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Publication no. C-2003-1110-03R
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ARTICLE
Effect of Steeping Corn with Lactic Acid on Starch Properties.
Mónica
Haros (1,2), Oscar E. Perez (3), and Cristina M. Rosell (1). (1) Instituto de
Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones
Científicas, P.O. Box 73, 46100 - Burjassot, Valencia, Spain. (2) Corresponding
author. E-mail: <mharos@iata.csic.es> (3) Facultad de Ciencias Exactas y
Naturales, Universidad de Buenos Aires, 1428 - Buenos Aires, Argentina. Cereal
Chem. 81(1):10-14. Accepted June 27, 2003. Copyright 2004 American Association
of Cereal Chemists, Inc.
Pasting and thermal properties of starch from corn steeped in the presence of
lactic acid and at different steeping times (8, 16, 24, 32, and 40 hr) were
investigated. Corn kernels were steeped at 52°C with 0.2% (w/v) SO(2) and with
and without 0.5% (v/v) lactic acid. The isolated starch obtained by corn
wet-milling was characterized by determining starch recoveries, retrogradation,
and melting transition properties of the lipid-amylose complex by differential
scanning calorimetry (DSC), and pasting properties by the Rapid Visco Analyser
(RVA). Damaged granules and the starch granule size were determined by using
microscopic techniques. Starches from corn steeped in the presence of lactic
acid (LAS) were compared with control starch (CS) steeped without lactic acid.
Greater starch recoveries were obtained for LAS samples than for CS samples, and
practically no damaged starch was present in the former preparations. The
presence of lactic acid affected the RVA profiles and steeping time affected the
viscosities of the starch suspensions. In general, the RVA parameters of LAS
suspensions were lower than those of CS suspensions. No great modification of
the thermal properties was observed; only a slight decrease in amylopectin
retrogradation and in the melting enthalpy of the amylose-lipid complex was
observed. Hydrolysis of the starch during steeping seems the most probable
explanation to the starch modifications produced by lactic acid addition.
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