อุดมรัตน์ สามสี. Degradation Kinetics of Pigments from Monascus puntreus during Storage. Master's Degree(Food Engineering). King Mongkut's University of Technology Thonburi. KMUTT Library. : King Mongkut's University of Technology Thonburi, 2010.
Degradation Kinetics of Pigments from Monascus puntreus during Storage
Abstract:
This research was aimed to investigate the effects of temperature and atmospheric condition
on the kinetics of pigment degradation in red yeast rice powder during storage. Red yeast
rice powder obtained from solid state fermentation of Monascus purureus was packed in 5
in. x 8 in. plastic bag laminated with OPP, PE, aluminum foil and PE. The bag thickness
was 80 micrometers with the oxygen transmission rate at 23 C and 0% relative humidity of
0.06 cm3/m2 day bar, and water vapor transmission rate at 38?C and 90% relative humidity
of 0.06 glm2 day. The samples were stored at the temperatures of 4, 20, 30 and 50?C under
vacuum and atmospheric conditions for 4 months. The results showed that the storage
temperature directly affected the pigment degradation of red yeast rice. Storage at higher
temperatures resulted in higher rates of pigment degradration. The retentions of red, yellow
and orange pigments of the samples stored at 4 DC were 76.43+-3.67, 79.01+-2.32 and
73.41+-5.41%, respectively, after 4 months. However, atmospheric condition did not affect
the pigment degradation. The pigment degradation of red yeast rice followed a first-order
kinetic reaction. The temperature dependence of the reaction rate constants is well
explained by the Arrhenius relationship. The activation energy (Ea) of red, orange and
yellow pigment degradations are 27. 78+-2.07 x 10 3, 21.81+-0.43 x JOland 32.07+-1.28 x10 3
J/mol, respectively.