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Potato starch based warp yarn sizing: new ray of hope for the rural farmers of bangladesh

Abstract: Potato starch a promising sizing material, is unable to get its proper concentration in the textile industry because Bangladesh uses only a few amounts of imported potato starch for delicate yarn sizing which is costly.

But Bangladesh can easily produce good quality potato starch domestically for the textile weaving sector in order to create a new market and replace the existing starch market.

As well as by using domestically produced starch, a new ray of hope and happiness can be created for the rural potato farmers. This can be one of simplest ways of making surplus potatoes more value-added.

Potato starch based warp yarn sizing

Introduction: World’s 2nd largest textile producing country (Latifee, 2016) is quite lagging in woven production and export. Only 35% of export oriented woven fabrics are produced in Bangladesh and the rest of the fabrics are imported. (Subrata, 2013)

An effective sizing process can improve the scenario as sizing is known as the heart of weaving.

Nowadays potato starch is getting more popularity as an effective sizing material worldwide. The global potato starch market is anticipated to reach a volume of 4.20 Million Tons by 2022, growing at a CAGR of nearly 3% during 2017-2022. (DUBLIN, Jan. 4, 2018)

According to the statistical data, Bangladesh already imported the high amount of starches and residue of starches till June 2018 (the fiscal year 2017-18).

Product Trade Value (thousands) Share (%) Growth (% 5yr)
Starches 6,814 0.02 334.56
Residues of Starch 852 0.00 0.00
*Top Products Imported by Bangladesh, June 2018

Though Bangladesh is also exporting some raw potatoes and starch but the total amount are not significant enough to impact on total economy. Till 2018 (fiscal year 2017-18), import statistics can be like:

Product Trade Value (thousands) Share (%) Growth (% 5yr)
Potatoes 1,596 0.00 963.64
Starches 41 0.00 0.00
*Top Products Exported by Bangladesh, June 2018

Using locally potato starch as a sizing material can be a very good replacement according to the perspective of Bangladesh. The rate of potato production is quite higher in Bangladesh.

Each and every year huge amount of potato remains unsold and became wastage. These potatoes can be used effectively for starch production.

In the 2017 fiscal year the total amount of potato produced was 10 million tons (Bangladesh expects huge potato surplus due to increased supply and sluggish demand, 2017) where total demand of potato was around 7 million tons. (Zaman, 2017)

So, 3 million tons of potatoes of 44 variety remains as the surplus amount (Potato Production in Bangladesh hits an all-time high, 2016). The scenario of economic status related to potato production in 2017 can be like:

Table 2.1: Calculation of loss related to potato wastage
Reason Problem Quantity
of Potato
Economic value
Surplus of
Wastage 2 Million
More Than 2000 Crore BDT
(If Per Kg Potato is 10 BDT)
Surplus/ Greedy
Mindset of
Price of
potato falls
down in
storage gate.
Around 1360 Crore BDT
(If loss per Kg Potato is 5TK
in storage gate)
Overall Loss: More Than 3300 Crore BDT

2.1. Objectives of the study

  • To extract starch from Bangladeshi potatoes
  • To analyze its performance as a standard natural sizing chemical.
  • To analyze the feasibility of potato starch as a sizing material
  • To analyze sizing market scenario

The project has five parts. Firstly the present market analysis. Then, the process or methodology of execution will be described. Next, the properties of potato starch as a size material will be explained.

Then the feasibility comes forward and the paper concludes with the further scopes and possibility description.

3. The methodology of the Project:

  • The whole project can be divided into 4 steps. Initial idea generation,
  • Product development
  • Experimental data analysis
  • Feasibility analysis

3.1. Intial idea generation 

Bangladesh is wasting potato drastically from last several years as because of its surplus production. Potato farmers become frustated and loss their interest in potato production. Sometimes they are planning to keeping their land vacant instead of potato cultivation. If this project works then it can ensure the happiness of the rural farmers as potato will get its market back and on the other hand woven manufacturers will also bacome happy as they can use their local potato starch on low price.

3.2. Product development
Procedure of starch extruction from raw potatoes are described below:

Starch Extraction Procedure
Figure 3.1: Starch Extraction Procedure.

Around 5-6kg of potatoes will require to extract 1kg of dry starch powder.

Potato starch extruction machine design: Manual extruction of potato starch is quite time consuming and difficult. In order to ensure bulk production below type machines can be use with a very easy operating mechanism.

Potato starch extruction machine design

Sizing of Warp Yarn: After preparing dry starch powder, sizing can be done by using that starch powder. Generally three different types of sizing recipe can be follow for commercial warp yarn sizing. Light, pure, medium and heavy sizing. In this project pure sizing recipe was followed.

Sizing Recipe: Sizing Ingredients:
Water: 85%
Total Sizing Ingredients: 15%
Starch: 100 lbs
Clay: 34lbs
Tallow: 15lbs
2: 1 gallon
2: ½ gallon

3.3. Result & Discussion: Sizing chemicals must have to show some properties, so that it can be accepted widely into the commercial market for sizing.

Appearance of Potato Starch
Figure 4.1: Appearance
of Potato Starch.

Evaluation of potato starch as a sizing material is described below:

Property Result
Visual Appearance Solid Powder Form
Color Pure White
Size Pick Up % 18.6%
General pH Value 6.6 ~ 7.0 (Neutral)
Transparency of size solution Liquid Colorless
Odor Very Slight
Desizing Procedure Slight Alkaline Wash.
Film Property Non-Stiff starch film with good elasticity.
Adhesive Property Very good
  • Determination of Starch Content Percentage: Total stacrh conent present in grams per kilogram of diamond potato extracted solid powder is calculated below:
    According to ISO 6493, starch content of a test sample can be calculate by this equation,
    equation Here, w = numerical value of starch content (in grams per killogram)
    𝑎1 = numerical value of total optical rotation (in degree’s) of HCl soluble
    substances = 53.4⁰
    𝑎2 = numerical value of total optical rotation (in degree’s) of ethanol soluble
    substances = 18.70⁰
    𝑚1= numerical value of the mass (in grams) of the test portion for the
    determination of optical rotation after adding HCl =2.5+2.5g = 5g

    𝑚2= numerical value of the mass (in grams) of the test portion for the
    determination of optical rotation after adding Ethanol =2.5+2.5g = 5g
    𝑎𝐷20= numerical value of the specific optical rotation (in degree’s)
    For potato starch
    According to the equation, total content of starch in diamond potato extracted powder is 861.6 gm per killogram. So, starch percentage will be 86.16%. Total percentage of starch in extracted powder can vary according to the varriartion of potato.
  • Appearance/ Hairiness of Yarn After Sizing: Potato starch coated the warp yarn excellently after sizing. Coating propertly of potato starch based sizing material is quite impressive as like commercial starch (i.e. corn starch) even by accurate sizing procedure it can show much better properties than compared to corn starch.

    Appearance of (A) Unsized, (B) Corn Sized, (C) Potato Sized Yarn
    Figure 4.2: Appearance of (A) Unsized, (B) Corn Sized, (C) Potato Sized Yarn.
  • Viscosity of the Sizing Solution: Another important factor for good sizing is maintainance of proper viscosity in the sizing solution. If viscosity of the solution is too low then size materials will loss it’s ability of coating protruding fibers. Again if viscosity of solution becomes too much then sizing property also be hampered.

Table 4.2: Comparison of Viscosity between Corn & Potato Based Sizing Solution

Corn starch based
sizing solution
Potato starch based sizing
Viscosity: 130 mPas
Temp: 25.6
0C to
Viscosity: 225 mPas
Full Scale Percentage: 59.3%
Temp: 30.3
0C to 30.20C

Viscosity of potato starch based sizing solution is slightly more than the viscosity of corn starch based sizing solution. But, viscosity of potato starch based sizing solution in controllable. By using less amount of potato starch good label of viscosity can be observe as potato starch shows very good adhesive property.

  • Effect on Yarn Strength & Elongation After Sizing: Potato starch ensures good strength and elongation property of yarn after sizing. According to strength and elongation test method ASTM D2256-10 effect of potato starch based sizing on cotton yarn shown below:
    Property Before Sizing of Yarn After Sizing of Yarn
    Mean Elongation % 6.1% 6.8%
    Mean Breaking Strength 555.3 CN 618.4 CN

    Ratio of strength and elongation of sized and unsized yarn can be describe presicely by below table and chart:

    No. (Yarn)
    Of Sized
    Ratio of
    At Break (%)
    Of Sized
    At Break (%)
    Of Unsized
    Ratio of
    At Break
    01 639.66 568.17 1.126 6.93 6.15 1.127
    02 598.48 533.66 1.121 6.42 5.79 1.109
    03 578.76 557.46 1.038 6.48 6.27 1.033
    04 676.81 551.55 1.227 7.66 6.12 1.252
    05 585.74 532.65 1.100 6.09 6.06 1.005
    06 614.45 558.94 1.099 6.74 6.00 1.123
    07 616.82 562.20 1.097 7.03 6.29 1.118
    08 605.96 569.48 1.064 6.82 6.51 1.048
    09 625.39 568.34 1.100 6.98 5.85 1.193
    10 641.70 550.17 1.166 7.11 5.77 1.232
    Mean 618.38 555.26 1.114 6.83 6.08 1.123
    29.18 13.43 0.4329 0.2372
    nt of var.
    4.72% 2.42% 6.34% 3.90%

    Graphical Representation of Result:
    potato sizing

  • Effect on Yarn Count After Sizing: Potato starch based sizing increase yarn diameter as because of the protective sizing layer. As a result of potato sizing yarns of 35.9 Tex increased into 41.6 Tex.

Cost Feasibility: Usually Bangladesh uses imported potato starch which is quite costly (Approx 120-150 BDT per kg). But the cost of locally produced potato starch is cheaper than the imported one, in fact, it’s also cheaper than the market rate of another widely used starch powder “corn starch”. 

According to the table, the cost of producing per kg potato starch is approx. 77.2 BDT which is around 30-40% cheaper than the market price. If selling price of per kg starch will be 90 BDT (around 13 BDT profit per kg), even then the price will be minimum 30-60 BDT lower than the market price.

In this cost estimation, the market price of potato is estimated. But if potato can be collect from raw farmers price will decrease the minimum of 40%-50% per kg of potato. In that case, price will be reduced more.

Ingredients Amount Cost
Raw Material (Potato) 5-6 Ton 60000 BDT
Manpower (2 girls 3
boys) For the whole
Process line
Girls Per shift Salary
400 BDT each.
Boys Per Shift Salary
800 BDT each.
=3200 BDT
Electricity Charge Per Shift 2000BDT
Labor Cost &
Transportation Cost
5-6 Ton Potato Per Kg Potato=2 BDT
6 Ton Potato=12000BDT
Total Cost of Per Ton
Starch Processing
77200 BDT
Total Cost Per Kg of
Starch Processing
(77200/1000) =77.2 BDT

3.4.Feasibility Analysis

Economic Feasibility
• Minimize loss related to potato wastage (approx. value 3300 crore BDT in 2016-17 fiscal year)
• Minimize potato starch importing cost
• Less amount of potatoes have to store which ensures low storage cost
• Proper market price of potato make farmers economically strong
• Residual potato pulp can contribute in food industry (basically chips

Social Feasibility
• Farmers will become interested again on potato cultivation
• Locally produced potato starch will uphold the local dignity of Bangladesh towards the world.
• Root label farmers will get empowerment
• Bridge between textile & agriculture sector was established

Environmental Feasibility
• As potato is a naturally grown product, no possibility of spreading toxicity
• Dumping and wastage rate of potato will decrease
• Potato starch is a complete bio-degradable product
• Can be used as a food item also. (As a replacement of corn starch)

4.3. Discussion & Implementation
According to the properties and test results, it can be stated that potato starch can use as a sizing material. It complies with almost all properties of standard sizing material. It shows good strength, elongation, etc properties which is mandatory for weaving as well as potato starch is completely sustainable and environmentally friendly as a chemical.

Implementation of potato starch can be done initially in a small scale to experiment with the commercial acceptance of the material. Residual potato pulp can be used in the chips industry as a low carbohydrate-containing crunchy chips.

4.4. Limitations & Further Scope
There are still a lot of scope to accomplish work on this issue. Potato starch has to be evaluated from each and every possible aspect before initializing its use as a commercial starch. Due to time shortage, various processes couldn’t be executed in a proper way. Further scopes of study can be like:

  • Determination of wearability of yarns sized by potato starch
  • Detail comparison among commercially used starches like corn starch, maze starch etc. with potato starch
  • Properties of potato-sized yarn when it sized with other sizing recipes like light sizing, medium sizing, heavy sizing, etc
  • Market analysis and feasibility study of locally produced potato starch
  • Study about the detailed process of potato starch production. etc

4. Conclusion 

Potato starch based sizing material is a technique which can be an effective solution of the surplus of potato production. It can help the raw potato farmers who lost their hope of profit. It can save the cost of imported potato-based starch material.

The effectiveness of potato starch-based sizing material is quite similar with the commercially usable starches. But by using this method, Bangladesh can make a new ray of hope which will make a bridge between the textile and agriculture sector of the country.

It is not impossible that, near future, Bangladesh will also establish its name as a potato starch exporting country. The most important thing is this technique can make the raw farmers happy who are the actual hero of Bangladesh.

If anyone has any feedback or input regarding the published news, please contact: info@textiletoday.com.bd

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