PHYSICOCHEMICAL PROPERTIES OF YELLOWFIN TUNA (THUNNUS ALBACARES) SKIN GELATIN AND ITS MODIFICATION BY THE ADDITION OF VARIOUS COENHANCERS

摘要

A gelatin preparation was produced from yellowfin tuna (Thunnus albacares) skinsrnand its physicochemical properties were evaluated against bovine skin gelatin. Thernfish gelatin obtained exhibited higher gel strength and similar viscosity when comparedrnwith its mammalian counterpart, but showed a significantly lower meltingrnpoint than the latter.rnIn a follow-up study, four compounds (NaH2PO4, MgCl2, CaCl2 and glycerol) atrnvarious concentrations were investigated in order to improve fish gelatin’s physicalrnproperties. Addition of NaH2PO4 at concentrations of 0.3 and 0.5 mol/L yieldedrngelatin gels that exhibited the highest gel strength, while the highest viscositiesrnwere noticed for gelatin solutions containing 0.3 and 0.5 mol/L CaCl2. The highestrnmelting points were observed in the sample gels containing glycerol, irrespectivernof glycerol concentration. Results suggested that selected physical properties ofrnfish skin gelatin can be modified by the addition of the above compounds at thernappropriate concentration levels.