Effect of instantaneous controlled pressure drop (DIC) on physicochemical properties of wheat, waxy and standard maize starches

• Published in: Journal of cereal science 2009-05, Vol.49 (3), p.346-353
• Main Authors: Maache-Rezzoug, Z., Maugard, T., Zarguili, I., Bezzine, E., El Marzouki, M.-N., Loisel, C.
• Format: Article
• Language: English
• Subjects: alpha-amylase; Biological and medical sciences; Cereal and baking product industries; Chemical and Process Engineering; corn starch; DIC hydrothermal treatment; Engineering Sciences; enthalpy; enzymatic hydrolysis; Enzyme hydrolysis; Food industries; Fundamental and applied biological sciences. Psychology; Gelatinization; glucan 1,4-alpha-glucosidase; heat treatment; instantaneous controlled pressure drop; pasting properties; physicochemical properties; pressure treatment; rheological properties; Starch; Starch and starchy product industries; thermal properties; waxy corn; waxy corn starch; wheat starch
• ISSN: 0733-5210; 1095-9963
• DOI: 10.1016/j.jcs.2008.10.005

Standard maize starch (SMS), waxy maize starch (WMS) and wheat starch (WTS) were hydrothermally treated by the Instantaneous Controlled Pressure Drop (DIC) process. This process consists in a short pressurisation obtained by the injection of saturated steam at fixed pressure during a predetermined time followed by a sudden pressure drop towards vacuum. The effects of DIC conditions on thermal characteristics, enzyme susceptibility, pasting (Brabender) and rheological properties of treated starches were investigated. For treated starches, an increase of transition temperatures ( T o and T p), a narrowing of the width of gelatinization endotherms and a decrease of the gelatinization enthalpies (Δ H) were observed as the severity of processing conditions increased. WMS, SMS and WTS showed a significant increase in enzymatic hydrolysis after treatment. The saccharification yield showed an increase from 19% (native) to 44%, 21% (native) to 59% and 55% (native) to 79% for SMS, WMS and WTS, respectively. The study suggests that the structural modifications due to the previous DIC treatment influence the in-vitro hydrolysis and the access to the ultrastructure of starch granules; the susceptibility to hydrolysis increases from SMS to WMS and WTS. For all treated starches, the decrease in peak viscosity and in apparent viscosity was related to the processing conditions.