Choosing the right potato cultivar is an important step in reducing acrylamide formation. Some cultivars are more suitable than others to make chips thanks to their size, shape and low reducing sugar content. The composition of raw potatoes is a primary factor in acrylamide formation, as is frying temperature.
Acrylamide formation during frying has been attributed to Maillard reactions, which develop from reducing sugars and asparagines, depending on frying temperature. A low reduction of sugar content has been recommended to make chips; however, the way the complexity of the medium affects chemical reactions, promoting acrylamide formation during frying, is yet unclear. Technicians from the Universitat Politècnica de Catalunya BarcelonaTech in Spain compared three cultivars—Kennebec, Red Pontiac and Agria—to determine the relationship between acrylamide precursors in raw potatoes and the properties of chips. Experiments were carried out in three conditions: 190 degrees Celsius for 160 seconds; 170 degrees for 240 secongs; and 150 degrees for 330 seconds.
“Acrylamide increases with higher frying temperatures, but cultivars behave differently,” the study reads. “As regards Red Pontiac, a significant increase of acrylamide was detected at 170°C (~ 40%) as well as an increase in color. In addition, lower oil absorption and higher humidity content were obtained with a higher temperature. Significant positive correlations were observed between the acrylamide content and reducing sugars and sucrose in raw potatoes.”
The acrylamide content in Agria potatoes could be due to sucrose hydrolysis during frying. A significant positive correlation was noticed in chips between shear force and acrylamide. All significant correlations obtained between color and structure, color and oil absorption, and structure and acrylamide content, indicate that there is an intrinsic relation between chip characteristics and acrylamide content.
Frying at 190 degrees produced chips with a higher acrylamide content, lower oil absorption, higher humidity, and a darker color and toughness than those fried at 150 degrees. Reducing sugars and asparagine aside, there are also other aspects of acrylamide formation.
“Sucrose and oil absorption may have played an important role in the final acrylamide concentration, so these aspects must be kept into consideration,” the study observes. “According to our findings, chips fried at 170 to 190 degrees Celsius—which had a humidity content over 65 percent and an absorbed oil content over 15 percent—may have a higher acrylamide content.”
After these first results, the research will continue to assess the various correlations, especially for potatoes with low sugar content.
Results of the study can be found here in the journal Food Control.