Focused beam reflectance measurement (FBRM) for determination starch granule diameter distribution and monitoring granule change and gelatinization degree during the gelatinization process

In the food industry, the particle size and gelatinization degree of starch granules have great influence on the properties of starch.However, the current methods can only statically determine the particle size distribution and gelatinization degree.In this study, Focused beam reflectance measurement (FBRM) was used to realize the dynamic determination of starch granules size distribution and gelatinization degree. In this paper, the test conditions of FBRM were evaluated. Then compared with the microscopic method and laser scattering method, FBRM exhibited good reproducibility, and it could determine the granule diameter distribution.And finally, FBRM was applied to monitor the change and the gelatinization degree of starch granules during gelatinization. In the gelatinization process, the number of corn starch granules increased at 55 °C and then decreased at 60 °C, with the sharpest decline at 70 °C. The number of potato starch granules steadily decreased, with the sharpest decline at 70 °C. The number of tapioca starch granules also steadily decreased but had the sharpest decline at 65 °C. The gelatinization of corn starch and potato starch was mainly at 70 °C while the gelatinization of tapioca starch was mainly at 65 °C. The gelatinization of small granules of corn starch, potato starch and tapioca starch was more difficult than that of large granules, and the gelatinization of small granules required higher temperature. The larger the particles, the easier the gelatinization. The large granules of potato starch were easier to gelatinize than those of corn starch and tapioca starch. The small granules of tapioca starch granules were easier to gelatinize than those of corn starch and potato starch. • FBRM was used to determine the starch granule diameter distribution and had good reproducibility. • FBRM realized the online monitoring of the change in starch granules during gelatinization. • A new method for measuring starch gelatinization degree based on “starch granule variation/original quantity” was proposed.