Pre-Gelatinisation of Rice Flour and Its Effect on the Properties of Gluten Free Rice Bread and Its Batter.

In order to improve the quality of the gluten free rice bread (GFRB), pre-gelatinised rice flour (PGRF) was made and used to partially replace natural rice flour in the production of GFRB. The pre-gelatinisation parameters were optimised and the effects of PGRF on the quality of the GFRB and its batter were studied. The results showed that optimal PGRF was obtained when 50% total water was mixed with 1.0% rice flour and the mixture heated at 80 °C for 2 min. Supplementation with PGRF significantly improved the properties of GFRB by affecting its baking properties, textural properties, colour, and crumb grain features. Effects of PGRF on GFRB were mainly caused by the more closely packed gel structure of rice starch in the bread batter, the higher onset temperature during gelatinisation and the complex effect of PGRF on water-binding capacity in bread batter during the baking process. As the pre-gelatinisation parameters of flours and their effect on gluten-free baked products varied with grain variety, processing properties should be studied before using them, and emphasis should be placed on new techniques such as flour pre-gelatinisation to obtain gluten-free foods with improved quality.

Effect of Curdlan on the Rheological Properties of Hydroxypropyl Methylcellulose.

This work focuses on the effect of curdlan (CL) on dynamic viscoelastic property, thermal reversible property, viscosity, and the fluid types of hydroxypropyl methylcellulose (HPMC) at different temperatures. Compared to the blends at 25 °C, the blends had a smaller linear viscoelastic region (LVR), a higher gel strength, and larger storage modulus (G') and loss modulus (G") values at 82 °C. G', G", gel strength, and viscosity increased with the increase of CL. Repeated temperature sweep led to increased G' and G" of HPMC/CL blends. For HC6 and HC8, the gel formation temperature of the repeated temperature sweep was significantly lower than that of the first sweep. The samples at 82 °C, except for the sample with 8% CL, were all yield-shear thinning fluids, and the samples at 40 °C were shear thinning fluids. The creation of HPMC/CL and its rheological research might provide some methodological references for the study of other thermal-thermal gel blends.

Microstructures, physical and sustained antioxidant properties of hydroxypropyl methylcellulose based microporous photophobic films.

Hydroxypropyl methylcellulose (HPMC)/sodium citrate (SC)/lipid tea polyphenol (LTP) photophobic films with different pore sizes from micron scale to nanometer scale were prepared by regulating the SC content (1-7%). The microstructures, physical and sustained antioxidant properties of these films were studied by using wide angel X-ray diffraction, small angle X-ray scattering (SAXS), scanning electron microscope, whiteness meter, ultraviolet spectrophotometer, texture analyzer and peroxide value test. Composite films with higher SC content showed larger pore size and whiteness. With the increasing SC content, crystallinity first increased then decreased. The addition of SC decreased the Ds (surface fractal dimension) value, smoothness of the cross-section structure, tensile strength, elongation and modulus of composite films. HPMC/SC/LTP microporous films possessed control-release property in oil system, reflected by the lowest peroxide value of peanut oil enclosed in film with 3% SC during three weeks, meaning this film showed the best sustained antioxidant property.

Multi-scale structures of cassava and potato starch fractions varying in granule size.

Large-, medium-, and small-sized granules were separated from cassava and potato starches. Fourier transform infrared spectroscopy, wide angle X-ray diffraction, small angle X-ray scattering, nuclear magnetic resonance and scanning electron microscope were used to investigate the supramolecular structures of cassava and potato starch fractions. The crystallinity of small-sized potato starch (SPS) was lower than that of its counterparts, while crystallinities of all cassava fractions were similar. The contents of lamellar structure of small-sized granules were the smallest, while those of their counterparts were similar. The lamellar repeat distance was similar for the starch fractions. Self-similar structure of SPS showed mass fractal with the lowest compactness, while that of small-sized corn starch showed surface fractal with the largest compactness. The NMR test revealed that SPS had the highest total double helix content, while its counterparts showed similar values. Moreover, a new 13C peak at 64 ppm was observed for SPS.