Characterization of the frying process of fresh and blanched potato strips using response surface methodology

Characterization of the frying process of potato strips was carried out using response surface methodology. Frying was performed on either fresh or blanched strips following a conventional water treatment. The independent variables of the process were frying temperature (between 170 degrees C and 200 degrees C) and frying time (between 4 min and 6 min). A central composite rotatable design was adapted to study the effects of the independent variables on different quality attributes of potato strips. Textural quality was measured by texture profile analysis, Volodkevich tests and multiple puncture tests. Colour parameters and moisture and oil contents were also determined. The effect of frying time was more significant than the effect of frying temperature on the quality attributes, and when blanching was carried out before frying most attributes were independent of frying temperature. Frying of fresh strips at 185 degrees C for 4.5 min resulted in minimum optimal points for hardness 1, hardness 2. Volodkevich parameters and oil content and saddle points for colour parameters in approximately the same combination. For models fitted for most of the quality attributes of blanched fried strips, r(2) was better and the lack of fit was not significant, although high-temperature short-time blanching before frying resulted in loss of firmness and discolouring, and increased the percentage of oil retained by the strips, causing sensorial quality loss.