Potato blanching method saves on water and energy costs

The technology uses a closed system for the blanching process. The same water can be used repeatedly for blanching, instead of being replaced when it becomes saturated with sugars.

Aviko said it has succeeded in converting the sugars in the blanching water into other natural substances. This prevents the blanching water from becoming saturated with the sugars, which can therefore be used to continuously blanched them out of the potatoes.

"There is almost no need to replace the water, so less wastewater has to be discharged and less groundwater has to be abstracted,"​ the company stated in a description of the project. "Moreover, less energy is required to bring the blanching water up to the necessary temperature."​

Aviko is owned by Royal Cosun and is one of Europe's two largest potato processing companies, with a production volume of 1.2 billion tonnes per year. It produces about 50 deepfreeze and fresh potato products in eight production facilities, employing 1,400 people.

Currently processors use hot water to blanch potatoes in the production of chips and other potato-based products. The process is necessary to inactivate enzymes, gelatinise starch and reduce sugar content.

Aviko currently processes 1.4 million tonnes of potatoes, using 350,000 cubic metres of water for potato blanching, as well as 88,200 gigajoules of energy to heat the water, according to the company.

Current blanching techniques neither recycle water nor recover heat from the water, emitting both water and heat to wastewater treatment plants instead. Furthermore, about 10 to 30 per cent of potato solids are leached out during the process, resulting in a loss of 50,400 tonnes of raw material a year in the form of potato sludge.

Valuable nutrients such as amino acids, vitamins and minerals, which Aviko says it would prefer to keep in the potato.

Aviko's saturated blanching water is channelled into the wastewater network of the regional water board and, after appropriate treatment, is discharged into surface water, according to descriptions of the project from the EU and Royal Cosun.

Aviko's wastewater also contains valuable substances, which are lost when it is discharged. In addition, Aviko must regularly pump up groundwater and heat it to the blanching temperature.

"Aviko expects that the closed loop blanching method will considerably reduce its consumption of groundwater and discharges of blanching water,"​ the company stated. "This represents a major reduction of the burden on the environment. Moreover, Aviko will no longer lose valuable substances."​

While the sugars are converted into other substances, the amino acids, minerals and vitamins remain in the blanching water. The water becomes saturated with them and therefore cannot absorb any more of them from the potatoes.

This has no effect on the transfer of sugars from the potatoes to the water, but means that the other valuable substances remain in the potatoes. The system therefore improves the yield from the processed substances, the company stated.

Aviko said its process technologists and the process engineers have succeeded in finding a solution to the problem of converting the sugars in the blanching water into another natural substance.

Since 1992, the EU's LIFE Environment programme has co-funded about 2500 projects, to which it has committed 1.5 billion euros. Last year 534 applications were submitted from 17 countries. The European Commission selected 89 projects to receive funding.