Eco-friendly Cling Film 環保保鮮紙 JBBC11

AbstractAbstract Cling film brings human convenience but harm to the environment as well. The manufacture of plastic products

comes with a heavy environmental price tag, including soil, water and air pollution.[2] Used cling film is treated as do-

mestic waste, which occupy the landfill and further cause pollution problems. Besides, laboratory studies linked BPA

with breast and prostate cancer and early sexual development in women. This draws our awareness to the safety

concerning the use of BPA in the cling films.

Inspired by the edible utensils invented by Bakeys[3] and the edible agar bottle designed Ari Jonsson[4], our group

would like to make an edible cling film which is biodegradable in the landfill; more they can be eaten after used so

that the amount of domestic waste could be reduced.

Methodology and ResultsMethodology and Results

ImprovementImprovement Extract from 'Chocolate Mint' was added into the milk film to in-

crease its bacterial resistance. The mint could give a fresh smell

and contained menthol with antimicrobial property.

ReferencesReferences 1. Plastic warp. Wikipedia. https://en.wikipedia.org/wiki/Plastic_wrap

2. Eco-friendly alternatives to cling film and foil. http://www.beashadegreener.com/clingfilm-foil-alternative-food-leftovers/

3. Move over, disposable utensils, because Bakeys edible cutlery is here. http://www.treehugger.com/green-food/move-over-disposable-utensils-because-bakeys-edible-cutlery-here.html

4. This Edible Biodegradable Algae-based Water Bottle Can Be A Green Alternative To Plastic.

http://www.awakeningstate.com/science/edible-water-bottle/

5. Don't be so clingy: Amid mounting evidence that plastic food wrap harbours a host of toxins, even doctors are urging people to stop using it. http://www.dailymail.co.uk/health/article-3207138/

6. Made from milk... the cling film you can eat! Edible wrap that will help reduce the mountain of plastic waste could hit shelves within three years. http://www.dailymail.co.uk/news/article-3752075/

7. Describe why food spoils. Foodsafetysite.com. http://www.foodsafetysite.com/educators/competencies/general/spoilage/spg1.html

Screening of materials

1 2 3

Although all the samples could so-

lidify after heating, most failed to form

thin films. Besides, some samples like

the rice flour failed in the clearance

test. Only the agar and gelatin can be

poured into a mould for making thin

film, but agar is too soft to form a solid

film.

Making the thin films — The best formula

50 ml mixture: Gelatin powder + glycerol + water

Steps:

1. Mix

2. Heat

3. Incubate at 35˚C

Test 1 – Solubility test

Finding:

The film (3g gelatin) did not dis-

solve in the first week until it was

stirred continuously on day 7, it

broke into smaller pieces.

Finding:

2 ml of glycerol could opti-

mize the softness of the film.

Too much glycerol would

make the film too soft to be

pulled up from the mould.

Test 2 – Flexibility test

Test 3 – Clearance test

Finding:

The films with higher milk

content showed a higher

cloudiness, yet, it was still

transparent even tough 20 ml

of milk was added.

Test 4 – Permeability test

The lower the permeability to water vapour, the better

the food wraps to keep the food in good quality.

Moisture greatly affects the

keeping qualities of food. Ex-

cessive moisture pickup can

result in spoilage caused by

microorganisms and chemi-

cal reactions.

Relative permeability of film with different milk protein contentRelative permeability of film with different milk protein content

The higher the milk (protein) content, the lower the per-

meability of the film to water vapour. However, the films

failed to solidify when more than 40% of milk was added.

Therefore, the best formula to make a milk gelatin film

contained 40% milk in it.

The best formula

* Relative Permeability = Decrease in mass of experimental set-up x 100% Decrease in mass of control

Average Relative Permeability of films with different gelatin Average Relative Permeability of films with different gelatin and glycerol content and glycerol content

3 g Gelatin + 2 ml Glycerol + 20 ml Milk + 30 ml Water

The best formula of a milk gelatin film:

Guava film — A better film with more flavor, higher nutritional value and longer persistence

It was found Guava juice was even better than milk

in blocking the water vapour from evaporating

away. In terms of anti-microbial property, the milk

films got deteriorated quickly within 1 week if it

was moistened at room temperature while the gua-

va films could maintain their quality.

Day 5 Day 5

(Left) A clear Guava film without bacterial growth (Right) A cloudy milk film with bacterial growth

Chocolate Mint Milk Film Guava Juice Film