Germination

Question 1

What are the main enzymes involved in the modification of barley endosperm?

Answer 1

Enzymes that break down endosperm cell walls, protein matrix, and starch granules

These enzymes are crucial for the mashing process, facilitating starch and protein breakdown.

Question 2

What is the target for the action of the enzymes during barley germination?

Answer 2

Barley endosperm cells containing barley starch

The endosperm cells act as a protective barrier for starch granules.

Question 3

What are the two forms of starch found in barley granules?

Answer 3

Amylose and amylopectin

Amylopectin has a branched structure requiring limit dextrinase for conversion to sugars.

Question 4

What is the role of β-glucan solubilase in the endosperm?

Answer 4

Breakdown of protein in cell walls

It facilitates the degradation of the protective cell wall to access starch granules.

Question 5

What enzyme breaks down viscous β-glucans?

Answer 5

Endo-β-glucanases

These enzymes are important for modifying the cell walls of the endosperm.

Question 6

What is the action of pentosanases in barley germination?

Answer 6

Breakdown of viscous pentosan gums

This action aids in the modification of the cell wall structure.

Question 7

What do endo and exoproteases break down during germination?

Answer 7

Protein matrix surrounding starch granules

This breakdown produces free amino nitrogen (FAN) and polypeptides.

Question 8

What is the function of α-amylase in the endosperm?

Answer 8

Breakdown of small starch granules to produce sugars for embryo growth

This enzyme plays a vital role in providing energy for the growing embryo.

Question 9

What does β-amylase do during barley germination?

Answer 9

Converts starch to sugars

It specifically acts on the ends of the starch chains.

Question 10

What is the role of limit dextrinase in starch modification?

Answer 10

Converts branched amylopectin into sugars

This enzyme is essential for complete starch hydrolysis.

Question 11

On which day of germination does carboxypeptidase first become active?

Answer 11

Day 1

This enzyme starts the process of protein breakdown early in germination.

Question 12

Which enzymes become active on Day 2 of germination?

Answer 12

Endo peptidase and β-glucanases

These enzymes further aid in the breakdown of proteins and cell wall components.

Question 13

During which days are α-amylase enzymes activated?

Answer 13

Days 2-4

This activation period is crucial for starch degradation.

Question 14

When does limit dextrinase first become active in the germination process?

Answer 14

Days 4-6

This enzyme is important for the final stages of starch conversion to sugars.