THERMODYNAMIC PROPERTIES OF BARU FRUITS (<i>Dipteryx alata Vogel</i>)

Resende, Osvaldo; Oliveira, Daniel E. C. DE; Costa, Lílian M.; Ferreira, Weder N.

doi:10.1590/1809-4430-Eng.Agric.v37n4p739-749/2017

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Scientific Paper, Post-Harvest Science and Technology • Eng. agríc. 37 (04) • Jul-Aug 2017 • https://doi.org/10.1590/1809-4430-Eng.Agric.v37n4p739-749/2017 copy

THERMODYNAMIC PROPERTIES OF BARU FRUITS (Dipteryx alata Vogel)

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT:

The objective of this study was to determine and evaluate the thermodynamic properties for different equilibrium moisture contents in baru fruits (Dipteryx alata Vogel), using the direct static method to obtain the experimental data. The Modified Halsey model was used to determine the thermodynamic properties of baru fruits. Results concluded that thermodynamic properties are influenced by moisture content. The water vaporization latent heat increases with the decrease in equilibrium moisture content. The baru fruit desorption process is controlled by enthalpy. Gibbs free energy is positive for the temperatures studied with the increase over desorption, which describes a non-spontaneous process.

KEY WORDS:
latent heat; enthalpy; entropy; Gibbs free energy

Xe (% db)	Temperature (°C)
Xe (% db)	20	25	30	35
4.2	0.0856	0.0947	0.1043	0.1145
4.5	0.0992	0.1091	0.1195	0.1304
4.6	0.1077	0.1181	0.1289	0.1402
5.7	0.1842	0.1974	0.2110	0.2250
6.8	0.2526	0.2674	0.2823	0.2973
7.7	0.3093	0.3246	0.3400	0.3554
8.6	0.3635	0.3789	0.3944	0.4097
8.8	0.3710	0.3865	0.4019	0.4172
9.0	0.3813	0.3967	0.4121	0.4274
9.1	0.3870	0.4024	0.4177	0.4330
9.7	0.4172	0.4325	0.4476	0.4627
12.4	0.5254	0.5395	0.5534	0.5670
21.7	0.7255	0.7351	0.7445	0.7535
24.1	0.7547	0.7635	0.7720	0.7803
24.3	0.7574	0.7661	0.7745	0.7827
25.9	0.7739	0.7821	0.7900	0.7977
28.4	0.7951	0.8026	0.8099	0.8169
29.5	0.8041	0.8113	0.8183	0.8251

Moisture content (% db)	Ratio L/L’	Moisture content (% db)	Ratio L/L’
4.2	1.3317	9.1	1.1281
4.5	1.3118	9.7	1.1180
4.6	1.3006	12.4	1.0868
5.7	1.2283	21.7	1.0433
6.8	1.1856	24.1	1.0380
7.7	1.1583	24.3	1.0375
8.6	1.1365	25.9	1.0346
8.8	1.1338	28.4	1.0309
9.0	1.1301	29.5	1.0294

a	b	m	R² (%)	P (%)
1.2886 × 10⁻¹³^ Significant at 1% by t-test.	-30.4896^ Significant at 1% by t-test.	-0.0448^ Significant at 1% by t-test.	99.99	1.50

Thermodynamic properties	Equations	R² (%)	P (%)
Differential enthalpy	h_st=84.6574^ Significant at 1% by t-test. +1942.4311^ Significant at 1% by t-test. .exp(-0.2384^ Significant at 1% by t-test. .Xe)	99.73	4.869
Differential enthropy	S=0.1700^ Significant at 1% by t-test. +3.9019^ Significant at 1% by t-test. .exp(-0.2384^ Significant at 1% by t-test. .Xe)	99.73	4.867

Xe (% db)	Temperature (°C)
Xe (% db)	20	25	30	35
4.2	332.91	324.66	316.53	308.52
4.5	312.91	305.16	297.51	289.98
4.6	301.72	294.25	286.88	279.62
5.7	229.10	223.43	217.83	212.32
6.8	186.29	181.67	177.12	172.64
7.7	158.90	154.96	151.08	147.25
8.6	137.04	133.64	130.29	127.00
8.8	134.25	130.93	127.65	124.42
9.0	130.56	127.32	124.14	120.99
9.1	128.56	125.37	122.23	119.14
9.7	118.38	115.44	112.55	109.70
12.4	87.13	84.98	82.85	80.75
21.7	43.46	42.38	41.32	40.28
24.1	38.11	37.16	36.23	35.31
24.3	37.63	36.69	35.78	34.87
25.9	34.71	33.85	33.01	32.17
28.4	31.05	30.28	29.52	28.78
29.5	29.53	28.79	28.07	27.36

Temperature (°C)	Equation	R² (%)	P (%)
20	ΔG = 798.729^ Significant at 1% by t-test. exp (-0.238^ Significant at 1% by t-test. Xe)+34.812^ Significant at 1% by t-test.	99.73	4.869
25	ΔG = 778.944^ Significant at 1% by t-test. exp (-0.238^ Significant at 1% by t-test. Xe)+33.949^ Significant at 1% by t-test.	99.73	4.869
30	ΔG = 759.435^ Significant at 1% by t-test. exp (-0.238^ Significant at 1% by t-test. Xe)+33.099^ Significant at 1% by t-test.	99.73	4.869
35	ΔG = 740.213^ Significant at 1% by t-test. exp (-0.238^ Significant at 1% by t-test. Xe)+32.261^ Significant at 1% by t-test.	99.73	4.869

Associação Brasileira de Engenharia Agrícola SBEA - Associação Brasileira de Engenharia Agrícola, Departamento de Engenharia e Ciências Exatas FCAV/UNESP, Prof. Paulo Donato Castellane, km 5, 14884.900 | Jaboticabal - SP, Tel./Fax: +55 16 3209 7619 - Jaboticabal - SP - Brazil
E-mail: revistasbea@sbea.org.br

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[1] *Corresponding author. Instituto Federal de Educação, Ciência e Tecnologia Goiano - Campus Rio Verde/ Rio Verde - GO, Brasil, E-mail: osvresende@yahoo.com.br

Isokinetic temperature (T_B)	497.81
Harmonic mean temperature T_hm	299.48
Isokinetic temperature Variance Var (T_B)	0.000039
Isokinetic temperature interval	[497.83; 497.79]