Reduction of acrylamide formation in potato slices during frying

Reduction of acrylamide formation in potato chips was investigated in relation to frying temperature and three treatments before frying. Potato slices (Tivoli variety, diameter: 37 mm, width: 2.2 mm) were fried at 150degreesC, 170degreesC and 190degreesC until reaching moisture contents of similar to1.7 g water/100 g (total basis). Prior to frying, potato slices were treated in one of the following ways: (i) soaked in distilled water for 0 min (control), 40 min and 90 min; (ii) blanched in hot water at six different time-temperature combinations (50degreesC for 30 and 70 min; 70degreesC for 8 and 40 min; 90degreesC for 2 and 9 min); (iii) immersed in citric acid solutions of different concentrations (10 and 20 g/l) for half an hour. Glucose and asparagine concentration was determined in potato slices before frying, whereas acrylamide content was determined in the resultant fried potato chips. Glucose content decreased in similar to32% in potato slices soaked 90 min in distilled water. Soaked slices showed on average a reduction of acrylamide formation of 27%, 38% and 20% at 150degreesC, 170degreesC and 190degreesC, respectively, when they were compared against the control. Blanching reduced on average 76% and 68% of the glucose and asparagine content compared to the control. Potato slices blanched at 50degreesC for 70 min surprisingly had a very low acrylamide content (28 mum/kg) even when they were fried at 190degreesC. Potato immersion in citric acid solutions of 10 and 20 g/l reduced acrylamide formation by almost 70% for slices fried at 150degreesC. For the three pre-treatments studied, acrylamide formation increased dramatically as the frying temperature increased from 150degreesC to 190degreesC. (C) 2004 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.