Heat stability of commercial preparations of phytase has been of concern for quite some time, and efforts have been made to
develop new preparations of this enzyme. A study was conducted to determine the stability of commercially available phytase
product (granulate; Phytase A) and the new experimental product (powder; Phytase B). In the in vitro study, incubation of 100 mg
of each of Phytase A and B with 200 μl of buffer for 2 min (30 s at desired temperature) resulted in 27.6 and 10.4% loss of activity
at 60 °C and 80.6 and 53.9% at 70 °C, respectively. Both enzyme products were further subjected to steam pelleting in feed mills
located in Manitoba and British Columbia. In the Manitoba study, the temperature of pellets as recorded at the discharge averaged
67 °C and was similar to that determined in British Columbia (70 °C). Under such temperatures, which may have been lower than
the actual temperatures within the pellet mill, the loss of endogenous phytase activity averaged 58.5% (from 451 to 187 U kg−1)
and 42.5% (from 287 to 165 U kg−1) in the two mills, respectively. Following correction for endogenous phytase activity, Phytase
A and B recovery averaged 36.4 and 49.9%, respectively, at the Manitoba site and 44.1 and 49.4% at the British Columbia site. It
appears evident from this study that the heat stability of enzyme (protein) per se rather than the granulation technology is a primary
factor determining the stability of microbial phytase during steam pelleting.
Heat stability of commercial preparations of phytase has been of concern for quite some time, and efforts have been made to
develop new preparations of this enzyme. A study was conducted to determine the stability of commercially available phytase
product (granulate; Phytase A) and the new experimental product (powder; Phytase B). In the in vitro study, incubation of 100 mg
of each of Phytase A and B with 200 μl of buffer for 2 min (30 s at desired temperature) resulted in 27.6 and 10.4% loss of activity
at 60 °C and 80.6 and 53.9% at 70 °C, respectively. Both enzyme products were further subjected to steam pelleting in feed mills
located in Manitoba and British Columbia. In the Manitoba study, the temperature of pellets as recorded at the discharge averaged
67 °C and was similar to that determined in British Columbia (70 °C). Under such temperatures, which may have been lower than
the actual temperatures within the pellet mill, the loss of endogenous phytase activity averaged 58.5% (from 451 to 187 U kg−1)
and 42.5% (from 287 to 165 U kg−1) in the two mills, respectively. Following correction for endogenous phytase activity, Phytase
A and B recovery averaged 36.4 and 49.9%, respectively, at the Manitoba site and 44.1 and 49.4% at the British Columbia site. It
appears evident from this study that the heat stability of enzyme (protein) per se rather than the granulation technology is a primary
factor determining the stability of microbial phytase during steam pelleting.
การแปล กรุณารอสักครู่..
