Valorization of Smoked Trout Skins as a Gelatin Source: Analysis of Technological and Structural Properties

Fish processing by-products are increasingly used as alternative sources of functional biopolymers such as gelatin. This study aimed to evaluate the potential of smoked trout skins for gelatin production and to compare their properties with non-smoked trout gelatin. Gelatin was obtained by extraction from smoked trout skins. Technological and structural properties of smoked trout gelatin were analyzed and compared with non-smoked trout gelatin. Gelatin yield (9.89%) and gel strength (45 g) obtained from smoked skins were lower than those from non-smoked trout gelatin. Despite this, the emulsion activity index is higher compared to non-smoked trout gelatin, while the foam capacity and protein content remain at a similar level. The color difference obtained was quite significant, with a ΔE of 18.93 (very pronounced). Spectroscopic analysis confirmed that the functional groups were preserved. Smoked trout skin offers a good opportunity for food and other sectors as a sustainable and alternative gelatin source.