Study of thermodynamic water properties and moisture sorption hysteresis of mango
     skin

Souza, Silvio José Ferreira de; Alves, Aline Inácio; Vieira, Érica Nascif Rufino; Vieira, José Antônio Gomez; Ramos, Afonso Mota; Telis-Romero, Javier

doi:10.1590/1678-457X.6557

Acessibilidade / Reportar erro

Brasil

Food Science and Technology

Español English

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Research Paper • Food Sci. Technol (Campinas) 35 (1) • Jan-Mar 2015 • https://doi.org/10.1590/1678-457X.6557 copy

Study of thermodynamic water properties and moisture sorption hysteresis of mango skin

Authorship SCIMAGO INSTITUTIONS RANKINGS

The equilibrium moisture content for adsorption and desorption isotherms of mango skin was determined using the static gravimetric method at temperatures of 20, 26, 33, 38 and 44 ^oC in the 0.056 to 0.873 water activity range. Both sorption curves show a decrease in equilibrium moisture content as the temperature increasing. The hysteresis effect was observed at constant water activity. The Guggenheim, Anderson, and de Boer (GAB) model presented the best fitting accuracy among a group of models and was used to determine the thermodynamic properties of water sorption. Integral enthalpy and integral entropy areas showed inverted values for the adsorption and desorption isotherms over the wide range of water activity studied. These values confirm, in energetic terms, the difference between adsorption and desorption isotherms observed in the hysteresis phenomenon. Finally, the Gibbs free energy revealed that the sorption process was spontaneous for both sorption isotherms.

agricultural waste; gravimetric method; integral properties; modelling; water content

T (°C)	a_{_w}	X (kg/kg, d.b.)
T (°C)	a_{_w}	Adsorption	Desorption
20	0.000	0.000 ± 0.000	0.000 ± 0.000
	0.066	0.005 ± 0.000	0.007 ± 0.001
	0.118	0.011 ± 0.002	0.012 ± 0.001
	0.138	0.009 ± 0.000	0.015 ± 0.001
	0.249	0.023 ± 0.000	0.031 ± 0.001
	0.329	0.028 ± 0.001	0.045 ± 0.003
	0.547	0.087 ± 0.010	0.107 ± 0.005
	0.589	0.103 ± 0.012	0.134 ± 0.007
	0.752	0.196 ± 0.031	0.280 ± 0.025
	0.772	0.256 ± 0.040	0.304 ± 0.019
	0.820	0.344 ± 0.054	0.413 ± 0.026
	0.873	0.507 ± 0.046	0.622 ± 0.022
26	0.000	0.000 ± 0.000	0.000 ± 0.000
	0.063	0.005 ± 0.000	0.006 ± 0.000
	0.114	0.007 ± 0.001	0.010 ± 0.001
	0.138	0.011 ± 0.000	0.013 ± 0.000
	0.234	0.020 ± 0.000	0.023 ± 0.000
	0.326	0.033 ± 0.001	0.040 ± 0.001
	0.534	0.064 ± 0.005	0.094 ± 0.005
	0.571	0.074 ± 0.006	0.112 ± 0.006
	0.739	0.151 ± 0.014	0.232 ± 0.016
	0.760	0.168 ± 0.015	0.260 ± 0.017
	0.810	0.226 ± 0.023	0.350 ± 0.030
	0.851	0.333 ± 0.016	0.464 ± 0.016
33	0.000	0.000 ± 0.000	0.000 ± 0.000
	0.060	0.004 ± 0.000	0.004 ± 0.000
	0.109	0.006 ± 0.000	0.011 ± 0.001
	0.137	0.010 ± 0.001	0.009 ± 0.001
	0.220	0.017 ± 0.000	0.020 ± 0.000
	0.322	0.029 ± 0.001	0.028 ± 0.001
	0.519	0.054 ± 0.002	0.080 ± 0.003
	0.552	0.062 ± 0.001	0.091 ± 0.003
	0.725	0.125 ± 0.001	0.175 ± 0.003
	0.747	0.140 ± 0.003	0.230 ± 0.007
	0.800	0.190 ± 0.004	0.311 ± 0.007
	0.828	0.251 ± 0.006	0.366 ± 0.009
38	0.000	0.000 ± 0.000	0.000 ± 0.000
	0.059	0.003 ± 0.001	0.004 ± 0.000
	0.106	0.007 ± 0.001	0.006 ± 0.001
	0.136	0.009 ± 0.001	0.011 ± 0.000
	0.210	0.014 ± 0.000	0.018 ± 0.000
	0.319	0.025 ± 0.000	0.033 ± 0.001
	0.510	0.055 ± 0.001	0.059 ± 0.003
	0.540	0.062 ± 0.001	0.067 ± 0.002
	0.715	0.136 ± 0.000	0.135 ± 0.003
	0.738	0.156 ± 0.001	0.152 ± 0.005
	0.793	0.189 ± 0.001	0.206 ± 0.004
	0.812	0.248 ± 0.003	0.256 ± 0.001
44	0.000	0.000 ± 0.000	0.000 ± 0.000
	0.056	0.003 ± 0.000	0.004 ± 0.000
	0.103	0.005 ± 0.000	0.006 ± 0.000
	0.135	0.008 ± 0.000	0.010 ± 0.000
	0.199	0.011 ± 0.000	0.015 ± 0.000
	0.316	0.021 ± 0.000	0.029 ± 0.001
	0.499	0.043 ± 0.002	0.050 ± 0.003
	0.525	0.056 ± 0.003	0.056 ± 0.003
	0.704	0.107 ± 0.007	0.114 ± 0.008
	0.727	0.116 ± 0.008	0.128 ± 0.009
	0.784	0.177 ± 0.015	0.174 ± 0.013
	0.794	0.183 ± 0.007	0.203 ± 0.009

Model	Isotherm type	Parameter model	Value	C.I (95%)	R²_{_adj}	RMSE
GAB	Adsorption	X_{_m} (kg/kg, d.b.)	2.940×10⁵	2.940×10⁵ – 2.940×10⁵	0.987	0.011
		C_₀ (dimensionless)	1.059×10^-5	7.685×10^-6 – 1.351×10^-5
		K_₀ (dimensionless)	13.069	12.394 – 13.744
		H_{_m} (kJ/mol)	40.209	40.209 – 40.209
		H_{_n} (kJ/mol)	50.808	50.808 – 50.808
	Desorption	X_{_m} (kg/kg, d.b.)	1.114×10⁴	1.114×10⁴ – 1.114×10⁴	0.989	0.013
		C_₀ (dimensionless)	4.077×10^-7	3.474×10^-7 – 4.680×10^-7
		K_₀ (dimensionless)	36.862	36.862 – 36.862
		H_{_m} (kJ/mol)	60.167	60.167– 60.167
		H_{_n} (kJ/mol)	53.468	53.468 – 53.468
BET	Adsorption	X_{_m}(kg/kg, d.b.)	5.712×10^-2	5.465×10^-2 – 5.959×10^-2	0.966	0.018
		C_{_B} (dimensionless)	2.559×10^-6	2.099×10^-6 – 3.018×10^-6
		H_{_m} (kJ/mol)	19.604	19.604 – 19.604
		H_{_n} (kJ/mol)	-12.663	-12.663 – -12.663
	Desorption	X_{_m}(kg/kg, d.b)	8.519×10^-2	8.519×10^-2 – 8.519×10^-2	0.993	0.010
		C_{_B} (dimensionless)	2.660×10^-10	2.532×10^-10 – 2.788×10^-10
		H_{_m} (kJ/mol)	30.723	30.723 – 30.723
		H_{_n} (kJ/mol)	-23.784	-23.784 – -23.784
Halsey	Adsorption	a (dimensionless)	0.858	0.271 – 1.445	0.984	0.012
		b (1/K)	-1.156×10^-2	-1.359×10^-2 – -9.537×10^-3
		c (dimensionless)	0.776	0.747 – 0.805
	Desorption	a (dimensionless)	3.384	2.767 – 4.002	0.990	0.012
		b (1/K)	-1.947×10^-2	-2.159×10^-2 – -1.735×10^-2
		c (dimensionless)	0.818	0.791 – 0.846
Iglesias & Chirife	Adsorption	a (dimensionless)	0.295	0.267 – 0.322	0.978	0.015
		b (1/K)	-7.882×10^-4	-8.806×10^-4 – -6.958×10^-4
		c(kg/kg, d.b.)	-6.506×10^-4	-1.751×10^-3 – 6.052×10^-3
	Desorption	a (dimensionless)	0.613	0.593 – 0.633
		b (1/K)	-1.780×10^-3	-1.847×10^-3 – -1.713×10^-3	0.995	0.009
		c(kg/kg, d.b.)	6.491×10^-4	-1.093×10^-3 – 2.391×10^-3
Oswin	Adsorption	a (dimensionless)	0.294	0.258 – 0.331	0.977	0.015
		b (1/K)	-7.855×10^-4	-9.011×10^-4 – -6.699×10^-4
		c(kg/kg, d.b.)	1.008	0.974 – 1.041
	Desorption	a (dimensionless)	0.624	0.594 – 0.654	0.995	0.009
		b (1/K)	-1.813×10^-3	-1.909×10^-3 – -1.719×10^-3
		c (dimensionless)	1.011	0.992 – 1.028

T (°C)	C		K
T (°C)	Adsorption	Desorption	Adsorption	Desorption
20	1.370×10^-7	6.368×10^-6	0.864	0.818
26	1.495×10^-7	6.026×10^-6	0.823	0.796
33	1.648×10^-7	5.666×10^-6	0.779	0.772
38	1.762×10^-7	5.432×10^-6	0.749	0.756
44	1.904×10^-7	5.172×10^-6	0.718	0.738

Sociedade Brasileira de Ciência e Tecnologia de Alimentos Av. Brasil, 2880, Caixa Postal 271, 13001-970 Campinas SP - Brazil, Tel.: +55 19 3241.5793, Tel./Fax.: +55 19 3241.0527 - Campinas - SP - Brazil
E-mail: revista@sbcta.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] *Corresponding author: javier@ibilce.unesp.br