Experiment :

To investigate Anaerobic Respiration In Yeast.

Problem statement :

What are the products of fermentation in food?

Variables :

Manipulated variables : Presence of yeast

Responding variables :Changes in the properties and the taste of the

glutinous rice.

Fixed variables : Anaerobic condition

Hypothesis :

In the absence of oxygen, yeast undergoes anaerobic respiration to allow the

fermentation process to happen in glutinous rice and give sweet taste to the

glutinous rice after the fermentation process.

Materials :

5% of Yeast, 5% of peppercorn powder, some glutinous rice.

Apparatus :

Two small container with container cover.

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Technique :

Note that the changes in properties and taste of the glutinous rice after a

night.

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Glutinous rice Glutinous rice divided into two container

Yeast

Peppercorn Powder Yeast and peppercorn powder are mix together

The mixture were scattered into container labeled A

The mixture are not added into container B

Both container were closed tightly with it’s cover

Both container are left for 2 days at room temperature

Container A after the first day Container B after the first day Container A after the second day

Container B after the second day

Procedure :

1. The glutinous rice is clean and dips into clean water for 2 hour to make

the glutinous rice soften.

2. After two hour, the glutinous rice is steam-cooked till the glutinous rice

is cook.

3. The glutinous rice is then divided into two portions and is put into

container for each of the portion. The glutinous rice is flattened in the

container and each container are marked with A and B

4. 5% of yeast and 5% of peppercorn powder is then mixed in the other

container.

5. The mixture of yeast and peppercorn powder is then scatter onto the

glutinous rice and the mixture is scattered to whole over the glutinous

rice in container A. Container B only contain glutinous rice without the

mixture of peppercorn powder and yeast.

6. Both containers are then closed with container cover and are left for 2

days. The fermentation process will happen during that period.

7. The changes were observed on the next day to see the changes in the

properties of the gluttonous rice in both container.

8. The container cover were open on the second day and the properties

and the taste of both glutinous rice in container A and B were observe,

tasted and recorded.

9. The results are recorded in the table.

Results :

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CONTAINER

BEFORE EXPERIMENT AFTER EXPERIMENT

PROPERTIES

OF

GLUTINOUS

RICE

TASTE OF

GLUTINOUS

RICE

PROPERTIES

OF

GLUTINOUS

RICE

TASTE OF

GLUTINOUS

RICE

A

B

Discussion :

1. The peppercorn powder is use to help the process of fermentation. The

peppercorn powder will help increase the temperature of the yeast thus

accelerate the process of fermentation.

2. The mixture of peppercorn powder and yeast is scattered whole over

the glutinous rice to ensure that the fermentation process will occur on

the whole surface of the glutinous rice.

3. The container is kept close to ensure that oxygen would not enter the

container and to allow the fermentation process to occur.

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4. The experiment were left for two days to ensure that the fermentation

process can occur smoothly.

5. The taste of the glutinous rice will become sweet although there is no

sweeteners were put into the container A.

Conclusion :

In the absence of oxygen, yeast undergoes anaerobic respiration to produce

sweet taste for the food through fermentation process, thus the hypothesis is

accepted.

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