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How to speed up the ripening process of bananas?

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Have you ever heard of any ways to speed up the ripening process of bananas? Let’s form groups of 3 to 4 students to find out how to do so.

[pic] Pre-experimental research and discussion

1) Buy and store bananas

Your group will need to buy a bunch of bananas for conducting the experiment. What should you consider when choosing the bananas? And what is the proper way to store bananas?

2) Causes of fruit ripening

When fruits ripen, a substance which speeds up the ripening and aging process of the fruits will be formed. Do you know what the substance is? Search the answer from the Internet.

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[pic] Conducting the experiment

In this experiment, we are going to store an unripe banana with two other kinds of food respectively and then put them in different eenvironments.

Materials and equipment

|Materials: |Equipment: |

|Greenish banana with similar degree of maturity　　　 |Transparent food container 1 |

|4 |Label 4 |

|Apple 1 | |

|_______________________ | |

|Another kind of food (e.g. orange) 1 | |

| |[pic] |

Procedure

1. Label each of the bananas from A to D.

2. Prepare the experimental set-ups as shown below and place them in cool and dry place:

|Set-up A |Set-up B |

|Put a banana in a food container |Put a banana in a food container with an apple |

|[pic] |[pic] |

| | |

|Set-up C |Set-up D |

|Put a banana in a food container with another kind of food (e.g. |Put a banana in open air |

|orange) you choose | |

|[pic] |[pic] |

3. Take a photo of each experimental set-up and describe the bananas’ appearance at day 0 (i.e. the day you set up the experiment).

4. For each of the following 4 days, record the change in appearance of the bananas. At the last day, take photos of each experimental set-up.

5. Compare the appearance of the bananas and draw a conclusion.

Results

1) Appearance of the bananas (50 marks)

| |Set-up A |Set-up B |Set-up C |Set-up D |

|Day 1 | | | | |

|Day 2 | | | | |

|Day 3 | | | | |

|Day 4 | | | | |

2) Photos of the experimental set-ups

Day 0 (the day to set up the experiment)

|Set-up A |Set-up B |Set-up C |Set-up D |

| | | | |

Day 4

|Set-up A |Set-up B |Set-up C |Set-up D |

| | | | |

Conclusion

According to the result of the experiment, which experimental set-up can speed up the ripening of the banana? Arrange their effectiveness in descending order. (10 marks)

Set-up ___________ > Set-up ___________ > Set-up ___________ > Set-up ___________

Discussion (10 marks)

1. What is the function of set-up D?

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2. What is the principle of speeding up the ripening process of banana in each experimental set-up?

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3. Are there any other factors affecting the rate of ripening process of fruits?

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Score /100

I’ve heard that putting a certain kind of food together with a banana can speed up the ripening process. But I’m not sure if it works.

Jasmine, do you know if there’re any methods to make this banana ripe more quickly?

Chloe

Jasmine

Score of Part A /30

Buying tips for bananas

← firm, bright in appearance;

← free fron bruises;

← those with green ends or with practically green color have not developed their full flavor potential

Storing tips for bananas

• Remove bananas from plastic bags as soon as you get them home. Plastic bags will hold too much moisture and could cause the fruit to rot

• Store green bananas at room temperature. Refrigerating or freezing bananas before they ripen prevents the fruit from being able to properly ripen even after brought back to room temperature.

• Put the bananas in the vegetables drawer of the refrigerator after they are fully ripe. Refrigeration can slow the ripening process considerably.

Some fruits such as apple and bananas produce a chemical called ethylene when ripening. Ethylene is responsible for the changes in texture, softening, color, and other processes involved in ripening. Ethylene is also thought as the aging hormone in plants, which can cause plants to die.

Score of part Bÿ /70

Teaching notes:

Teachers can teach students the following expressions to describe the ripening of bananas:

← with greenish B： /70

Teaching notes:

Teachers can teach students the following expressions to describe the ripening of bananas:

with greenish yellow colour;

← turned more yellow;

← turned mostly yellow with a little bit greenish at both ends;

← turned completely yellow;

← with / without black spots;

← turned black

Set-up D is a set-up to show what will happen to bananas if they are allowed to ripen naturally in open air.

( For set-up A: Ethylene produced by the banana was trapped and concentrated in the box which could sprrd up the ripening of the banana.

( For set-up B: The apple released ethylene which speeded up the ripening of the banana.

( For set-up C: Free answer

( Temperature: Since high temperature activates the enzymatic activity in fruits, it speeds up the ripening process.

( Sunlight: Direct exposure to sunlight reduces the ripening period of fruits.

( Water loss: Water loss causes fruits to lose their firmness, the peel becomes soft and shriveled, resulting in reduced ripening period.

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