Scientific report: "Current status and post-harvest losses of some agricultural products in Quang Ngai-Vietnam" docx

85 Postharvest status and losses of some agricultural products in Quang ngai province - Vietnam Thực trạng và tổn thất sau thu hoạch của một số nông sản tại tỉnh Quảng Ngãi- Việt Nam

85

Postharvest status and losses of some agricultural

products

in Quang ngai province - Vietnam

Thực trạng và tổn thất sau thu hoạch của một số nông sản

tại tỉnh Quảng Ngãi- Việt Nam

Le Van Tan 1 , Le Van Luan 2 , Nguyen Van Toan 2 , Tran Ngoc Khiem 2 , Tran Văn Minh 2

1 Hochiminh city University of Industry, Vietnam

2 Department of Post harvest Technology Hue University of Agriculture and Forestry - Vietnam

TÓM TẮT

Các thí nghiệm nghiên cứu của nhóm tác giả từ năm 2003-2006 trên những nông sản sau: Dưa hấu, mía, sắn, lạc, ngô và lúa Kết quả cho thấy rằng tổn thất sau thu hoach của các nông sản này là rất cao: Dưa hấu 6.6 – 12.6 % , mía 1.46 - 3.26 %, Ngô 8.88 - 18.01 %, lúa 8.36 - 12.25 %, Lạc 13.33 - 17.02 %, Sắn lát 13.27 - 17.49 % và sắn bột 5.17 - 8.22 % Bằng các phương pháp đánh giá chất lượng, kết quả cũng chỉ ra rằng tổn thất chất lượng cũng rất cao Từ kết quả nghiên cứu, nhóm tác giả đề xuất các giải pháp sơ chế và bảo quản nhằm hạn chế tổn thất sau thu hoạch các nông sản này

Từ khóa: Dưa hấu, lạc, lúa, mía, sắn, tổn thất sau thu hoạch

SUMMARY

The experiments were conducted during the year 2003 - 2006 with the following products: watermelon, sugar cane, cassava, groundnut, maize, and rice The results have shown that the postharvest losses of the above agricultural products in Quang Ngai, a province of central Vietnam, were very high: 6.6 – 12.6 % in watermelon, 1.46 - 3.26 % in sugar cane, 8.88 - 18.01 % in maize, 8.36 - 12.25 % in rice, 13.33 - 17.02 % in groundnut, 13.27 - 17.49 % in sliced cassava, and 5.17 - 8.22 in refined cassava powder Accordingly, the assessments in quality and quantity were implemented The findings presented the quality losses making up very high percentage From the results, the solutions are suggested to improve storing these types of agro-products

Keywords: Cassava, groundnut, maize, post harvest losses, rice, sugar cane, watermelon

1 INTRODUCTION

Postharvest losses are an issue attracting

attentions all over the world as well as in Vietnam

It is very difficult to make an increment in the yield

just by some percentages on a unit area (with great

efforts in creating new varieties, fertilizers,

pesticides and so on) but the losses in quality and

quantity during postharvest period are very high

and even higher than the yield increase if the

products are not stored properly There exist many

types of agro-products in the central regions in

Vietnam but the cultivating areas vary and the

quantity of these products (after harvesting) depends on the change of different seasons The climate in the area is not suitable for storing harvested agricultural products and it normally results in losses and it is very difficult to control these losses Quang Ngai is a province in the Central of Vietnam where crops such as watermelon, groundnut, cassava; rice, sugar cane etc are grown widely with high productivity Statistical figures show that Quang Ngai province produces a large quantity of agro-products every year The annual output of 503,364 tons of sugar cane; 311,672 tons of paddy; 24,902 tons of maize;

90,658 tons of cassava; 7,964 tons of groundnut

and so on These figures are rather high in

comparison with those in the same area (statistic

book 1996 – 2000) If the minimum estimated loss

after harvesting is 10 - 15 %, the quantities of

products wasted every year are 75,505 tons of sugar

cane; 46,750 tons of paddy; 3,735 tons of maize;

13,600 tons of cassava; 1,195 tons of groundnut

and they are worth about 120 billion VND The

matter to be taken into consideration is how to

prevent the losses during the stage of harvesting,

transporting, storing and processing these

agro-products

2 MATERIALS AND METHODS

 Following the researching results and

evaluated of special council, Watermelon, rice,

maize, groundnut, sugar cane and cassava are

chosen to conduct experiment

 For 1st period, Nghia hanh, Mo Duc, Binh

Son, Tu Nghia of Quang Ngai province are selected

to be the place to get findings

 Investigated households were randomly

selected

 Findings were collected from 2002 to 2004

and analyzed in the cropping season of the above

products

 Sampling was done at the site and during the

cropping season of studied products

 Evaluation method: Evaluate quantitative

and qualitative losses Findings were obtained by

PLA method, Gwiner et al (1996) and quality

attributes were analyzed in the laboratory of Hue

University of Agriculture and Forestry (Harris and

Lindblad, 1978; House and la Gra, 1979) :

a Sugar cane: analysis Bx, AP, Pol, RS, CCS,

fibre content and pH level

b Groundnuts: evaluate protein and lipid level

of contents

c Cassava: analysis starch, cellulose, sugar,

HCN level of contents

d Water-melon: analysis sugar, pH, Bx level

of contents

3 RESULTS AND DISCUSSION

Postharvest losses affect quantity and quality

of products Thus, the condition of the product after

harvest should be evaluated so that the solutions to

minimize these losses will be raised

3.1 Watermelon

3.1.1 Post harvest status

Watermelon is a high value product It gives

a higher profit for the growers in comparison with other crops on the same cultivation area Mechanization was only used in transportation and storage after harvesting 20.7% of farmers were used by small trucks, 21.4% used bicycles, 44.8% of motorbikes, and 10.2% other primitive means to transport products Those data clearly described the mechanisms used in transportation after harvesting In order to ensure the quality of products in post harvest period the melons have to

be picked at the mature stage The figures showed that 89.7% of farmers harvested the melons upon the characteristics of fruits, 62.1% based on cultivation schedule, and 27.6% acted on market demand Farmers normally used scissors to cut melons from their plants, which occupied 96.66% and the rest used knives Farmers mostly used primitive transportation means like motorbike, bicycle, and cart – 70% to wooden structure to help reducing the quality losses The melons were gathered and stored in yard or houses for sale Findings presented that 49.33% of farmers did not regularly clean the fruits, storage place, tools, and means of transportation

3.1.2 Postharvest losses

The findings of postharvest loss evaluation are presented in the following tables

Postharvest losses in terms of quantity of watermelon are very high from 6.6-12.6% The loss

at harvest was caused by improper handling technique and additionally most farmers did not pay attention to cleaning the fruits and fields while harvesting During transportation and storage melons are damaged due to lack of suitable containers (compared with statistical figures from 1996-2000 of Quang Nam, the losses of watermelon is from 10-11.2%) So the losses of Quang Ngai are rather high

The dry matter and sugar content decreased quickly after 9 days of storage The decrease was higher when the storage reached the 12th days due to the evaporation of water and activities of available microorganisms present in the fruits These are the main reasons that reduced quality and shortened the shelf life of melons The rot quickly increased on the 12th day, covered

87

23.5% and then whole bulk of melons got rotten

(Table 2)

Table 1 Post harvest losses in quantity of watermelon

Table 2 Postharvest losses in terms of quality of watermelon after 15 days of storage

Table 3 Quantitative postharvest losses of sugarcane

Table 4 Quality changes during storage of sugar cane in the field

Bx: Brix, Pol: Polarimeter Ap: RS: Reducing Sugar, CCS: Commercial Sugar Cane

3.1.3 Proposed solutions

As a result of the evaluation the situation after

harvest, losses in quantity and quality of

watermelons could be reduced if following two

solutions were adopted

 Suitable containers should be invested such

as bamboo basket, carton box, bags etc to avoid

damage of fruits during transportation

 Harvested melons should be cleaned,

classified, and stored properly to prevent damage

and spoilage

3.2 Sugarcane

3.2.1 Post harvest status

Sugar cane was harvested 100% manually and

the tools used are knife, axe, hoe etc of which 97.1%

were axe After cutting, waiting for transportation of

sugar cane was very common, (around 75%) and this

decreased significantly the sugar content Most of

farmers used primitive means to transport sugar cane,

it was found that 78.3% of them used bicycles, 1.4%

used small trucks, and the rest 20.3% carried cane

bundles by hand This reflects the difficulty in

transportation within the fields Research showed

there were 49.3% cases that sugar cane had to remain

on site for a long time (3 days or more) due to lack of

transportation means; 37.7% due to lack of manpower

for cutting and 43.5% due to bad road that

prevented transportation Therefore, it is necessary

to invest in infrastructure especially transportation

system inside the fields and this applied not only

for sugarcane but also applied for another crops

There were 83.33% households that do not cover

the sugarcane bulk whereas 16.67% covered them

with tarpaulin, sugar-cane, and/or coconut leaf etc

During the storage of cane in the field awaiting

transportation, there were 61.1% households that

checked regularly the condition of cane and other

38.9% did not care about the cane quality

3.2.2 Quantitative postharvest losses

The quantitative losses from harvest to

transportation stages are 1.46 - 4.35% (Table 3)

Losses during storage in the field are rather high

(between 0.89% - 2.16%) and it is necessary to

cover sugarcane stalks to limit the damage caused

by mice and insects (according to Ngo 1987 (1),

these losses are acceptable)

3.2.3 Qualitative post harvest losses

Two bulks of sugarcane, which had been stored in the field, marked as A (without cover) and

B (with cover) were analyzed record the changes in quality within 7 days after cutting (Table 4)

A faster decrease in sugar content in the sugarcane stalks without cover in comparison with those covered (Table 4) The longer storage makes

pH lower and this facilitates conversion of sucrose into invert sugars As a result the CCS will decrease quickly Therefore, harvested sugarcane should be transported to factory early to avoid losses during storage (according to Ngo, 1987, the quality losses needs to be reduced, especially of CCS)

To prevent the losses, the following solutions can be applied

 Cover the harvested sugarcane stalk in the field

 Minimize the storage time in the field

 Cut sugarcane at mature stage, do not let them become overripe (cane blossom)

 Close coordination between factory and cane growers should be established to enable to issue cutting slips in time

 Construct transportation system inside the field and establish temporary cane stores appropriate place for easier transport

3.3 Maize, rice, groundnuts

3.3.1 Postharvest status of maize

There were 70.8% of farmers who store shelled maize whereas 29.2% kept them intact with cob and leaf Most of farmers (70.8%) stored maize kernels in pottery jars, barrels, wooden boxes, rolled bamboo mat and bag Shelling corn was done manually (95.8%) Most of farmers dried maize on brick or concrete paved yards and flat bamboo baskets Improved drying structure and flat bed dryers were available but none of them used them for storing maize There were 39.2% households that did not clean containers before using them for storing maize This caused spoilage by pests and microorganisms

3.3.2 Postharvest status of groundnut

Mechanization was used during post harvest operations for transportation, drying, shelling, and oil pressing Farmers used the following transportation means to bring groundnut from the field to their houses: 17.8% by truck, 66.7% by small trucks, and the rest used motorbike, bicycles,

Formatted: Bullets and Numbering

Formatted: Bullets and Numbering

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and other primitive means Drying was done

(100%) by sun and there were no household using

mechanical dryers Groundnut shelling was done

manually by100% farmers Out of those 85.2%

used hands to do the job and 14.8% used simple

tools Groundnut were dried on the brick or

concrete paved yards after harvesting with a

thickness of groundnut layer varying between 3 - 7

cm Evaluation of situation of groundnut post

harvest shows that following points that are to be

taken into consideration

 Groundnut percentage left in the ground is

rather high in harvest stage

 In transportation, groundnuts were dumped

into the vehicles without covering the latter and thus

the percentage of loss due shattering was very high

 In many cases drying groundnuts were

exposed to rain and got damp for a long time

resulting in spoilage due to germination and

moulds

 Significant losses occurred in storage

especially with regard to groundnut quality

3.3.3 Postharvest status of rice

Mechanization applied at various stages of rice

post harvest such as cutting, threshing, grading,

drying, shelling, milling, and transportation Survey

shows that harvesting dates were selected by

farmers on the basis of the following factors:

hardness of grains 70%, cultivation schedule of

each variety 59.1%, characteristics of varieties

41.8%, and climate 16.4% Most farmers used

primitive tools to harvest: 93.6% used sickle, 1.8%

used bush knife, and 4.6% used mowers The

majority of farmers (92.7%) used bicycle to

transport rice whereas the rest used small trucks,

motorbike and bamboo frame carried by people

After cutting, rice was transported to a threshing

yard This was the main operation in production

line after harvest and this process included:

bundling, transporting, temporary storing for

threshing and transporting rice grains to the houses

Research showed that 43.6% households gathered

rice at temporary place and 12.5% had to keep rice

overnight The main reason of keeping rice

overnight was lack of transportation means 11.8%,

lack of manpower 18.2%, bad road obstructed the

transportation 30.9% and waiting in line for

threshing 28.2%

Threshing, cleaning, and primary grading

required significant manpower and time The

majority of farmers (81%) in surveyed locations

used motorized threshing and 19% used pedal type

one The figures show that the percentage of mechanized operations involved in this process had significantly increased in comparison with the previous decade Farmers dried rice mostly using sunshine and wind There were 26.4% households drying on brick paved yards, 34.5% on concrete yard, 10.9% directly on the ground, and 18.2% on tarpaulin Cleaning containers and equipment before storage is a must to avoid cross contamination by insects and microorganisms from previous rice crops to newly harvested ones

Research showed that 23.6% households did not clean the containers and equipment before storage and this affected the spoilage percentage of grains after storage There were only 58.2% of the households that monitored moisture content and insects during rice storage

3.3.4 Quantitative post harvest losses of maize, groundnut and rice

The following comments are drawn from the figures showed in table 5 Losses in quantity during post harvest operations of the above products are rather high, of which:

 Losses of maize are 10.88 - 18.01%

 Losses of groundnut are 13.33 - 16.82%

 Losses of rice are 8.36 - 13.37%

Two stages that have biggest losses and have

to be taken care of are drying and storage (compared with statistical figures from 1996 - 2000

of Thua Thien Hue, and according to Chuong, 2002 (4), the losses of maize are between 4.97 - 9.35 %, the losses of groundnuts are between 9.97 - 18.02

%, the losses of rice are between 7.15 - 14.02 %)

So the losses of Quang Ngai are rather high

3.4 Cassava

3.4.1 Post harvest status

Survey showed that 60% of farmers used hoe to harvest, 33.33% used clamp to pull it and 6.66%

used levers There were 83.33% of households that did not clean the place where the cassava was placed and only 16.66% households cleaned that place

There were 4.3% households using bamboo basket

to store dried sliced cassava, 21.3% stored it loose in their house, 42.6% kept in barrels, pottery jars, and 14.9% used bags lined with plastic sheet and the rest used any kinds of available containers for storage

3.4.2 Post harvest losses

Results of loss evaluation during storage and semi-process of sliced cassava are represented in table 6

Formatted: Bullets and Numbering

Formatted: Bullets and Numbering

The losses in sliced cassava and refined

powder of cassava are very high Thus, the post

harvest technologies with cassava plants and

products processed from them have to be taken into consideration

Table 5 Quantitative losses of maize, groundnut, and rice

(%)

Maize

Groundnut

Rice

Table 6 Post harvest losses in production of sliced cassava

(%)

Table 7 Post harvest losses in production of refined cassava powder

(%)

91

Processing refined powder, grinding

4 CONCLUSION

The losses in quantity of watermelon are

estimated at 6.6 - 12.6 % Dried substances (%) and

sugar content (%) gradually decrease as opposed to

pH in 15 days of storage

The quantitative losses of sugarcane are

estimated at 1.46 - 3.26 % Commercial sugarcane

gradually decreases during 7 days of storage

The quantitative losses of maize are estimated

between 10.88 - 18.01 % The quantitative losses of

groundnut are estimated between 13.33 - 16.82 %

The quantitative losses of rice are estimated

between 8.36 - 13.37 %

The quantitative losses of cassavaare estimated

between 13.27 - 17.49 % for sliced cassava and

5.17 - 8.32 % for refined cassava powder

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Amezquita, R and J La Gra (1979) A

methodological approach to indentifying and

reducing posthaverst food losses

Inter_American Institute for cooperation in

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(Manihot esculenta Crantz) Vol 1 Pub by

Cassava Information Center, Cali, Colombia

Araullo, E.V., B Nestel and M Campbell (1974)

Cassava processing and storage Proceedings of

an interdisciplinary workshop held in Pattaya,

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Tropical Science 16: 49-63

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Cereal Chemists

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