A RAPID AND CONVENIENT METHOD FOR ALPHA-A MYLASE ANALYSIS OF WHEAT BYAN AUTOANALYZER AND ITS APPLICATION TO ESTIMATION OF MAXIMUM AMYLOGRAPH VISCOSITY

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.