Functional characterization of extruded rice noodles with corn bran: Xanthophyll content and rheology

The rheological changes in rice noodles by the substitution of corn bran and the effect of temperature on the xanthophyll content (lutein and zeaxanthin) of the corn bran-rice flour noodles were evaluated. The use of corn bran increased the water holding capacity of rice flour at room temperature while the opposite results were observed after heating. The pasting parameters of rice flour-corn bran mixture were reduced with increasing levels of corn bran and the mixture paste exhibited more dominant liquid-like behavior. The noodles containing corn bran exhibited lower expansion ratio and softer textural properties. The levels of lutein and zeaxanthin in raw corn bran were 336.9 and 123.1 mu g/100 g, respectively and were significantly reduced (P < 0.05) by heating. While lutein and zeaxanthin were not detected in the control noodles without corn bran, their levels in corn bran-incorporated noodles ranged from 56.2 to 1373 mu g/100 g and from 37.9 to 61.9 mu g/100 g, respectively and were significantly reduced by 37.7-45.4% (P < 0.05) after cooking. Thus, the heat-labile characteristics of two xanthophylls were clearly observed. This study provides useful information on the processing performance and xanthophyll content of corn bran, possibly extending its use in a wider variety of foods. (C) 2014 Elsevier Ltd. All rights reserved.