PEF for potato treatment
Product examples: French fries (see picture above of surface of French fry), frozen potato products, chilled potato products, potato crisps, mashed potatoes, starches
Aim PEF treatment: Cell disintegration, structure modification, reduction of turgor pressure (osmotic pressure). The picture in the header shows the surface of a French fry, untreated and PEF treated. The picture is made with Atomic Force Microscopy. After PEF treatment of the potato: a better cutting quality, higher cutting yields, smoother surfaces, less oil absorption, no feathering and less breakage.
PEF systems instead of preheaters
In potato processing, for example in French fry production, PEF systems are an excellent alternative for traditional preheaters. PEF technology not only results in superior cut quality and a reduction of French fry breakage and shattering, but also improves drying efficiency. The pulsed electric field causes tiny pores in the potato cell walls, also known as cell permeabilization, which facilitates cutting, blanching, drying and frying processes.
Potatoes are considered excellent conductors because they are uniformly solid, contain about 80 percent water and are rich in potassium. By permeabilizing cell membranes PEF enables tissue softening and enhanced mass transport, resulting in improved cutting of potatoes, higher product quality and increased process capacity. Osmotic pressure or turgor pressure in the cells (turgidity) has been reduced by permeabilizing the cell membranes. Potatoes become more homogeneous with pulsed electric field processing, evening the structure and resulting in the reduction of seasonal variation.
Depending on the potato variety, appropriate field strengths range from 0.8 to 3.0 kV/cm and the subsequent energy delivery goes from 0.2 to 1.5 kJ/kg.
As a result of PEF treatment potato cutting is improved, with smooth surfaces, sharp edges and approximately 40% less cutting force for whole potatoes as main results. PEF technology enables cutting at optimal product texture. French fries cutting at optimum product texture results in less breakage and shattering, producing longer thin French fries. Improved cutting of crisps results in smoother surfaces and less coloration. The subsequent reduced oil uptake and water retention leads to crunchier crisps.
In potato mash production, pulsed electric field processing evens out the structural variations in potatoes, resulting in a large reduction of the number and size of lumps and a smoother mash for a better bite.
Remaining enzyme activity, see: Enzymes
- Improved cut quality and subsequent reduction of French fry breakage and shattering
- Blanching, drying and prefrying times are shortened
- Reduced water and energy consumption
- Reduced frying oil absorption
- Softer tissue structure allows the use of different potato varieties and cutting technology to create new product shapes
- For potato crisps production also: thinner and smoother crisps, more even and lighter color, crunchier bite
- For potato mash production also: evening out the structural variations in the potatoes resulting in a large reduction of lumps and a smoother mash
Pulsemaster has developed a range of industrial scale equipment – named Conditioner – with treatment capacities from 1,000 kg/h to 50,000 kg/h (110,000 lb/h) for cell disintegration of potatoes. There are practically no size limitations. Our largest industrial sized PEF equipment up to 100kW per system, allows processing capacities as high as 154.000-176.000 lb of potatoes per hour (70-80 tons per hour) to meet the growing demand for higher input capacities in potato industry. All of which results in improved output of French fries in lb/h or tons per hour, reduced costs of ownership and higher product quality.
On a commercial scale total costs of 1 Euro/ton (0.1 Eurocent per kg / 0.056 US Dollarcent per lb) have to be expected.