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Physicochemical, mechanical and thermal properties of brown rice grain with various moisture contents
Author(s) -
Cao Wei,
Nishiyama Yoshio,
Koide Shoji
Publication year - 2004
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2004.00849.x
Subject(s) - brown rice , ultimate tensile strength , water content , differential scanning calorimetry , amylose , compressive strength , materials science , moisture , glass transition , composite material , starch , food science , chemistry , thermodynamics , physics , geotechnical engineering , engineering , polymer
Summary The effects of moisture content on the mechanical and thermal properties of either a short‐grain variety (Akitakomachi) or two long‐grain varieties (Delta and L201) of brown rice were studied. Total starch contents of the three varieties were comparable, but the amylose content of L201 was significantly higher than that of the other two varieties. The maximum compressive strength of brown rice grain was much higher than the maximum tensile strength. L201 showed the highest maximum compressive and tensile strengths. The phase transition temperatures (glass transition temperature T g and melting temperature T m ) were examined by differential scanning calorimetry. The T g and T m for L201 were higher than those for Delta and Akitakomachi. The maximum compressive strength, maximum tensile strength, T g and T m for the three varieties of brown rice grains decreased with increasing moisture content. The T g of individual brown rice kernels decreased from 53 to 22 °C as moisture content increased from 12 to 25% wet basis. A statistical model was calculated by using linear regression to describe the change in T g in terms of moisture content.