Modification Analyses

Question 1

What does the modification parameters index provide?

Answer 1

An index of malt modification

It indicates both the extent and evenness of modification.

Question 2

What is the Calcofluor method used for?

Answer 2

Determining malt modification

It involves staining kernels with calcofluor to assess cell wall integrity.

Question 3

How many kernels are used in the EBC Calcofluor method?

Answer 3

Three sets of 40 kernels

These are embedded in a clay fixation block for analysis.

Question 4

What happens to the kernels during the Calcofluor method?

Answer 4

They are sanded longitudinally until half of the corn is removed

This prepares the kernels for staining and analysis.

Question 5

What does calcofluor bind to in the cell walls?

Answer 5

High molecular weight β-glucan

This binding allows for fluorescence under UV light.

Question 6

What indicates intact cell walls in the Calcofluor method?

Answer 6

Areas that fluoresce under UV light

These indicate incomplete modification of the kernels.

Question 7

How is the modification percentage calculated in the Calcofluor method?

Answer 7

Total area of fluorescence divided by total endosperm area multiplied by 100, then subtracted from 100

This formula provides the modification percentage of a sample.

Question 8

What are the two indirect methods for determining malt modification?

Answer 8

Soluble Nitrogen Ratio (SNR) and Kolbach Index (KI)

These methods assess the extent of protein modification.

Question 9

What is the formula for calculating the Kolbach Index (KI)?

Answer 9

KI = (TSN / TN) × 100

TSN is total soluble nitrogen and TN is total nitrogen.

Question 10

What does a low Kolbach Index (KI) value indicate?

Answer 10

Partial protein modification

This suggests that the protein matrix has not been extensively broken down.

Question 11

What does a high Kolbach Index (KI) value indicate?

Answer 11

Extensive protein modification

A KI greater than 45 suggests over modification.

Question 12

What is the significance of the values obtained from KI and SNR?

Answer 12

They indicate the level of protein matrix breakdown

Different malts have varying specifications for these values.

Question 13

What KI or SNR value suggests that malt is under modified?

Answer 13

Below 38

This indicates insufficient modification of the malt.

Question 14

What KI or SNR value suggests that malt is over modified?

Answer 14

Greater than 45

This indicates excessive modification of the malt.