Could Parma Ham Waste Power Next Protein-Snack Revolution? Scientists Put Idea to Test

A piece of Parma ham left behind during slicing may look too small or uneven for a retail pack, yet it still contains valuable protein, essential amino acids and micronutrients. Researchers have now explored how these overlooked trimmings could become nutritious savoury snack bars instead of being sold cheaply for animal feed or stuffed-pasta production.

The study, titled 'Valorisation of Prosciutto di Parma PDO By-products for the Development of Protein-Rich Snacks,' was published in the journal Frontiers in Nutrition. Filippo Rossi and colleagues developed six experimental bars combining cured-ham residues with pork, unconventional corn varieties and either pork gelatine or psyllium fibre, creating products designed around both nutrition and circular food production.

Parma Ham Waste Becomes the Main Ingredient

Pre-packed cured meats are a major part of Italy's food market, with sliced products becoming popular among consumers looking for convenience. Slicing and packaging can leave behind trimmings equal to roughly 10% of the original product, creating an economic loss and an environmental burden despite the material remaining rich in high-quality nutrients. The researchers used these residues as 35% of every snack formulation, adding fresh pork meat, water, lemon juice and one of three corn ingredients: red pigmented corn, blue pigmented corn or yellow amylose-extender corn, a variety known for starch that is less easily digested.

Six bars were created by changing the corn, binding ingredient and binder concentration. Three contained 5% pork gelatine with red, blue or yellow corn, while the other versions paired yellow high-amylose corn with either 5% or 10% gelatine or psyllium fibre. Each mixture was shaped and baked at 110°C for two and a half hours. The team measured energy, protein, fat, carbohydrates, fibre, amino acids, protein digestibility, starch digestion and the phenolic compounds naturally present in the corn.

Every Prototype Delivered a Strong Protein Content

The finished bars contained between 26.67% and 38.14% protein, with the yellow-corn bar containing 10% gelatine recording the highest level. Fat remained within a narrow range of 10.24% to 12.21%, while carbohydrates accounted for 14.8% to 18.4%. Energy values ranged from 279 to 313 calories per 100 grams, giving the prototypes a moderate calorie density alongside more protein than many cereal-based snack bars.

All six formulations obtained more than 20% of their energy from protein, meaning they met the European requirement for a 'high protein' nutrition claim. Fibre varied far more widely because of the binder and corn selection, ranging from 2.59% in the blue-corn gelatine bar to 30.76% in the version containing 10% psyllium. The 5% psyllium bar also contained a substantial 17.27% fibre. Products made with psyllium could be labelled high in fibre, and some yellow-corn and gelatine formulations may qualify as a source of fibre, although the analytical classification of gelatine-related material requires careful regulatory confirmation.

High Digestibility Meets Slower-Digesting Starch

Laboratory digestion tests produced protein digestibility values between 95.3% and 96.2% across the prototypes. The researchers linked these results partly to Parma ham's curing period of at least ten months, during which some proteins are naturally broken into forms that digestive enzymes may access more easily. Digestible Indispensable Amino Acid Scores ranged from 74.3 to 79.6, matching the regular Protein Scores of about 75 to 80. Valine was the first limiting amino acid in five bars, and sulphur-containing amino acids limited the blue-corn version. Leucine was usually the second limiting amino acid, and its ratio to valine remained below the level considered ideal for stimulating muscle protein synthesis.

Corn type and binder choice changed how the starch behaved during digestion: Yellow high-amylose corn produced less rapidly digestible starch and more resistant starch than red or blue corn when all three were combined with 5% gelatine. Psyllium reduced starch digestibility compared with pork gelatine because its gel-forming structure can absorb water and restrict digestive enzymes from reaching the starch. The 5% psyllium formulation recorded 21.6% resistant starch, falling to 15.2% when psyllium was increased to 10%. The yellow high-amylose formulations contained enough resistant starch to potentially support an authorised claim related to reduced post-meal blood-glucose response, subject to the finished product meeting every regulatory condition.

Promising Nutrition Still Needs Real-World Testing

High-resolution analysis identified 490 phenolic compounds across the corn samples, including 291 flavonoids, 100 phenolic acids and 11 stilbenes. Yellow corn unexpectedly recorded the highest total phenolic content at 1,166.75 milligrams of phenolic equivalents per kilogram, followed by blue corn at 866.17 and red corn at 717.16. Blue corn led in anthocyanins and luteolin-related compounds, and yellow corn contained larger quantities of phenolic acids, stilbenes and several other phenolics. The profiles placed red and blue corn together as chemically similar pigmented varieties, with yellow corn forming a distinct group.

These savoury bars could serve people with increased protein needs, including athletes and older adults at risk of losing muscle mass. Their nutritional numbers do not yet prove that they improve recovery, muscle growth, blood sugar control or health in daily life. All digestion work was conducted in laboratory conditions; no human or animal trials were performed, and taste, texture, consumer acceptance and shelf life were not evaluated. Psyllium may also behave differently inside the digestive tract, where its gel could make proteins less accessible than the laboratory results suggest, and stronger industrial heating could reduce lysine availability through the Maillard reaction.

The research offers a convincing early demonstration of how Parma ham slicing residues can become a higher-value food rather than a low-value by-product. Among the tested recipes, the bar combining yellow high-amylose corn with 5% psyllium presented one of the strongest overall balances of protein quality, fibre and resistant starch. Further recipe refinement, added leucine, sensory testing, storage studies and human trials will be needed before these experimental bars are ready for supermarket shelves.