From Bird Feathers to Bioactive Peptides. How Waste Becomes a Functional Protein

Keratins are the main proteins found in feathers, hair, nails, and horns. They provide tissues with strength, flexibility, and resistance to damage. Structurally, they are similar to collagen present in skin and bones. However, unlike collagen, keratin is more difficult to convert into a form that can be assimilated by humans without degrading its biological properties. M.Sc. Eng. Antoni Taraszkiewicz, as part of his doctoral dissertation, developed a method for obtaining soluble keratin hydrolysates, which serve as a source of bioactive peptides potentially absorbable by humans.

– We managed to develop a method that allows isolating keratin from feathers in a pure form, soluble in water and susceptible to digestive enzymes, without significant degradation of the protein structure. The obtained material resembles gelatin – says M.Sc. Eng. Taraszkiewicz, a graduate of the Doctoral School at Gdańsk Tech and a research and teaching staff member at the Faculty of Chemistry.

Bioavailability, bioactivity, and... meaty aroma

The research involved several stages, and as the scientist explains, the most challenging was transitioning from feathers to a high-quality extract. Although methods for obtaining soluble keratin are known, they often come with limitations related to solubility, preservation of biological activity, sensory properties, or process efficiency.

In the first stage, an extract was prepared from purified feathers. Next, enzymatic hydrolysis was carried out, resulting in keratin peptides. In the final stage, the Maillard reaction was examined, which occurs between reducing sugars and proteins or peptides, resulting in a brown-colored product. This process occurs naturally in food and is responsible, among other things, for the aroma and taste of thermally processed products.

– Peptides derived from feather keratin are an attractive substrate for the Maillard reaction due to their high cysteine content, which can form products with a pleasant, meaty aroma when reacting with sugars. By applying this process, which has so far been rarely used concerning keratin peptides, we managed not only to improve the sensory properties of the obtained preparations but also to increase some parameters of biological activity and in vitro bioavailability – explains M.Sc. Eng. Taraszkiewicz and assures that the laboratory-scale research results are promising. – The results indicate that the process has potential for further optimization and evaluation for industrial applications – he adds.

Functional properties and safety in laboratory studies

As the scientist notes, proteins and protein hydrolysates can exhibit a range of functional properties important for industry. For example, in the food industry, they are used for stabilizing foam and emulsions, forming gels, and as structuring components in food production, including functional foods and dietary supplements. As part of the conducted research, keratin preparations obtained from poultry feathers were assessed in this regard, demonstrating that their technological properties are comparable to those of proteins derived from conventional raw materials.

– The research results also confirmed the antioxidant properties of the obtained peptides as well as the absence of toxicity in vitro. Currently, I am examining their biological activity regarding preventive potential in the context of metabolic diseases such as diabetes and hypertension. Initial results indicate that our peptides may exhibit activity significant for the prevention of these diseases (at the in vitro research stage) – says the graduate of the Doctoral School at Gdańsk Tech.

Tens of millions of tons of feathers annually

Within the research conducted for the doctoral dissertation, five scientific publications were produced, including four original research articles. Another article is currently under preparation in connection with the project led by M.Sc. Eng. Taraszkiewicz, funded by the National Science Centre under the Preludium grant program.

The research, through the recovery of raw materials from feathers containing protein and imparting them new properties, aligns with the concept of sustainable waste management in the poultry industry. Poultry feathers constitute up to about 10 percent of the body weight of an adult chicken, with approximately 40 million tons produced worldwide each year.

The thesis supervisor was Dr. Hab. Eng. Hanna Staroszczyk, prof. Gdańsk Tech. The initial research on obtaining peptides from keratin was started by the scientist during his master’s thesis written under the supervision of Dr. Eng. Izabela Sinkiewicz, prof. Gdańsk Tech.

Research in Ireland, Preludium grant success

During his studies at the Doctoral School at Gdańsk Tech, M.Sc. Eng. Antoni Taraszkiewicz completed two scientific stays at the Teagasc research institute in Fermoy, Ireland, where he investigated the in vitro bioavailability of keratin peptides using cell models.

– These stays really gave me a lot. They were very valuable scientifically and allowed me to develop my research skills. However, the most important and happiest moment of my studies at the Doctoral School was winning the Preludium grant. The news about being awarded over two hundred thousand PLN funding for my research was a great honor – emphasizes Taraszkiewicz.