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Sand storage, an innovation to extend the shelf-life of fresh sweetpotato for home consumption and market sales - findings from Ghana and Malawi

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Abstract and Figures

A uni-modal rainfall pattern causes a fairly short harvest season, where the sweetpotato is abundant and cheap in the markets, followed by a long dry season during which the sweetpotato is scarce and if it is there it will be extremely expensive. Generally, the crop is consumed, processed, or sold shortly after harvest. In Malawi, ambient temperatures during the dry season are relatively cool while in northern Ghana, the temperatures are far warmer, but the start of the dry season is characterized by cooler night temperatures low relative humidity which occurs during the harmattan season. Since sweetpotato is an important crop in parts of northern Ghana and in Malawi, it would be subsequently incredible to extend the shelf-life of this crop for both home consumption and sale. In Malawi, three types of storage were evaluated at the community level. Introduced orange-fleshed sweetpotato (OFSP) Zondeni variety and locally grown white and yellow fleshed sweetpotatoes were used in the trial. The types of storage were ventilated pit potato store introduced from Afghanistan and storage in dry sand of pit-steps and of a granary. In Ghana, local moistened heap store and sandbox were compared. Weight loss in the storage trials has a significant attribution to determine the quality of sweetpotato fresh roots and its shelf-life. In Malawi, at each storage interval, losses were calculated relative to the quantity stored at the beginning of the period, and thus were not cumulative. At 1.5 months there were not striking differences among treatments, but by 3.5 months the ladder pit method was starting to emerge as consistently superior, a trend that continued through 6.5 months. Losses in granaries were largely due to shrivelling, while in the ladder pits were due to termites, and rats (if sand cover was not thick). Losses in ventilated pits were due to termites, rats and Java black rot. Sprouting was consistently high in the ladder pit, but sprouts were simply removed at assessments, and roots returned to storage. At 6.5 months, the beta-carotene of Zondeni storage roots was steadily traceable. Farmers gained high price when selling them in the market because it was the period where the storage roots were scarce. Women favoured the pit step store as it was easy for them to manage both for home-consumption and sales. In Ghana, the dry sand storage was superior to local moistened heap store. Methods designed so far would be suitable for home consumption, but will require modification for commercial application.
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Journal of Food Science and Engineering 6 (2016) 227-236
doi: 10.17265/2159-5828/2016.04.005
Sand Storage, Extending the Shelf-Life of Fresh
Sweetpotato Roots for Home Consumption and Market
Sales
Putri Ernawati Abidin1, John Kazembe2, Richard A. Atuna3, Francis Kwaku Amagloh3, Kwabena Asare1, Eric
Kuuna Dery1 and Edward Ewing Carey1
1. International Potato Center (CIP), c/o CSIR Savanna Agricultural Research Institute (SARI), P.O. Box 3785, Kumasi, Ghana
2. CIP, P.O. Box 31600, Lilongwe 3, Malawi
3. University for Development Studies (UDS), P.O. Box TL 1350, Tamale, Ghana
Abstract: Uni-modal rainfall pattern has long dry spell wherein sweetpotato is scarce, expensive but cheap at harvest. The crop is
mostly consumed, processed or sold. Extending shelf-life of roots is crucial for Malawi and Northern Ghana as the crop has high
value. Trials were conducted in the countries at the community level. In the dry season, temperature is cool in Malawi while warm in
Ghana, but thru harmattan, the night is cool with low relative humidity. In Malawi, orange-fleshed sweetpotato Zondeni var., white
and yellow types were assessed in three types of storage, Afghan ventilated pit store, storage in dry sand of pit-steps, and of a granary.
In Ghana, local moistened heap and sandbox were compared. In Malawi, weight losses were calculated relative to the quantity stored
at start, it was not cumulative. At 1.5 months no significant difference was among treatments. By 3.5 months the pit-steps method
emerged to be superior and continued to 6.5 months. Losses in granary were due to shriveling, in the pit-stepsdue to termites and rats,
and in ventilated pit due to termites, rats and Java black rot. Sprouting was high in pit-steps, but it was simply removed and roots
returned to storage. At 6.5 months, the beta-carotene of Zondeni roots was traceable. Farmers gained high price when selling them as
roots were scarce. Women favored the pit-steps because it was manageable. In Ghana, the sandbox was superior to local moistened
heap. Methods designed were suitable for home consumption, but will require modification for commercialization.
Key words: Sand storage, sweetpotato, orange-fleshed sweetpotato, local knowledge, shelf-life of storage roots, beta-carotene.
1. Introduction
The sweetpotato is widely grown in tropical,
subtropical, and temperate areas between 40° North
and 32° South. A wide range of cultivars is suitable
for different soils and climates [1-3]. The crop is
mostly grown in small plots by subsistence farmers in
low-input agricultural systems [4, 5]. In Malawi,
sweetpotato is an important crop after maize and
cassava [6, 7] and it is increasingly becoming an
Corresponding author: Putri Ernawati Abidin, Ph.D.,
research fields: sweetpotato seed systems, sweetpotato
value chains, linking agriculture, nutrition, health and
wealth using orange-fleshed sweetpotato, postharvest
handling for sweetpotato for food security and
nutrition security.
important crop among other root and tuber crops in
Ghana since the last few years [8]. A uni-modal
rainfall distribution pattern is typically having a long
dry season and causes a fairly short harvest season.
With respect to sweetpotato cropping system, farmers
normally treat sweetpotato as a rain-fed crop for
storage root production, consequently, during the
harvest season, abundant roots are found at the farms’
gates and in markets. By that time, the sweetpotato is
mostly consumed, processed, or sold quickly by
farmers, due to the fact that the sweetpotato storage
roots have a short shelf-life. This condition becomes a
major constraint for sweetpotato farmers in
Sub-Sahara Africa. Considerably, the price of the
storage roots is significantly cheap. In contrast, at out
D
DAVID PUBLISHING
Sand Storage, Extending the Shelf-Life of Fresh Sweetpotato Roots for
Home Consumption and Market Sales
228
of the harvest season, the sweetpotato becomes scarce
and expensive.
In tropical environments, where refrigerated storage
is not economically feasible, roots will generally keep
for only a few weeks. This happens mostly in
developing countries. When subjected to normal
marketing practices, it is clearly having a negative
impact on reduced marketing opportunity to a few
week staking part in the sweetpotato value chains.
This means that fresh roots can be eaten only for 2-3
months of a year. Extending the shelf-life would allow
people to sell and eat fresh sweetpotato for a longer
period of time, and would make the crop more
attractive and market orientation. Hence it will be
improving incomes of many resource-poor farmers.
Farmers have developed various methods to extend
sweetpotato shelf-life, i.e. storage in soil, grass or ash,
storage in pits like in Malawi [6] or other countries in
the South and Eastern Africa, or simply left in the
ground and harvested piecemeal as required such as in
Uganda [4, 9] or other countries in East Africa, or
processed into sun-dried chips such as in Northeastern
Uganda [4] as well as in many more countries in
Sub-Sahara Africa. Normally these indigenous storage
methods are only effective for a month or two, after
which quality declines due to rots, infestations by
pests and physiological deterioration. Recently the
“Triple-S” (Storage in Sand and Sprouting) method
[10] has been developed as a way of storing the
non-marketable clean roots at room temperature for
subsequent use in producing the planting material for
the next planting season. Since this method has shown
an effective technique of storing the sweetpotato roots
for a few months, we therefore reasoned that the
storage in sand method can be realistic for keeping the
fresh marketable size of storage roots in the sand store
for a longer period of time. Furthermore, we have also
considered in a number of literatures knowing the
impact of getting beta-carotene-rich orange-fleshed
sweetpotato (OFSP) varieties into the diets of rural
and urban consumers, especially on young children in
Sub-Sahara Africa [11-13]. Therefore, we inspired
ourselves to include the OFSP varieties into our
postharvest trials. It is well recorded that Malawi and
Ghana have a high number of the children below five
of age living with malnutrition and vitamin A
deficiency (VAD). At present, the local sweetpotato
varieties predominantly found are white and yellow
flesh. The objective of the experiments was to develop
and evaluate the indigenous postharvest methods
commonly used by farmers in Sub-Sahara Africa and
bringing the knowledge of farmers in Afghanistan
who are successfully using a ventilated pit to store
their Solanum potato for a few months. This method
was introduced by a scientist of Catholic Relief
Services (CRS) to Solanum potato farmers in
Sub-Sahara Africa. The trials were conducted at the
community level in Northern Malawi and Northern
Ghana. Both countries have a similar rainfall
distribution pattern, i.e. uni-modal rainfall distribution
pattern.
2. Materials and Methods
2.1 Geographical Area of Trials
2.1.1 Malawi
Three communities with a total of 90 households
were chosen, one community in Mzimba District of
Northern Region and two in Kasungu District of
Central Region. The trials were situated at the 13°
South and its mid-elevations of ~1,200 m above sea
level (masl). One introduced orange-fleshed
sweetpotato (OFSP) Zondeni variety, one white and
one yellow locally grown varieties were investigated
in the three types of storage, Afghan ventilated pit
store, storage in dry sand of pit-steps, and of a granary.
If there was more than one local variety, these were
bulked together in each of the storage treatments at
each location. Each store was replicated thrice in
every community. The storage trials were initiated in
May 2014, during the harvest period. Assessments of
weight loss and taste were done at 6 weeks or 1.5
Sand Storage, Extending the Shelf-Life of Fresh Sweetpotato Roots for
Home Consumption and Market Sales
229
months after stored (MAS), 3.5 MAS, and 6.5 MAS.
Taste was also assessed prior to initiation of storage
and it was conducted in May 2014. This taste
assessment was consistently done at each storage’s
observation interval. Another notably important
assessment was also made, it was an evaluation on the
market value of roots after being stored for a certain
period of time. The market assessment was done at 1.5
MAS, i.e. in June 2014 during the peak harvest, and at
6.5 MAS, i.e. in Nov. 2014 when roots were normally
scarce or not found at all.
Good agricultural practices (GAP) for sweetpotato
and careful handling during harvesting were
introduced to farmers to minimize mechanical damage
on sweetpotato storage roots prior to be stored and
investigated throughout the postharvest trial. The
farmer participants in this trial were trained on
sweetpotato production, multiplication, pest and
disease management, drip irrigation, postharvest
handling, and OFSP utilization and processing. Since
the β-carotene rich orange-fleshed sweetpotato was
unknown by farmers in that area, we needed to
sensitize farmers on the benefit of having the vitamin
A rich OFSP in their daily diet. They also needed to
know its processing and utilization. Traditional curing
was practiced, farmers kept the roots in their
house-yards under the sun for 3 days and then in a
storeroom for another 3 days. In this way, farmers in
Malawi believed that sweetpotato became sweeter. In
fact, the farmers like sweetpotato to be sweeter.
Baseline and Endline survey were done to accomplish
the trial results to be more meaningful.
2.1.2 Ghana
The results from Ghana were treated as a
complimentary result for the Malawi’s storage trial.
More details from Ghana could be found in another
publication elsewhere. Five communities with a total
of 100 households were selected in Bawku, Upper
East Region. The trials were recorded at 11° North
and its mid-elevation of ~220 masl. The temperature
was hotter compared to Malawi, whereas during
harmattan, the night temperature was relatively cool.
Although Ghana has a similar uni-modal rainfall
pattern with Malawi, but rainfall was more erratic than
the rainfall was being experienced in Malawi. Two
OFSPs and one white variety were assessed in the two
types of storage, local moistened heap and sandbox.
Farmer participants were trained on sweetpotato
production, multiplication, pest and disease
management, postharvest handling and OFSP
utilization and processing. Traditional curing was
practiced. Baseline and Endline survey were also
done.
2.2 Storage
The Afghanistan pit namely Afghan pit, is a
ventilated pit storage adapted from the method
successfully used for Solanum potato storage by
Catholic Relief Services in Afghanistan. Two
indigenous methods from Malawi are pit storage and
traditional raised granary. The pit storage was
modified with steps also called as pit ladder to allow
easy access to lower levels. Inside of the traditional
raised granary structure was plastered with
clay-cement. The dry sand was used in both pit-steps
and granary. The dry sand covered layer-by-layer on
the arrays of storage roots. The roots should not touch
on each other while being stored. One indigenous
method from Ghana, the moistened heap was compared
to a newly introduced sandbox. The sandbox was a box
made from a concrete and plastered by cement. The
sweetpotato storage roots were stored in such away on
an array, then the dry sand was added on this array
layer-by-layer as it is similarly described in the
methods for pit-steps and raised granary structure
from Malawi. The room wherein the sandbox was
built was roofed with the grass-thatched.
2.3 Data Collection
Weight loss measurement in the storage trials was
indicated to be a significant attribution in order to
determine the quality of sweetpotato fresh roots and
Sand Storage, Extending the Shelf-Life of Fresh Sweetpotato Roots for
Home Consumption and Market Sales
230
its shelf-life. The weight loss included shriveling, rots
and pest damage were measured. In Malawi, data of
weight loss, taste test, RH and temperature were
collected, at regular intervals up to 6.5 MAS. At each
storage interval, losses were calculated relative to the
quantity stored at the beginning of the period, and thus
were not cumulative. Furthermore, the market
assessment and β-carotene analysis were done at 1.5
(June 2014) and at 6.5 MAS (November 2014). In
Ghana, losses in stores were monitored at 6, 12, and
18 weeks of storage. Genstat [14] A and STATA
program were used for the statistical analyses.
3. Results and Discussion
3.1 Malawi
Baseline survey has revealed that farmers already
shifted to grow sweetpotato as a cash crop in the last
few years. The northern region farmers used to be the
commercial tobacco producers. There was a case that
the tobacco crop was banned in the world markets of
agricultural commodity, and Malawi was among the
countries which got this negative effect on the
economic importance of this crop especially for
farmers in this region. Hitherto, the OFSP was not
chosen to be commercial crop but the white and
yellow flesh sweetpotato were among the cash crops
in this particular region. Farmers believed that the
OFSP could easily rot because of its short lifespan,
therefore this orange type had no value for them. But
farmers still liked it that was a reason why they
continued growing the orange type of sweetpotato in
the garden. They mostly used it only for
home-consumption. After completing the trials, it was
noticed from the Endline survey that a change
occurred at the opinion of these farmers. Farmers have
chosen the orange type varieties (OFSP) to be
included in their commercialized commodity after
participating in the postharvest trial. This was due to
the noble performance of the OFSP throughout the
trials along with recognizing its health benefit
importance as the Vitamin A powerhouse.
Fig. 1 presents the results of weight loss in the
storage trials. Further details and statistical
significance are provided in Table 1. At 1.5 MAS
there were not striking differences among treatments,
but by 3.5 MAS the pit-steps (sand pit) method was
starting to emerge as consistently superior, a trend that
continued through 6.5 MAS. Losses in granaries were
Fig. 1 Percentage weight loss observed after 1.5 MAS, 3.5 MAS, and 6.5 MAS during the dry/winter season of 2014 across
the three types of storage (p value < 0.01 and LSD 5% = 9.6; MAS p value < 0.001 and LSD 5% = 9.6; sites p value < 0.1 and
LSD 10% = 8.2; varietal differences: ns).
15
23 24
16
8
25
910 56
12 14
35
44
12 15
41 46
GRANARY
LOCAL VARS GRANARY
OFSP
ZONDENI
SAND PIT
LOCAL VARS SAND PIT
OFSP
ZONDENI
VENTILATED
PIT LOCAL
VARS
VENTILATED
PIT OFSP
ZONDENI
%WeightLoss
June(1.5months) Aug(3.5months) Nov(6.5months)
Sand Storage, Extending the Shelf-Life of Fresh Sweetpotato Roots for
Home Consumption and Market Sales
231
Table 1 Averaged percent weight loss by sweetpotato
roots according to type of storage, sweetpotato varieties,
sites and months of observation in 2014.
Items % weight lost per unit
Type of storage
Granary with dry sand 22.8
Pit ladder storage with dry sand 12.9
Ventilated Afghan pit storage 27.6
P-value **
LSD 5% 9.6
Varieties
Local 20.1
OFSP—Zondeni variety 22.1
P-value ns
LSD -
Site
ZombeAlaki (Kasungu District) 23.8
Chizerema (IKasungu District) 24.5
Champira (Mzimba District) 15.1
P-value (*)
(LSD 10%) (8.2)
Months after stored (MAS)
June (after 1.5 months) 18.5
August (after 3.5 months) 9.2
November (after 6.5 months) 35.6
P-value **
LSD5% 9.6
MAS across type of storage
Granary in June_1.5 months 19.2
Granary in Aug_3.5 months 9.5
Granary in Nov_6.5 months 39.8
Pit-steps storage in June_1.5 months 19.9
Pit-steps storage in Aug_3.5 months 5.2
Pit-steps storage in Nov_6.5 months 13.7
Afghan in June_1.5 months 16.5
Afghan in Aug_3.5 months 12.9
Afghan in Nov_6.5 months 53.3
P-value **
LSD5% 16.7
Grand mean 21.1
cv% 24.9
largely due to shriveling, while in the ladder pits were
due to termites, and rats (if sand cover was not thick).
Losses in ventilated pits were due to termites, rats, and
Java black rot. Sprouting was consistently high in the
pit-steps, but sprouts were simply removed at
assessments and roots returned to storage. Farmers
believed that by removing the sprouts and returning
the roots to storage did not give any effects on losses.
Unfortunately, temperature and humidity in stores
were not logged constantly during experiments.
However, they were measured at sampling times, at
which point relative humidity was observed to be
consistently lower in granaries and open air, compared
with the pit storage methods. This would explain the
shriveling that occurred in granaries (Fig. 2).
Moreover, as seen from Fig. 2, the weight loss is less
when the percentage of relative humidity is relatively
high, between 60% and 70% while the temperature is
constantly at average of 26 °C. According to Ref. [15],
the temperatures above 15 °C lead to more rapid
sprouting and weight loss. Strikingly, we have found
that the weight loss was reduced when the relative
humidity was high, although the temperature above
15 °C. Furthermore, Cantwell [15] gave an example
on commonly being practiced by sweetpotato farmers
in the USA. They noticed that the optimal keeping
storage roots in the dry box or bins or keeping them
loose is at 12.5 °C to 15 °C with 95 percent relative
humidity (RH). Moreover, the farmers never put the
storage roots in the refrigerator up to selling to the
market or bedding for vines production. In this way,
the sweetpotato farmers can keep their roots up to 10
months [15]. Regulating the relative humidity to be
relatively high in the granary and in the dry sand
pit-steps can be an important indicator to reduce the
weight loss of storage roots in these types of storage,
with the assumption of keeping the temperature in the
storage not above 26 °C and so. It is not easy to get
this temperature in the hot tropical areas. Nevertheless,
the temperature of the dry sand covering the storage
roots, in principle, can be mechanically regulated to
reach this point.
The ambience of the storage causing the fluctuation
of the percentage of the relative humidity could be
significantly influenced by the physiological activity
of the storage roots, such as respiration and
metabolism, of which its mechanism will be ending up
232
Fig. 2 Corr
e
Fig. 3 Resu
Malawi, Jun
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of producin
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20
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40
50
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GRANLOCAL
GRANOFSP
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n Temperatu
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.
This might
storage tri
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GRANLOCAL
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Endline su
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SANDPITLOCAL
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p
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Afghanis
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to access th
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%
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Te
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RH
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Sand Storage, Extending the Shelf-Life of Fresh Sweetpotato Roots for
Home Consumption and Market Sales
233
roots being stored in the subsequent steps, unlike the
Granary. It was easy to construct and used by both
men and women. The low adoption or low preference
by farmer participants was the Afghanistan method.
Farmers said that because it was less effective in
keeping the roots be fresh, and they experienced high
percentage of rotting. They recommended that
pit-steps and granary storage facilities were socially
inclusive technologies as perceived by respondents.
An interesting—but possibly
instructive—inconsistency was introduced to the
experiments at storage initiation, when roots of OFSP
“Zondeni” variety were “cured” at all locations,
whereas the roots of the local varieties were not
subjected to the same treatment as they were not
deemed ready for harvest. While the cure method may
contribute to sweetness, it is not the correct way to
cure the sweetpotato—a process that allows for wound
healing under high temperature and humid conditions
[17]. Whether the “curing” treatments contributed to
differences in weight losses of local varieties and
“Zondeni” among storage methods may be worthy of
further investigation.
Taste tests conducted at storage initiation and after
each storage interval indicated that farmers or
consumers by and large appreciated the appearance
and taste of the OFSP “Zondeni” variety over the local
non-OFSP varieties. These preferences held up at 1.5
MAS, 3.5 MAS, and 6.5 MAS. Although some
consumers rated the boiled “Zondeni” as too sweet,
they still largely preferred it (data not shown). The
main observations from farmer assessments of retail
prices from the beginning of the experiment to the end
was that by the end, prices were higher and they were
distinguishing prices for OFSP and local varieties
(Tables 2 and 3).
Moreover, from the Endline survey report, the gross
margin analysis revealed that with sand pit-steps (pit
ladder) storage technology, farmers could realize an
increase in gross margin as storage period increases.
With other storage technologies, farmers are better off
selling at harvest time in the month of May than when
they sell at 1.5 MAS or 3.5 MAS. The worst case was
when using the ventilated Afghan-pit store, the gross
margin was minus or below 0 (data not shown).
Results from the beta-carotene analyses in June and
November 2014 are shown in Table 4. OFSP
“Zondeni” variety was still within the range of
moderate beta-carotene, it was between 40-129 µg/g
based on the β-carotene content that was grouped and
categorized by Simonne [18]. ß-carotene is the
carotenoid with the highest pro-vitamin A activity
(100%) because it can be entirely converted into two
molecules of vitamin A (retinol) [19]. From 100 g of
“Zondeni” there are 9,180 µg of beta-carotene,
equivalent to 765 µg of retinol activity equivalents
(RAE), which is more than 150% of the recommended
daily allowance for a child under 5.
3.2 Ghana
Parts of the study from Ghana as a complimentary
result towards Malawi’s results are also written in this
paper. Fig. 4 shows that in the course of time, the
weight loss significantly increased, however, the
incidence of weight loss in the traditional heap was
much higher compared to sandbox at 6 weeks of being
stored but slightly increased in the direction of the
traditional heap at 18 weeks after being stored.
Table 2 The first market assessment done at the peak harvest (June 2014).
District EPA/Sites Description of roots Price (Malawi Kwacha)
Kasungu ZombeAlaki 10 small roots (< 100 g) 100
4 big roots (> 100 g) 150
Kasungu Chizerema 17 small roots (< 100 g) 100
5 big roots (> 100 g) 100
Mzimba Champira 5 small roots (< 100 g) 100
3 big roots (> 100 g) 150
234
Table 3 Th
e
Site
1.Zombealak
i
(Kasungu)
2. Chizerema
(Kasungu)
3. Champhira
(Mzimba)
Table 4 β-c
a
Varieties
Local (Kenya
OFSP, Zonde
n
Fig. 4 Weig
Tables 5
based on e
a
storability
a
improveme
n
stored. Usi
n
length of s
home consu
m
Sa
n
e
second mark
Group typ
e
i
Women
Men
Women
Men
Women
a
rotene ((µg/g
)
& Zimbabwe)
n
i
ht loss from s
w
and 6 hav
e
a
ch sweetpot
a
a
nd market
n
t in the l
e
n
g the sandb
o
weetpotato
f
m
ption as w
e
n
d Storage,
E
et assessment
d
e
Variety
Zondeni
Local
Zondeni
Local
Zondeni
Local
Zondeni
Local
Zondeni
Local
)
status for ea
c
w
eetpotato du
r
e
given det
a
a
to variety r
demand. It
e
ngth of sto
o
x method c
o
f
resh roots
t
e
ll as for mar
k
0
20
40
60
80
100
Percentweightloss
E
xtending the
Home Cons
u
d
one when sw
e
Descriptio
n
Small root
s
Big roots (
>
Small root
s
Big roots (
>
Small root
s
Big roots (
>
Small root
s
Big roots (
>
Medium ro
Medium ro
Medium ro
Medium ro
Small root
s
Big roots (
>
Small root
s
Big roots (
>
c
h variety at 1
.
June (1.5
M
10.7
83.9
r
ing 18 weeks
o
a
iled inform
a
egarding va
r
was foun
d
rage root b
o
uld increas
e
t
o be store
d
k
et orientatio
n
6(n=72)
W
Shel
f
-Life o
f
u
mption and
e
etpotato root
s
n
of roots
s
(< 100 g)
>
100 g)
s
(< 100 g)
>
100 g)
s
(< 100 g)
>
100 g)
s
(< 100 g)
>
100 g)
ots (> 100 g)
ots (> 100 g)
ots (> 100 g)
ots (> 100 g)
s
(< 100 g)
>
100 g)
s
(< 100 g)
>
100 g)
.
5 and 6.5 MA
S
M
AS)
o
f storage at h
a
tion
r
ietal
d
an
eing
e
the
d
fo
r
n
. At
lea
s
ant
i
b
e
tw
o
the
r
the
ma
r
12(n=89)
W
eeksinstor
a
f
Fresh Swee
t
Market Sale
s
s
were scarce
(
# of roots p
e
heap
8
4
6
6
5
5
6
5
8
11
8
7
8
4
14
9
S
.
Β-caro
t
ouseholds in 4
s
t, the OF
S
i
cipated to h
stored in t
h
o
communi
t
r
e was no
m
baseline,
b
r
keting it.
18
a
ge
t
potato Root
s
s
(
Nov 2014).
e
r Weight of
r
(kg)
1
1.75
1
1
1.5
2
1
1
1
1
1.5
1
1
1.5
1.5
2.5
t
ene (µg/g)
Nov (6.5 M
A
7.4
91.8
communities,
S
P Apomud
e
ave poor sto
h
e sandbox
u
t
ies being
m
arket for A
p
b
ut after t
h
Sa
n
He
a
s
for
r
oots Price/he
a
kwacha)
200
200
100
200
150
250
150
200
250
300
300
250
250
350
300
400
A
S)
Bawku.
e
n variety,
o
rage charact
e
u
p to 4.5
m
observed.
F
p
omuden rec
o
h
e trial, p
e
n
d
a
p
a
p (Malawi
which wa
s
e
ristic, coul
d
m
onths in th
e
F
urthermore
,
o
rded durin
g
ople starte
d
s
d
e
,
g
d
Sand Storage, Extending the Shelf-Life of Fresh Sweetpotato Roots for
Home Consumption and Market Sales
235
Table 5 Varietal storability and market demand at Buya-Natinga/Old Ninkongo.
Variety/Cultivar Max. storage length (before the
project) in months Max. current length of storage in
months Comments
Kuffour 1 month 4 months Good when produced early
Obaari White 3 months 7 months Best market demand
Asankunaboro 3 months - -
Awaal 3 months - -
Asaamadek 2 months maximum 5 months Better market
Apomuden Anticipate poor storage 4.5 months Poor market demand, mainly
for HH consumption
Table 6 Varietal storability and market demand at New Ninkongo.
Variety/Cultivar Max. storage length (before the project)
in months Max. current length of storage
in months Comments
Asaankasnaabbogor Good storage - Good market
Asaamadek Stores well (2 months) - Good market—white
fleshed Sweetpotato
Obaari Good storage 6.5months Best market
Kuffour Poor storage 4months Early market
Awaal Good storage - Good market
Apomuden (“NasaraDankali”)
Storage probably poor. Yet to observe
how it stores as it has just been
introduced 4.5 months No market baseline, but
now people market it
4. Conclusion
Sand storage has shown a great potential to be
promoted to the sweetpotato farmers in Malawi,
Ghana and may be elsewhere in the future. In Malawi,
the OFSP fresh storage roots could be obtained from
the sand storage at 6.5 months after being stored.
Meanwhile, in Ghana, having more harsh environment
than Malawi, farmers could still enjoy eating the fresh
roots up to 4.5 months for the OFSP Apomuden
variety. Both countries showed a good prospect on the
marketing opportunity of the OFSP roots. This is
because the result has revealed that the shelf-life of
sweetpotato storage roots could be extended up to the
period of which the sweetpotato storage roots were
usually scarce in the locality. It is suggested the
findings can be scaled out with a slight modification
based on the local condition and its circumstances so
that more resource-poor farmers can gain out of it.
The improvement of local knowledge on the storage
methods on sweetpotato can contribute to reducing
hunger, improving nutrition status and strengthening
the household income to reduce the poverty. It is
certainly having its significance in combating the
effect of climate change.
Acknowledgement
USAID-OFDA, Irish Aid through CIP-led project
“Rooting out Hunger in Malawi with Nutritious
Orange-Fleshed Sweetpotato”, Ministry of Agriculture
partners in Ghana and Malawi, CIP-Malawi & Ghana;
CRS-Malawi & Ghana; Mzuzu-CADECOM, and Dr.
Michael Pots (CRS, New Zealand).
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ResearchGate has not been able to resolve any citations for this publication.
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