Influence of Roasting on the Water Sorption Isotherms of Argentinean Algarroba (Prosopis alba Griseb) Pods

Figures & data

Figure 1 Water sorption isotherms of raw and roasted flour of Prosopis pod at 5 °C (▴), 25 °C (•) and 45 °C (▪). Experimental data (open symbols, raw flour; closed symbols, roasted flour).

Table 1 Parameter values obtained from fitting the BET model to isotherms of raw and roasted flour of Prosopis pod and specific surface of adsorption (S)

Temperature (°C)	Sample	w 0	C	R^2	S (m^2/g solid)
5	Raw	0.0634	5.0472	0.9661	221.90
	Roasted	0.0541	4.9798	0.9718	189.46
25	Raw	0.0476	5.8431	0.9678	166.61
	Roasted	0.0393	5.8586	0.9687	137.51
45	Raw	0.0378	7.1680	0.9720	132.34
	Roasted	0.0286	7.1254	0.9721	100.11
w 0: monolayer moisture content (g water/g dry solids); C: constant related to the heat implied in the sorption process.

Table 2 Parameter values obtained from fitting the GAB model to the isotherms of raw and roasted flour of Prosopi s pod

Temperature (°C)	Sample	w 0	C	K	R^2
5	Raw	0.0644	4.8867	0.9778	0.9526
	Roasted	0.0550	5.0037	0.9798	0.9528
25	Raw	0.0515	4.7079	1.0139	0.9677
	Roasted	0.0425	4.7157	1.0138	0.9677
45	Raw	0.0413	4.7021	1.0480	0.9212
	Roasted	0.0329	4.6380	1.0477	0.9166
w 0: monolayer moisture content (g water/g dry solids); C: Guggenheim constant related to monolayer sorption heat; K= correction factor related to multilayer sorption heat.

Figure 2 Enthalpy of sorption (ΔH) as a function of equilibrium moisture (w _e) content for raw (○) and roasted (•) flour of Prosopis pod.

Figure 3 Gibbs free energy of sorption (ΔG) at 25°C as a function of equilibrium moisture content (w _e) for raw (○) and roasted (•) flour of Prosopis pod.

Figure 4 Entropy of sorption (ΔS) at 25°C as a function of equilibrium moisture (w _e) content for raw (○) and roasted (•) flour of Prosopis pod.

Figure 5 Isosteric heat of sorption (Q _s) as a function of equilibrium moisture (w _e) content for raw (○) and roasted (•) flour of Prosopis pod.