Kinetics of infrared drying of avocado (Persea americana) pulp with different formulations

Figures & data

Figure 1. The flowchart of avocado pulp preparation.

Table 1. The tested mathematical models for infrared drying of avocado pulp with different formulations.

No	Model	Equation	Refference
1	Newton	$\text{MR}=\hspace{0.17em}\mathrm{\text{exp}}\hspace{0.17em}\left(-\text{kt}\right)$	(Nasiroglu & Kocabiyik, 2009)
2	Page	$\text{MR}=\hspace{0.17em}\mathrm{\text{exp}}\hspace{0.17em}\left(‐\mathrm{k}{\mathrm{t}}^{\mathrm{n}}\right)$
3	Modified Page (II)	$\text{MR}=\hspace{0.17em}\mathrm{\text{exp}}\hspace{0.17em}\left(-{\left(\text{kt}\right)}^n\right)$
4	Modified Page (IV)	$\text{MR}=\text{aexp}\left(‐\mathrm{k}{\mathrm{t}}^{\mathrm{n}}\right)$
5	Henderson and Pabis	$\text{MR}=\text{aexp}\left(-\text{kt}\right)$
6	Logarithmic	$\text{MR}=\hspace{0.17em}\mathrm{\text{exp}}\hspace{0.17em}\left(-\text{kt}\right)+\mathrm{c}$
7	Midilli	$\text{MR}=\text{aexp}\left(-\text{kt}\right)+\text{bt}$
8	Weibull	$\text{MR}=\alpha -\text{bexp}\left(‐\mathrm{k}{\mathrm{t}}^{\mathrm{n}}\right)$
9	Wang and Singh	$\text{MR}=1+\text{bt}+\mathrm{a}{\mathrm{t}}^2$

Table 2. The results of non-linear regression analysis in infrared drying of avocado pulp with different formulations at different drying temperatures.

Formulations	Temperature (°C)	Coefficients	Statistical parameters
			R^2	RMS (%)
Newton model
With maltodextrin	65	k = 0.0505	0.98226	12.69
	70	k = 0.0716	0.98338	14.19
	75	k = 0.0779	0.98536	13.04
	80	k = 0.0840	0.98538	12.56
Without maltodextrin	65	k = 0.0591	0.97727	16.77
	70	k = 0.0746	0.98688	12.88
	75	k = 0.0836	0.98631	13.32
	80	k = 0.0892	0.98734	12.24
Page model
With maltodextrin	65	k = 0.0201; n = 1.293	0.99891	3.30
	70	k = 0.0291; n = 1.319	0.99928	3.14
	75	k = 0.0343; n = 1.299	0.99964	2.17
	80	k = 0.0378; n = 1.300	0.99935	2.87
Without maltodextrin	65	k = 0.0238; n = 1.301	0.99878	3.88
	70	k = 0.0337; n = 1.285	0.99966	2.19
	75	k = 0.0383; n = 1.291	0.99893	3.97
	80	k = 0.0435; n = 1.274	0.99886	3.96
Modified Page (II) model
With maltodextrin	65	k = 0.0486; n = 1.293	0.99891	3.30
	70	k = 0.0684; n = 1.319	0.99928	3.14
	75	k = 0.0747; n = 1.299	0.99964	2.17
	80	k = 0.0805; n = 1.300	0.99935	2.87
Without maltodextrin	65	k = 0.0566; n = 1.301	0.99878	3.88
	70	k = 0.0714; n = 1.285	0.99966	2.19
	75	k = 0.0798; n = 1.291	0.99893	3.97
	80	k = 0.0854; n = 1.274	0.99886	3.96
Modified Page (IV) model
With maltodextrin	65	a = 0.9858; k = 0.0171; n = 1.339	0.99890	3.32
	70	a = 0.9946; k = 0.0281; n = 1.329	0.99931	3.29
	75	a = 0.9985; k = 0.0340; n = 1.302	0.99965	2.34
	80	a = 0.9956; k = 0.0369; n = 1.307	0.99937	3.09
Without maltodextrin	65	a = 0.9931; k = 0.0178; n = 1.397	0.99960	2.45
	70	a = 0.9959; k = 0.0329; n = 1.292	0.99968	2.29
	75	a = 0.9948; k = 0.0372; n = 1.299	0.99896	4.24
	80	a = 0.9952; k = 0.0424; n = 1.282	0.99889	4.29
Henderson and Pabis
With maltodextrin	65	a = 1.056; k = 0.0531	0.98635	11.68
	70	a = 1.048; k = 0.0747	0.98625	13.69
	75	a = 1.044; k = 0.0810	0.98784	12.71
	80	a = 1.038; k = 0.0868	0.98735	12.62
Without maltodextrin	65	a = 1.067; k = 0.0626	0.98227	15.53
	70	a = 1.043; k = 0.0774	0.98910	12.46
	75	a = 1.038; k = 0.0864	0.98811	13.26
	80	a = 1.033; k = 0.0918	0.98879	12.45
Logarithmic model
With maltodextrin	65	a = 1.172; k = 0.0388; c = −0.1479	0.99771	5.04
	70	a = 1.123; k = 0.0597; c = −0.0958	0.99466	9.12
	75	a = 1.125; k = 0.0641; c = −0.1019	0.99622	7.65
	80	a = 1.138; k = 0.0665; c = −0.1211	0.99675	7.01
Without maltodextrin	65	a = 1.145; k = 0.0492; c = −0.1041	0.99250	10.65
	70	a = 1.102; k = 0.0642; c = −0.0774	0.99554	8.52
	75	a = 1.104; k = 0.0706; c = −0.0840	0.99532	8.98
	80	a = 1.118; k = 0.0723; c = −0.1042	0.99726	6.74
Midilli model
With maltodextrin	65	a = 0.9858; k = 0.0180; n = 1.313; b = −3.1.E-04	0.99937	2.65
	70	a = 0.9962; k = 0.0297; n = 1.304; b = −2.0.E-04	0.99940	3.31
	75	a = 1.0000; k = 0.0368; n = 1.265; b = −3.6.E-04	0.99984	1.72
	80	a = 0.9979; k = 0.0409; n = 1.256; b = −5.6.E-04	0.99967	2.49
Without maltodextrin	65	a = 0.9946; k = 0.0186; n = 1.378; b = −1.2.E-04	0.99966	2.42
	70	a = 0.9968; k = 0.0341; n = 1.276; b = −1.3.E-04	0.99972	2.32
	75	a = 0.9963; k = 0.0395; n = 1.271; b = −2.7.E-04	0.99909	4.33
	80	a = 0.9979; k = 0.0479; n = 1.220; b = −7.0.E-04	0.99941	3.49
Weibull model
With maltodextrin	65	α = −0.0199; b = −1.007; k = 0.0184; n = 1.301	0.99941	2.56
	70	α = −0.0109; b = −1.007; k = 0.0301; n = 1.296	0.99942	3.24
	75	α = −0.0161; b = −1.017; k = 0.0369; n = 1.258	0.99985	1.69
	80	α = −0.0237; b = −1.022; k = 0.0411; n = 1.246	0.99969	2.41
Without maltodextrin	65	α = −0.0262; b = −1.036; k = 0.0262; n = 1.251	0.99902	3.84
	70	α = −0.0069; b = −1.004; k = 0.0343; n = 1.270	0.99973	2.27
	75	α = −0.0131; b = −1.010; k = 0.0400; n = 1.260	0.99913	4.23
	80	α = −0.0295; b = −1.028; k = 0.0482; n = 1.206	0.99945	3.37
Wang and Singh model
With maltodextrin	65	b = −0.0370; a = 3.5.E-04	0.99907	3.06
	70	b = −0.0513; a = 6.6.E-04	0.99833	4.76
	75	b = −0.0560; a = 7.9.E-04	0.99804	5.10
	80	b = −0.0610; a = 9.5.E-04	0.99902	3.51
Without maltodextrin	65	b = −0.0424; a = 4.5.E-04	0.99793	5.30
	70	b = −0.0529; a = 7.0.E-04	0.99706	6.47
	75	b = −0.0599; a = 8.8.E-04	0.99804	5.38
	80	b = −0.0638; a = 1.0.E-03	0.99846	4.61

R2, determination coefficient; RMS, the root mean square; k is the drying constant, n, a, b, c, α are the empirical constants.

Figure 2. The changes of moisture content in the avocado pulp during the infrared drying at different temperatures; (a) formulations with maltodextrin (9 g/ 100 g pulp); (b) formulations without maltodextrin.

Figure 3. The photographs of avocado flesh, avocado slices, avocado pulp and avocado powder via infrared drying.

Figure 4. The drying rate curves in the infrared drying of the avocado pulp at different temperatures; (a) formulations with maltodextrin (9%, w/w); (b) formulations without maltodextrin.

Figure 5. The graph of lnMR versus drying time in the infrared drying of avocado pulp.

Table 3. The effective diffusivity and activation energy in infrared drying of avocado pulp with different formulations.

Formulations	Temperature (°C)	Deff values (m^2/s)	Activation energy (kJ/mol)
With maltodextrin	65	5.24 × 10^−10 (0.9474)	30.77 kJ/mol (0.9056)
	70	6.99 × 10^−10 (0.9851)
	75	7.92 × 10^−10 (0.9681)
	80	8.41 × 10^−10 (0.9648)
Without maltodextrin	65	6.10 × 10^−10 (0.9834)	26.74 kJ/mol (0.9982)
	70	7.07 × 10^−10 (0.9846)
	75	7.96 × 10^−10 (0.9870)
	80	9.18 × 10^−10 (0.9670)

Notes: Results were displayed as values and determination coefficients in brackets.

Nasiroglu, S., & Kocabiyik, H. (2009). Thin-layer infrared radiation drying of red pepper slices. Journal of Food Process Engineering, 32(1), 1–16. https://doi.org/10.1111/j.1745-4530.2007.00195.x

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Data availability statement

The data used to support the findings of this study are included within the article and are also available from the corresponding author upon request.