To render enzymes inactive before freezing, the processing potatoes must be blanched. In addition to the inactivation with minimal energy use, blanching stops the loss of beneficial and efficient compounds.

Additionally, blanching helps decrease vitamin losses and eliminates some surface dirt and microbes, while at the same time expelling the trapped air inside the cells.

Even at freezing temperatures, changes in color, fragrance, taste, and aroma composition happen as a result of distinct enzyme activity. It is impossible to determine a minimum temperature for enzymatic processes. At a temperature of 15 °C, catalase and peroxidase were discovered to be active, whereas lipase and lipoxidase were found to be active at 30 °C and invertase at 40 °C. So, blanching potatoes before freezing them is essential to their quality.

Blanching is the process of briefly scorching the product in steam or boiling water. It is usually followed by an immediate, complete chilling in ice or very cold water.

The use of an industrial potato blanching machine can efficiently prevent the potato oxidation to brown color and preserve the color of products like potato chips, strips, and diced potatoes. The process of blanching is thus crucial to the production of potato chips and French fries.

Using the proper blanching time for the vegetable’s size is also important. It is worse to under-blanch than not to blanch at all because it increases enzyme activity. An excessive amount of blanching results in partial cooking and the loss of vitamins, minerals, flavor, and color.

Blanching Equipment

Steam or water systems can be used to complete the blanching procedure. One thing unites immersion and deluge water blanching, regardless of how it’s accomplished with a rotary, auger, double draper, or belt-conveying system: the product is immediately exposed to food-grade water, which is normally between 70°C and 100°C in temperature.

When using steam blanching, the product is transported inside a chamber and exposed to 100°C food-grade steam directly. To improve heat transfer efficiency, certain steam blanchers include convection technology, which drives steam through the product bed. Other steam blanchers arrange the produce in a single layer and quickly blanch each piece individually (IQB). Some steam blanchers follow the heat penetration stage with a holding stage that permits the product’s core temperature to rise without the addition of more steam to reduce the amount of time the product is exposed to heat.

You can read the rest of this article in your complimentary e-copy of Issue 3 of Potato Business Digital 2022 magazine, which you can access by clicking here.