Effect of combining conventional frying with radio-frequency post-drying on acrylamide level and quality attributes of potato chips.

BACKGROUND: In conventional manufacturing of potato chips, achieving an extremely low moisture content (2% by weight) in the final product necessitates prolonged exposure of potato slices to high oil temperatures. This promotes acrylamide formation and causes an exponential increase in acrylamide level toward the end of the frying process. In this regard, frying potato slices partially in hot oil followed by a radio-frequency (RF) drying treatment to selectively heat the remaining moisture appears to be a viable approach in terms of limiting acrylamide formation. RESULTS: RF post-drying of partially fried potato slices resulted in lower acrylamide levels (80.4 ng g(-1) for control, 59.4 ng g(-1) for RF post-dried potato slices partially fried for 95 s, 54.8 ng g(-1) for RF post-dried potato slices partially fried for 80 s). This process modification also led a to 12% reduction in oil content in the final product. According to instrumental analysis results, RF post-dried samples had lower hardness and a slightly lower degree of browning in comparison to control. No significant difference (α = 0.05) was found between samples in terms of sensory characteristics. CONCLUSION: Results demonstrate that RF post-processing may be an effective strategy for minimising acrylamide levels of potato chips without adversely affecting quality attributes.

Processing treatments for mitigating acrylamide formation in sweetpotato French fries.

Acrylamide formation in sweetpotato French fries (SPFF) is likely a potential health concern as there is an increasing demand for good-quality fries from carotene-rich sweetpotatoes (SP). This is the first report on acrylamide formation in SPFF as affected by processing methods. Acrylamide levels in SPFF from untreated SP strips fried at 165 °C for 2, 3, and 5 min were 124.9, 255.5, and 452.0 ng/g fresh weight, which were reduced by about 7 times to 16.3, 36.9, and 58.3 ng/g, respectively, when the strips were subjected to processing that included water blanching and soaking in 0.5% sodium acid pyrophosphate before frying. An additional step of strip soaking in 0.4% calcium chloride solution before par-frying increased the calcium content from 0.2 to 0.8 mg/g and decreased the acrylamide levels to 6.3, 17.6, and 35.4 ng/g, respectively. SPFF with acrylamide level of <100 ng/g or several times lower than that of white potato French fries can be obtained by integrating processing treatments commonly used in the food industry.

Effect of cooking method (baking compared with frying) on acrylamide level of potato chips.

The effect of cooking method (baking compared with frying) on acrylamide level of potato chips was investigated in this study. Baking and frying experiments were conducted at 170, 180, and 190 degrees C using potato slices with a thickness of 1.4 mm. Raw potatoes were analyzed for reducing sugars and asparagine. Surface and internal temperatures of potato slices were monitored during the experiments to better explain the results. Fried and baked chips were analyzed for acrylamide content using an LC-MS method. The results showed that acrylamide level of potato chips prepared by frying increased with frying temperature (19.6 ng/g at 170 degrees C, 39 ng/g at 180 degrees C, and 95 ng/g at 190 degrees C). In baking, however, the highest acrylamide level was observed in potato chips prepared at 170 degrees C (47.8 ng/g at 170 degrees C, 19.3 ng/g at 180 degrees C, and 29.7 ng/g at 190 degrees C). The results showed that baking at 170 degrees C more than doubled the acrylamide amount that formed upon frying at the same temperature, whereas at 180 and 190 degrees C, the acrylamide levels of chips prepared by baking were lower than their fried counterparts.

Reduction of acrylamide level in french fries by employing a temperature program during frying.

In this study, the effect of employing an oil temperature program during frying on the acrylamide content of French fries was investigated. The frying conditions that could lead to lower acrylamide levels in French fries were first simulated by means of an experimentally validated frying model. Then, experiments were conducted to test the simulated conditions in real frying process. Different time/temperature combinations (4 min at 170 degrees C, 2 min at 170 degrees C + 2 min at 150 degrees C, 1 min at 170 degrees C + 3 min at 150 degrees C, 1 min at 190 degrees C + 3 min at 150 degrees C) were employed for frying potato strips (8.5 x 8.5 x 70 mm), and the resultant acrylamide levels were determined with a gas chromatography-mass spectrometry (GC-MS) method. The results indicated that acrylamide levels in French fries can be reduced by half if the final stage of the frying process employs a lower oil temperature. Therefore, the method appears to be an effective way of controlling the acrylamide level in the final product.