Potatoes are not only used as a vegetable for consumption at home but also at restaurants. Global consumption of potato as a food item has seen a shift from fresh potatoes to value-added products. It is estimated that a little less than 50 percent of potatoes grown worldwide are consumed fresh. The remaining are processed into potato food products and food ingredients like animal feed, processed into starch for industry, and re-used as seed for growing next season’s potato crop.
Worldwide there is increase in production and trading of potato starch. On average, each year the import of potato starch is increasing at a rate of 6.73% worldwide and 20% in Pakistan. Pakistan has abundance of unprocessed potatoes, especially in Punjab province. However, many companies in Pakistan are importing potato starch to meet their demand due to lack of potato processing facilities in Pakistan. In 2015, Pakistan imported 6,019 tons of potato starch worth 4.27 million dollars from the world (i.e Denmark, France, Germany, etc.).
The proposed unit having capacity to produce 6,480 tons of potato starch a year based on 180 days, can meet the local demand and enter into global market for export. Although it is not recommended to use cold storage potatoes for producing potato starch, a dedicated cold storage facility maintaining an ideal temperature (e.g. 8ºC) with appropriate maintenance levels may yield quality potato starch. However, this pre-feasibility study proposes use of fresh potatoes as raw material for producing potato starch.
Potato Starch Uses in Pakistan
Potato Starch is a fine, powdery thickener consisting of starch extracted from potatoes. It looks, feels and acts a great deal like corn starch. Potato starch is made from the dried starch component of peeled potatoes. It has no potato flavor so works well in most recipes. As part of the starch component of a gluten-free flour blend, potato starch lends a light, fluffy texture to baked goods. As a dehydrated vegetable, Potato Starch can be used in a wide variety of industries including: food production, textile, chemical, paper, pharmaceutical, agriculture / animal feed, and various other industries. It can be used as:
- Additive for food processing, food starches are typically used as thickeners and stabilizers in foods such as puddings, custards, soups, sauces, gravies, pie fillings, and salad dressings, and to make noodles and pastas
- Finishing fabrics and starch fabrics especially dyeing, weaving and wrap sizing
- It is also used in technical applications as wallpaper adhesive
- Antibiotics in pharmaceutical industry
- Nutritional supplement in food production
- Bread improver in baking
- Breading for fried foods; frozen fried chicken and seafood products
- Thickening agent; used in soup mixes sauces and baby foods
- Base material for many snack foods including potato-chip like fried products
Production Process of Potato Starch in Pakistan
Production process of potato starch is given below in detail:
Weighing / Transporting / De-stoning
The potatoes will be stored in the day storage after weighed. From the day storage the potatoes will be transported by water stream through a trough into a set of potato pumps which transport the potatoes to the de-stoner as well as washing without damage. Unloading of potatoes could be done in two ways:
- Dry – using elevators and tippers,
- Wet – using strong jet of water.
The potatoes will be transported by potato pumps through a trough into the gravity de-stoner where present stones and other heavy particles will be separated. Then the potatoes will be transported to de-watering grid, where the potatoes are separated from the washing water containing a lot of impurities and dirty. The washing water is discharged into the water treatment pool through gutter; the
potatoes are transported to first stage washer by water stream.
The potatoes will be transported by water stream further into the drum washer. Coarsely cleaning of potatoes takes place during the transport of potatoes to the scrubber by channel. In addition, before the scrubber, straw and stones separators are installed. Course particles as leaves, branches, wood and others will be sieved off on a screen (in front of water treatment pool).
The main cleaning is conducted in scrubber (different kinds of high specialized machines are used). The remaining stones, sludge and light wastes are removed at this step. Water used for washing is then purified and recycled back into the process.
The washed potatoes will be taken up by an inclined belt conveyor, which transports them into the rasping storage hopper.
The potatoes will be transported by water stream further into the drum washer. This drum works at a low water level and takes care of an intensive cleaning of the potatoes. The potatoes rub and impact each other via the rotating drum to get cleaned. The fresh water is fed into the outlet of washer and washes the potatoes counter-currently. Then the impure wash water is discharged from the drain of potato inlet of the washer. The wash water stream will work completely in counter current.
Course particles as leaves, branches, wood and others will be sieved off on a screen (in front of water treatment pool). The used washing water is discharged into the water treatment pool. After the impurities are separated as sediment, the water is reused as transporting water in water transporting section. The washed potatoes will be taken up by an inclined belt conveyor, which transports them into the rasping storage hopper.
Rasping of the Tubers
The special designed Stainless Steel rasper is easy to operate. The most effective but simple clamping system guarantees an optimal position of the rasper blades and the clamping working. Demounting and mounting can be done by unskilled labor. The Stainless Steel sieve plate is one part and can be replaced without tools which ensure optimal efficiency and high starch yields.
The purpose of this stage is disruption of cell walls, which therefore release the starch. In practice, potato cells are not entirely destroyed and part of the starch remains in the mash.
De-Sanding / Fiber Extraction
After rasping the obtained potato slurry will be pumped by a centrifugal pump into a de-sanding cyclone unit. In this unit sand will be collected into the collecting vessel and can be discharged periodically automatically by means of two automatic operating discharge valves.
From the de-sanding unit the potato slurry enters into the extraction unit consisting of 3 conical rotary sieves with integrated fiber and starch slurry pumps. By this 3 step sieving the fibers are washed out counter currently by fruit water from the multi cyclone unit. The washed fibers will be pumped into the de-watering sieve, where they will be de-watered. This pulp can be sold as feed.
The washed-out starch slurry from the extraction unit will be pumped into the multistage concentration and starch milk washing unit. The overflow of the concentration is partly used in the washing of the fibers in the extraction unit and will partly leave the installation as effluent. The overflow from the concentration part is almost starch free. The concentrated starch milk from the last stage will enter the washing unit. Here the starch is washed in counter current with clean wash water. The overflow from the first washing stage is send to the fine fiber sieving unit and is, after sieving, pumped back to the washing unit. The collected fibers are pumped to the final pulp de-watering in the extraction unit. The fibers are washed with clean water.
De-watering of Refined Starch Milk and Starch Drying
It is a suspension of starch in water, which needs de-watering up to 20% of moisture. This is equivalent to the moisture content of commercial starch when stored. High temperatures cannot be used in this process because of the danger of starch gelatinization which destroys granular structure. It may result in significant changes of the functional starch properties. Therefore, removal of excess water from milk shall be done only under conditions that prevent the gelatinization of starch.
The final starch milk is collected in a tank with agitator. From this tank the starch milk is pumped to the filter trough of the rotary vacuum filter. The starch milk is diluted with water. The vacuum is created by a watering vacuum pump. The starch is sucked against the surface of the rotating drum and is scraped off by a fixed scraper device.
Drying / Bagging
After de-watering of the starch milk, the starch cake is transported by belt conveyors to the feed hopper from where it is forced into the hot air stream inside of the drying duct. The hot air is created by a steam-heated heat exchanger. The starch is heated by the hot air and the present water will be evaporated. After the drying, the starch is separated from the air by a set of cyclones, at the bottom side closed by a rotating airlock. The humid air is leaving the cyclone through the overflow and will be blown by the ventilator into the atmosphere. The collected dried starch is transported by a set of screw conveyors to a vibrating sieve unit, where the eventual coarse materials will be separated from the fine starch. After sieving, the starch is transported into a starch silo, where the starch is cooled by retention time. From the silo the starch is extracted by the bagging installation, where the starch is bagged into 25kg bags.
Waste / Bi Products
Potato juice is a liquid waste product separated from the potatoes pulp after the rasping, using centrifuges or decanters. It contains about 5% of dry substance, including about 2% valuable protein of the potato of high nutritional value, minerals, vitamins and other. Modern starch plants separate the juice from the mash.
Potato protein can be extracted from the juice by coagulation with heat at low pH. About 600 kg of coagulated protein from each 1000 kg of potato protein can be recovered this way. The coagulated protein product contains about 80% protein (with the digestibility of about 90%), 2.5% minerals, 1.5% fat, 6% nitrogen-free substances and 10% water. Because of the full range of the exogenic amino acids the formulation is a valuable protein feed. The remaining potato Juice is used as fertilizer.
Potato pulp is a side product of washing the starch from the mash. It contains all non-starchy substances insoluble in water (fragments of wall of cells) fibers and bounded starch which cannot be mechanically separated from the blended parties of potato. The dry substance of the pulp contains 30% of starch, which makes it a good source for animal feed. The pulp contains a lot of water, dry solids about 16%, which is inconvenient in transportation and storage. That’s why it is really often dried and dehydrated.
Juicy water is a liquid side product obtained after refining of starch milk. It is ten times diluted potato juice. As it is a sludge and it cannot be discharged to open water. It must be treated as waste water or is used as fertilizer.
Success Factors for Potato Starch Production Business in Pakistan
Following principles need to be pursued for the best productivity of Potato Starch:
- Prices of Potatoes are volatile, so due care and diligence should be taken while procuring fresh potatoes. An experienced procurement officer having good knowledge and understanding of potatoes quality and price fluctuation should be permanently hired for the facility.
- Potatoes with high solid contents and low sugar are best to produce dehydrated products. These types of potatoes are widely available in Pakistan.
- Quality raw (potato) material and adaptive research & development is necessary for the project.
- Storage management and quality improvement is needed.
- Policy intervention and government support is required.
- Enhance the skill of the contract farmers and the process relevant staff and management should be ensured.
- Capacity building of the farmers, company staff and the management are lacking as this is a newly ventured sector, infusion of technical services & appropriate know-how are always a catalyst for the better performance.
- Run project on 3 shifts in peak season of potatoes harvesting as the raw material will be available at cheap price and the quality of Potato Starch will be of high standards, while, it will save cost of storage.
- Genetic modification of the potato plant is a key aspect of the potato starch market. The development of potatoes that contain only amylopectin, which is the majorly used ingredient, is an active area of research and is touted to greatly increase efficiency and profitability for the starch manufacturers.
The unit can be installed anywhere in Pakistan where the raw material (fresh potatoes) is easily accessible. As per current agricultural practices, Okara is the largest producer of Potatoes not only in Punjab Province but Pakistan. In 2014-15, Okara district produced 1.4 million tons of Potatoes which is 37% of the production of Punjab and 34% of the Pakistan’s total Potato Production. Total production of Potatoes in Pakistan during 2014-15 was 4.16 million tons out of which Punjab province is producing 97% of the potatoes production.
Keeping in view the above statistics and availability of raw material (fresh potatoes), the proposed unit will be installed near district Okara in Punjab. Potato Starch imports may be reduced by installation of such units.
The targeted customers for these products are food production, textile, chemical, paper, pharmaceutical, agriculture / animal feed, and various other industries. The main export markets for Pakistani processed Potatoes are Middle East, Far East, China, Malaysia, and neighboring countries.
Investment Required for Potato Starch Manufacturing Unit in Pakistan
The installed production capacity of potato starch unit is 1.5 tons per hour which adds up to producing 6,480 tons of potato starch per year based on 180 working days (24 hours a day). However, the capacity utilization during the first year of operations is assumed to be 75% i.e. 4,860 tons of potato starch. The proposed unit comprises a total investment of 189.86 million rupees with fixed investment of Rs. 171.84 million and working capital of Rs. 18.02 million. The Net Present Value (NPV) of the project is Rs. 98.08 million with an Internal Rate of Return (IRR) of 26% and a payback period of 4.53 years. Details of these financials can be studied in the potato starch business plan in Pakistan.