The poultry industry generates large amounts of protein- and mineral-rich by-products that remain underutilized. This study investigated the use of chicken skin protein hydrolysate and chicken bone protein–mineral mass (PMM) as functional ingredients in emulsified poultry sausages. The hydrolysate was characterized by a high protein content (52.25%) and high water- and fat-binding capacity (142% and 125%, respectively), while the PMM served as a source of protein and minerals with stable physicochemical and rheological characteristics. These ingredients were incorporated into sausage formulations at different substitution levels. Partial replacement of poultry meat increased protein and mineral content and affected key technological properties, including water-binding capacity, emulsion stability, cooking loss, and shear force. Moderate inclusion levels were associated with a more cohesive protein matrix, lower cooking losses, and improved structural stability, whereas excessive substitution resulted in increased firmness and less favorable sensory characteristics. Among the tested formulations, the combination of 18% PMM and 4% protein hydrolysate showed the most balanced technological and sensory performance. The findings suggest that poultry by-products processed into functional ingredients may have potential for application in value-added sausage formulations.

This study evaluated the potential of chicken by-products (hearts, gizzards, and skin) as functional raw materials for protein–fat emulsions to partially replace animal fat in pâtés. Five variants of pâté (PV1–PV5) were prepared, including a control without emulsion and four samples with increasing emulsion levels. Emulsions were formulated from chicken by-product mixtures and vegetable oil with potato starch, sodium bicarbonate, and salt to improve solubility and viscosity. The chemical composition of by-product mixtures varied with organ ratio: heart-rich mixtures supplied higher protein, supporting emulsion stability, whereas skin-rich mixtures contributed more fat for texture. Emulsion composition ranged from 6.6–8.1% protein, 19.1–28.4% fat, and 56.7–66.9% moisture. Functional properties depended on formulation balance: water-holding (58–67%), fat retention (70–83%), emulsifying capacity (50–62%), and stability (47–55%). Variant 5 achieved the most favorable combination of composition, stability, and viscosity. In pâtés, emulsion addition reduced protein and fat but increased ash and carbohydrate contents (p < 0.05), improving hydration and stability. Fat retention rose up to 83% and emulsion stability up to 62%. Drip loss declined markedly from 9.2% in the control to 3.6% in Variant 5, while yield stress decreased by 25%, producing softer, more spreadable products. Sensory evaluation favored emulsion-containing samples, with PV-5 scoring highest in texture and appearance. TBARS values rose with the amount of emulsion due to higher PUFA, but acid numbers increased more slowly, indicating reduced hydrolytic rancidity. Overall, pâté with 25% of emulsion offered the best balance of technological performance, sensory quality, and lipid stability, highlighting chicken by-products as sustainable emulsifiers in pâté production.

This study investigated the valorization of chicken feet, an underutilized poultry by-product, through enzymatic hydrolysis to obtain a protein hydrolysate with improved functional properties. Enzymatic treatment was carried out using Enzy-Mix U100 and collagenase from Streptomyces lavendulae, with cheese whey applied as a process medium. The resulting protein hydrolysate contained 59.1% protein and was characterized by high levels of glycine (31.64 g/100 g protein), hydroxyproline (10.91 g/100 g protein), and alanine (10.58 g/100 g protein). The hydrolysate exhibited strong techno-functional performance, with a water-binding capacity of 580%, an emulsifying activity index of 166 m²/g, and an emulsion stability index of 31 min. Microstructural analysis revealed irregular porous particles typical of freeze-dried protein hydrolysates, reflecting structural modification of collagen during enzymatic treatment. Mineral analysis showed notable levels of sodium (463.1 mg/100 g) and magnesium (351.8 mg/100 g). Microbiological evaluation demonstrated high sanitary quality, with a total viable count of 100 CFU/g and absence of coliforms, Escherichia coli, yeasts, and molds in 1 g of product. The technological process reduced the characteristic odor of chicken feet while maintaining a light color and good dispersibility. These findings confirm the potential of enzymatic hydrolysis as a sustainable strategy for converting poultry by-products into safe, value-added functional protein ingredients for food applications.

Chicken skin and related poultry by-products are rich in collagen and lipids but remain underutilized, creating opportunities for their conversion into value-added functional ingredients. This study developed chicken-skin-based protein–fat emulsions and evaluated the effect of changing the fat-to-hydrolysate ratio on their physicochemical, techno-functional, compositional, rheological, oxidative, and microbiological properties. Four formulations containing 13.5–15.0% chicken fat and 6.8–5.3% chicken skin protein hydrolysate were prepared, while chicken skin and water were maintained at 36.4 and 43.3%, respectively. Three independent production batches were prepared for each formulation. The emulsions showed similar pH (4.82–4.99) and water activity (0.979–0.996) (p > 0.05). Water-holding capacity decreased from 78.74% to 73.60%, whereas fat-holding capacity increased from 41.00% to 62.40% (p < 0.05). Variant 3 showed the highest emulsion stability (22%) and an emulsifying capacity of 56%, while Variant 4 had the highest apparent viscosity (577 mPa·s) but the lowest yield stress (2.011 Pa). The emulsions exhibited a collagen-rich amino acid profile, and oleic, palmitic, and linoleic acids predominated in the lipid fraction. During refrigerated storage, TBARS increased from 0.34–0.37 to 2.19–2.51 mg MDA/kg, while total viable counts reached 3.83–4.03 log CFU/g by day 14. Among the tested formulations, Variant 3 showed a favorable combination of stability and emulsifying and rheological properties. These results identify chicken-skin-based protein–fat emulsions as candidate functional ingredients for further evaluation in food formulations.

This study developed a complex functional ingredient based on beef offal paste, whey, rapeseed and sunflower cake powder, and flax flour, and evaluated its effect on beef cutlets formulated with 0, 5, 10, and 15% additive. The study examined chemical composition, pH, water activity, functional and technological properties, color, fatty acid profile, texture, sensory quality, and refrigerated storage stability. The additive improved the nutritional profile of the cutlets by increasing the protein content from 16.20% in the control to 17.78% at the highest inclusion level, while reducing fat content from 12.50% to 11.20%. The lipid fraction also became more favorable, as total polyunsaturated fatty acids increased from 7.03% to 13.34%, and α-linolenic acid appeared only in additive-containing samples. The additive also modified the functional and structural characteristics of the products. The 10% formulation showed the most pronounced improvement in texture, with the highest hardness, gumminess, and chewiness values, while sensory quality remained comparable to the control at 5 and 10% inclusion but declined at 15%. During 7 days of refrigerated storage, additive-containing samples showed lower acid and peroxide values than the control, together with a slight reduction in microbial growth. Overall, the developed additive acted as a multifunctional ingredient that improved nutritional and technological quality. Among the tested formulations, the 10% inclusion level provided the best balance between quality, storage stability, and sensory acceptability.