Effect of Temperature on Salt Diffusion into Vegetable Tissue

Figures & data

Table 1 Dimension of samples used to determine equilibrium distribution coefficient (K) and diffusion coefficient (D _s )

Measurement	Equilibrium distribution coefficient (K)		Diffusion coefficient (Ds )
Item	Diameter (m)	Thickness (m)	Diameter (m)	Thickness (m)
Celery	0.01031	0.00305	0.0103	0.0009
Mushroom	0.01031	0.00089	0.0169	0.0014
Water chestnut	0.01031	0.00254	0.0189	0.0006
Precision of the measurement is ±0.000127 m.

Figure 1 Schematic of diffusivity cell.

Figure 2 Sample holder showing sample dimensions for celery and mushroom. For water chestnut, samples were 0.0006 m thick and 0.0189 m in diameter.

Figure 3 Schematic diagram of the system used in the model.

Table 2 Equilibrium distribution coefficient (K) and diffusion coefficient (D _s ) of sodium chloride in celery, mushroom, and water chestnut tissue at three temperatures

Material	Temperature (°C)	K	SD	Ds (10^−8 m^2/s)	SD (10^−8 m^2/s)
Celery	25	1.5^a	0.105	3.37^x	0.0001
	50	1.36^a	0.013	20.5^y	5.6
	80	1.16^b	0.025	26.4^y	3.3
Mushroom	25	1.35^c	0.029	1.99^u	0.09
	50	1.31^c	0.016	11.2^v	0.35
	80	1.14^d	0.068	17.6^w	0.2
Water chestnut	25	1.09^e	0.0012	0.0297^r	0.0007
	50	1.00^f	0.0055	0.068^r,s	0.016
	80	1.06^g	0.0034	0.118^s	0.046
Means followed by the same letter in each column for each material are not significantly different (p > 0.05).

Table 3 Comparison of K and D _s values between our study and the study by Sarang and Sastry.[10]

Temperature (°C)	K	K in Sarang and Sastry[10]	Ds (10^−10 m^2/s)	Ds (10^−10 m^2/s) in Sarang and Sastry[10]
25	1.09	1.09	2.97	7.5
80	1.06	1.06	11.84	17.00

Figure 4 Changes in salt concentration of celery in the receiver over time. Error bars for data at 25°C are not visible on this scale.

Figure 5 Changes in salt concentration of mushroom in the receiver over time.

Figure 6 Changes in salt concentration of water chestnut in the receiver over time.

Table 4 Activation energy (E _a ) and reference temperature constant (D _o ) for salt diffusion in celery, mushroom, and water chestnut

Materials	Ea (kJ/mol)	Do (m^2/s)	r ^2
Celery	32.7	2.34 × 10^−2	0.838
Mushroom	34.7	2.94 × 10^−2	0.895
Water chestnut	22.0	2.24 × 10^−6	0.987
Water chestnut ^a	12.7	1.37 × 10^−7	0.951
Water chestnut ^b	17.0	5.158 × 10^−7	0.580
^aData from Sarang and Sastry.[10]
^bCombined data from our study and Sarang and Sastry.[10]

Figure 7 Microscopic images of water chestnut: (a) untreated sample and (b) treated sample heated at 80°C. (Color figure available online.)

Figure 8 Microscopic images of celery: (a) raw sample and (b) sample heated at 80°C. (Color figure available online.)

Figure 9 Arrhenius plot for the diffusion coefficient (D_s ) where T is the absolute temperature. Error bars are not visible for certain data sets due to low standard deviation.

Sarang , S. and Sastry , S.K. 2007 . Diffusion and equilibrium distribution coefficient of salt within vegetable tissue: Effects of salt concentration and temperature . Journal of Food Engineering , 82 : 377 – 382 .

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