Comparison of water and infrared blanching methods for processing performance and final product quality of French fries

The main objective of this work was to compare infrared blanching (IRB) with water blanching (WB) as a pretreatment method for producing lower calorie French fries. It was observed that complete inactivation of polyphenol oxidase enzyme for 9.43 mm potato strips could be achieved in 200 s and 16 min by using IRB and WB, respectively. Following the blanching, the samples were deep-fat par-fried at 174 °C for 1 min and were then deep-fat finish-fried at 146, 160, and 174 °C for 2, 3, 4 and 5 min. At all frying times and temperatures infrared blanched samples had less oil content than water blanched ones. The energy analysis of both blanching operations showed that energy expenditure-wise the operation cost for pre-treating French fries with IRB would be head-to-head with WB. The final moisture contents of infrared and water blanched samples were between 40% and 50% after 5 min of finish-frying. The chromatic color components of infrared and water blanched samples were significantly (P < 0.05) affected by finish-frying time and temperature and the a* and b* values for infrared blanched samples developed faster than water blanched samples during deep-fat finish frying.