Lynne Wong's PhD thesis

Table 6.5. Characteristic parameters obtained from the net isosteric heat-entropy
relationship for the nine cane components of R 570 aged 52 and 36 weeks.
Sample 52 weeks 36 weeks
R 2 Slope Intercept= ∆G/kJ mol -1 T β/K R 2 Slope Intercept= ∆G/kJ mol -1 T β/K
Stalk fibre 0.999 -373.80 0.2420 373.80 0.999 -380.96 0.5139 380.96
Stalk pith 1.00 -345.02 0.5352 345.02 0.985 -265.29 2.2753 265.29
Rind fibre 1.00 -363.57 0.2431 363.57 1.00 -355.28 0.3731 355.28
Rind fines 1.00 -401.55 0.1676 401.55 0.999 -419.85 -0.0243 419.85
Top fibre 1.00 -360.67 0.1874 360.67 1.00 -366.76 0.1579 366.76
Dry leaf fibre 1.00 -357.92 0.2092 357.92 1.00 -352.27 0.1640 352.27
Dry leaf fines 0.997 -367.35 0.0465 367.35 0.999 -380.49 0.4431 380.49
Green leaf fibre 0.995 -406.66 0.2946 406.66 1.00 -358.37 0.2794 358.37
Green leaf fines 1.00 -374.95 0.2617 374.95 1.00 .358.24 0.4324 358.24
6.7 PRIMARY, SECONDARY AND TERTIARY BOUND WATER
Kaleemullah and Kailappan (2007) determined the equilibrium moisture content of red
chillies at various water activities within the temperature range of 25 – 45 °C, and obtained
binding energies of three different types of water bound to the surface of the material
studied.
They calculated the heat of sorption of the primary adsorbed layer H 1 by using the BET
model which described the sorption behaviour of red chillies well. They then calculated
the net isosteric heat of sorption q st , and multiplied it by the Universal gas constant R
(8.3143 J mol -1 K -1 ) to obtain, what they called, the binding energy, which was then plotted
against the moisture content. From this plot they determined the moisture content of the
secondary layer from where the break in the curve occurred and they marked the end of the
tertiary layer where the binding energy became zero. For the primary layer, the value of
the binding energy H 1 was read off from the y-axis, a horizontal line was placed and from
where it intersected the curve determined the corresponding moisture content was deemed
to be the primary layer.
In a similar manner, calculations were carried out for cane components aged 52 and 36
weeks, and the results are shown in Figs 6.11 and 6.12. The moisture content of the
primary, secondary and tertiary bound water layers were compared to the Brix-free water
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