IJERD – International Journal of Environmental and Rural Development (2021) 12-2

Research article
erd

Measurement of Postharvest Losses of Sesame (Sesamum
indicum L.) from Harvesting to Storage at Farm Level
HNIN THIDA NYO*
Department of Agriculture, Ministry of Agriculture, Livestock and Irrigation, Myanmar
Email: hninnyo@gmail.com

NYEIN NYEIN HTWE
Department of Agricultural Extension, Yezin Agricultural University, Myanmar

KYAW KYAW WIN
Yezin Agricultural University, Myanmar
Received 20 January 2020

Accepted 26 November 2021(*Corresponding Author)

Abstract During a crop’s transition from farm to consumer, much of the crop is lost due toseveral factors, including improper handling, inefficient processing facilities, andbiodegradation due to microorganisms and insects. This study was conducted with two
objectives: to measure the extent of postharvest losses of pre-monsoon and post-monsoon
sesame in field operations, i.e. in the harvesting, stacking, drying of stalks, threshing andwinnowing processes, and also to determine the quantity lost with the use of different typesof packaging materials used for storage. The research was conducted in Pwintphyu andPakokku Townships, Magway Region, Myanmar in July and December 2016. The
postharvest losses were measured at harvesting, stacking, stalk drying, threshing and thewinnowing stages on the farms. When comparing postharvest losses, losses were higher in
pre-monsoon sesame than post-monsoon sesame, except at the harvesting stage. The total
losses were found to be more in the pre-monsoon crop (21.34%) compared to the postmonsoon crop (11.88%). In regard to contribution to total losses, the storage loss accounted
for the major part (71.42%) of the total postharvest losses in pre-monsoon sesame. For theremaining losses, 22.35% occurred during stalks drying and threshing process, 3.47% whenstacking, with 1.45% of loss during harvest and 1.31% at winnowing. For post-monsoon
sesame, storage losses comprised 91.08% of total losses, followed by harvest loss (6.48%),stalks drying and threshing (1.68%), winnowing (0.59%) and stacking (0.17%). To assess thestorage losses resulting from the use of different packaging materials, two types of packaging
materials were tested. The harvested sesame seed was stored in pioneer superbags and woven
polypropylene bag for eight months at farmers’ houses. At the end of this period, weightlosses for the pre-monsoon sesame occurred in sesame stored in both superbags and woven
polypropylene bags. However, losses for the post-monsoon sesame occurred only the woven
polypropylene bag.
Keywords sesame, postharvest, losses, stacking, stalks drying, storage

INTRODUCTION
Reducing postharvest losses, especially in developing countries, could be a sustainable solution toincrease food availability, reduce pressure on natural resources, eliminate hunger and improve
farmers’ livelihoods (Hodges et al., 2011). During the crop transition from farm to consumer, it
undergoes several operations such as harvesting, threshing, cleaning, drying, storage, processing andtransportation. During these processes, crop is lost due to several factors. These include improper
handling, inefficient processing facilities, biodegradation due to microorganisms and insects, etc.
(Kumar and Kalita, 2017). Postharvest losses increase with an increase in area under crop and withincreased time of storage, while they decrease with improvements in the type of storage and methodof storage (Nag et al., 2000).
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Postharvest losses in less developed countries have been subject to a relatively small number ofstudies, and are mostly guesstimates derived from questionnaires rather than actual measurements.
However, this approach may be misleading because postharvest losses may be due to a variety offactors which varies from commodity to commodity, from season to season, and to the variety ofcircumstances under which commodities are grown, harvested, stored, processed and marketed(Tyler, 1982). Therefore, it is important not only to work with figures that are good estimates related
to a particular crop, time and place, but also to be aware that there will be variations at other times
and in other situations.
OBJECTIVESThe study was conducted with two objectives: to measure the extent of postharvest losses of premonsoon and post-monsoon sesame in field operations and to determine the quantity losses
associated with the use of different types of packaging materials used during storage.

METHODOLOGY
Field Experiment
The research was conducted in Pwintphyu and Pakokku Townships which are situated in the Magway
Region of Myanmar, in July 2016 and December 2016. The experiments were carried out in six
farmers’ fields in Pwintphyu Township for the pre-monsoon sesame crop and in six farmers’ fields
in Pakokku Township for the post-monsoon sesame. The plot size was 15m x 15m with two plots ineach farmer’s field. The variety of sesame grown in this study was black sesame (Samou Nei). The
postharvest losses were measured at the harvesting, stacking, stalks drying, threshing and thewinnowing stages on the farms.
Determination of Quantity Losses
Harvest losses: The sesame plants in the experimental plots were harvested according to normal
practice (using a sickle). Left over sesame pods on the harvested plots (both on the ground and on
unharvested standing plants) were thoroughly collected, cleaned, dried, weighed and stored
separately in paper bags. Losses for each plot are determined by the following equation (Appiah
et.al., 2011).
Harvesting losses = Weight of left over grains / Total weight of harvested grains × 100
Stacking losses: The harvested sesame stalks are placed on plastic nets. Stalks were separately piled
for each plot, and this method was used in the field stacking. After removing the stalks for drying,
all the grains remaining on plastic nets were collected, cleaned, dried and kept in paper bags for eachplot. If farmers used a threshing floor, the stalks were piled on the floor directly and the grains on
the floor were collected by the farmers. After the farmers’ had finished the stacking stage, the grains
remained on threshing floor were collected to determine losses (Appiah et.al., 2011).
Stacking losses = Weight of left over grains / Total weight of harvested grains × 100
Stalk drying and threshing losses: The ground was covered with canvas and the stalks were placed
upright and dried on these canvases. This method was used for in-field processing but not for thosedried on a threshing floor. After drying, stalks were moved and threshed on another canvas groundcover. The sesame grains for each plot that remained on all canvases were collected, cleaned, dried
and kept in paper bags. Where farmers did their drying on a threshing floor, the stalks were dried on
the floor directly and the grains on the floor were then collected by farmers. After they had completed
this process, the grains remaining on the threshing floor were collected to determine losses (Appiah
et.al., 2011).

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Drying and threshing losses = Weight of left over grains / Total weight of collected grains × 100
Winnowing losses: Two canvasses were spread on the floor, one for the winnowed grain and theother for the discarded chaff. Grains from the discarded chaff were collected, cleaned, dried andweighed the grain to determine losses (Appiah et.al., 2011).
Winnowing losses = Weight of grains collected from chaff / Total weight of collected grains × 100
Storage losses: Two different packaging materials were used to store the grain; woven
polypropylene bag and pioneer superbags, with storage in six farmers’ houses for a period of eightmonths. The quantity loss was determined at two-month intervals during this storage period. Quantity
losses is calculated using the formula (Appiah et.al., 2011).
Storage losses = (Initial weight of grains – Final weight of grains) / Initial weight of grains × 100
RESULTS AND DISCUSSION
Total Postharvest Losses for Pre-monsoon and Post-monsoon Sesame
When comparing postharvest losses, the losses were higher in pre-monsoon sesame than postmonsoon sesame except in regards to harvesting losses. The losses that occurred on farm before
storage were found to be at a maximum in the stalks drying and threshing stage (4.77%) followed bystacking losses (0.74%), harvest losses (0.31%) and winnowing losses (0.28%) for the pre-monsoon
crop. In post-monsoon sesame, the maximum quantity losses were found at the harvest stage (0.77%)
followed by the stalks drying and threshing process (0.2%), winnowing (0.07%) and stacking(0.02%). The total losses were greater in the pre-monsoon crop (21.34%) than the post-monsoon crop
(11.88%) (Table 1). The losses during harvesting and stacking showed a highly significant difference
between the two different crops. Also, stalks drying and threshing losses, winnowing losses and total
losses showed a significant difference, but storage losses were non-significant between the pre andpost-monsoon crops (Table 1).

Fig. 1 Proportion of postharvest losses of (a) pre-monsoon (b) post-monsoon sesame
In regard to total losses, storage loss comprised the major part with 71.42% of the total
postharvest losses for pre-monsoon sesame. The remaining losses consist of, 22.35% in stalks drying
and threshing process, 3.47% during stacking, 1.45% at harvest loss and 1.31% of during winnowing(Fig. 1 a). In post-monsoon sesame, storage losses represented 91.08% of total losses, followed byharvest loss at 6.48%, stalks drying and threshing loss with 1.68%, and winnowing loss at 0.59% of
total losses. The loss during the stacking process was only 0.17% of total losses (Fig. 1 b). The losses
during storage are a result of several factors, both biotic (insects, pests, rodents, fungi) and abiotic(temperature, humidity, rain) (Abedin et al., 2012). In India, the postharvest losses of sesame were
estimated at different stages across four different marketing channels. The total losses at farm level
were 46.75%, 37.58%, 35.85% and 51.84% respectively as part of the total losses in supply chain.
Harvest losses of sesame in four different marketing channels were 10.57%, 9.32%, 6.72% andⒸ ISERD

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16.54% of total losses. Collection losses were 4.88%, 4.66%, 5.88% and 9.93% of total losses; while
8.94%, 5.59%, 6.16% and 8.46% of total losses occurred at the threshing stage. Winnowing lossesof sesame, 8.13%, 7.45%, 6.72% and 4.78% were found in these four marketing channels, and aconsiderably high amount of losses occurred in drying/packaging with these being 8.94%, 7.45%,7%
and 8.09% respectively. The storage losses at the processing level in the four marketing channels
were 15.04%, 8.07%, 8.12% and 12.13% of total losses in the supply chain (Kumarasamy and Sekar,2014).
Table 1 Postharvest losses of pre-monsoon and post-monsoon sesame
Pre-monsoon

Post-monsoon

Percentage of losses

Percentage of losses

Activity
Harvest losses
Average
Range
Stacking losses
Average
Range
Stalks drying and threshing losses
Average
Range
Winnowing losses
Average
Range
Storage losses
Average
Range

0.31
0.77
0.11 to 0.71
0.58 to 1.17
t = -3.788, P = 0.004‫٭٭‬, df = 10
0.74
0.02
0.24 to 1.11
0.01 to 0.06
t = 4.195, P = 0.008‫٭٭‬, df = 5.021
4.77
0.20
1.91 to 10.09
0.04 to 0.37
t = 3.582, P = 0.016‫٭‬, df = 5.021
0.28
0.07
0.09 to 0.56
0.03 to 0.09
t = 3.148, P = 0.024‫٭‬, df = 5.225
15.24
10.82
7.63 to 21.93
3.19 to 23.43
t = 1.235, P = 0.245ns, df = 10

Total losses
Average
Range

21.34
11.18 to 29.99
t = 2.27, P = 0.047‫٭‬, df = 10
Note: **significant at 1% level; *significant at 5% level; ns = non-significant

11.88
4.42 to 24.41

Effects of Packaging Materials and Storage Durations on Total Weight of Stored Sesame
The harvested sesame seed/grain was dried, weighed and stored in two types of packaging materials,
pioneer superbags and woven polypropylene bag, for eight months at the farmers’ houses. Every twomonths during this period, samples were taken, cleaned and weighed. Pests were found in the stored
sesame, therefore, one of the main factors causing reduction in weight may be pest infestations during
the storage period. Insects alone can cause 36 to 43 percent storage loss (Bala et al., 1990).
Sufficiently airtight storage systems, although allowing insects and other aerobic organisms toinitially survive, oxygen concentrations are decreased below those permitting further insect
development (Chanda, 2013). In pre-monsoon sesame, the weight of stored seed/grain (500 g)
decreased significantly in two months (482.88 g) a trend that continued until four months (477.96 g),
and which then again significantly decreased by six months, with a loss of 464.97 g and on into theeighth month, when sesame weight decreased to 446 g. In post-monsoon sesame, the initial stored
weight (500 g) was not significantly reduced in the first two months (497.19 g), or for the periods
following (in four months (494.45 g), in six months (494.24 g), but it then decreased significantly inthe six to eight month period to 469.84 g. Therefore, it can be seen that storage losses of pre-monsoon
sesame (10.8%) was higher than post-monsoon sesame (6.03%) in the eight months of storage (Table
2).

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Table 2 Mean effects of packaging materials and durations on total weight of stored sesame
Stored weight (g)Treatment

Pre-monsoon sesame
Post-monsoon sesame
Packaging materials (P)Superbag484.01 a497.12 a
Woven polypropylene bag
464.72 b
485.17 b
LSD0.05
6.46
5.93
Storage duration (D)Initial storage
500.00 a
500.00 a
2 months
482.88 b
497.19 a
4 months
477.96 b
494.45 a
6 months
464.97 c494.24 a
8 months
446.00 d
469.84 b
LSD0.05
10.22
9.38
Pr > FP
0.00000.0002D
0.00000.0000
P×D
0.00030.0000CV (%)
2.62
2.32
Note: In each column, means with the same letter are not significantly different at 5 % level

Fig. 2 Combination effect of packaging materials Fig. 3 Combination effect of packaging
materials and storage duration on
and storage durations on the total weight of
total weight of post-monsoon
stored pre-monsoon sesame
sesame stored pre-monsoon sesame
The combination effect of packaging materials and storage durations on the total weight ofstored pre-monsoon sesame is shown in Fig. 2. In the first two months of storage, the weight ofseed/grain stored in the superbags did not fall, whereas seed stored in the woven polypropylene bags
was significantly reduced. After four months storage, the weight of sesame stored in the superbags
was significantly different to the weight at initial storage. The weight of stored sesame in the woven
polypropylene bags was also not significantly different than the weight of stored seed/grain weight
for two months, however, it was significantly different to the weight of sesame after six months
storage. From six months to eight months storage, the weight of sesame stored in superbags did not
significantly decrease, while the weight of sesame stored in woven polypropylene bag had decreased
significantly by eight months from the weight at six months (Fig. 2). By the end of the storage period
measured (eight months), the weight loss of pre-monsoon sesame stored in superbags was 6.36%,
while for sesame in woven polypropylene bag there was a loss of 15.24%.
The combination effect of packaging materials and storage durations on the total weight ofstored post-monsoon sesame is shown in Fig. 3. The weight of stored sesame in superbags did not
significantly decrease over eight months storage, while the weight of sesame stored in woven
polypropylene bag maintained similar weights for the first six months and then decreased
significantly at eight months storage with a 10.82% weight loss (Fig. 3). As the packaging materials
are airtight, insects and aerobic microorganisms creates an inhibitory environment over time byⒸ ISERD

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increasing carbon dioxide concentration and decreasing oxygen due to their respiratory metabolism(Adler et al., 2000). If the weight loss of pre-monsoon and post-monsoon sesame during storage iscompared, losses of pre-monsoon sesame occurred in both the superbags and woven polypropylenebags, however, losses of the post-monsoon sesame were found only in the woven polypropylene bags.
This might be due to the initial seed moisture content at time of storage, as the initial moisture content
of pre-monsoon sesame was higher than that of post-monsoon sesame. When using airtight storage
methods, it is important to have a very well dried product at the beginning of the storage period(Hayma, 2003). Also Ben et al. (2009) reported that one of the main challenges of using hermetic
bags is that the grain to be stored should be thoroughly dried to avoid mold and the rotting of grains.
CONCLUSION
The range of the total postharvest losses of pre-monsoon sesame and post-monsoon sesame were(11.18% to 29.99%) and (4.42% to 24.41%). Storage losses were the highest contributor to losses
among all the postharvest processes for sesame in both seasons. Storage losses can be mitigated byuse of efficient storage technology, and upgrading both infrastructure and storage practices. When
comparing postharvest losses, the losses were higher in pre-monsoon sesame than for post-monsoon
sesame, except for harvest losses. Although the losses in harvesting, stacking, stalk drying andthreshing, winnowing and total post-harvest losses were significantly different, the difference in theamount lost during the storage stage for pre and post-monsoon crops were non-significant. The
differences of losses that occurred during stacking, stalk drying and threshing and winnowing were
due to the different handling practices of farmers. Therefore, if farmers had a good threshing floor,
post-harvest losses would be reduced and a better quality product produced. In regard to the
packaging materials, a significant difference of total weight of stored sesame that was lost can beseen for the different packaging materials surveyed. Storage in superbags resulted in far less sesame
weight loss than storage in woven polypropylene bags.
ACKNOWLEDGEMENTS
This study was financially supported by Technical Cooperation Program of Japan International
Cooperation Agency (JICA-TCP).
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