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“Experience with sweet cherry”
Citation preview
Serie Documentos
Importance of Managing Humidity
and Temperature from Harvest
to Packinghouse
Peter M.A. Toivonen
www.poscosecha.com/es/publicaciones/
Grupo THM
Serie Documentos Humedad en poscosecha
www.poscosecha.com/es/publicaciones/
Grupo THM
2
Importance of Managing Humidity
and Temperature from Harvest to Packinghouse
“Experience with sweet cherry”
Contents
Introduction 3
Experience with sweet cherry 3
References 5
Comercial Information
AgriCoat 9
Agro Technologie 11
Maf Roda Agrobotic 12
Serie Documentos Humedad en poscosecha
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3
Introduction
The time from harvest to delivery of fruits and vegetables to the
packing facility can be the most critical in determining potential quality at
the market place. While focus is placed on cooling or keeping the fruit or
vegetable cool, often little thought is placed on the importance of relative
humidity. Temperature and relative humidity are of equal importance,
particularly for prevention of water loss. We have conducted research over
the years looking at approaches to managing fruit and vegetable
temperature and humidity immediately after harvest and during transport to
the packing facility. The results have been consistent in that quality can be
best maintained only if both humidity and temperature are managed
together and this has be found important for fruits or vegetables that would
be sold as fresh or for processing.
Experience with sweet cherry
The discussion will focus on experience with sweet cherries. In the
past, it was recommended that sweet cherries be covered with wet foam
pads after harvest in the field. However that practice is cumbersome, can
be unreliable and lead to decay problems in the fruit. Others have
suggested in-field hydro-cooling, however that is an expensive approach.
In British Columbia we adapted an inexpensive technology that was
previously developed to cover and protect forest tree seedlings prior to
planting in remote mountainous areas. The reflective tarpaulin (Silvicool
tarp) has been used for several decades by the tree planting industry
(www.bushpro.ca) and we have tested this extensively for use in herbs,
vegetables and tree fruit. We do not specifically endorse this product since
there may be similar products available in other jurisdictions. The tarpaulin
is made in a three layer construction, the inner layer (facing the produce) is
a silvered Mylar™, the core is a standard woven polyethylene tarpaulin
material and the outside is a bright white coating (Photo 1). The result of
covering produce with this tarpaulin is that a condition equivalent to deep
shade in a forest is created (i.e. cool with high humidity).
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Photo 1. Left shows the inner silvered layer facing cherries and outer white layer facing the sun. Note that the tarps are attached to bins at edges with Velcro fasteners. Photo on right shows bin after filling with cherries and prior to
transport to packing house.
Stem browning was one of the most important marketing issues over a
decade ago for sweet cherries. The stems of cherries are long and thin,
having a high surface area to volume ratio. This means that the stems are
much more susceptible to water loss than the fruit which have a low surface
area to volume ratio – i.e. the fruit are almost a perfect round ball shape. In
our initial evaluation of the problem we determined that stem browning was
largely associated with the time from harvest to delivery to the packing
house. Most browning was visible within one day after packing. Covering
the fruit with the Silvicool tarp resulted in the fruit maintaining the fruit
harvest temperature and the humidity quickly rose to 100 percent around
the fruit. In fruit that was uncovered or fruit covered with cardboard or
conventional tarpaulins, the temperature rose steadily until delivery to the
packing house and the humidity declined (Figure 1). Stem browning was
eliminated by covering with the Silvicool tarp (Figure 2) and fruit quality was
also better retained in storage (Photo 2). In work done in Washington State,
it was found that the Silvicool tarp was much more effective at controlling
cherry temperature than the wet foam pads used by some orchards in that
state.
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Figure 1. Cherry core temperature and humidity at 3 inches below the top of the surface of the fruit for cherries covered with a reflective 'Bushpro' tarp or for
uncovered bins held under tree shade.
Figure 2. Stem browning on cherries either uncovered or covered with reflective 'Bushpro' tarp at harvest and either hydro-cooled or air-cooled before storage.
Serie Documentos Humedad en poscosecha
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Photo 3. Visual quality of cherries after 4 weeks storage at 1 ° for fruit left uncovered or covered with reflective 'Bushpro' tarp.
Since cherries are hydro-cooled, there was some thought that perhaps
hydro-cooling could reverse any damage to the stems or fruit by virtue of
“adding water back” to the product (Figure 3). However, in our
experiments we showed that once the water loss had occurred, the injury
caused (particularly for the stems) could not be reversed (Figure 2).
Therefore the adage “an ounce of prevention is worth a pound of cure” is
appropriate to this discussion. It is also worth adding a comment about
the hopes that packaging can help control problems such as stem
browning in sweet cherries, but the reality is that if the fruit are not
protected immediately after harvest and until delivery to the packing
house no sophisticated package will undo this injury. It is essential to
care for the fruit at the harvest stage onward to obtain any incremental
benefit offered by packaging for transport and distribution.
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Figure 4. Stem browning on cherries either uncovered or covered with reflective 'Bushpro' tarp at harvest and either hydro-cooled or air-cooled before storage
Similar benefits have been found with the use of reflective tarps for
blueberries (fresh and processed), broccoli and fresh herbs. Controlling
temperature and humidity at harvest and during transport to the packing
house is a difficult challenge. Product exposure to heat of the sun and low
humidity will cause excessive initial water loss and injury that cannot be
reversed by any subsequent postharvest handling procedure. That initial
water loss and injury results in lost shipping and shelf life potential that is
seen by the buyer and consumer. Use of reflective tarps to prevent solar
heating and to surround the fruit or vegetable with high humidity is an
inexpensive and reliable approach to ensuring maximal shipping and shelf
life potential for almost any fruit or vegetable. The use of reflective tarps is
now a general practice with BC growers who export their sweet cherries
around the world.
References
Joanne Schick, and Peter M.A. Toivonen. 2002. Reflective Tarps at harvest reduce stem
browning and improve fruit quality of cherries during subsequent storage. Postharvest Biology
and Technology 25:117-121.
P.M.A. Toivonen, P.J. Delaquis, S. Stan, and K. Stanich. 2004. The use of reflective tarps
at harvest to improve postharvest quality of blueberries. Canadian Journal of Plant Science
84: 873-875.
Serie Documentos Humedad en poscosecha
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Grupo THM
8
Importance of Managing Humidity
and Temperature from Harvest to Packinghouse
Peter M.A. Toivonen
Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre,
Summerland, British Columbia, Canada V0H 1Z0
Semperfresh, to maintain the quality during storage
and enchance shelf life in sweet cherries
Semperfresh is a sucrose ester based coating used widely in the fruit industry, but particularly on
sweet cherries to maintain quality during storage and enhance shelf life. Semperfresh has been
applied by some of the larger cherry growers/packers in the US and South America for some years,
and now other important cherry producing countries such as Turkey are following the trend.
The coating creates a selectively permeable film that inhibits water loss while allowing gas exchange
between the fruit and its environment. The modified atmosphere created by Semperfresh reduces
weight loss and excess respiration, resulting in firmer cherries with less pitting. Cherry stems stay
greener and softer and are retained by the fruit longer due to greater moisture retention. The product
can be applied by dip tank, flume, drench, or spray application, and can be mixed with all commonly
used fungicides.
Where Modified Atmosphere Packaging (MAP) has been replaced by ‘clamshell’ packaging (non MA),
which now makes up much of the market, the use of Semperfresh has been found to be essential for
maintaining quality. Semperfresh maintains cherry quality in clamshells significantly better than
clamshells alone. Semperfresh has shown benefits similar to MAP in commercial trials. Where the best
fruit is required, Semperfresh can be used in combination with MAP to give an improved quality
product and helps especially in maintaining quality once the product is removed from the MA pack.
Semperfresh plus MAP liners results in fruit quality superior to either method alone.
Trials in collaboration with a UK cherry grower compared untreated and treated Sweetheart variety
cherries destined for supermarket sale.
The objective of this trial was to assess any improvement in quality, particularly during supermarket
shelf life (after removal from MA), which might be achieved through treating cherries with
Semperfresh.
Cherries were picked and transferred the same day to the packing line, where they pass through three
isolated baths or flumes, for washing and hydro-cooling. The final bath was dosed with the
recommended concentration of liquid Semperfresh. Fruit was packed, 6 kg at a time, into MA liners
onto open plastic trays and were transferred to the cold store for a couple of weeks. After a seventeen
day storage period, the fruit was removed from the MA liners and packed into smaller plastic clamshell
punnets (non MA) for sale.
The first chart below gives detail of the samples held in MA box liners for 17 days. The second chart is on fruit that was then held in clamshells for 7 days after the initial 17 days in MAP
(blue, the control; lilac, MAP; clear, MAP + Semperfresh)
The following benefits over and above those seen with MA packaging alone, were observed in
fruit treated with Semperfresh in combination with MA packaging
- Increased shine, which was not lost over time.
- More uniform colour, with fewer very dark fruit, which was maintained after the fruit were
removed from MA.
- Less dehydration after removal from MA.
- Firmer fruit, particularly after removal from MA. 5)Greener stems, particularly after removal
from MA.
Hugh Douglas, Regional Sales Manager. AgriCoat Natureseal Ltd, Mantrose UK Ltd. Granada,
Spain, [email protected], Tel: +44 (0)1488 648988
1 Agro Technologie, a trademark of Apollinaire Ltd
www.agro-technology.co.uk
Agro Technologie – Instruments for cherries
AGROMORPHA®2 is a dendrometer / biomorphographer.
If has 2 functions :
- Register each 10 seconds to each 15 minutes a tree branch
diameter
- Register ambient temperature
For making its photosynthesis, a plant absorbs water through its roots, and
losses water through its sheets. As far as the plant losses more water than it
absorbs, it uses its own reserves. And the size of the cells is decreasing. This
small variation is registered by AGROMORPHA®2
It is a very good toll for agronomic research. You can determine the effect of
watering, or the contribution of a fertilizer.
You have the possibility to follow this diameter continuously during 2 years
without changing the batteries. Then you can determine whether the
growth of the tree, fruit or corn was regular, and whether the plant has
suffered
Advantages compared to existing products :
- Very small
- Battery capacity 2 years (Standard battery to be changed after 2
years)
- Registering capacity 2 years
- You just put a Usb key, and all data is transferred to an Excel file
You do ’t ha e to re o e the syste
- The usb key is automatically detected, and the transfer of data is
automatically made – The data in the internal memory is
automatically deleted
Up to 16 systems can be put in a field, the Excel files on your key have the
numbers 1 to 16
It takes a few seconds to collect the data
AGROSTA®100Field (Durofel) is a portable durometer firstly designed for tomatoes. Many other uses
have been found like firmness measurement of apricots, plums, blueberries, cherries, olives, peppers,
peaches, strawberries... As well as fruits in sugar sirup, jelly... It measures the firmness through a mobile
tip that gives a unit each 0.025 mm (Measurement of the deformation of the fruits when pressed by the
tip) - It is a very accurate device, calibrated through a process defined by the national tests laboratory
The AGROSTA®100Field displays the measurements one after each other without pressing any button.
Data is registered for each batch, and the device gives instantly the average and standard deviation
The latest innovation from the creators of the "DUROFEL"
connected to a tactile console with 32GB memory, the
AGROSTA®100Touchscreen measures the firmness of soft-
skinned and soft fruit. It stores and analyses a huge amount
of data. It is the most technologically advanced instrument
on the market to measure fruit and soft and semi-hard
materials No more manual caliper, no templates.... Your fruits cross the door, their size is automatically registered. The
data is classified by batch names The software proposes complete database management (delete old batches,
rename batches, export to Excel, print, display comparative graphs...)
The device is proposed in 2 main versions :
- Agrosize®X which has to be connected to a computer, and is provided with a software compatible
with Windows Vista, Millenium, XP, 7 and 8
- Agrosize®Touchscreen which is a portable device, autonomous with 2 batteries. Memory : 32 Gb,
embedded with an Intel processor, resistive touchscreen, stylet. The tablet is working under Windows
7 operating system (Same software as the X version) - But you do ’t ha e to use i do s Which is hidden by the Agrosize software, starting automatically when you switch on the tablet - Closed
automatically when you switch off the tablet)