A pumpkin protease cuts peanut proteins but does not erase the allergy

A pumpkin in the allergy lab

Peanut allergy is among the scariest food allergies. A trace of protein can trigger a sudden reaction in a sensitized person, including anaphylaxis. Avoiding the product works only until the first hidden ingredient in processed food.

A team from the Wrocław University of Environmental and Life Sciences and Wrocław Medical University is testing another path. They take a serine protease from figleaf gourd (Cucurbita ficifolia) and use it to “cut” peanut proteins. The goal is not culinary. It is to reduce how those proteins are recognized by antibodies linked to allergy.

A paper in Food Chemistry (DOI: 10.1016/j.foodchem.2026.150272) shows a reverse that sounds almost too simple: a pumpkin enzyme weakens the immunoreactivity of peanut proteins in laboratory tests. And immediately the other side of the same coin: after hydrolysis, short peptides remain that still bind antibodies. This is not safe food for someone with peanut allergy. It is a controlled experiment on how far the IgE signal can fall before anyone even thinks about a product.

Why the peanut defends itself so well

Many allergenic proteins have been described in peanut. Ara h 2 and Ara h 6 matter especially — they rank among the strongest allergens in this group. They are also fairly resistant to ordinary food processing and digestion. Baking or classic heat treatment alone often fails to lower their allergenic properties in a meaningful way.

The mechanism is simple to describe and hard in practice. In allergic people, IgE antibodies recognize specific protein fragments — epitopes. If enzymatic hydrolysis changes the protein structure in the right way, some of those sites may disappear or become less accessible. Immunoreactivity measured by ELISA and immunoblotting then drops.

Ewa Willak-Janc of the 1st Department and Clinic of Pediatrics, Allergology and Cardiology at Wrocław Medical University stresses the scale of the problem: even a small amount of allergen can trigger a severe reaction. Hence the search for methods that do not only “break” the protein, but deliberately change its immunological properties.

The food industry already knows enzymatic hydrolysis. It mostly uses commercial digestive enzymes, sometimes combined with heat. The Wrocław team takes another route: a non-commercial extracellular serine protease from figleaf gourd — a readily available plant previously tested by the same center on milk proteins.

Reverse one: a tool from the garden, not the catalog

The idea was not a whim. Long-running work at the Wrocław University of Environmental and Life Sciences showed that the same protease effectively breaks down milk proteins and changes their properties. The question now was whether a similar protocol would work on peanut proteins, which are tougher immunologically.

Joanna Bajzert of the Department of Immunology, Pathophysiology and Veterinary Prevention at UPWr speaks plainly about control. Hydrolysis should not only shorten the protein chain. It should let researchers steer the change in properties — including the ability to bind antibodies.

That is the narrative reverse. Pumpkin evokes the kitchen and the season. Here it becomes a source of a molecular tool. Peanut evokes a snack and, at the same time, one of the hardest food allergies. Meeting both in a test tube does not promise a magical “safe peanut.” It promises a measurement: how far antibody recognition of the protein falls when the enzyme works longer and warmer.

What was actually done on the bench

The researchers isolated proteins from raw peanuts and treated them with C. ficifolia protease under different conditions. They tested enzyme activities of 150, 300 and 600 U per milligram of protein, temperatures of 37 and 42 °C, and times of 0, 1, 5 and 24 hours.

The longer the enzyme worked, the further protein breakdown went. Time and temperature had the greatest effect on the drop in immunoreactivity. In those measurements, enzyme activity proved less decisive. The lowest antibody binding was obtained for hydrolysates after 24 hours at 42 °C — in tests with chicken anti-peanut antibodies (competitive ELISA and immunoblotting).

That result is easy to misread. “Lowest binding” does not mean “zero risk.” It means: in this laboratory setup, the immunoreactivity signal fell most at longer, warmer hydrolysis. It is a process-parameter map, not a food-safety certificate.

Reverse two: less signal, epitopes still there

Hydrolysis clearly lowered the immunoreactivity of the proteins. It did not remove it. After the process, smaller fragments remained that still reacted with antibodies. Among allergens that kept binding ability, Ara h 2, Ara h 6 and Ara h 3 are listed.

Bajzert calls this the key finding. Immunoreactivity can be reduced substantially. Hydrolysis alone is not enough to eliminate allergenic properties completely. The material after processing is therefore not a product safe for people with peanut allergy.

Here the reverse closes without ornament. Methodological success and product failure sit in the same results paragraph. For a TRL09 reader that matters more than a superlative in a press headline. It shows where food chemistry ends and clinical immunology begins.

The paper abstract goes further in caution: small peptides after hydrolysis still react with antibodies, so complete removal of allergenicity by this route is impossible at the present stage. Next experiments should check cell activation — including basophil activation tests — to see whether the drop in the ELISA signal translates into a lower ability to trigger degranulation.

From immunoblot to a functional food ingredient

Anna Mandecka of the Department of Functional Food Products Development at UPWr points to a wider horizon. Hydrolysis changes more than protein size. It yields peptides with different biological and technological properties. That opens design of ingredients with a specific profile — lower immunoreactivity, but also other use properties.

Anna Dąbrowska, who initiated this research line, states the goal without euphemism: it is not about simply “removing” the protein. It is about learning how to modify it and control the properties of the resulting peptides. Only then does a prospect of a new generation of food ingredients appear.

That is honest foodtech language. The market for hypoallergenic hydrolysates and foods for special medical purposes already exists, especially in infant nutrition and products for people with allergies. Entering with a new plant enzyme requires three things at once: repeatable isolation and enzyme activity at scale, acceptable taste and texture after processing, and evidence that the laboratory signal drop matters biologically in cell models and later clinically.

TRL without decoration

Today the work sits around TRL 3–4. There is a peanut protein isolate, a pumpkin enzyme, a grid of time–temperature–activity conditions, ELISA and immunoblotting. There is a clear negative result: no elimination of IgE binding. There is not yet a food product, in vivo validation, or a registration path as hypoallergenic food.

For an investor and a food technologist this is a different risk type than typical “lack of scale.” Here the risk is immunological. You can have a nice drop on the ELISA curve and still activate allergy effector cells. That is why the announcement of basophil activation tests is not ornament in a press note. It is a gate without which shelf talk is not worth starting.

Competition is not idle either. Industry combines hydrolysis with pressure, ultracentrifugation, heat and enzyme mixtures. A new protease from C. ficifolia must show an edge: efficacy against Ara h 2/6, isolation cost, batch purity and taste impact. The mere fact that the enzyme comes from pumpkin does not sell a product. What sells is a repeatable risk drop at acceptable sensory quality — and the paper does not yet prove that.

Poland: the angle is not glued on

Unlike many TRL09 pieces about labs in Asia or the US, the affiliations here are Wrocław from start to finish. The University of Environmental and Life Sciences brings food enzymology and functional ingredient design. The Medical University brings the pediatric allergology perspective. That is a natural bridge between foodtech and the clinic.

For the Polish food industry and local ingredient firms the point is simple. Food allergies are rising in statistics and in consumer awareness. EU allergen labeling long ago forced label discipline. The next level — ingredients with lowered immunoreactivity — will fight not with a “from pumpkin” slogan, but with BAT data, process stability and price per kilogram of hydrolysate.

Wrocław has something rare in this paper: its own molecular hero (the C. ficifolia protease), its own clinical problem (peanut allergy) and its own unexaggerated verdict (works in the assay, does not work as a safety guarantee). That is better material for a spin-off or an industry R&D project than another metaphor without numbers.

Europe has both hard novel-food regulation and rising demand for “free-from” food. Whoever can lower epitopes without ruining the product trades in trust. Whoever promises safety after an immunoblot alone trades in legal risk.

Buyers, barriers and what is not in the paper

There are several buyers in this story at once. Plants that make plant and milk-replacement hydrolysates. Food-allergy startups looking for an ingredient with a measurably lower IgE signal. Diagnostic labs that already live on antibody-binding tests — though that is more a thematic neighbor than the enzyme’s first customer.

The barriers are as concrete as the ELISA result. Isolation of the C. ficifolia protease must scale, or a stable recombinant production route must be found without losing cleavage specificity. The effect of hydrolysis on the taste and texture of peanut paste or protein isolate must be checked. And the work must move from immunoblot to cell models before anyone uses the word “hypoallergenic” on a label.

The paper does not promise that. It shows a time- and temperature-dependent drop in immunoreactivity and the method’s limit at Ara h 2, Ara h 6 and Ara h 3. That is enough to treat the topic as worth following at TRL09. It is not enough to announce the end of peanut allergy.

What remains of the reverse for tomorrow

The opening reverse can now be said without a trick. Yes, a figleaf-gourd enzyme can, under controlled conditions, strongly lower the immunoreactivity of peanut proteins — most at longer hydrolysis at 42 °C. Yes, after the same process, Ara h 2, Ara h 6 and Ara h 3 fragments remain that still bind antibodies. Both are true because they describe two layers of the result: the lab-test signal and the safety threshold for the patient.

A question the publication does not close remains. Does the hydrolysate after optimization activate basophils more weakly than the starting protein? Can the process be shortened or combined with other processing to bring 24 hours down to factory scale? Will taste and texture survive what the epitope survives?

For now Wrocław shows something more valuable than a “breakthrough for allergy sufferers.” It shows a parameter map and an honest limit of the method. In foodtech, limits are currency. Without them, marketing eats the science.

Sources

Magdalena Wyspiańska et al., Pumpkin power: The influence of serine protease isolated from Cucurbita ficifolia on peanut proteins, Food Chemistry (2026). DOI: 10.1016/j.foodchem.2026.150272
Phys.org — coverage of the UPWr / UMW team: Pumpkin-derived enzyme weakens peanut protein recognition