Lima FF, Andrade CT. Effect of melt-processing and ultrasonic treatment on physical properties of high-amylose maize starch.
ULTRASONICS SONOCHEMISTRY 2010;
17:637-641. [PMID:
20133177 DOI:
10.1016/j.ultsonch.2010.01.001]
[Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 11/29/2009] [Accepted: 01/03/2010] [Indexed: 05/28/2023]
Abstract
High-amylose maize starch (Hylon VII) was submitted to melt-processing in an internal mixer at 100 degrees C and 40 rpm for 8 min. Glycerol was used as a plasticiser at different polymer/glycerol ratios. Torque and temperature curves were obtained. After glycerol extraction with ethyl alcohol, the samples were dispersed at 5 g/L, and treated by ultrasound radiation at the same conditions for 30 min. Samples were characterised by (1)H NMR spectrometry, viscosity measurements, and X-ray diffractometry. The results revealed that both glycerol and water had an important role on the crystallinity properties of the resulting products. Melt-processed and sonicated samples showed similar (1)H NMR spectra. Ultrasound treatment caused a significant reduction in intrinsic viscosity for the sample previously processed with the highest glycerol content, probably because of its higher solubility in water.
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