Modeling the effect of blanching conditions on the texture of potato strips

In current practice of manufacture of frozen French fries, obtaining the target texture of potato strips from the blancher relies on line operators’ “to-bite” assessment performed in a trial-and-error manner. In this paper, we present a quantitative description of the texture changes in terms of mechanical properties of the strips as affected by the blanching conditions (temperature and time). Tubers from different growers in Manitoba Canada were sorted according to solids content. Strips from the central planes of each sorted tuber were excised, and blanched in a steam-heated kettle at temperatures in the range from 62.8 °C to 90.6 °C for 2–20 min. Texture of blanched strips was evaluated using an indentation method. We found that at lower temperatures (<74 °C), blanching time had little effect on the texture of blanched strips. However, at higher temperatures (⩾74 °C), the texture, as expected, softened as temperature and time increased. A model was developed to describe the change of texture with blanching temperature and time. The model, validated using tubers from the next year’s crop, provides guidelines to line operators to manipulate blancher conditions so that the operators can consistently hit the target texture of blanched strips.