Authors: Jairo Andrés Camaño Echavarría | Amine Nekkaa | Philippe Arnoux | Christelle Mathé | Céline Cakir‐Kiefer | Loïc Stefan | Cédric Paris | Katalin Selmeczi | José E. Zapata | Laetitia Canabady‐Rochelle
Source: Applied Food Research (article, 2025-07-02)
Field: Materials Science — Biomaterials

Gelatin from red tilapia (Oreochromis spp.) scales: Optimization of its extraction and detailed characterization of its chemical and viscoelastic properties • Gelatin extraction from tilapia scale was optimized by fractional factorial design. • The best extraction conditions of tilapia scale gelatin are 10 mL/g, 3 h, 85 °C. • The optimal gelatin presents the best size profile and viscoelastic properties. • Gelatin from tilapia scale offers suitable gelling and melting capacities. • Red tilapia scale is a by-product of high interest for its gelatin content. Gelatin is widely used in food and pharmaceutical industries for its functional and bioactive properties. When extracted from fish by-products, the environmental impacts of these former waste are reduced. This study aimed to optimize the gelatin extraction from red tilapia scales using a fractional factorial design and evaluate its physicochemical and viscoelastic properties. The effects of solvent-to-solid ratio (2-10 mL/g), extraction time (1-3 h), temperature (65-85 °C) and ultrasound (0-60 min) were investigated on the crude protein content (CPC), the free amino groups (FAG) and the protein extraction yield (PEY). The CPC extracted (95.4-99.2 %) was in agreement with protein isolates (>85 %) and the extraction time and temperature had a significant positive effect on FAG and PEY. Extraction conditions after optimization were: 10 mL/g solvent-to-solid ratio, 3 h, 85°C, and without ultrasounds. Gelatin obtained under optimal condition improved highly the protein extraction and exhibited the best molecular weight distribution profile (α1/α2 chain ratios: 1.7) to offer suitable viscoelastic properties in term of gelling (18 °C) and melting capacities (25.8 °C). This finding highlights the important potential of such natural protein source as a tailored gel for food or cosmetic formulations. Abbreviations: AA, Amino acid; Adeq precision, Adequate precision; AAA, Aromatic amino acids; ANOVA, Analysis of variance; BCAA, Branched chain amino acids; CD, Circular dichroism spectroscopy; CPC, Crude protein content; EAA, Essential amino acids; FAG, Free amino group; FFD, Fractional factorial design; FTIR, Fourier-transform infrared spectroscopy; G′, Storage modulus, G′′, Loss modulus; HAA, Hydrophobic amino acids; LMWA, Low molecular weight aggregates; M, Protein marker, NCAA, Negatively charged amino acids; PCAA, Positively charged amino acids; PEY, Protein extraction yield; OPA, o -phthalaldehyde; SDS-PAGE, Sodium dodecyl sulfate polyacrylamide gel electrophoresis; TSF, tilapia scale flour; TSG, tilapia scale gelatin. Tilapia ; Viscoelasticity ; Gelatin ; Extraction (chemistry) ; Characterization (materials science) ; Oreochromis ; Biological system ; Biology ; Chemistry ; Fish <Actinopterygii> ; Materials science ; Fishery ; Chromatography ; Nanotechnology ; Composite material ; Biochemistry Collagen: Extraction and Characterization ; Meat and Animal Product Quality ; Protein Hydrolysis and Bioactive Peptides