Modelling of isotherms and their hysteresis analysis in gelatin from different sources

Figures & data

Table 1. Sources of gelatin considered in this research project.
Tabla 1. Tipos de gelatina considerados en el presente proyecto de investigación.

Source	Key	Supplier
Pig skin^a	A-270	Sigma Chemical (UK)
Bovine^b	B-225	Sigma Chemical (UK)
Fish skin^a	FG-260	Rousselot (FR)
Poultry^a	PG-240	Healan Co. (UK)
Notes: ^aAcid; ^bAlkali.

Table 2. Coefficients of the GAB and Peleg models obtained from the fitting of experimental data of gelatin. The values in brackets represent ±1 SD.
Tabla 2. Coeficientes de los modelos de GAB y Peleg obtenidos del modelado de datos experimentales de la gelatina. Los valores entre paréntesis representan ±1 SD.

GAB model						Peleg model
Gelatin	m o (% db)	k	C G	R ^2	Residual sum (Sq)	k 1 (% db)	n 1	k 2 (% db)	n 2	R ^2	Residual Sum (Sq)
Sorption coefficients
A-270	6.06 (0.2)	0.91 (0.0)	6.43 (0.9)	0.999	0.575	16.0 (1.3)	0.81 (0.07)	35.6 (2.2)	6.5 (0.72)	0.998	0.773
B-225	5.95 (0.2)	0.92 (0.0)	6.67 (0.9)	0.999	0.605	16.1 (1.3)	0.82 (0.07)	37.5 (2.5)	6.8 (0.75)	0.998	0.797
FG-260	6.09 (0.2)	0.91 (0.0)	6.41 (0.9)	0.999	0.574	15.9 (1.3)	0.81 (0.07)	34.8 (2.0)	6.5 (0.71)	0.999	0.764
PG-240	6.09 (0.2)	0.91 (0.0)	6.46 (0.9)	0.999	0.566	34.8 (2.1)	6.62 (0.70)	16.1 (1.3)	0.8 (0.07)	0.998	0.792
Desorption coefficients
A-270	9.61 (1.0)	0.77 (0.04)	27.9 (18.6)	0.975	15.719	22.7 (0.6)	0.52 (0.02)	77.0 (25.5)	15.0 (2.6)	0.998	1.170
B-225	9.30 (1.0)	0.77 (0.04)	19.0 (10.6)	0.981	11.511	22.1 (0.9)	0.59 (0.04)	56.8 (24.9)	13.6 (3.5)	0.996	2.155
FG-260	10.39 (0.5)	0.75 (0.02)	234.3 (122.6)	0.977	10.855	20.4 (1.4)	0.29 (0.04)	29.2 (8.1)	7.1 (2.1)	0.985	7.188
PG-240	9.49 (0.7)	0.78 (0.03)	47.3 (30.6)	0.977	13.945	22.3 (0.6)	0.48 (0.02)	55.3 (14.1)	12.3 (2.05)	0.998	1.384

Figure 1. Isotherm sorption and desorption of bovine gelatin powder B-225.

Figura 1. Isotermas de adsorción y desorción de gelatina bovina en polvo B-225.

Figure 2. Sorption isotherms of gelatin at 25°C fitted with GAB and Peleg model. Key: (a) = A-270; (b) = B-225; (c) = FG-260; (d) = PG-240.

Figura 2. Isotermas de adsorción de gelatina a 25°C modeladas con los modelos de GAB y Peleg. Clave: (a) = A-270; (b) = B-225; (c) = FG-260; (d) = PG-240.

Figure 3. Desorption isotherms of gelatin at 25°C fitted with GAB and Peleg model. Key: (a) = A-270; (b) = B-225; (c) = FG-260; (d) = PG-240.

Figura 3. Isotermas de desorción de gelatina a 25°C modeladas con los modelos de GAB y Peleg. Clave: (a) = A-270; (b) = B-225; (c) = FG-260; (d) = PG-240.

Figure 4. Hysteresis loops obtained from sorption and desorption data of gelatin from different sources.

Figura 4. Ciclos de histéresis obtenidos de los datos de adsorción y desorción de gelatina proveniente de diferentes orígenes.

Figure 5. Schematic representation of capillary condensation of water in porous material. During desorption stage, the capillary may not empty completely, leading to a formation of a hysteresis loop. Adapted from Orr (1976).

Figura 5. Representación esquemática de la condensación capilar de agua en un material poroso. Durante la etapa de desorción, los capilares no se vacían completamente, originando la formación de un aro de histéresis. Adaptado de Orr (1976).