Asparaginase in Food Processing: Reducing Acrylamide Formation
What Is Acrylamide and Why It Matters
Acrylamide, a potential carcinogen, is formed when starchy foods are fried or baked above 120°C. Acrylamide can form in carbohydrate-rich foods during high-temperature processing, especially when free asparagine reacts with reducing sugars through Maillard-type chemistry.
Formation pathway: Free L-asparagine + reducing sugars (glucose, fructose) at high heat → Maillard reaction → acrylamide.
Foods at risk: Biscuits, cookies, crackers and crispbread, bread, rolls, toast, breakfast cereals, extruded cereals, potato chips, French fries, formed potato products, fried baked roasted or dried starchy snacks, coffee, infant cereal foods.
Regulatory pressure: EU Regulation 2017/2158 sets benchmark levels – e.g., bread 50 µg/kg, biscuits 350 µg/kg, potato chips 750 µg/kg. Manufacturers expected to implement mitigation measures. Acrylamide Toolbox from FoodDrinkEurope lists asparaginase as primary tool.
How Asparaginase Works
Enzymatic Mechanism
Asparaginase is specialist food enzyme used as processing aid for acrylamide mitigation. In industrial production, applied before high-temperature baking, frying, roasting or drying so free L-asparagine can be converted into L-aspartic acid and ammonia, reducing availability of key acrylamide precursor during Maillard reaction.
Product identity: Common names L-Asparaginase, L-asparagine amidohydrolase, acrylamide-reduction enzyme. CAS 9015-68-3, EC 3.5.1.1, Hydrolase acting on carbon-nitrogen bonds in amides. Catalyzed reaction: L-asparagine + H2O → L-aspartic acid + NH3.
Enzymes reduce acrylamide formation through specific catalytic mechanisms. There is amide group on side chain of asparagine, and this amide group converted into aspartic acid and ammonia by asparaginase enzyme. As result, aspartic acid does not engage in Maillard reaction, thereby substantially reducing formation of acrylamide.
Acrylamide can form in carbohydrate-rich foods during high-temperature processing, especially when free asparagine reacts with reducing sugars. Asparaginase reduces precursor pool by hydrolysing L-asparagine into L-aspartic acid and ammonia before baking, frying, roasting or drying. Because L-aspartic acid is not same acrylamide precursor under these conditions, reaction pathway shifted away from acrylamide formation.
Performance Factors
Performance depends on enzyme activity, substrate availability, water accessibility, contact time, temperature, pH and how evenly enzyme distributed before thermal inactivation. Enzyme should therefore be evaluated through plant-specific trials and analytical acrylamide testing rather than selected only by product name.
Applications in Food Processing
Bakery and Cereal Systems
Most relevant where manufacturing objective is measurable reduction of acrylamide formation in heat-treated foods containing free asparagine and reducing sugars.
Biscuits, cookies, crackers and crispbread
Bread, rolls, toast products and cereal-based bakery items
Breakfast cereals, extruded cereals and baked cereal snacks
Useful in doughs, batters, cereal slurries and hydrated mixes where enzyme can contact free asparagine before baking. Requires sufficient water availability and mixing uniformity. Processing teams should evaluate mixing time, proofing time, resting time and dough temperature.
Finished-product testing should monitor acrylamide, colour, flavour, texture, volume and shelf-life impact. Over-processing or unsuitable conditions may reduce enzyme effectiveness before main heat step.
Trial results: L-asparaginase enzyme catalyses hydrolytic cleavage of L-asparagine precursor into L-aspartic acid and ammonia, thus reducing formation. Objective was to test enzyme at two concentrations (150 and 300 U/kg flour) under normal baking conditions. Results showed use of 300 U/g enzyme led to reduction of 78% in acrylamide, meeting reference level reported by Reg (EU) 2017/2158 (50). Specifically samples prepared with different dosages (150 and 300 U/kg flour) baked under standard conditions (260°C for 40 min). Results demonstrate enzymatic treatments able to reduce acrylamide content by 61% and 78% respectively in bread treated at 150 and 300 U/kg, without unacceptable sensory changes.
In homemade bread processed with L-asparaginase – reduction similar.
Recombinant hyperthermophilic asparaginase TsAI effectively reduced acrylamide content in simplified food system, by hydrolyzing L-asparagine along with D-enantiomer. Lowest acrylamide level 1.0–1.1% of control values observed in baked samples pretreated with TsAI at enzyme dosage 20 U/mL, treatment temperature 90°C, incubation 20–25 min – shows potential of thermostable enzymes.
Potato and Snack Processing
Potato chips, French fries, formed potato products – L-asparaginase can hydrolyze L-asparagine precursor to acrylamide, reducing toxic acrylamide formation in fried foods. Currently commercial L-asparaginases primarily produced by wild-type filamentous fungi; however these enzymes often exhibit rapid activity loss during high-temperature processing due to limited thermal stability – new thermostable variants being developed.
May be evaluated in potato strips, slices, flakes, doughs or formed products before frying or baking. Works best when enzyme contact possible before surface dehydration or high-temperature treatment. Important variables include blanching, soak time, pH, temperature, strip thickness, solids and sugar profile. Trials should compare acrylamide reduction with colour, crispness, oil uptake and sensory quality. Raw-material variability can require seasonal dosage adjustments.
Other Applications
Fried, baked, roasted or dried starchy snacks
Coffee, coffee substitutes and selected roasted plant materials – more challenging due to low moisture
Infant-food, cereal-food and clean-label reformulation projects requiring acrylamide control
Key Process Parameters to Define Before Trials
Successful Asparaginase trial requires clear processing window. Enzymes sensitive to environment and same enzyme grade can perform differently in dough, slurry, potato tissue, cereal paste or dry-mix systems.
Substrate level: Measure or estimate free asparagine and reducing sugars in raw material
Moisture: Ensure enough water activity or hydration for enzyme movement and substrate contact
pH: Compare process pH with supplier's declared activity range – typically pH 5-8 optimal
Temperature: Check enzyme's optimum range and thermal inactivation point – most commercial asparaginases from Aspergillus niger/orzae optimum 50-60°C, inactivated >80°C
Contact time: Define how long enzyme remains active before heat step – minimum 15-30 min in dough resting, up to 2 hours for potato soaking
Mixing: Confirm uniform distribution to avoid untreated zones and inconsistent acrylamide results
Dosage: Trial multiple dosage levels within supplier guidance and regulatory/customer limits – typically 100-500 U/kg flour or 500-2000 U/kg potato solids
Validation: Analyze acrylamide after full commercial-style processing, not only in lab dough or slurry
Industrial Formulation and Process Considerations
Handling and Storage
Enzyme preparations require controlled handling to protect activity and operator safety. Asparaginase should be stored and used according to supplier recommendations, especially for temperature, humidity and open-pack handling. Powdered enzymes may create dust, while liquid enzymes may require mixing, controlled dosing and microbiological attention after opening.
Store unopened material within temperature range specified
Keep containers closed when not in use to protect activity and avoid contamination
Use calibrated dosing equipment and validated mixing procedures
Control dust formation and follow safety data sheet for respiratory and skin protection
Avoid adding enzyme at point where temperature or pH rapidly inactivates it
Retain batch samples and COAs for traceability and customer audits
Verify enzyme performance periodically through finished-product acrylamide testing
Packaging may include sealed bags, cartons, drums, pails, bottles, jerrycans or temperature-controlled containers depending on whether grade is powder, granule or liquid. Enzymes may have shorter shelf lives than many commodity additives, so buyers should check remaining shelf life before shipment and confirm whether cold-chain transport recommended.
Specification Checklist for Buyers
Professional specification should describe enzyme preparation clearly enough for food safety, process validation, purchasing comparison and regulatory review. Because enzyme activity units not always directly interchangeable between suppliers, buyers should compare both declared activity and supplier's activity-assay definition.
Declared enzyme activity and exact unit definition
Activity assay method, substrate, pH, temperature and analytical conditions
Source organism and production strain – e.g., genetically modified Aspergillus niger strain AGN by DSM Food Specialties – genetic modifications do not give rise to safety concerns – free from viable cells and DNA – intended to prevent acrylamide formation
Production method, including fermentation and downstream processing
Carrier, diluent, stabilizer, preservative or formulation components
Physical form, appearance, colour, odour, particle size or viscosity
Recommended pH range, optimum pH and practical application pH range
Recommended temperature range, optimum temperature and inactivation conditions
Dosage guidance by application type and expected acrylamide-reduction range – e.g., 61% at 150 U/kg, 78% at 300 U/kg
Microbiological spec, heavy metals, allergen, GMO, halal, kosher, vegan declarations
Shelf life, storage temperature, packaging format and batch traceability
Regulatory and Processing-Aid Status
Food enzyme regulation is market-specific. Asparaginase may be treated as processing aid in some applications and jurisdictions, but classification, authorization, labelling and documentation requirements depend on destination market, source organism, production method, carrier ingredients, residual enzyme expectations and food category. Manufacturers should verify both local production rules and export-destination rules before commercial use.
US: GRAS – processing aid – no label declaration required if enzyme inactivated and no technical function in final food
EU: Food enzyme – safety evaluation of food enzyme asparaginase from genetically modified Aspergillus niger strain AGN – approved – must be included in Union list of food enzymes
Labeling: In regions where acrylamide mitigation specifically expected or benchmarked for certain food categories, Asparaginase can be part of broader control strategy together with raw-material selection, storage control, blanching, soaking, recipe reformulation, sugar management, time-temperature control and finished-product monitoring
Trial Design Best Practice
Establish baseline acrylamide level from current process. Document raw-material lot, recipe, reducing sugar level and asparagine level where available. Run at least one untreated control and multiple enzyme dosages. Keep mixing, holding time, temperature and pH consistent. Use validated acrylamide analysis method or accredited external lab. Check sensory and physical quality alongside acrylamide reduction. Repeat trials across raw-material seasons if potato, grain or cereal variation significant. Document final validated dosage, process point and contact time for production SOPs.
Certain processing steps can effectively lower acrylamide levels. Key steps: Pretreatment with Asparaginase – enzyme targets and breaks down asparagine, amino acid that is primary precursor to acrylamide formation during cooking. Removing asparagine before processing significantly reduces potential for acrylamide synthesis.
Working Source Links:
Acrylamide mitigation in cereal-based foods: comprehensive review of enzymatic treatments – amide group converted into aspartic acid and ammonia by asparaginase – substantially reducing formation – https://link.springer.com
Reducing acrylamide concentration in homemade bread processed with L-asparaginase – 150 and 300 U/kg flour – 78% reduction – https://iris.unina.it
Asparaginase | Food Enzyme for Acrylamide Mitigation | Global Food Additives – Product identity CAS 9015-68-3 EC 3.5.1.1 L-asparagine + H2O → L-aspartic acid + NH3 – Application fit biscuits, bread, cereals, potato chips – https://foodgradeadditives.com
Safety evaluation of food enzyme asparaginase from genetically modified Aspergillus niger strain AGN – intended to prevent acrylamide formation – https://efsa.onlinelibrary.wiley.com
Benzoic Acid (E210) CAS: 65-85-0
