Effect of thawing conditions and corresponding frying temperatureprofiles on the formation of acrylamide in French fries

This study attempted to determine the effects of thawing conditions and corresponding frying tempera-ture profiles on the formation of acrylamide in French fries. Frozen par-fried potato strips were thawedunder three different conditions, at room temperature, using a chiller, and using a microwave. Unthawedpar-fried potato strips were used as the control samples. Thawed (or unthawed) par-fried potato stripswere deep-fat fried in palm oil at 180 ± 5°C for 3.5 min. The temperature drop was monitored every15 s for a total of 6 min; 3.5 min of frying time plus an additional 2.5 min until the oil temperaturereturned to 180°C. The acrylamide content, oil content and colour of the French fries were measured.The frying temperature dropped substantially (more than 30°C) from the initial temperature in the first45 s of frying for all thawing conditions. After 90 s of frying, the smallest temperature drops wereobserved for French fries thawed using a microwave (20%), and the largest temperature drop prior torecovery was seen with the control sample (24%). At the end of the frying period (after 210 s), French friesthawed using a microwave had reached the highest final temperature (154°C), and the control samplehad reached the lowest final temperature (145°C). The acrylamide contents of the French fries werefound to be in the range of 77.4–106 ng/g, whereas the oil contents ranged from 16.4 to 20.5%. The lowestlightness, highest redness and highest yellowness were found for French fries thawed using a microwave.Although the thawing conditions did not significantly affect the formation of acrylamide, microwavethawing was found to be the best thawing method due to the resulting (relatively) low acrylamideand oil contents of the French fries and their desirable colour attributes. The results of this study canbe used to recommend that the manufacturers of frozen par-fried potato strips specify the use of a micro-wave for thawing as part of the frying instruction on the packaging.