Interfacial properties of gelatin from goat skin as influenced by drying methods

• Goat skin gelatin was extracted and dried with different methods.
• Foaming property of spray-dried gelatin was superior to freeze-dried counterpart.
• Spray-dried gelatin was higher surface hydrophobicity than freeze-dried gelatin.

Interfacial properties of spray-dried goat skin gelatin (SDGG) and freeze-dried counterpart (FDGG) were determined, in comparison with commercial bovine gelatin (BG). SDGG had the highest surface hydrophobicity (p < 0.05), followed by FDGG and BG, respectively. FDGG became more positively or negatively charged than SDGG at pH below or above pIs (4.83–4.88). Foam expansion and stability of all gelatins increased with increasing concentrations (10–30 g/L) (p < 0.05). SDGG had higher foam expansion and stability than FDGG. Emulsion containing SDGG had the higher droplet size (d32, d43) and flocculation factor than that stabilized by FDGG (p < 0.05). The former also showed the lower stability as indicated by the higher coalescence index with lower negative charge after 10 d of storage. Thus, drying methods affected both foaming and emulsifying properties of goat skin gelatin.