Reduction of acrylamide level through blanching with treatment by an extremely thermostable L-asparaginase during French fries processing

Extremophiles. 2015 Jul;19(4):841-51. doi: 10.1007/s00792-015-0763-0. Epub 2015 Jun 16.

Abstract

Bacterial L-asparaginase catalyzes the hydrolysis of L-asparagine to L-aspartic acid. It is normally used as an antineoplastic drug applied in lymphoblastic leukemia chemotherapy and as a food processing aid in baked or fried food industry to inhibit the formation of acrylamide. The present study demonstrates cloning, expression, and characterization of a thermostable L-asparaginase from Thermococcus zilligii AN1 TziAN1_1 and also evaluates the potential for enzymatic acrylamide mitigation in French fries using this enzyme. The recombinant L-asparaginase was purified to homogeneity by nickel-affinity chromatography. The purified enzyme displayed the maximum activity at pH 8.5 and 90 °C, and the optimum temperature was the highest ever reported. The K m, k cat, and k cat/K m values toward L-asparagine were measured to be 6.08 mM, 3267 s(-1), and 537.3 mM(-1) s(-1), respectively. The enzyme retained 70 % of its original activity after 2 h of incubation at 85 °C. When potato samples were treated with 10 U/mL of L-asparaginase at 80 °C for only 4 min, the acrylamide content in final French fries was reduced by 80.5 % compared with the untreated control. Results of this study revealed that the enzyme was highly active at elevated temperatures, reflecting the potential of the T. zilligii L-asparaginase in the food processing industry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylamide / chemistry*
  • Archaeal Proteins / chemistry*
  • Archaeal Proteins / genetics
  • Asparaginase / chemistry*
  • Asparaginase / genetics
  • Food Handling / methods*
  • Solanum tuberosum / chemistry
  • Thermococcus / enzymology*
  • Thermococcus / genetics

Substances

  • Archaeal Proteins
  • Acrylamide
  • Asparaginase