Abstract
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.