ABSTRACT

Bangladesh is climatically a very good country for potato production, and production is

increasing very fast, but excess production sometimes creates havoc due to a glut in the

market. The country is geographically not in a position for good export, nor can the nation

always consume the total national production, because Bangladeshi people are ethically rice

consumers. That is why good production is often bad luck to the farmers. In order to solve

this problem, processing was thought to be the most ideal means, but practically there remain

constraints and problems in the processing potato value chain. The climatic conditions of

Bangladesh do not permit easy access to processing as that of more temperate countries. The

cost of production becomes high due to low dry matter content of the tubers produced under

Bangladesh conditions; owing to short day length and short winter period. But Bangladesh

has great aspect for processing of potato. The demand for processed product of potato has

increased. Many new industries has entered into the production of potato products like, chips,

French fries, cubes, cookies, ethanol, flour etc. For processing of potato the self life has

increased and the value of potato has also increased. Though the processing of potato has

great prospect there are many limiting factors also that may hamper the processing activities

of potato.

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INTRODUCTION

Potato (Solanum Tuberosum L.) is one of the most important vegetable crops and having a balanced

food containing about 75 to 80% water, 16 to 20% carbohydrates, 2.5 to 3.2% crude protein, 1.2 to

2.2% true protein, 0.8 to 1.2% mineral matter, 0.1 to 0.2% crude fats, 0.6% crude fiber and some

vitamins (Schoenemann,1977). It is a staple diet in European countries and its utilization both in

processed & fresh food form is increasing considerably in Asian countries (Brown, 2005). Moreover,

number of processing industries and potato products are increasing with the demand of specific

varieties. Besides culinary consumption, the use of potato has progressively increased as a raw

material by the processing industry (Iritani, 1981). Now a days, the most important features of potato

production is tuber quality (Brown, 2005). So quality attributes should take into account to fulfill the

customers and industry demand. Potato must meet a number of requirements including high dry

matter content and good color to fulfill the requirement of processing. Presently there is no variety for

processing purpose, developed locally, despite the increasing demand of acceptable yield and

processing quality. The yield and processing characteristics of available potato genotypes are largely

unidentified. Keeping in view the consumers requirement, it is important to identify varieties that

possess traits to meet the domestic demand and provide growers the opportunity to meet the

challenges of frequently changing market, production circumstances and improving their economic

condition (Connor et al., 2001).

Objectives1. To determine the prospects of potato product.

2. To determine the limitation of potato products.

3. To know and discuss about the product of potato.

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REVIEW OF LITERATURE

Ghulam Abbas,et al (2012) observed that french fry color exhibited negative correlation with

reducing sugar (r = -0.7046), total sugars (r = -0.6659) and positive correlation with dry

matter (r = 0.5013).This screening is helpful to the ongoing efforts to select the best genotype

for the emerging processing industry of Pakistan.

Macrae & Robinson (1993) One hundred grams of cooked potato contribute 250 mg of

potassium and can supply 6% and 12% of the daily iron requirement for children and adults,

respectively .

Martens (1995) The use of vacuum packaging greatly inhibits the progress of oxidative

reactions and inhibits the growth of aerobic microorganisms, which generally lead to

deterioration of foodstuffs during storage.

Rommens et al.(2010) High dry matter content increases chip yield, crispy-consistency, and

reduces oil absorption during cooking.

Wang-Pruski & Nowak, 2004). Low reducing sugars and phenol contents are required to

avoid dark color and bitter taste of processed products, which negatively affect consumer

acceptance .

Wiltshire & Cobb (1996) Higher temperatures increase metabolism, respiration and

physiological aging of potato tubers, resulting in the observed earlier sprouting and higher

carbohydrate consumption .

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Materials and methods

The secondary data were collected from different scientific papers, journals and theses by

using internet.

DISCUSSION

General manufacturing process

Fully ripe and matured potatoes are selected and they are thoroughly washed in either soak tanks or rotary washers to remove dust and dirt. Then they are peeled and cut into cubes or slice or stick form. Then they are dewatered and dried for a period of 3 to 4 hours to bring down the moisture level to around 10%. Further drying is carried out in a bin dryer to bring down the moisture level to around 5%. Then they are cooled and packed. To make potato powder, dehydrated slices are pulverized to the required mesh size and during this process; a small quantity of aluminum silicate is added to avoid formation of cake. CFTRI, Mysore, hasSuccessfully developed the process know-how. Process Flow Chart is as under:

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Figure 1: general flow chart of processing of potato

Processed products of potato

Potato chips

Potato chips are very thin pieces (1.27–1.78mmthick) of potatoes fried to a final oil and

moisture contents of 35% and 1.7%, respectively (Moreira et al., 1999). Potato chips contain

a significant amount of fat, reaching in many cases 1/3 of the total food product by weight

(Mellema, 2003). This ensures a high level of satiety, but can also pose a risk. Especially over

the last decade the desirability of the reducing fat content of deep fried products has been

recognized.

Peeling and washing technology

The first step in processing snack foods is preparation of the raw product. For potato chip

processing raw potatoes are pre-washed and stones removed to protect damage from the

processing equipment. The APS (Abrasive Peeling System) is the next step in preparing the

potatoes for slicing and frying. The peeler features adjustable peeling and brushing levels

improving product yield and the high speed virtually eliminates water consumption. The

innovative SWS (Slice Washing System) combine slicing with gentle washing. Featuring a

counter-flow wash system, fresh water consumption is reduced by 40% or more and lowers

the content of starch and proteins in the oil. An optional CBS (Continuous Blanching System)

features a cross circulation water bath to ensure even blanching of each slice. By evenly

blanching each slice, lower sugar content is achieved creating a more uniform color chip after

frying. This offers greater flexibility in the style of potatoes use to process chips. The potato

slices are then rinsed one more time and conveyed for more effective removal of surface

water before entering the fryer.

Frying technology

The frying process is the most important operation in the processing of potato chips. The ZFS

(Zonal Frying System) ensures even frying by adding and extracting oil through several inlets

and outlets. This allows controllable and more uniform temperature profiles along fryer and

minimizes oil volume. To promote separation, potato slices are separated in the front end of

the fryer by our patented FIST (Flow Injection Side Turbulent) system. The FIST and Zonal

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Flow systems combine to provide the lowest possible FFA (Free Fatty Acid) values. To

maintain high quality oil and to achieve even heat transfer, the fryer is equipped with an outer

frying oil circulation system. A continuous oil filter, circulation pump, and heat exchanger

combine to supply and maintain the freshest oil. Many processors are interested in providing

a lower fat, healthier product. With the LFS (Low Fat System) fat content can be reduced by

as much as 35% over typical levels. This innovative, proprietary high temperature steam

process reduces product fat content and preserves the recovered oil quality.

Storing technology

Once fried, the crispy potato chips are ready for inspection to ensure a quality packaged

product. The Guardian Sorter scans for defects and tonal variations such as green and black

spots on the finished product.

Flavoring technology

The potato chips are now ready for flavoring. From highly viscous oils to hydroscopic

coatings, PPM Technologies offers a variety of coating and seasoning solutions. Our broad

range of applicators includes Continuous Oil Applicators, Dry Ingredient Applicators, and

Slurry Coating Applicators ensuring the snack is flavored evenly. And, the Libra Technology

offers improved seasoning yield by controlling seasoning to real-time product flow.

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Figure:2. Potato chips processing machine

Product handling technology

Once flavored, product is ready to be packaged. PPM Technologies offers a variety of

product handling solutions. The VF Advance product line offers processors a simple, reliable

electromagnetic option for conveying, virtually eliminating maintenance. And our Special

Delivery and eclipse conveyors provide a gentle horizontal motion alternative for your

delicate products.

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Figure: 3 . Potato chips

Weighing technology

For weighing needs, PPM Technologies offers a series of Libra™ range of weighing

technology. We also work with various suppliers to offer complete, integrated lines. With

over 35 years in providing snack solutions, PPM Technologies has the knowledge and

experience to provide you with the complete solution for your processing needs.

French Fries

French fries are the main frozen products constituting 80-95% of the letters total volume.

Before being frozen, these are either finish-fries or are par-fried. Home prefer finish-fries

which can be serve after being heated in oven only. As per-fries, needed to be finish-fried in

deep oil or fat. French fries have high specific gravity and low reducing sugar content.

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Figure 4 : French Fries

Process Description for French Fries

De-stoning, washing and peel removal

The line is assumed to be fed with raw material (fruits and vegetables) in bulk boxes, which

are emptied direct in feed hopper. The bulk boxes are tipped in the dosing hopper, which

brings the product into the line. The line has an elevator behind the dosing hopper.De-stoning

takes place in a flume de-stoner with a stone catching trap. In the trap is an upward water

flow to prevent potatoes from trapping. The flume de-stoner ends with a dewatering sieve or

a drum washer. In the cyclone de-stoner the product comes in spiral water movement, stones

and heavy particles will sink against the current in to the stone collecting chamber. The

potatoes are floating over the drum washer. From the drum washer, the product is collected in

a screw conveyor to bring the product to the peeler.Peeling is done through steam peeler, in

this method the peel loses are less than with abrasive peeling. In steam peeling method,

potatoes are brought under pressure by means of steam and by means of steam heat; the outer

layer of the product is heated above atmospheric boiling temperature. Then the pressure is

released rapidly, so the potato cell moisture starts boiling and rubs the cell wall. The skin will

hang loose around the tuber. In the dry brush machine this loose skin is brushed away. The

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dry removal gives relative dry peel waste, which is directly usable as cattle feed. To clean the

last starch dirt form potatoes, an after washer is used followed by an inspection belt for

manual inspection belt fro manual inspection.

Cutting sorting and blanching

The product is collected in a dosing screw with an increased receiving hopper. This hopper

has a buffer for at least 10 minutes to cope with fluctuations in the feed or even with small

cleaning breaks or coffee breaks of the inspectors. The product is brought to the in-feed of the

hydro cutting system. For cutting high quality product the demand to the product is that the

product should be square and straight. This can only be achieved by using a hydro cutting

system. In hydro cutting system knives to cut square or rectangular product or wedges can be

place. A pre-heater can be placed to soften the structure of the potato and give the advantage

that during cutting less cells will be damaged and less product breakage and oil take-up. In

hydro cutting system the flexible hose will be adapted to the size of the potatoes to be cut.

This leads to improve length specifications. Behind the cutter the thin side-pieces (silvers)

and the too short pieces (nubbins) aregrader. The sequence of these two machines depends

mostly on the combination with the cutting equipment. Over the silver remover a spray bar

for fresh water is mounted to remove free starch from the product, which has come free by

cutting through the potato cells. The last check of the product is done manually or through

optical sorters. An inclined belt elevator brings the product to the blancher. The most

common actual blanching process is to blanch short in hot water, followed by long time in

less hot water. The first blancher has a retention time up to 2 minutes, the water temperature

control is able to maintain the water temperature on approx. 90°C. The product moves

directly over to the second blancher, which is calculated for a retention time of 40 minutes

and is commonly set on a temperature of approx. 70°C. The second blancher is one with

pump discharge system to bring the product up to the chemical dip flume. The type of

blancher is adapted to the amount of product passing that blancher.

Drying

The high quality demands equal colour of the stick and prevention of after cooking

darkening. To achieve this product should be dipped for 45-60 seconds in hot (80°C)

solution. The product is de-watered as much as possible and divided over the width of the

dryer belt. The dryer has to remove a certain amount of the water from the product to

improve crispiness of the stick and shorter frying times. The drying takes place on a two-belt

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system with as well as hot upward airflow as a downward airflow alternating. By a tipping

over from one belt to the other belt the equal; drying is achieved. The maximal weight

removal is 20%. Nevertheless, the product needs time to equilibrate (10 minutes) its internal

moisture prior to frying.

Frying

The product of the dryer is collected on a collecting belt or converging in-feed vibrator to

bring the product directly into the fryer. The fryer is a pan filled with oil, on the bottom a

wire link conveyor is present is present to transport the product. The oil is injected in the

bottom over the width of fryer. The fryer assembly includes an oil circulation system with

belt filter for the course of dirt remover, a thermal oil heat exchanger and a circulation pump.

To complete the system a removed from the product flow by means of a roller silver remover

and a vibratory nubbin grader. The sequence of these two machines depends mostly on the

combination with the cutting equipment. Over the silver remover a spray bar for fresh water

is mounted to remove free starch from the product, which has come free by cutting through

the potato cells. The last check of the product is done manually or through optical sorters. An

inclined belt elevator brings the product to the blancher. The most common actual blanching

process is to blanch short in hot water, followed by long time in less hot water. The first

blancher has a retention time up to 2 minutes, the water temperature control is able to

maintain the water temperature on approx. 90°C. The product moves directly over to the

second blancher, which is calculated for a retention time of 40 minutes and is commonly set

on a temperature of approx. 70°C. The second blancher is one with pump discharge system to

bring the product up to the chemical dip flume. The type of blancher is adapted to the amount

of product passing that blancher.

Cooling and freezing

The product is taken over from the de-fatting vibrator by the ambient air – cooling tunnel.

The belt is moving through a cabinet where outside air is taken in by means of fans and

blown through the product and discharged again. The achieves a relatively easy temperature

drop from 90°C incoming product temperature till 5°C above ambient air temperature for the

out coming product. The belt of the ambient cooling tunnel is designed in such a way that the

product is directly dropped over to the freezer belt. This drop over point corresponds with the

solidification point of the fat. So, if product has stick together, the relatively week bonds are

easily broken apart. The retention time in the ambient air-cooling tunnel is approximately 4

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minutes. In the freezer the product is individually quick-frozen. This means that a high

capacity cold airflow is blowing upward through the product, fluidizing the product bed. The

first belt part brings the product on the general solidification point of water ( 1°C).

The second belt of the freezer has a thicker has a thicker layer of product and the product

layer is cooled down further till -18°C in average a retention time in a freezer is

approximately 9 minutes.

Dehydrated potato

Dehydrated potato products in different forms like cubes, slices, sticks or powder are in

vogue since long and they are considered to be tasty and easy to make. Since they are

dehydrated, their shelf-life is longer. Preparations made from these products are popular

during the days of religious fasting. There also exists a large institutional market. Hotels,

restaurants, clubs, railways and defence establishments are some of the major consumers.

Potato powder has ready market in inaccessible hilly/mountainous areas.

Manufacturing process

Fully ripe and matured potatoes are selected and they are thoroughly washed in either soak

tanks or rotary washers to remove dust and dirt. Then they are peeled and cut into cubes or

slice or stick form. Then they are dewatered and dried for a period of 3 to 4 hours to bring

down the moisture level to around 10%. Further drying is carried out in a bin dryer to bring

down the moisture level to around 5%. Then they are cooled and packed. To make potato

powder, dehydrated slices are pulverised to the required mesh size and during this process, a

small quantity of aluminium silicate is added to avoid formation of cake. CFTRI, Mysore, has

successfully developed the process know-how.

Flour

Fresh sweet potato roots are bulky and highly perishable therefore sweet potato roots can be

sliced, dried, and ground in order to produce flour that remains in good condition for a long

time. Sweet potato, either fresh, grated, cooked and mashed, or made into flour, could with

high potential for success, replace the expensive wheat flour in making buns, chapatis (flat

unleavened bread) and mandazis (doughnuts). The flour is used as a dough conditioner for

bread, biscuit, and cake processing (it may substitute for up to 20% of wheat flour), as well as

in gluten-free pancake preparation . Sweet potato flour can add natural sweetness, color, and

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flavor to processed food products. It can also serve as a source of energy and nutrients and

minerals and contributes to the daily nutrient needs for β-carotene, thiamin, iron, vitamin C,

and protein. Sweet potato flour provides 14%-28% of the dietary reference intake (DRI) for

magnesium and 20-39% for potassium. The flour can be stored for 6 months or more in

sealed containers. It can be used as a substitute for wheat flour in the following amounts:

100% in white sauces, 25-50% in cookies, cakes and flat breads, and 15- 20% in breads. SP

flour would be marketed as a low cost alternative for imported wheat flour, especially for

snack food and noodle producers. Small flour production and use trials were made using local

varieties. Much technical research on SP flour carried out in developing country institutions

has focused on product formulation using SP flour rather than on efficient, low-cost, small

scale processes to produce the flour . Sweet potato based products are of high quality and

could compete with existing products in the market.

Cookies

The wheat flour (gluten free flours) can be replaced in cookies in order to increase the fiber

and other nutrients. The objective was to develop cookies with good taste texture and

appearance, which resembles as closely as possible to the wheat flour based product. The

textural property and sensory quality of cookies are taken into consideration to improve the

quality of cookies.

Fresh cut potato

Fresh-cut potatoes (peeled, sliced or diced, and packed) are considered to have commercial

interest in fresh-cut market as an alternative to pre-cooked or frozen potatoes.

One of the main causes of quality decay in fresh-cut potatoes is the enzymatic browning of

the cut surfaces; this oxidation reaction can compromise seriously the shelf-life of the

product. The rate of enzymatic browning in fruit and vegetables depends on the concentration

of active PPO (polyphenol oxidase) and phenolic compounds, and on the presence of

antioxidant compounds, such as ascorbic acid, that may control the PPO activity. In fresh-cut

potatoes, the enzymatic browning is positively correlated to the PPO activity and phenol

content.

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Bio-ethanol

Ethanol fermented from renewable sources for fuel or fuel additives are known as bio-

ethanol. Additionally, the ethanol from biomass-based waste materials is considered as bio-

ethanol. Currently, there is a growing interest for ecologically sustainable bio-fuels. The

target in the European Union is to increase bio-energy contributions in total energy

consumption from 3 to 12 % by the year 2010. In Finland bio-ethanol is already used as

additive in some gasoline products instead of toxic MTBE and TAME. Bio-ethanol

production from potatoes is based on the utilization of waste potatoes. Waste potatoes are

produced from 5-20 % of crops as by-products in potato cultivation. At present, waste

potatoes are used as feedstock only in one plant in Finland. Oyo Shaman Spirits Ltd in

Trinova (near Oulu) uses 1.5 million kilograms of waste potatoes per year. Because this

potato-based bio-ethanol production is just in embryo in Finland, there is a strong need for its

research and development. Therefore, the aim of this study was to develop different

analytical methods for bio-ethanol production from waste potatoes and to study the effect of

potato cultivar on bio-ethanol production. As well, the waste solution from the distillation

process was analyzed.

Prospects of potato processing in Bangladesh

Potato is a very prospective crop in Bangladesh. The soil and the climate both are suitable for

vertical and horizontal expansion. If the process of utilization and marketing of the fresh and

processed products are developed, the potato industry will boost up, the employment

opportunities, gender deployment, poverty alleviation, etc. at a significant rate. The

utilization of potato is being diversified day by day with value addition. New emerging areas

are poultry, animal, fish meal & feeds besides seed business, export, and industrial &

domestic processing. Farmers’ economy will be changed with social security, and service

oriented organization will develop (Cold storages & agro-processing centers). There are

several reasons for expecting so.

o Growing demand (both local and global market) for potato products (Chips,

French fries, Flakes, Powder, starch, rings, crakers, dehydrated potato

products, etc.).

o Possibility to produce high quality products which are competitive with

international brands.

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o Growing number of private sector market actors entering the market (six

medium type enterprises companies currently working and a few are expected

to come soon.

o Support to a few companies will lead to higher demand of fresh potatoes and

process product.

Some limiting factors of processing in Bangladesh

Location of production

The photoperiod, light intensity and temperature are not quite favorable in some areas for

high yield, good size and high dry matter content of tubers which are the important

requirements for processing. So it is very important to take into account the location of

production while producing a potato crop for processing purposes.

Variety

Desirable potato variety is the single most important event for processing. It is very hard to

get any variety with above 20% DM content because of the short life span induced by the

climatic factors. So high selection pressure is necessary while identifying a variety for

processing either from imported varieties or local hybrids.

Agro-techniques

Farmers are used to produce high yield ignoring all other qualities. They must be trained and

motivated in order to apply specified agro-techniques required for desirable processing

qualities in the tubers.

Short supply chain

Processing industries need uninterrupted supply of raw materials. Potatoes are harvested in

Bangladesh during hot and humid months. There is very little scope of storing potatoes at

ambient temperature after harvest. So, technologies must be developed so that potatoes can

be stored in rustic or cold storages without much loss of quality and cost involvement.

Lack of production plan

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Each industry management must have a complete production plan before going into

operation. That must include variety, quality, quantity, marketing and economics.

CONCLUSION

Potato is an important food and cash crop that plays a major role in food security.French fries

and potato crisps are the most consumed industrially processed potato products in

Bangladesh, especially in the major urban centers. Processors have, however, complained of

inadequate supply and low quality of potatoes currently supplied in the market. The annual

diet of an average global citizen in the first decade of the 21st century included about 33 kg

(73 lb) of potato. However, the local importance of potato is extremely variable and rapidly

changing. It remains an essential crop in Europe (especially eastern and central Europe),

where per capita production is still the highest in the world, but the most rapid expansion

over the past few decades has occurred in southern and eastern Asia. China is now the world's

largest potato-producing country, and nearly a third of the world's potatoes are harvested in

China and India. The demand of potato products has increased , so the processors should

provide more concern on it.

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REFERENCES

Bouchon, P. (2002). Modeling oil uptake during frying. PhD Thesis. Reading University,

England.

Johnson FB, Hoffman I, Petrasovits A (1968). Distribution of mineral constituent and dry

matter in the potato tuber. American Potato Journal 45:287–9.

Krause MV, Mahan LK (1985). Dietetic necessities recommended and adequate diet. In:

Food, Nutrition and Diet Therapy (eds MA Krause & LK Mahan), pp. 215–46. W.B.

Saunders Company: New York.

Martens T (1995). Current status of sous vide in Europe. In: Principles of Modified-

Atmosphere and Sous Vide Product Packaging (eds JM Farber & KL Dods), pp. 37–

68. Technomic Publishing Inc: Lancaster.

Macrae R, Robinson RK (1993). Potatoes and related crops. In: Encyclopaedia of Food

Science, Food Technology and Nutrition (eds R Macrae, RK Robinson & MJ Sadler),

pp. 3672–86. Academic Press Inc: San Diego, CA.

Mellema, M. (2003). Mechanism and reduction of fat uptake in deep-fat fried foods. Trends

in Food Science and Technology, 14, 364–373.

Moreira, R. G., Castell-P´erez, M. E., & Barrufet, M. A. (1999). Deep fat frying:

fundamentals and applications. Gaithersburg, MD, Aspen Publishers.

Pedreschif; Moyano P; Kaack K; Granby K. 2005. Color changes and acrylamide formation

in fried potato slices. Food Research International 38: 1-9.

Percival Rg; Baird L. 2000. Influence of storage upon light-induced chorogenic acid

accumulation in potato tubers (Solanum tuberosum L.). Journal of Agricultural and

Food Chemistry 48: 2476-2482.

Reyes-Moreno C, Parra-Inzunca MA, Milan-Carrillo J, Zazueta-Niebla JA (2001). A

response to surface methodology approach to optimise pretreatments to prevent

enzymatic browning in potato (Solanum tuberosum L) cubes. Journal of the Science

of Food and Agriculture 82:69.

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Rodriguez-Saona LE; Wrolstad RE. 1997. Influence of potato composition on chip color

quality. American Potato Journal 74: 87-106.

Liimatainen H, Kuokkanen T & Kääriäinen J (2004) Development of Bio-ethanol Production

from Waste Potatoes. In: Pongrácz E (ed.) Proceedings of the Waste Minimization

and Resources Use Optimization Conference, June 10th 2004, University of Oulu,

Finland. Oulu University Press: Oulu. p.123.- 129.

Wang-Pruski G; Nowak J. 2004. Potato after-cooking darkening. American Journal of Potato

Research 81: 7-16.

Wiltshire JJJ; Cobb AH. 1996. A review of the physiology of potato tuber dormancy. Annals

of Applied Biology 129: 553-569.

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