食品檢測(cè)

Enzymes in Bread Making –?In bread production, a knowledge of both the alpha-amylase content and the water absorption of the flour?is essential. Heavy rainfall and high humidity at the time of harvesting leads to preharvest sprouting, and the synthesis of amylase. High levels of this enzyme in flour leads to excessive starch dextrinisation in the baking process, which results in a sticky loaf, which is difficult to slice. Water added to flour is absorbed by protein, pentosans and starch. The major variable affecting water absorption is the level of damaged starch granules which are produced during the milling of the grain.

In modern baking practices the endogenous flour enzymes are commonly supplemented with enzymes of microbial origin e.g. α-Amylase, xylanase, and in some cases, proteases. Xylanase, through the modification of wheat flour arabinoxylans, can give up to a 10% increase in loaf volume. Proteases can be added to soften, particularly tough (bucky) glutens. However, high protease levels will destroy the gluten properties.

Xylazyme AX?finds widespread application in the measurement of xylanase in wheat flours and bread improvers mixtures. alpha-Amylase is routinely measured using?Ceralpha: α-amylase assay reagent. The need for rapid and simple procedures for the measurement of protease in bread improvers mixtures led to the development, by Megazyme, of?Protazyme AK Tablets?and?Azo-Casein?(which is far superior to the Azo-Casein currently commercially available from other suppliers).