Enzyme from Pumpkin Relative Helps Reduce Peanut Allergenicity

Peanut allergy remains one of the most severe and unpredictable food allergies, capable of triggering life-threatening anaphylaxis from very small exposures in some individuals. In a promising new study published in Food Chemistry, researchers from the Wroclaw University of Environmental and Life Sciences and Wroclaw Medical University found that a natural plant enzyme isolated from the figleaf gourd (Cucurbita ficifolia) can significantly decrease the immunoreactivity of major peanut allergens. While the findings do not yield an allergen-free peanut product, they demonstrate a promising biochemical approach toward developing food ingredients with reduced allergenic potential.

The need for new allergen-modifying methods stems in part from the fact that very small amounts of peanut can trigger serious reactions in some sensitized individuals. “Peanut allergy is particularly challenging because even a small amount of the allergen can trigger a serious reaction in sensitized individuals, including anaphylaxis,” explained study co-author Ewa Willak-Janc, MD, PhD, of Wroclaw Medical University. “We are therefore looking for methods that can modify allergenic proteins and reduce their recognition by the immune system.”

Rather than relying solely on commercial digestive enzymes or aggressive industrial processing, the team turned to an extracellular serine protease naturally isolated from Cucurbita ficifolia, a relative of the pumpkin. The enzyme hydrolyzes peanut proteins by cleaving peptide bonds, breaking the proteins into smaller fragments and altering or disrupting epitopes that antibodies recognize. “Protein structure is one factor that determines whether the immune system can recognize it. In people with allergies, antibodies react with specific protein fragments called epitopes,” highlighted co-author Joanna Bajzert, PhD, Eng. “If enzymatic hydrolysis appropriately modifies protein structure, its ability to bind antibodies may be reduced. In the case of allergens, this approach is particularly interesting because it allows us not only to break down the protein, but above all to control changes in its properties.”

The researchers treated peanut protein isolate under varying conditions, including different enzyme activities, temperatures, and reaction times, and examined the effects on allergenic proteins, including Ara h 2 and Ara h 6. Time and temperature proved especially important: longer hydrolysis and the higher temperature tested produced greater changes, with the lowest antibody-binding properties observed after 24 hours at 42°C. By contrast, increasing enzyme activity did not significantly affect immunoreactivity, suggesting that carefully controlling processing conditions may be particularly important in reducing antibody recognition of peanut proteins.

Despite the marked reduction in antibody binding, the researchers emphasize that enzymatic hydrolysis did not eliminate allergic risk. Smaller peptide fragments remaining after treatment—including fragments derived from major peanut allergens—retained the ability to bind IgE antibodies, meaning the researchers could not conclude that the hydrolyzed material was non-allergenic. “This is a very important finding,” cautioned Dr Bajzert. “We have shown that we can significantly reduce immunoreactivity, but hydrolysis alone is not sufficient to completely eliminate allergenic properties. Therefore, we cannot say that the resulting material is safe for people with peanut allergy.”

Beyond reducing immunoreactivity, controlled enzymatic modification could offer possibilities for food formulation because the resulting peptides may have different functional and nutritional characteristics. “Using naturally derived enzymes makes it possible to modify proteins precisely,” stated Anna Mandecka, PhD, Eng., of the Department of Functional Food Products Development. “We are interested not only in whether we can reduce their immunoreactivity, but also in what new properties we can obtain through controlled protein breakdown. This may be important for developing functional foods and designing new food ingredients.”

Importantly, the study did not demonstrate that people with peanut allergy can safely consume enzyme-treated peanut. The researchers say additional testing is needed, including cell-activation studies to determine whether the remaining peptides can trigger degranulation and other cellular responses associated with allergy. As project initiator Anna Dąbrowska, PhD, DSc, concluded: “The aim is not simply to ‘remove’ the protein. The goal is to learn how to modify it appropriately and control the properties of the resulting peptides. This is what gives us the prospect of designing a new generation of food ingredients.”