What can you do with potatoes after the harvest? In other words – what potato processing steps are best for your business? Potatoes can be sold directly, stored, or, even better, processed. To do this, they are first sorted and used throughout the year for different products depending on the type of potato.
Potato processing steps begin with proper storage facilities. The storage of the potatoes begins with ventilation since it is essential to keep a constant airflow at your potatoes’ warehouse. The actual storage temperature should be around 50°F, with a humidity level between 90% and 95 %. If you are planning long-term storage, the temperature should be lower. Before sale, damaged, rotten and green potatoes are removed.
It is normal to have some storage losses; they always occur. Germs can cause even more significant losses during storage.
Post-harvest Treatment Before Processing
Before other industrial potato processing steps, harvest undergo specific treatment. After that the potatoes reach the market or a processing plant.
Firstly, the potatoes go through a sorting system that sorts them by size. This is usually done using a vibrating machine. It consists of lattices on several levels, which become more and more closely meshed towards the bottom. Only the largest potatoes remain on the upper level, while smaller ones are collected towards the bottom. Damaged, stained, or sprouted potatoes are sorted out by machine or hand.
After harvest, potatoes from conventional cultivation may be treated with germ-inhibiting agents to prevent the potatoes from germinating during storage. Potatoes treated in this way usually must be identified by the note “Treated after harvest”.
The most commonly used sprout inhibitor is chlorpropham. It degrades throughout storage, so producers must wait a few weeks before placing the goods on the market without exceeding the permitted maximum residue levels.
If you want to sell potatoes without this treatment, you can market them as organic goods, in which only caraway or peppermint oil may be used to inhibit germination. Fresh potatoes are also usually untreated, as they are unsuitable for long-term storage.
Processed Potato Products
As mentioned before, potato processing steps depend on the final product intended. There are many uses of potatoes, such as:
- feed for animals;
- raw material to obtain alcohol;
- raw material to get starch;
- and of course, the best potatoes are processed into potato products, mainly frozen products;
The following table gives you a brief overview of the essential potato products:
|French fries:||French fries, oven french fries|
|Ware potatoes:||Slices, strips, cubes, puree, powder, flakes, granules|
|Preformed doughs:||croquettes, balls, potato figures and hearts, potato waffles|
|Fried products:||potato pancakes, fried potatoes, roasted potatoes, hash browns, cookies, medallions, patties, roasts|
|Potato dumplings:||dumplings in a cooking bag, dumpling dough|
|Snack products:||chips, stacked chips, sticks|
Potato Processing Steps For French Fries and Chips
It’s a long way from potatoes to french fries or chips. Many production steps have to be gone through. But let’s hear some story first.
Fries were probably invented around the same time as potato schnapps. According to tradition, they come from Europe, Belgium. The Belgians loved to fry fish in plenty of fat, and when there was a year with little fish, they quickly fried the side dish, namely the potatoes. This is how french fries came about. Of course, it was only much later – after the Second World War – that fries became an industrially prefabricated mass product.
From the potato to the fries, the following manufacturing steps are required:
- Sorting: Large potatoes are best for processing. The potatoes must be free from diseases, damage caused by feeding, or other defects.
- Washing: The potatoes are cleaned.
- Peeling: The peel is loosened with hot steam and then scrubbed off by round brushes or potato peelers.
- Cutting: The potatoes are shot through a sharp grid knife with high water pressure, resulting in even potato sticks.
- Blanching and drying: The sticks are pre-cooked in water at 158°F. Then they are dried in a hot air tunnel – dehydrator.
- Frying: The fries are fried in vegetable oil for two minutes at 347°F. Excess fat is shaken off on a vibrating belt.
- Shock freezing: At minus 35°F, the French fries are quickly frozen for 20 minutes and packed in bags.
Potato Chips Processing
Potato chips, on the other hand, are an American invention. However, it took them a long time to become established in non-English Europe. The first customers for potato chips were the American soldiers stationed in Germany in the early 1950s.
How are potato chips made?
- Sorting, washing, peeling: the first three production steps are analogous to French fries production.
- Cutting: The potatoes are cut into wafer-thin slices.
- Washing: The potato slices are rewashed and distributed evenly on a conveyor belt.
- Frying: The potato slices run through a fryer on the conveyor belt. As the water in the potatoes evaporates, the potato slices shrink and become deformed.
- Seasoning: In a large drum, twirl the chips and seasoning and mix well.
- Packing: very accurate weighing scale is usually used to weigh and pack.
Extraction Of Starch From Potato
Like all potato products, the starch was initially produced at home using the simplest means. Only with industrialization did starch production from potatoes begin on a large scale. Until then, wheat was the number one source of starch, but now the potato also had its chance.
The technology of starch production differs depending on the raw material used. However, all processes have in common the principle of “wet-milling”. In the process, the starch is washed out of the cell tissue of the previously shredded raw material. This technology makes it possible to obtain starch from renewable raw materials with high purity.
In addition, obtaining starch means that not only is starch washed out, i.e., extracted, but also proteins, dietary fibers, and fats are obtained as a side result. This almost 100 percent raw material usage makes the starch industry highly efficient and sustainable.
The starch obtained through the separation is dried and prepared for the following processing steps. Starch and products made from starch are versatile because of their stabilizing, binding, thickening, and gelling properties.
You can find native and modified starch, also such products as glucose syrup, glucose-fructose syrup, and by-products of starch production (e.g., wheat or corn gluten) in almost all sectors of the food industry, the chemical – extensive and versatile use in the technical and pharmaceutical industries as well as in the animal feed industry.
Starch production is somewhere between agriculture and the chemical industry.
Dried Potatoes Products
Any potato product from which moisture has been removed can be called dehydrated potatoes. Dehydrated potato products are popular because the potatoes are much lighter with the water removed. Less weight means lower transportation costs for dried potato products. Also, dehydrated products have a much longer shelf life than unmodified potatoes.
Dehydration contains the following potato processing steps. Potatoes that need to be dehydrated are usually peeled, washed, cut, blanched, or steamed. Depending on how you want to use them, they can be cut in various ways, including slices, cubes, or shreds.
The potatoes are then dried in large industrial dehydrators, which are essentially low-temperature ovens with very dry circulating air currents that dry the potatoes without actually cooking them further. This process is often done entirely with a conveyor system for continuous production rather than in batches.
Once dried, the potatoes can be further processed or packaged. Dehydrated potatoes are often ground or pulverized into a powder, rehydrated, then made into fine flakes or granules, and dried again.
These products are sold as instant potatoes or instant mashed potatoes and are a typical affordable food for cooks and chefs who don’t want to be troubled by making mashed potatoes from scratch. Dehydrated potato powder is sometimes ground very finely and sold as potato flour, used in baking, and as a thickening agent.
Having covered the essential potato processing aspects, let’s look at particular machines used for this process.
Potato Washing Machine
A potato washing machine is one of the first machines used in potato processing steps. In addition to actual washing, the cleaning process may also include stones and earth removal. There are a variety of reasons why the use of effective machines is essential:
- minimizing leftovers
- saving production time and costs
- satisfactory results
The washing drum machine might be your best solution if you are looking for a low-maintenance potato washing machine. A V-belt drives the device. The resulting rotation causes the potatoes to rub against each other and clean. You can adjust the filling level of the drum by lowering or raising the discharge pipe, making it possible to process both large and small product quantities.
To ensure the perfect cleanliness of the potatoes, the washing drum contains a spray tube that extends through the drum. Leftovers and wastewater are drained at the bottom of the drum. Usually, such washing machines are suitable not only for potatoes but also for beetroots, carrots, and others.
This equipment is best for industrial purposes and is worth your consideration if you plan to set up a food processing company.
The Roller Peeler
Another must-have solution in the potatoes processing industry is a roller peeler. It is suitable for continuously peeling potatoes, carrots, kohlrabi, beetroot, celery, etc.
The machine is designed with several peeling rollers on which carborundum is attached and a screw conveyor that transports the product to be peeled evenly through the roller peeler. The number of peeling rollers and the carborundum lining attached largely determine the roller peeler’s capacity.
The peeling rollers in the roller peeler are usually mounted next to each other. The middle two peeling rollers are the lowest, and the following rollers are mounted slightly higher.
The peeling rollers, equipped with quick-release fasteners for easier assembly, are driven by toothed belts, and each rotates at different speeds. This achieves an optimal peeling result with a high capacity. You can supply the machine with a control cabinet with which the speed of the peeling rollers and the screw conveyor can be adjusted independently of each other. Thus you can adapt desired peeling result to each product type.
It is just another type of industrial potato peeler. The carborundum and knife peelers are suitable for peeling all tuberous products such as potatoes, beetroot, and kohlrabi. In the carborundum version, the machine is designed with a carborundum wall and a carborundum disc.
The removable peeling disc has bulges that keep the product moving in the machine so that the product is peeled evenly all around. Due to the minimal gap between the disc and the wall, you can peel even small potatoes without loss.
This type of peeler can also be equipped with a knife instead of a carborundum disc and walls, so you get an optimally peeled end product. Due to the perfect arrangement of the blades and the hygienic blue rubber lining on the wall, peeling loss is minimal, and the product remains undamaged.
Due to the compact design, the carborundum peeler is very easy to clean.
Cutter / Slicer
Are you going to produce a product that requires cutting or slicing? If so, you will need an industrial cutter/slicer. For example, your raw material can be cut into corners, slices, or sticks with a rotary fruit and vegetable cutter. Depending on the size of input materials, you can process even more than one product simultaneously.
Equipping your business with the right industrial machinery raises your production standards regarding hygiene, ease of use, tool change speed, high performance, multifunctionality, and the perfect cutting pattern.
Complete Potato Processing Line – How Does It Look Like?
Finally, let us briefly talk about the complete potato processing line. Just say we want to wash, peel, and cut or dice potatoes up to a capacity of 2,500 lbs per hour.
The processing is started centrally via a control box of the processing line, and the procedure is as follows:
- The belt is filled with potatoes and is ready to elevate them from a water bunker/washer continuously.
- The peeling and emptying duration of the potato peeling machines are set on the switch box, and automatic operation can start.
- Two potato peeling machines are automatically filled via an exchange pipe. The filling and peeling cycle alternates automatically. The potatoes are washed clean and gently peeled in one operation; the carborundum system enables the shell to be removed.
- The peeled potatoes are transported to the cutting machine via a roller sorting table onto an ascending belt.
- The cutting machine cuts or dices the potatoes according to your specifications.
- The following steps depend merely on the final product you have decided to produce (French fries, potato chips, etc.)
Here are some technical advantages of the processing line as described above:
- Robust water bunker belt for pre-cleaning
- The potatoes are filled into the water bunker belt for pre-cleaning and then transported to the exchange pipe via a cleated belt.
- The peeling and emptying times of the machine are set on the control box, and automatic operation is started. The two potato peeling machines are filled via an interchangeable pipe, and the filling and peeling cycles change automatically.
- The potatoes are washed clean and gently peeled in one operation; the corundum system enables the shell to be removed very thinly.
Additional technical details:
- Potatoes: 330 lbs in one cycle
- Roller sorting table for visual inspection
- The roller sorting table is set up directly after the potato peeling machines. This allows you to control the peeling quality or sort out bad quality potatoes.
- The washed, peeled, and sorted potatoes are automatically transferred from the roller sorting table to the belt cutting machine through the elevator belt.
- A wide range of tool accessories is available if you decide to acquire an industrial cutter/slicer: e.g., wing knives for infinitely variable adjustment of cutting thickness, serrated knife discs, dicing devices, pin knife discs, grating/grating discs, adjustable knife discs and much more.