2.4. Perten Fungal (α-Amylase) Falling Number (FFN)
In the past, systematic documentation of the addition of enzymes, for example for flour improvement, by the standard falling-number method presented certain problems. The problems were greater when fungal α-amylase was used than with α-amylase concentrates obtained from cereals (malt flour). In tests on treated and untreated milled products it was possible to trace these changes better with the Brabender Amylograph, particularly with the maximum viscosity (Brümmer, 1984a).

The new development by Perten Instruments is a modified Falling Number method that uses the ability of amylases to liquefy gelatinized starch and therefore to reduce measurable viscosities. The material used is a suspension of potato starch in a buffer solution (pH 5.3, as in the swelling curve after Drews (1971), to which the milled product to be tested, enzyme preparations or other relevant raw materials are added. Preparation of the sample to be tested and measurement of the changes in viscosity are then carried out much as in the familiar standard Falling Number method.

Both cereal and fungal amylases can be detected by this modified method. Since the fungal amylases are inactivated at lower temperatures than the cereal amylases, it is possible to differentiate between them. The influence of "side activities" such as xylanase or protease is usually slight, although these may alter the Falling Number at least if the dose is too high. But the FFN did seem to react sensitively to different flours, i.e. if the same enzyme preparations were used on flours from different wheat varieties and these were subsequently tested. This may be due to differences in the susceptibility of the ingredients to enzymatic attack.

All in all it may be said that the enzymatic changes in raw materials could still be detected better and with greater differentiation by the maximum viscosity of the Brabender Amylogram curves than by various Falling Number methods. However, the Brabender Amylogram only records total activity and cannot help to distinguish between cereal and fungal amylase as the modified Perten Falling
Number method does.

Further series of tests need to be performed to establish how far microbial contamination of cereal, e.g. with fusaria, can be determined directly or by comparison with the standard Falling Number. Washings from deliberately contaminated cereal have so far shown only slight effects on the measurements. It was concluded from this that the enzymatic activity of fusaria, for example, is only slight. It was not possible to decide whether or not a sample was contaminated with fusaria or whether technological effects can be expected to result from the micro-organisms.

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