S. Nakatsu et al., A RAPID AND CONVENIENT METHOD FOR ALPHA-A MYLASE ANALYSIS OF WHEAT BYAN AUTOANALYZER AND ITS APPLICATION TO ESTIMATION OF MAXIMUM AMYLOGRAPH VISCOSITY, Nippon Sakumotsu Gakkai Kiji, 66(1), 1997, pp. 35-41
In order to estimate the maximum amylograph viscosity of wheat, an aut
omatic method for the measurement of alpha-amylase activity was develo
ped using a commercial blocked rho-nitrophenyl maltoheptaoside as a su
itable substrate. A Type AAIIauto-analyzer (Bran + Luebbe) partially m
odified can rapidly and conveniently analyze alpha-amylase activity at
almost 50 samples per hour, and can save the cost of reagents as comp
ared to manual analysis. There was no significant difference between a
lpha-amylase activity measured by hand and the auto-analyzer. The alph
a-amylase activity in flour correlated well with the maximum amylograp
h viscosity (r=-0. 922*). The correlation coefficient between alpha-a
mylase activity and maximum amylograph viscosity was slightly lower in
ground wheat (r=-0.906*). With regard to fresh wheat, there was no a
pparent relationship in wheat sampled before maturity, but a high corr
elation (r=-0.884*) was exhibited after maturity. To monitor the leve
ls of maximum amylograph viscosity in cargo samples and classify grade
s, we made tentative criterion for alpha-amylase activity in fresh whe
at. Group 1 : most of the wheat with alpha-amylase activity below 300
mU/g showed a high amylograph Viscosity (mean = 755B.U.). Group 2 : wh
eat with alpha-amylase activity between 300 to 500 mU/g widely ranged
from low to high viscosity (mean = 502B.U.). Group 3 : most of the whe
at with alpha-amylase activity over 500 mU/g showed unacceptably level
s of amylograph viscosity (mean=109B.U.). Therefore, the autoanalyzer
can be utilized to rank wheat quality at receival points, and can also
be adapted as a selection method for the development of low alpha-amy
lase varieties in wheat breeding.