Structural and mechanical properties of fish gelatin as a function of extraction conditions

Effects of Selected Process Parameters on Physical and Sensorial Properties of Yellowfin Tuna (Thunnus albacares) Skin Gelatin

“…The undisputed protein fragments, present in gelatin preparations, are the α ‐ (monomer), β ‐ ( α ‐chain dimer) and γ ‐ ( α ‐chain trimer) chains with an approximate molecular weight (MW) of 100, 200 and 300 kDa, respectively (Eysturskard et al . ; Karayannakidis and Zotos ). Numerous studies in this field have shown that besides the aforementioned protein fragments, gelatins comprise of additional proteins and peptides with MW > 300 kDa and/or <100 kDa (Gómez‐Guillén et al .…”

Mechanical Properties of Mammalian and Fish Gelatins as a Function of the Contents of α-Chain, β-Chain, and Low and High Molecular Weight Fractions

“…The gel-promoting effect of the fractions of β-chains and HMW molecules is in agreement with previously published data for fish gelatin. [19][20][21] Not surprisingly, the fraction of LMW molecules contributes negatively to the dynamic storage modulus. Previous report suggested that the subunits were too short to create functional junction zones Table 1 Fractions of LMW, α-chains, β-chains, and HMW in acid porcine skin gelatins (F, G, H, and I) and lime bovine bone gelatins (J, K, and L), measured and PLSR-calculated Bloom values, and the calculated residual and/or elastically active segments or may even perturb the helix reformation and, thus, reduce the gel strength.…”

“…The pretreatment and the gelatin extraction were carried out according to the method reported by Eysturskarð et al 21 The five cold water fish gelatins (A-E) were extracted under the following conditions: extract A (0.01 M acetic acid (VWR International Ltd, Oslo, Norway), 24 h, 22°C); extract B (0.01 M acetic acid, 24 h, 45°C); extract C (0.01 M acetic acid, 12 h, 65°C); extract D (0.1 M acetic acid, 12 h, 65°C); and extract E (0.1 M acetic acid, 24 h, 65°C).…”

“…This is in agreement with earlier studies suggesting that longer gelatin chains can participate in longer and/or in more frequent triple helices leading to an overall fractional increase in the helix amount and thus increasing gel strength. 21 In contrast to the mammalian gelatin, the dependence of the α-chains seems to be more ambiguous for cold water fish gelatin. The dynamic storage modulus was found to decrease (moving from A to C) and increase (moving from E to C) by increasing fraction of α-chains (Figure 4b).…”

“…[7][8][9][10] Although the mechanical properties of gelatin from several fish species have been reported, [11][12][13][14][15][16][17][18] the effect of molecular weight distribution on the mechanical properties of fish gelatin has only been studied to a limited extent. [19][20][21] Muyonga, Cole, and Duodo 20 claim that the fraction of higher molecular weight molecules (>β-chains) is positively correlated with the gel strength while Gómez-Guillén, Turnay, Fernández-Díaz, Ulmo, Lizarbe, and Montero 19 suggested that the absence of β-and γ-components and the presence of low molecular weight fragments could explain the lower gel forming ability of gelatin from some fish species compared to others. Eysturskarð, Haug, Elharfaoui, Djabourov, and Draget 21 proposed that the mechanical properties increase with increasing weight average molecular weight and that the fraction of low molecular weight peptides do not participate in the three dimensional gel network.…”