A-Amylase fungal

An overdose of malt flour will introduce too much enzyme activity in the dough, potentially reducing the product to a sticky syrup. Fungal a-amylase is now much more commonly used than malt flour. However, some malt flour is still used, particularly in wholemeal bread. 

Other additions to flour are fungal a-amylase malt flour, malt grains or other mixtures of grains. Alternatively, the flour can be supplied untreated by the miller and any treatments needed can be applied in the bakery. This could be an attractive option for a bakery that made a mix of products, some of which needed untreated flour while others, e.g. bread, needed flour treatment. 

The reason for the non-response of the Hagberg Falling Number to fungal a-amylase is that it is inactivated at 75°C rather than the 87°C of cereal a-amylase. It turns out that fungal a-amylase preparations improve loaf volumes considerably. Most of this effect is produced by a lipoxygenase enzyme that is also present. 

It has since been discovered that the very considerable increase in loaf volume that fungal a-amylase preparations can produce is not caused by the amylase but by a lipoxygenase that is also present. 

The Hagberg Falling Number test only just qualifies for this section as it is an effective way of measuring the a-amylase activity of wheat or flour. It has the considerable advantage that it is unaffected by any added fungal a-amylase. In addition, it only requires a supply of distilled water and electricity - there is no need for chemical glassware or any reagents. 

To date, several a-amylases have been identified in diverse organisms, e.g., Aed a 4 in yellow fever mosquito or Der p 4 in European house dust mite. Cereal a-amylases are important allergens for patients with baker s asthma involving the two crucial allergens from barley (Hor v 15 and Hor v 16). Some of these patients also show IgE reactivity to fungal a-amylases, e.g., Asp o 21 from Aspergillus, used as baking additives or present in mold contaminated flour. 

Starch is first liquefied and hydrolyzed to specific dextrose equivalents with hydrochloric acid. After evaporation to 60 percent solids, a saccharifying enzyme (fungal a-amylase) is added to continue hydrolysis to the desired level. By choosing two or more types of enzymes (such as a-amylase, -amylase, glu-coamylase, pullulanase) and adjusting the initial acid hydrolysis, syrups with different ratios of dextrose, maltose, and higher saccharides can be obtained.92... 

P. W. Hansen, Determination of Fungal a-Amylase by Flow Injection Analysis. Anal. Chim. Acta, 158 (1984) 375. 

While this paper deals with the chemistry and reaction characteristics of glucose isomerase, it should be noted that glucose oxidase, glucoamylase, aldose-1-epimerase, a-glucosidase, alcohol dehydrogenase, pullulanase, and fungal a-amylase have been successfully immobilized onto this support. 

The Perkin-Elmer model 191 grain amylase analyser has potential usefulness to the cereal industry for measurement of amylase.For example, it can satisfactorily measure the potency of fungal a-amylase supplements, With amylo-pectin as substrate, it can measure various concentrations of a- or )3-amylase. The analyser cannot, however, differentiate between the effects of these two enzymes, which are both normally present in cereals. This limits its present usefulness, particularly for measurement of a-amylase. Selective inactivation with HgClj or heat-treatment cannot guarantee that /3-amylase is completely destroyed or that a-amylase has not been affected. Manufacturer refinements to the prototype method and instrument such as developing a /3-limit dextrin substrate and increasing the sensitivity of the analyser may ultimately provide a simple, rapid assay of a-amylase. 

The affinity chromatographies of bacterial and fungal a-amylases on (4-chloromercuribenzoyl)-cellulose have been examined. ... 

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