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Content

Biosubstances

Essentially, these are enzymes -

  • proteases (to help break down proteins)
  • amylases (to help break down starches)

Proteases decompose big, water-insoluble protein molecules into small soluble units.

figure17

Figure 17: Part of a protein molecule (click to enlarge)

Amylases decompose big, water-insoluble starch molecules into small soluble units.

figure18

Figure 18: Part of a starch molecule (click to enlarge)

In both cases, the breakdown process is a hydrolysis reaction (reaction with water).

As indicated previously, enzymes have optimum pHs and temperatures, so this has to be built into the design of the washing cycle. Enzymes will be denatured and cease to function after the main wash cycle of the dishwasher program.

Activity

Question 6a

Suggest foods that are based on proteins

Answer 6a

Meats, cheese, egg etc

Question 6b

Suggest foods that are based on starches

Answer 6b

Bread, pasta, rice etc

Question 7a

Suggest what are the ‘small soluble units’ produced by the breakdown of proteins

Answer 7a

Amino acids

Question 7b

Suggest what are the ‘small soluble units’ produced by the breakdown of starches

Answer 7b

Sugars

Question 8a

Look at the structures in Figures 17 and 18. Each has one of the linkages where hydrolysis takes place circled.

Draw the products after hydrolysis has taken place for part of a protein molecule

Answer 8a

answer 8a

Click to enlarge

Question 8b

Look at the structures in Figures 17 and 18. Each has one of the linkages where hydrolysis takes place circled.

Draw the products after hydrolysis has taken place for part of a starch molecule

Answer 8b

answer 8b

Click to enlarge