Effects of Concentration, Bloom Degree, and pH on Gelatin Melting and Gelling Temperatures Using Small Amplitude Oscillatory Rheology

Figures & data

Figure 1 Storage modulus G′ during frequency sweep of gelatin gel at 10°C, pH 3, and 0.06% strain. Gelatin gel strength: a) 180 Bloom; b) 220 Bloom; c) 240 Bloom. Gelatin concentrations (w/v): ▪: 5%; ▴:7%; ♦: 10%.

Figure 2 Melting temperature T_m determination through storage modulus (G′) and loss modulus (G″) variations during temperature sweeps at a heating rate of 1°C/min for 180 Bloom gelatin gels at 1 Hz, pH 3, and 0.06% strain. Gelatin concentrations (w/v): a): 5%; b): 7%, and c): 10%.

Table 1 Melting (Tm) temperature dependence on gel strength, gelatin concentration, and pH∗

	Melting temperature Tm (°C)
	180 Bloom			220 Bloom			240 Bloom
pH	5%	7%	10%	5%	7%	10%	5%	7%	10%
3	31.88 ± 0.13	32.21 ± 0.18	33.30 ± 0.17	30.73 ± 0.32	31.33 ± 0.14	31.25 ± 0.15	29.82 ± 0.03	30.84 ± 0.09	31.30 ± 0.13
4	34.04 ± 0.23	33.15 ± 0.22	34.53 ± 0.30	32.60 ± 0.50	33.31 ± 0.35	34.27 ± 0.08	32.02 ± 0.07	32.88 ± 0.26	32.88 ± 0.28
5	34.82 ± 0.17	35.24 ± 0.18	36.57 ± 0.23	33.70 ± 0.09	33.96 ± 0.06	36.22 ± 0.06	32.98 ± 0.14	34.09 ± 0.25	34.42 ± 0.09
6	35.22 ± 0.06	35.10 ± 0.16	36.44 ± 0.10	33.76 ± 0.19	34.76 ± 0.18	36.63 ± 0.35	33.56 ± 0.04	34.46 ± 0.14	36.76 ± 0.07
7	35.22 ± 0.24	35.97 ± 0.11	36.50 ± 0.02	33.69 ± 0.01	34.63 ± 0.00	36.64 ± 0.25	33.61 ± 0.02	34.77 ± 0.01	36.84 ± 0.04
8	35.24 ± 0.21	36.21 ± 0.05	36.44 ± 0.02	33.63 ± 0.03	34.64 ± 0.25	36.70 ± 0.10	33.64 ± 0.06	34.41 ± 0.11	36.61 ± 0.18
9	35.18 ± 0.007	36.07 ± 0.16	36.53 ± 0.007	33.71 ± 0.10	34.77 ± 0.007	36.82 ± 0.38	33.68 ± 0.07	34.79 ± 0.04	36.78 ± 0.20
∗Mean value ± standard deviation.

Table 2 Gelling (T_g) temperature dependence on gel strength, gelatin concentration, and pH∗

	Gelling temperature Tg (°C)
	180 Bloom			220 Bloom			240 Bloom
pH	5%	7%	10%	5%	7%	10%	5%	7%	10%
3	17.81 ± 0.30	20.36 ± 0.01	22.55 ± 0.23	19.67 ± 0.09	21.16 ± 0.08	23.03 ± 0.18	18.95 ± 0.04	21.43 ± 0.06	23.09 ± 0.02
4	19.69 ± 0.16	22.88 ± 0.11	24.21 ± 0.007	21.72 ± 0.18	23.41 ± 0.007	24.90 ± 0.16	20.33 ± 0.33	23.22 ± 0.16	25.68 ± 0.30
5	21.53 ± 0.03	24.01 ± 0.21	25.06 ± 0.11	22.92 ± 0.36	24.73 ± 0.17	25.99 ± 0.17	22.56 ± 0.33	24.10 ± 0.11	26.35 ± 0.04
6	21.30 ± 0.25	23.70 ± 0.04	25.63 ± 0.08	22.91 ± 0.02	24.85 ± 0.14	26.44 ± 0.25	22.62 ± 0.07	24.63 ± 0.09	28.11 ± 0.16
7	21.61 ± 0.06	23.85 ± 0.21	25.87 ± 0.18	23.06 ± 0.11	24.61 ± 0.16	26.55 ± 0.26	22.54 ± 0.06	24.51 ± 0.40	27.74 ± 0.19
8	21.26 ± 0.18	23.19 ± 0.007	25.45 ± 0.02	22.98 ± 0.24	24.44 ± 0.06	26.76 ± 0.05	22.36 ± 0.18	24.43 ± 0.09	27.26 ± 0.04
9	21.00 ± 0.39	23.44 ± 0.08	25.76 ± 0.13	22.69 ± 0.05	24.30 ± 0.13	27.01 ± 0.51	22.69 ± 0.12	24.24 ± 0.007	27.52 ± 0.18
∗Mean value ± standard deviation.

Table 3 Parameters of Eq. (6) for melting temperature T_m at different gelatin gel strength∗

Gel strength (bloom)	a	b	c	d	Corrected r^2
180	34.173 ± 0.990	0.252 ± 0.130	0.743 ± 0.182	0.002 ± 0.024	0.930
220	30.479 ± 0.734	0.657 ± 0.099	0.994 ± 0.140	−0.035 ± 0.017	0.976
240	30.430 ± 1.009	0.658 ± 0.136	0.897 ± 0.152	−0.030 ± 0.018	0.965
∗Parameter Estimate ± 95% Wald Confidence Interval.

Table 4 Parameters of Eq. 6 for gelling temperature T_g at different gelatin gel strength∗

Gel strength (bloom)	a	b	c	d	Corrected r^2
180	17.859 ± 1.600	0.811 ± 0.207	0.536 ± 0.310	0.018 ± 0.042	0.936
220	19.467 ± 0.955	0.756 ± 0.126	0.716 ± 0.184	−0.007 ± 0.023	0.970
240	17.713 ± 1.263	1.017 ± 0.166	0.640 ± 0.210	−0.002 ± 0.027	0.970
∗Parameter Estimate ± 95% Wald Confidence Interval.