Lesson 3 - Mashing Biochemistry SAQ
This lesson provides the opportunity for you to test yourself on the material covered in Lesson 2, Mashing Biochemistry and determine the level to which you have attained the expected outcomes.
SAQ Suggested Response - Q3
* Give short answers to the following:
a) What are the two forms of starch?
b) If one maltose molecule has its α-(1,4) bond hydrolysed, what is the result?
c) Which enzyme catalyses the hydrolysis of α-(1,6) glycosidic bonds?
d) How does starch liquefaction rely on gelatinisation?
Response
a) Amylose and amylopectin.
b) As maltose is a disaccharide consisting of two glucose residues, hydrolysing the α-(1,4) bond yields two glucose molecules.
c) Limit dextrinase catalyses the hydrolysis of α-(1,6) glycosidic bonds.
d) Liquefaction is where the starch molecules are hydrolysed to the extent that they are dispersed in water to form a liquid solution. It is not possible to liquefy solid starch granules because the enzymes of liquefaction (principally α-amylase) cannot access the chains of glucose. Gelatinisation disrupts the structure of the starch granules allowing them to accept water and exposes individual chains of glucose residues for enzyme-catalysed hydrolysis.