Measurement of β-amylase in cereal flours and commercial enzyme preparations
1989; Elsevier BV; Volume: 9; Issue: 1 Linguagem: Inglês
10.1016/s0733-5210(89)80018-9
ISSN1095-9963
AutoresBarry V. McCleary, Rachel Codd,
Tópico(s)Microbial Metabolites in Food Biotechnology
ResumoA procedure previously developed for the assay of cereal-flour β-amylase has been improved and standardised. The improved procedure uses the substrate p-nitrophenyl maltopentaose (PNPG5) in the presence of near saturating levels of α-glucosidase. PNPG5 is rapidly hydrolysed by β-amylase but less readily by cereal α-amylases. The substrate is hydrolysed by β-amylase to maltose and p-nitrophenyl maltotriose (PNPG3). With the levels of α-glucosidase used in the substrate mixture, PNPG3 is rapidly cleaved to glucose and p-nitrophenol, whereas PNPG5 is resistant to hydrolysis by the α-glucosidase. The assay procedure has been standardised for several β-amylases and the exact degree of interference by cereal α-amylases determined. The procedure can be readily applied to the selective measurement of β-amylase activity in cereal and malted cereal-flours.
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