INFLUENCE OF ALBUMIN ON GUAVA PULP POWDER OBTAINED BY FOAM-MAT DRYING

Maciel, Roberta M. G.; Afonso, Marcos R. A.; da Costa, José M. C.; Araújo, Tayla M. R.

doi:10.1590/1809-4430-Eng.Agric.v40n3p388-395/2020

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Sumário

Scientific Paper, Post-Harvest Science and Technology • Eng. agríc. (Online) 40 (3) • May-Jun 2020 • https://doi.org/10.1590/1809-4430-Eng.Agric.v40n3p388-395/2020 copy

INFLUENCE OF ALBUMIN ON GUAVA PULP POWDER OBTAINED BY FOAM-MAT DRYING

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Guava is a fruit that stands out for its aroma, intense flavor, vitamins, and minerals. Its availability as a powdered food enhances its commercial applications. This study aimed to evaluate mathematical models for adsorption isotherms and determine the properties and flowability of guava pulp powder obtained by foam-mat drying. The models of GAB, BET, Henderson and Oswin were fitted to determine the isotherms of powders with 4 and 8% albumin, at temperatures of 35°C and 45°C. The powders were evaluated by wall friction angle, flow index, apparent density, and particle microstructure analysis. The best fit to the isotherms was obtained by the GAB model. Wall friction angle ranged from 15.7 to 21.9° and from 13.6 to 20.4° for samples containing 4 and 8% albumin, respectively. Higher densities were observed in the powder containing 8% albumin. The powders were classified as easy flowing when the flow index was between 8.00 and 8.68. The presence of albumin in powders resulted in particles with less rough surfaces, less hygroscopicity, and improved flowability.

KEYWORDS
tropical fruit; food powder; isotherm

Model	Equation
GAB	$Xe = \frac{X_{m} . C . K . a_{w}}{(1 - K . a_{w}) . (1 - K . a_{w} + C . K . a_{w})}$
BET	$Xe = \frac{Xm . C {. a}_{w}}{(1 - a_{w})} [\frac{1 - (n + 1) . {(a_{w})}^{n} + n . {(a_{w})}^{n + 1}}{1 - (1 - C) . a_{w} - C . {(a_{w})}^{n + 1}}]$
Henderson	$Xe = {[\frac{- \ln (1 - a_{w})}{b}]}^{\frac{1}{a}}$
Oswin	$Xe = a . {[\frac{a_{w}}{1 - a_{w}}]}^{b}$

Flow type	Flow Index (I_f)
Non-flowing	I_f < 1
Very cohesive	1 < I_f < 2
Cohesive	2 < I_f < 4
Easy flowing	4 < I_f < 10
Free flowing	> 10

Model	Parameter	4% albumin		8% albumin
Model	Parameter	35 °C	45 °C	35 °C	45 °C
GAB	X_m	0.1172	0.1607	0.1821	0.2143
	C	0.9663	0.5939	0.7119	0.4598
	K	0.8637	0.8933	0.7754	0.8288
	R²	0.996	0.995	0.993	0.997
	E (%)	6.45	7.64	7.73	6.31
BET	X_m	0.3808	0.5071	0.4824	0.5411
	C	0.1308	0.1075	0.1200	0.09992
	n	5.32	5.55	4.42	4.98
	R²	0.987	0.994	0.987	0.993
	E (%)	10.05	8.43	8.41	8.97
Henderson	a	0.7774	0.6665	0.8440	0.7036
	b	4.61	3.35	5.11	3.75
	R²	0.996	0.994	0.993	0.995
	E (%)	4.93	9.38	8.16	7.89
Oswin	a	0.09039	0.09472	0.09587	0.09081
	b	0.7288	0.9349	0.6763	0.8916
	R²	0.991	0.992	0.983	0.995
	E (%)	11.76	7.01	15.93	5.45

4% albumin		8% albumin
σ₁ (kPa)	σ_c (kPa)	σ₁ (kPa)	σ_c (kPa)
1.587	0.309	1.937	0.322
3.429	0.436	4.461	0.498
7.301	0.770	9.232	1.145
15.339	1.825	19.594	1.965
30.717	3.954	38.956	4.621

Albumin concentration (%)	^ρ ρ – powder density (kg/m³)		^φ φ – wall friction angle (stainless steel). (°)
Albumin concentration (%)	higher	lower	higher	lower
4	653.8	401.7	21.9	15.7
8	688.9	445.4	20.4	13.6

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. Federal University of Ceara/ Fortaleza - CE, Brazil. E-mail: m.r.a.afonso@gmail.com