour between the two storage conditions (Fig. 1). After 8
days the fresh-cut rocket stored in light showed a strong leaf
yellowing, while in darkness the colour slightly changed. The
light affected the leaf pigments and the visual appearance during
storage as soon as after 8 days, therefore the economic value of
the produce was already compromised. The chlorophyll content
in fresh-cut rocket at the harvest time was in average 1.2 mg g-1 of
FW and decreased by 50% up to reach the 0.6 mg g-1 at the end of
the storage period (Fig. 1). The wash treatment with citric acid
(CA) did not have any effect in preventing chlorophyll degradation
during light storage (Fig. 1). On the contrary the rocket treated or
untreated with CA stored in darkness did not show any symptom
of chlorophyll degradation. In fact, the amount of total chlorophyll
per g of fresh weight remained unchanged from the beginning
of experiment until the end of the storage period (12 days). Total
carotenoids had the same trend observed for chlorophyll
degradation in both storage conditions (Fig. 2).
Swiss chard stored in light showed analogous results to
fresh-cut rocket stored in light. On the contrary, Swiss chard
stored at 5°C in darkness showed chlorophyll and carotenoids
reduction during storage. After 12 days of storage the total
chlorophyll was reduced by 43% and 37% respectively in Swiss
chard washed with water or CA (Table 1). No significant
differences were found between the washing treatments.
Carotenoids declined in both washing treatments by 33% and
26% using water or CA, respectively (Table 1).
Figure 1. Total chlorophyll content during cold storage (4°C) of chopped rocket stored
at light or dark condition, washed with water or citric acid.
LW (light water) light stored of chopped rocket washed with distilled water,
DW dark stored of chopped rocket washed with distilled water,
LCA chopped rocket stored in light and washed with citric acid,
DCA chopped rocket stored in darkness and washed with citric acid.
Values are the means ± standard errors. Data were subjected to two-ways ANOVA and
different letters mean that values are statistically different P<0.05.
0
10
20
30
40
50
60
70
80
04812
Storage time (days)
Carotenoids (mg g
-1
)
LW LCA
DW DCA
Figure 2. Total carotenoids degradation during cold storage (4°C) of fresh-cut rocket
stored in light or darkness, washed with water or citric acid.
LW light stored of fresh-cut rocket washed with distilled water,
DW dark stored of chopped rocket washed with distilled water,
LCA fresh-cut rocket stored in light and washed with citric acid,
DCA fresh-cut rocket stored in darkness and washed with citric acid.
Values are the means ± standard errors. Data were subjected to two-ways ANOVA, no
significant differences were found.
42 Journal of Food, Agriculture & Environment, Vol.2 (3&4), August&December 2004
On the contrary, fresh-cut chicory showed analogous results
of dark stored rocket (Table 2). In fact, no significant chlorophyll
degradation was observed during storage, while carotenoids
content significantly decreased respect to the initial value in both
treatments by 38% and 23% using water or CA, respectively (Table
2). However the washing treatment using CA had an overall
positive effect in preserving the visual appearance of all three
leafy vegetables, although the differences were not statistically
different.
Anthocyanins content expressed as cyanidin-3-glucoside
declined after 4 days of storage in light conditions, while no
significant differences were found in fresh-cut rocket stored in
darkness (Fig. 3). Anthocyanins concentration of fresh-cut Swiss
chard stored in light slightly increased but decreased in darkness
(Fig. 4). Chicory did not show significant variation of anthocyanins
in all treatments performed (data not shown).
Phenolic compounds: The methods used for polyphenols
determination are both spectrophotometric, nevertheless they
require different procedures and measurements at different
wavelengths. The results obtained with the two methods are in
very good agreement, showing no meaningful variation in
polyphenols content within 12 days from harvest, in any of the
different treatments. The polyphenols were only determined in
rocket (Table 3) and Swiss chard (Table 4) washed with deionised
water.
Discussion
The colour change is the first visible symptom of senescence in
many horticultural crops and may compromise their economic
value. Consumers usually purchase a fresh produce driven by
their visual appearance, while other components of quality such
as texture and aroma make the consumers to re-purchase again
the same produce the next time11. Inadequate storage conditions
may negatively affect the produce quality. A produce badly stored
may have a good visual appearance but altered taste or aroma.
Consumers that make experience with badly stored vegetables
will hardly buy that product again especially if it can be recognised
by label mark. The consumer will wrongly associate the bad quality
to it. Horticultural crops can be efficiently preserved if their
physiology and senescence processes are well understood. On
the basis of the physiological changes appropriate technologies
can be used for each crop during postharvest life. The optimal
temperature and relative humidity during storage may help to
reduce the degenerative processes that occur during the
postharvest stages11. Our work was carried out to understand the
behaviour of the three leafy vegetables during the hypothetical
storage period of 12 days. It is a long time storage considering
that the most part of produces must be usually sold within 6 days
after storage. However, the selling period varies from species to
species and from cultivars to cultivars. In fact, the shelf-life of
fresh-cut vegetables usually ranges from 7 to 14 days 12.
Table 1. Total chlorophyll and carotenoids in minimally processed Swiss chard leafy vegetables during darkness storage at 4-5°C for 12 days.
Chlorophyll (mg g
-1
) Carotenoids (mg g
-1
) Time (days)
Water Citric acid Water Citric Acid
0 1.36±0.11 1.36±0.11 55.86±3.48 55.86±3.48
4 1.23±0.06 1.06±0.26 41.18±7.84 52.98±9.12
8 0.78±0.05 0.87±0.10 33.96±2.25 37.94±4.59
12 0.86±0.14 0.94±0.10 38.12±5.55 41.55±3.72
Source of variation % of total variation P value % of total variation P value
Interaction 3.41 0.7380 ns 2.41 0.777 ns
Treatments 0 0.9961 ns 0.08 0.8521 ns
Time 53.75 0.0039** 62.62 0.0007***
The values are means with standard errors. Data were subjected to two-ways ANOVA, P< 0.01 **, P<0.001***.
Table 2. Total chlorophyll and carotenoids in minimally processed chicory leafy vegetables during dark storage at 4-5°C for 12 days.
The values are means with standard errors. Data were subje cted to two-ways ANOVA, P< 0.01 **, P<0.001***.
Chlorophyll (mg g-1) Carotenoids (mg g-1) Time (days)
Water Citric acid Water Citric Acid
0 0.93r0.07 0.93r0.07 50.38r2.59 50.38r2.59
4 0.92r0.07 1.07r0.10 47.11r1.69 50.77r4.28
8 0.93r0.04 0.96r0.05 40.87r1.56 43.23r1.01
12 0.76r0.08 0.87r0.02 31.52r3.33 39.01r0.73
Source of
variation
% of total variation P value % of total variation P value
Interaction 5.59 0.6671 ns 4.12 0.5027 ns
Treatments 8.30 0.2161 ns 6.39 0.1476ns
Time 28.86 0.0882 ns 61.65 0.0005***
Table 3. Total polyphenols measured as absorbances at 320 nm (methanol
extract) and 765 nm (Folin-Ciocalteu method) of cut leafy rocket stored in
light or darkness.
ABS (320 nm) ABS (765 nm) Time
(days) Light Dark Light Dark
0 6.24r1.91 6.24r1.91 0.57r0.29 0.57r0.29
4 5.48r1.58 4.49r0.98 0.56r0.28 0.40r0.13
8 5.66r1.07 5.59r2.16 0.79r0.41 0.41r0.20
12 6.71r1.67 3.62r0.78 0.74r0.23 0.26r0.10
The values are means with standard errors. Data were subjected to two-wa ys ANOVA, no significant differences were found.
Table 4. Total polyphenols measured as absorbances at 320 nm (methanol
extract) and 765 nm (Folin-Ciocalteu method) of cut leafy Swiss chard
stored in light or darkness.
ABS (320 nm) ABS (765 nm) Time
(days) Light Dark Light Dark
0 8.27r0.20 8.27r0.20 0.32r0.03 0.32r0.03
4 5.95r1.68 3.19r1.67 0.54r0.44 0.27r0.13
8 9.80r1.75 10.19r1.36 0.42r0.16 0.40r0.08
12 4.18r3.61 3.06r1.17 0.44r0.14 0.23r0.05
The values are means with standard errors. Data were subjected to two-ways ANOVA, no significant differences were found.
Journal of Food, Agriculture & Environment, Vol.2 (3&4), August&December 2004 43
Results show that light increases the degradation rate of
chlorophyll in all fresh-cut vegetables. This phenomenon might
be due to carotenoids degradation that unprotects the chlorophyll
from the light, which bleaches the chlorophyll pigments 13. In fact
the chlorophyll degradation did not occur in darkness even if
carotenoids decreased as in light conditions (Fig. 2). The
explanation may be found considering the action and proprieties
of chlorophyllase, which degrades the chlorophyll pigments. It
has been demonstrated that chlorophyllase is located in
the envelope membrane of chloroplast. This means that
chlorophyllase is separated spatially from chlorophyll14 and does
not come into contact with it until membranes are degraded.
Therefore the chlorophyllase activity should be correlated to
disruption of membranes.
Carotenoids, anthocyanins and polyphenols are involved in
leaf coloration but are also very important for the human health,
because of their antioxidant proprieties. These compounds are
also called phytonutrients and have been gaining importance in
the human diet. In particular, carotenoids are considered potent
antioxidants that may help to prevent age-related diseases 15, 16.
Figure 3. Anthocyanin (cyanidin-3-glucoside) content during cold storage (4°C) of
fresh-cut rocket stored in light or darkness for 12 days. The values are means with
standard errors. Data were subjected to two-ways ANOVA, no significant differences
were found.
Figure 4. Anthocyanin (cyanidin-3-glucoside) content during cold storage (4°C)
of fresh-cut Swiss chard stored in light or darkness for 12 days. The values are
means with standard errors. Data were subjected to two-ways ANOVA, no significant
differences were found.
Total carotenoids of fresh-cut vegetables tested were not stable
during storage and declined with time. The reduction of total
carotenoids corresponds a decrease of the antioxidant ability of
the produces. Our results suggest that fresh-cut vegetables should
be utilized within 4 days for getting benefit from their antioxidant
proprieties.
The anthocyanins do not respond to low temperatures and
light even if several cold genes are involved in the biosynthesis.
The lack of response may be due to wounds that affect the plant
metabolism machinery. In fact, rocket leaves stored without being
chopped showed an increase of anthocyanins (data not shown).
The wash treatment with CA did not affect the colour changes
even if slightly reduced the carotenoids degradation. The CA is
used as food additive because of its inhibitory effect on the
polyphenol oxidase, an enzyme responsible for enzymatic
browning in many fruits and vegetables 7, 17, 18. We did not find
any browning spots even in untreated leafy vegetables
suggesting that these species maybe already have enough
antioxidant compounds that work as endogenous inhibitors of
the polyphenol oxidase19. This hypothesis could fit with our
results, because the phenolic compounds did not change in
fresh-cut vegetables with time. In fact, it has been observed that
browning is associated with an increase of phenolic compounds
during the first 48 h and then slowly declines10. However, the
values of ABS320 in fresh-cut rocket and Swiss chard were 3-6
folds higher than those of lettuce 10. This high amount of phenolic
compounds may also play an inhibitory effect on the browning
appearance.
In conclusion the results showed that the rocket, chicory and
Swiss chard do not need prestorage antioxidant treatments and
the dark storage should be preferred. Further investigations
should be carried out to identify the optimum light intensity
threshold that does not compromise the leafy vegetable quality.
Perhaps a combined study considering the light intensity and
temperatures may be useful to create a chart for the best storage
conditions for each crop that may be sold as fresh-cut leafy
vegetable.
Acknowledgements
This work was supported by the Italian Government (MIUR)
throughout the project entitled “The management of closed
soilless growing systems: adaptability, optimisation and control
in Mediterranean areas for flowers and vegetables.”: paper n° 13.
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... Hence, fluorescent lamps are one of the artificial sources that can generate UV light (Tamuri et al., 2014). The effect of postharvest illumination by fluorescent light at various intensities and photoperiods has been studied on the quality and physiology of fresh vegetables (Büchert, Lobato, Villarreal, Civello, & Martínez, 2010;Costa, Montano, Carri on, Rolny, & Guiamet, 2013;Ferrante, Incrocci, Maggini, Serra, & Tognoni, 2004;Glowacz, Mogren, Reade, Cobb, & Monaghan, 2014;Lester, Makus, & Hodges, 2010;Liu et al., 2015;Martínez-Sánchez et al., 2011;Noichinda, Bodhipadma, Mahamontri, Narongruk, & Ketsa, 2007; Olarte, Toledo, Ueda, Imahori, & Ayaki, 2003;Witkowska, 2013;Zhan et al., 2013;Zhan, Li, Hu, Pang, & Fan, 2012). Besides, among the emerging approaches, UV hormesis has got the attention as it can both control the development of disease and delay senescence in green vegetables such as broccoli (Aiamla-Or, Kaewsuksaeng, Shigyo, & Yamauchi, 2010;Charles, Goulet, & Arul, 2008;Costa, Vicente, Civello, Chaves, & Martínez, 2006). ...
... Senescence of fruits and vegetables is an irreversible process that involves a series of biochemical, physiological (Glowacz et al., 2014), and metabolic changes, accompanied by a decline in nutrition and flavor, color, and shelf life (Xu et al., 2019). The loss of green color or appearing yellowing in the tissues (Ferrante et al., 2004;, an increase in reactive oxygen species, and tissue breakdown include in these processes (Glowacz et al., 2014). The green color is a critically important attribute in most leafy vegetables (Glowacz et al., 2014). ...
... The green color is a critically important attribute in most leafy vegetables (Glowacz et al., 2014). The loss of the green color is perceived by consumers as a symptom of senescence (Ferrante et al., 2004;Koukounaras, Siomos, & Sfakiotakis, 2009) and will result in reducing marketability (Glowacz et al., 2014). The yellowing due to senescence leads to the loss of the nutritional value of green vegetables as well . ...
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Postharvest illumination is an emerging nonthermal preservation technique used to preserve the quality of vegetables. This review aimed to provide an insight into the effect, importance, and limitations of postharvest illumination by fluorescent and ultraviolet (UV) light on the physical and nutraceutical properties of vegetables. It presents the current information on the postharvest application of these two lightings based on the vegetable species. According to the existing studies, both photoperiod and continuous (low-intensity) fluorescent lighting treatments were beneficial more toward preserving the quality (delaying senescence and deterioration) of postharvest vegetables, mainly leafy vegetables. However, inconsistent results are also possible with the light quality (intensity and duration) on the postharvest fluorescent lighting treatment. According to gathered information, both UV-B and UV-C postharvest irradiation has been beneficial in delaying senescence and chlorophyll degradation and inducing bioactive compounds accumulation in some vegetable species. UV-C application is appeared to have a relatively steady effect on the postharvest storage of vegetables. But UV-B irradiation effect on the postharvest quality of vegetables was appeared to be dose dependent and not stable. In conclusion, it is important to consider vegetable (species, cultivar, harvesting age, and intact or fresh-cut), previous treatments/conditions, optimum postharvest lighting condition (illumination source, dose, intensity, and duration), and the storage condition (temperature and relative humidity) for a successful implementation of postharvest illumination. More research is required to explore the postharvest application of fluorescent and UV (UV-A, UV-B, UV-C) irradiation on vegetables. Practical Applications Multiple research approaches have been taken to preserve the postharvest quality of vegetables while minimizing chemical preservation techniques. Postharvest illumination is a nonchemical preservation technique that has attained more interest due to the advantages it holds, such as being highly efficient and residue-free. Fluorescent and UV lighting on harvested leafy and non-leafy vegetables are beneficial in delaying senescence and chlorophyll degradation, preserving nutritional quality, and extending the shelf life. With the accessibility of more research data and innovative strategies, the future of postharvest illumination of fluorescent and UV maybe steer toward implementation on commercial scale vegetable production (e.g., during storage and/or transportation).
... Yellowing caused by the destruction of chlorophyll in leafy vegetables is one of the aging processes and the appearance of yellowing means that aging has already begun. This yellowing phenomenon can be controlled by storage conditions [37,38]. Moisture stress, temperature, and the occurrence of ethylene in the initial stage of the decomposition of chlorophyll accelerate the yellowing phenomenon [39]. ...
... It has been reported that bergapten is effective against leukemia, hepatitis, and skin tumors as it has high anti-inflammatory activity. In plants, it shows a rapid increase when under stress conditions such as bacterial infection or drying [37,43,44]. Additionally, in this study, the bergapten of the MPE treatment group was maintained at a higher amount during storage compared to the PE treatment group and showed an increasing pattern in the MPE treatment group from around 15 days of storage, but showed a sharp increase after 25 days of storage particularly when the yellowing phenomenon progressed (Figures 2A and 7A). ...
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In Korea, to prevent the extinction of Glehnia littoralis, a cultivation method to improve productivity is being studied and quality maintenance technology is required after harvest. The objective of this study was to determine the effect of MAP on the postharvest quality of G. littoralis. The control showed a weight loss rate of more than 5% after 3 days of storage and lost its marketability, whereas MAP treatment (PE or MPE) showed a weight loss rate of about 2–3% during storage for more than 30 days. In the control, MDA and electrolyte leakage increased due to chilling injury. The total chlorophyll content was low and remained constant until about 23 days of storage in the PE treatment group and 15 days in the MPE treatment group. Among the phenolic compounds, chlorogenic acid, rutin, isoquercetin, and nicotiflorin were maintained at significantly higher levels in the PE than in the MPE. In addition, bergapten showed a highly significant upward trend in the MPE, especially after 25 days of storage when the yellowing progressed. In conclusion, MAP treatment effectively maintains quality while minimizing lipid peroxidation and maintaining phenolic compounds during low-temperature storage after harvest of G. littoralis.
... Another important quality loss of garden cress leaves is the yellowing resulting from senescence. The postharvest water loss can be delayed by packaging or coating applications, whereas the yellowing caused by chlorophyll degradation cannot be prevented since it is a natural senescence process (Ferrante et al., 2004;Sağlam, 2015). Chlorophyll does not turn into another color pigment during the yellowing process; on the contrary, when chlorophyll breaks down, the yellow pigments already present in the plant become visible (Gross, 1991;Ergün, 2006). ...
... Thus, it indicates that the application of black cumin oil in the form of steam leads to a significant weight loss of samples. It is reported that the most important quality loss in cress leaves after harvest was shrinkage due to water loss, and this loss can be reduced by packaging or coating applications (Ferrante et al., 2004;Sağlam, 2015). However, no literature was found on the effect of black cumin oil vapor on the weight loss of garden cress leaves. ...
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Purpose: In this study, the effect of different concentrations of black cumin oil vapor on the quality of garden cress leaves during postharvest storage was investigated. Research Method: Three different doses of black cumin oil vapor including 11.4 ppm (CO1); 22.7 ppm (CO2) and 45.5 ppm (CO3) were used to treat garden cress leaf. The samples only water vapor-treated were taken as control (C). After the treatments, the samples were stored in a cold room set at 2±1 o C temperature and 85-90% RH for 15 days. Color values, chlorophyll content, chlorophyll SPAD, electrolyte leakage, and weight loss were determined at three days intervals during storage. Findings: The results of the study have shown that the black cumin oil vapor treatment maintained the green color and increased chlorophyll content of the garden cress leaves. According to these results, it was also found that 22.7 ppm and 45.5 ppm concentrations were more effective than an 11.4 ppm dose. Originality/Value: According to the results, the black cumin oil treatments, especially high doses, have been successful in preventing chlorophyll losses. It is concluded that spraying the black cumin vapor to garden cress before marketing will extend the storage life of garden cress leaves.
... The data showed that chl a degraded faster than chl b in all cases. These results were in accordance with previous experiments (Ferrente et al, 2004;Negi & Roy, 2000;ŽnidarČiČ et al., 2011). The ratio chl a/b (2.62) was similar to the values reported for other dark green leafy vegetables (Schwartz & Von Elbe, 1983). ...
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Purpose: The aim of this study was to investigate the effects of ambient temperature storage condition (27-29 °C) and domestic cooking on contents of carotenoids, chlorophylls, vitamins and minerals in the leaves of Gnetum africanum. Research method: Carotenoids were separated and analyzed by HPLC. Total-carotene content, vitamins and minerals were assessed spectrophotometrically. Main findings: Results indicated that G. africanum was rich in lutein (528.87 μg g-1 (dry weight basis) and total β-carotene (248.10 μg g-1). There was no statistical increase in total β-carotene content due to cooking, but there was a decrease due to storage. Total β-carotene isomerized more during thermal processing than in storage. Cooking decreased (p>0.05) the contents of chlorophylls, water soluble vitamins and minerals. Cooking and storage of G. africanum resulted in significant losses in ascorbic acid, riboflavin and niacin. Cooking also reduced the potassium, calcium, magnesium and zinc. Iron contents of cooked and stored samples were higher than that of the raw sample. Research limitations: We had to travel over 600 km to use facilities for carotenoid analysis. Originality/value: The concentrations of lutein, β-carotene and certain micronutrients in G. africanum are much higher than typical contents in conventional edible leafy vegetables. The results of this study therefore provide evidence that G. africanum leaf could be an important contributor for improving the nutritional status of rural and urban people.
... It has previously been reported that the chlorophyll content decreased three times slower at 4 • C than at environmental temperatures, when it decreased by almost half in the first few days after harvest [58]. The reduction in chlorophyll content during storage has been reported in leafy vegetables, such as rocket, chicory, and Swiss chard [61], with a consequent loss of market quality, since greenness is one of the main qualities valued by consumers. ...
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The iodine (I) and selenium (Se) deficiencies affect approximately 30% and 15%, respectively, of the global population. The biofortification of vegetables is a valid way to increase the intake of iodine and selenium through the diet. This study was carried out on baby-leaf lettuce to investigate the effects on plant growth, leaf quality, and leaf I and Se accumulation of adding potassium iodide and sodium selenate, separately and simultaneously, to the nutrient solution in a floating system and aeroponics. The effect of I and Se biofortification on post-harvest quality of lettuce leaves was also evaluated. Our results evidenced that the Se and I treatments increased the content of the two microelements in lettuce leaves without any negative interactions in the plants, when applied either separately or simultaneously. Both hydroponic systems proved to be suitable for producing Se and/or I enriched lettuce. Biofortification with Se was more effective when performed in aeroponics, whereas I biofortification was more effective in the floating system. Quality of leaves during post-harvest storage was not affected by neither of the treatments. Lettuce leaves enriched with 13 µM Se and 5 µMI could be good dietary sources of Se and I without inducing toxic effects in humans.
... Indeed, it is closely related to photosynthetic potential and plant productivity; it can be used as index to have an idea of the nutrient status of the plant since most of the nitrogen is incorporated in chlorophyll molecules, and it is also responsible for the visual appearance. This aspect is particularly important in leafy vegetables as a quality trait and affecting consumer preferences [52]. In this study, the level of chlorophyll in plants treated with borage extracts did not change significantly. ...
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The efficacy of plant-based biostimulants lays on the extraction of bioactive compounds that can trigger positive biological responses in plants. Their use has been increasing for lowering the production costs, enhance the yield and the stress tolerance, and improve the cropping systems’ sustainability. The aim of this work was to investigate the effect of maceration time on borage extracts, subsequently sprayed on rocket plants hydroponically grown. A preliminary test was also assessed to evaluate the extracts’ effect on seeds germination. Borage leaves and flowers were separated and macerated in the same conditions for different times. The obtained borage extracts were applied two times during the cultivation of rocket plants. The yield was not affected by the treatments, while the quality of leafy vegetables was improved. The results indicated that the flower extracts (FE) were more active than leaf extracts (LE) in stimulating the crop response. Promising results were observed on the nitrate assimilation, with reduced accumulation in the edible and commercial parts. Non-destructive analysis revealed that electron transport rates were significantly higher in treated plants. Biostimulant effects were also confirmed by the lowering of sucrose and sugars content in the treated plants and by a general increment of secondary metabolites.
... It, thus, reduced mitochondrial respiration, effectively preserving value-adding substances and retaining the quality of fresh and fresh packed products (Prange and Lidster 1991, Herppich 2003, Hasperué et al. 2016, Kong et al. 2021. In contrast, higher photon fluxes may increase temperatures inside the packaging and, thus, might even reduce product quality (Ferrante et al. 2004(Ferrante et al. , 2008. But this response seems to be species-specific (Zhan et al. 2012). ...
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Chlorophyll a fluorescence analysis (CFA) has been accepted to study postharvest activity and stability of photosynthesis of vegetables and salad greens, and some fruits. Commercial chlorophyll fluorescence imaging (CFI) systems may provide additional insight into spatial and temporal dynamics of photosynthesis. This yields valuable information on the effects of postharvest handling and processing (sorting, cutting, packaging, etc.) on physiological activity and 'internal quality' of green produce, and its changes. Here, meaning and physiological basics of relevant fluorescence parameters is briefly summarised, while major focus is on recent applications of CFI to evaluate quality and quality maintenance during postharvest handling and minimal processing of fresh fruits and vegetables. CFI is given surprisingly little attention in the monitoring of postharvest quality, although it is suitable for adjusting and/or optimising innovative postharvest techniques. Knowledge of the physiological base and the limit of interpretation is indispensable for meaningful interpretations of results to draw correct consequences.
... As reported in literature, significant genotypic variations were observed for chlorophylls, and the levels can be also influenced by the light conditions [11]. Considering that microgreens are mainly composed by cotyledons, it is evident that lower concentrations of chlorophylls, carotenoids, phenols, and anthocyanins were detected as opposed to baby leaf or adult vegetables of the same species [47,48]. Red basil microgreens reached, in general, the highest levels of phenolic compounds compared to the other species. ...
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The microgreens are innovative products in the horticultural sector. They are appreciated by consumers thanks to their novelty and health-related benefits, having a high antioxidant concentration. This produce can be adopted for indoor production using hydroponic systems. The aim of the present work was to investigate the influence of three growing media (vermiculite, coconut fiber, and jute fabric) on yield and quality parameters of two basil varieties (Green basil—Ocimum basilicum L., Red basil—Ocimum basilicum var. Purpurecsens) and rocket (Eruca sativa Mill.) as microgreens. Microgreens were grown in floating, in a Micro Experimental Growing (MEG®) system equipped with LED lamps, with modulation of both energy and spectra of the light supplied to plants. Results showed high yield, comprised from 2 to 3 kg m−2. Nutritional quality varied among species and higher antioxidant compounds were found in red basil on vermiculite and jute. Coconut fiber allowed the differentiation of crop performance in terms of sucrose and above all nitrate. In particular, our results point out that the choice of the substrate significantly affected the yield, the dry matter percentage and the nitrate concentration of microgreens, while the other qualitative parameters were most influenced by the species.
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The Swedish food system is dependent of transportation due to low self-sufficiency, centralization of the market, and highly variable climatic conditions in Sweden, which hampers local production of crops. In order to realize a "sustainable food system", transportation has to leave -fossil energy based platforms. Transporting goods that depend on a cold chain requires energy not only for the transport itself, but also to maintain the temperature at a level that does not compromise food safety and shelf life. Maximum temperature during transport of temperature-sensitive foodstuffs has been a recurring topic in many branches within the food system. In the present report, we addressed the significance of temperature (4 and 8 °C) during the transport of leafy vegetables for three highly generalized scenarios (200, 400 and 900 km) from a quality and food safety perspective, using Listeria monocytogenes as a model. The study is based on two battery-charging capacities (150 and 350 kW). We show that the charging infrastructure is the most decisive factor influencing shelf-life and food safety. The risk of reduced quality and in particular food safety increases considerably with long driving times at a temperature of 8 °C in the loading compartment.
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Chlorophyllase catalyzes the first step in the catabolic pathway of chlorophyll. It is a constitutive enzyme located in chloroplast membranes. In isolated plastids the hydrolysis of the endogenous chlorophyll does not take place unless the membranes are solubilized in the presence of detergent. The structural latency of chlorophyllase activity appears to be due to the differential locations of substrate and enzyme within the plastids. Envelope membranes prepared from both chloroplasts and gerontoplasts contain chlorophyllase activity. The isolation of envelopes is associated with a marked increase in chlorophyllase activity per unit of protein. Yields of chlorophyllase and of specific envelope markers in the final preparations are similar, suggesting that the enzyme may be located in the envelope. It is hypothesized that the breakdown of chlorophyll during leaf senescence requires a mechanism that mediates the transfer of chlorophyll from the thylakoidal pigment-protein complexes to the sites of catabolic reactions in the envelope.