Protease

also: Proteinase · Peptidase · Papain · Bromelain

A group of protein-digesting enzymes added to bread dough and other foods to improve texture, tenderness and processing.

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E1101

Protease

Proteases are enzymes that break protein chains into shorter peptides and amino acids.

How common it is in UK food

of the 43,325 UK supermarket foods we checked declare E1101 in their ingredients

That is under 0.1%, counted by its code or its name.

Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted

What protease is, what it does and where you will see it

What is it?

Proteases are enzymes that break protein chains into shorter peptides and amino acids. The E1101 category covers several distinct proteases from different sources: animal-derived (such as pancreatic trypsin and chymotrypsin from pig or cattle), plant-derived (papain from papaya, bromelain from pineapple, ficin from figs), and microbial-derived (from moulds such as Aspergillus oryzae and Bacillus subtilis, or from the fungus Rhizopus). Each type has a slightly different protein target and temperature range but all catalyse the same fundamental reaction.

What does it do?

Proteases weaken the gluten network in wheat dough by snipping glutenin and gliadin protein strands. This makes dough more extensible and easier to machine, reduces mixing time, and gives bread a finer, more uniform crumb. In meat processing they tenderise muscle fibres. In brewing they break down haze-forming proteins. The enzyme is typically inactivated during baking or cooking, so little or no active protease remains in the finished food.

Where you will see it

Most commonly used in commercial bread, rolls, pizza bases, crackers and biscuits as a dough conditioner. Also used in meat tenderisers, some cheeses, beer production, and certain soy protein products. Because proteases often function as processing aids rather than ingredients with a technological effect in the final product, manufacturers are not always required to declare them on the label. When declared, expect to see 'protease', 'protease enzyme', 'flour treatment agent (protease)' or 'enzyme (protease)' in the ingredients list.

What the science says

Occupational exposure and baker's asthma

Inhaling protease enzyme dust in bakery or food manufacturing settings is an established cause of occupational asthma and rhinitis. This is an airborne workplace hazard, not a risk from eating finished baked goods. The active enzyme is destroyed by heat during baking, so the inhalation risk does not carry over to consumers. The effect in workers is well-documented and underpins strict industrial handling controls.

Fungal and bacterial protease preparations used in baking are recognised causes of occupational asthma in bakery workers through inhalation sensitisation.

2019Regulatory reviewEFSA Panel on Food Additives and Nutrient Sources (ANS), re-evaluation of proteases as food enzymes

Protease enzyme dusts are listed among the high-molecular-weight respiratory sensitisers relevant to occupational asthma in the food industry.

RegulatoryHealth and Safety Executive (HSE), Occupational Asthma

Allergenicity from plant-derived proteases (papain, bromelain)

Papain (from papaya) and bromelain (from pineapple) are the plant-derived proteases most associated with allergic reactions in consumers. Papain is a known cross-reactive allergen in people with latex allergy or oral allergy syndrome linked to tropical fruits. Reactions range from mild oral tingling to, rarely, systemic responses. These plant proteases are sometimes used in meat tenderisers and supplements as well as processed food. If declared on the label, the source plant name usually appears.

Papain from papaya is a documented allergen capable of triggering IgE-mediated reactions in individuals sensitised to latex or tropical fruits, with cross-reactivity confirmed in clinical case series.

1997ObservationalBlanco et al., Annals of Allergy, Asthma and Immunology

Bromelain from pineapple has been reported to cause allergic reactions including urticaria and systemic symptoms, with cross-reactivity to other plant proteases.

1988ObservationalGailhofer et al., Clinical and Experimental Allergy

Animal-derived proteases and dietary considerations

Animal-sourced proteases (from pig or cattle pancreas) are not suitable for people following halal, kosher, or vegan diets unless the source is certified. Labels rarely specify the origin of a protease enzyme, making it impossible for consumers to determine the source from the ingredient list alone without contacting the manufacturer.

Food enzyme preparations derived from animal pancreatic tissue may be of porcine or bovine origin; this is not required to be declared on the UK label under current food labelling regulations.

RegulatoryUK Food Information Regulations 2014 and assimilated EU Regulation 1169/2011

Heat inactivation and residual activity

Most food protease preparations are inactivated at temperatures above 65 to 70 degrees Celsius, which is reached during baking, cooking or pasteurisation. Studies confirm that active enzyme in finished baked goods is negligible. However, proteases used in cold-processed products such as raw marinated meat or chilled beverages may retain activity in the final product.

Protease enzymes used in bread production are substantially inactivated during the baking process; residual enzymatic activity in finished bread is below detectable levels in standard assays.

2002LabKirk et al., Food Chemistry

Where it stands with the regulators

Approved for use in the UK and EU as a food additive (flour treatment agent) under E1101

Legal basis: UK FSA approved-additives list and assimilated EU Regulation 1333/2008 (Annex II). Individual protease enzyme preparations also undergo separate food enzyme assessments by EFSA under Regulation (EC) No 1332/2008 (the Food Enzymes Regulation), which requires pre-market authorisation for each preparation.
Permitted foods: Bread and rolls; Fine bakery wares (biscuits, crackers, cakes); Pizza bases; Pasta; Processed meat products; Beer and brewing
Maximum levels: Quantum satis (no fixed maximum; used at the level technologically necessary)
Safe-intake limit (ADI): No numerical ADI set
History: Proteases have long been used as processing aids and flour treatment agents in European baking. The Food Enzymes Regulation (EC) No 1332/2008 introduced a unified EU authorisation process for food enzyme preparations; EFSA began systematic re-evaluations of individual protease preparations from around 2019. Specific protease preparations must appear on the EU Food Enzymes List to be marketed; this list was still being compiled as of EFSA's rolling review programme. In Great Britain post-Brexit, the domestic food enzyme authorisation list has not yet been established. In the interim, enzymes may continue to be used in food if they meet the requirements of assimilated Regulation (EC) No 1332/2008. From 1 April 2025, the market authorisation process was modernised so that any future GB authorisations will come into effect via ministerial decision and be published in an FSA/FSS-maintained register, rather than being prescribed by statutory instrument. The FSA online register for regulated products serves as the primary source for authorised products in Great Britain.

Who should be careful

People with latex allergy or tropical-fruit oral allergy syndrome should be aware that some protease-containing products use papain (papaya) or bromelain (pineapple), which can trigger cross-reactive symptoms. Look for 'papain' or 'bromelain' on the label; these are more likely to appear in meat tenderisers and marinades than in bread. Anyone following a halal, kosher or vegan diet should contact the manufacturer to confirm the enzyme source, as the label entry 'protease' does not reveal whether the enzyme comes from animal, plant or microbial origin.

The honest read

Protease is one of the most routine and long-established categories of food enzyme. Its job is entirely technological: it modifies dough or meat proteins during processing and is mostly destroyed before the food reaches the plate. The allergenicity risks that exist are specific and well-characterised: inhalation by bakery workers, and oral reactions in people with latex or tropical-fruit allergies when the source is papain or bromelain. Neither concern applies to most consumers eating standard bread or biscuits. The harder-to-answer question for consumers who care about animal products or religious dietary law is the unlabelled source of origin. Current UK labelling law does not require manufacturers to state whether a protease is porcine, bovine, plant or microbial, so the label alone will not resolve that.

Common questions about protease

Is E1101 banned in the UK?

No. Protease is an approved food additive and processing aid in the UK under the FSA's approved-additives list and the assimilated EU Regulation 1333/2008. Individual protease enzyme preparations also require authorisation under the Food Enzymes Regulation.

Is the protease enzyme in my bread still active when I eat it?

Almost certainly not. Proteases used in dough are inactivated at the temperatures reached during baking (above around 65 to 70 degrees Celsius). In finished baked goods, residual activity is negligible. Proteases used in chilled or uncooked products may retain more activity.

What foods contain E1101?

Commercially produced bread, rolls, crackers, pizza bases, biscuits and fine bakery wares are the most common sources. Meat tenderisers, some marinated meat products, and certain beers also use protease enzymes. When used purely as a processing aid with no function in the final product, proteases may not appear on the ingredient list.

Is E1101 vegan?

Not always. Proteases can be derived from pig or cattle pancreas, from plants (papaya, pineapple, figs), or from microbial fermentation. The label entry 'protease' or 'enzyme (protease)' does not indicate the source. Contact the manufacturer if the origin matters to you.