Acrylamide formation in French fries was investigated in relation under different processing conditions and the content of glucose and asparagine of the strips before frying. Potato strips (0.8 x 0.8 x 5 cm) of Bintje variety were fried at 150, 170 and 190 degrees C until reaching moisture contents of similar to 40 g water/100 g (total basis). Prior to frying, potato strips were treated in one of the following ways: (i) immersed in distilled water for 0 min (control), 60 min and 120 min; (ii) immersed in a citric acid solution of 10 g/L for an hour; (iii) immersed in a sodium pyrophosphate solution of 10,g/L for an hour; (iii) blanched in hot water at six different time-temperature combinations (50 degrees C for 40 and 80 min; 70 degrees C for 10 and 45 min; 90 degrees C for 3 and 10 min). Acrylamide content was determined in French fries while the glucose and asparagine content in the potato strips before frying. Immersed strips in water for 120 min showed a reduction of acrylamide formation of 33%, 21% and 27% at 150, 170 and 190 degrees C, respectively, when they were compared against the control. Potato strips blanched at 50 degrees C for 80 min had the lowest acrylamide content when compared against strips blanched at different conditions and fried at the same temperature (135, 327 and 564 mu m acrylamide/kg for 150, 170 and 190 degrees C, respectively). Potato strip immersion in citric acid solution of 10 g/L reduced much more the acrylamide formation after frying than the strip immersion in sodium pyrophosphate solution of 10 g/L (53% vs. 17 /v, respectively-average values for the three temperatures tested). Acrylamide formation decreased dramatically as the frying temperature decreased from 190 to 150 degrees C for all the pre-treatments tested. Color represented by the total color difference showed high correlation (r(2) of 0.854) with the acrylamide content of French fries.
Journal of Food Engineering, 2007, Vol 79, Issue 4, p. 1287-1294
frying; asparagine; color; potato strips; acrylamide; glucose; French fries