天冬酰胺酶

Yes. Food-grade asparaginase has been assessed by JECFA, holds GRAS status in the US and is approved as a processing aid in Australia and New Zealand. It is inactivated by cooking and converts asparagine into aspartic acid, a normal dietary amino acid.

Supplier and published data report little or no change in taste, texture or colour. Long warm pre-treatment dips can affect texture, so sensory testing is still advised.

Laboratory studies report 60–85% when strips are blanched first; industrial trials have reported 35–50%. Results on frozen par-fry lines vary.

In most markets it is treated as a processing aid and is not declared. Rules differ by country, so check local requirements.

No. It works best on top of low-sugar raw material, correct storage, blanching and frying to a golden colour.

Potatoes contain free asparagine and reducing sugars. When they are fried or baked above about 120 °C, these react in the Maillard reaction and form acrylamide, mostly in the dry, browned outer layer.

No. Medical asparaginase usually comes from E. coli or Erwinia bacteria and is injected. Food asparaginase comes from Aspergillus moulds, is used in tiny amounts and is inactivated by cooking.

Some commercial asparaginases are produced with genetically modified production strains of Aspergillus. The finished enzyme preparation is purified and must be free of the production organism. Labelling rules for such enzymes differ by country.

It is made by microbial fermentation, not from animals. Halal, kosher and vegetarian status depends on each supplier's formulation and certification, so request certificates.

They work best together. In a Chilean study on chips, blanching alone and enzyme alone each gave modest reductions, while blanching followed by asparaginase cut acrylamide by almost 90%.

It is not sold for household use. At home, store potatoes in a cool, dark place rather than the fridge, soak cut potatoes in water before frying, keep oil at 160–175 °C and cook to a golden yellow colour.