title: Reduction of acrylamide level through blanching with treatment by an extremely thermostable L-asparaginase during French fries processing.
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.
authors.affiliation: State Key Laboratory of Food Science and Technology, Ministry of Education, Key Laboratory of Carbohydrate Chemistry and Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Zuo
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.forename: Wanmeng
authors.initials: W
authors.lastname: Mu
mesh_terms: D020106:Acrylamide / Q000737:chemistry*; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D001215:Asparaginase / Q000737:chemistry* / Q000235:genetics; D005511:Food Handling / Q000379:methods*; D011198:Solanum tuberosum / Q000737:chemistry; D019712:Thermococcus / Q000201:enzymology* / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D020106:Acrylamide; D001215:Asparaginase