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Título
Inactivation of Endogenous Rice Flour β-Glucanase by Microwave Radiation and Impact on Physico-chemical Properties of the Treated Flour
Autor
Año del Documento
2016
Editorial
Springer
Descripción
Producción Científica
Documento Fuente
Food and Bioprocess Technology. (2016) Vol 9 (9), p. 1562-1573
Abstract
The apparent reduction of β-glucan (BG) molecular weight in rice based gluten-free (GF) breads fortified with cereal BG concentrates reveals the presence of β-glucanase activity in rice flour. Inactivation of endogenous β-glucanase in rice flour thus seems to be necessary step when developing GF breads enriched with BG of high molecular-weight. The aim of this work was to study the thermal inactivation of endogenous β-glucanase in rice flour by means of microwave (MW) processing; rice flours preconditioned at four different moisture levels (13%, 16%, 19%, 25%) were treated by MW radiation at 900 W and five MW treatment times (ranging from 40s to 8 min, applied stepwise at 20s intervals). The effects of microwaves on starch crystallinity, pasting and thermal properties of MW-treated rice flours were also explored. The β-glucanase activity in rice flours was assessed by the rate of decrease in specific viscosity of a dilute solution of a purified β-glucan preparation, upon addition of flour extracts. MW proved to be a useful alternative for thermal inactivation of endogenous β-glucanase in rice flours when applied to moistened samples. The inactivation process followed a first order kinetic response and the apparent rate constant of thermal inactivation increased exponentially with the moisture content of the flour, M, according to the equation 0.0146·exp (0.212·M)
(R2 = 0.97). The MW time required for complete β-glucanase inactivation was only 4 min when the initial flour moisture increased to 25%. Following MW treatment, the starch crystallinity was unaffected (p>0.05) and the side effects of the treatment on flour pasting and thermal properties were rather negligible.
Palabras Clave
β-Glucanase inactivation
microwave treatment
pasting properties
rice flour
thermal properties
X-Ray diffractometry
ISSN
1935-5130
Revisión por pares
SI
Patrocinador
Ministerio de Economía, Industria y Competitividad - FEDER (Projects AGL2012-35088 and AGL2015-63849-C2-2-R)
Version del Editor
Idioma
eng
Derechos
openAccess
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