Acrylamide in Fried Sweetpotato: The Relationship with Free Asparagine and Effects of Asparaginase

Fried sweetpotato products are prone to acrylamide formation, and identification of the limiting substrate was investigated for mitigation. Chips were prepared from ‘Bayou Belle’ sweetpotatoes grown at 3 locations (2 years); sugars, free asparagine, total nitrogen, and acrylamide formation were measured. Acrylamide formation was correlated with free asparagine contents of raw sweetpotatoes (r = 0.924) with 82–89% being degraded during frying. Total nitrogen was moderately correlated (r = 0.505). Sugars were not correlated with acrylamide levels, and less than 30% were degraded in frying. Blanching and a postblanching asparaginase treatment reduced acrylamide levels by 89–95 and 98–99%, respectively. In model solutions, acrylamide formation was associated with free asparagine concentrations (p < 0.001), but other free amino acids had an antagonistic effect when total free amino acids exceeded reducing sugars. Free asparagine was the limiting substrate for acrylamide formation in fried sweetpotato, and management of its levels will minimize acrylamide formation in fried sweetpotato products.