Transcript Bio project finished(sandy).

Bio project
Group leader: Sandy Hui
Group member: Emily Yeung
Heike Lam
Objective
• To find out the amount of sugar different
drinks contain qualitatively.
• To investigate whether the sense of taste of
human is reliable.
Introduction
for the project
• As our goal of this project is to find out whether
the taste of human is truly reliable, the
interviewees were asked to taste 8 different
drinks which includes tastes like bitter, sour and
sweetness.
• Then the interviewees are asked to arrange the
degree of sweetness.
• The sweetest the drink is, the highest degree is
the result collected and it is checked with the
Benedict’s test we had carried out, which was
tried to test the amount of sugar qualitatively.
Introduction for Benedict's test
• Reducing and non-reducing sugar present in the 8 different drinks
are tested using Benedict’s test qualitatively.
• Acid are used to hydrolyze the non-reducing sugar and then
boiling is needed. Precipitate will form as sugar is present.
• Filter the precipitate and measure the weight of the precipitate.
A
Nestle milk tea
B
Nescafe(rich)
c
Lucozade (original flavor)
d
Lemon tea (less sweet)
E
Yakult
F
Hung Fook Tong Ginzen drink
G
Ribena(less sweet)
H
Kowloon Dairy Slimilk
Introduction of tasting
• Interviewees were asked to taste the 8
different drinks.
• Grades according to sweetness were given by
the interviewees.
• After each trial of one drink, interviewees
were required to drink water to wash away
the sweetness of the previous drink.
predictions
• For Benedict's test
• Brick red precipitate will be formed when
reducing and non-reducing sugar is present.
• The result is concordant with the nutritional
claim.
• For tasting test
• It is predicted that the sense of taste of human is
not reliable that they may be deceived by the
taste of bitter or sour---they may have the
misconception that drinks with bitter or sour
tastes contains less amount of sugar.
Assumptions
Benedict’s test
Tasting
The amount of precipitate is directly
proportional to the amount of sugar
present.
Respondent did remember all the
sweetness of the drinks when grades
were given by them.
Sugar is the only substance which forms
precipitate with Benedict’s solution.
Their taste buds had the same sensitivity.
All sugar present in the samples has
completely reacted with Benedict’s
solution.
The sense of taste of different genders
has no significant difference.
The acid can hydrolyse non-reducing
sugar completely
The sense of taste of the youngsters
(interviewees) can represent other age
groups
The drinks has the same low temperature.
The rinsing of mouth can return the taste
buds to normal sensitivity level
Variables
Variables
tests
Benedict’s test
Tasting
Independent
Types of drink
Types of drink
Dependent
Amount of red precipitate
The grades given by the
respondent
Controlled
Volume of sample used
Volume of sample given to
the respondent.
Volume of Benedict’s
solution
Volume of water drunk
after each tasting
Volume of acid
Apparatus/Materials
Apparatus/Materials
Amount
Apparatus/Materials
Amount
lucozade(original)
5ml
0.1M hydrochloric acid
10ml
vita lemon tea(less sweet)
5ml
0.1M sodium hydroxide
10ml
ribena(less sweet)
5ml
Benedict’s solution
100ml
nescafe(rich)
5ml
pipette
3
nestle milk tea
5ml
Test tubes
40
hung fook tong american
ginzen with honey drink
5ml
Filter paper
35
kowloon dairy hi-calcium
slimilk
5ml
Heater
1
Wash bottle
3
Filter funnel
14
1M glucose solution
5ml
Electronic balance
1
Oven
1
Glass stirrer
3
Pipette filler
3
test tube rack
4
Procedure for Benedict’s test
1.
2.
3.
Set up a water bath and boil it for later use.
Put the filter papers into oven to dry them up for 10 minutes
Add 1ml of the samples into different test tubes. Then add 5 drops of
0.1M HCL.
4. Mix them well and boil the mixture in the water bath for 5 minutes.
5. Add 5 drops of 0.1M NaOH into each test tube to neutralization.
6. Add 5ml Benedict’s solution and boil the mixture again for 5 minutes.
7. Take the filter papers out and measure their weight.
8. Carefully filter the precipitate with the weighted filter papers.
9. Wash all the precipitate of the test tubes into the filter papers. Be
careful not to add too much water or else the paper will be damaged
with holes.
10. Put the filter papers into 100℃ oven for 1 day.
11. Take out the filter papers after 1day and measure the weight of the
papers again.
Procedure for tasting test
1.
2.
3.
4.
rinse the mouth with water thoroughly.
Taste 8 different drinks in order.
After each trial of 1 drink, repeat step 1.
Record the grades of sweetness given by the
interviewees.
5. Ask the interviewees to distinguish which
drink is lite.
PRECAUTIONS
1.
2.
3.
Label all the test tubes to prevent any mixing up of the drinks.
Wash the pipette before use to avoid contamination.
Ensure the drinks contain no residue or else the precipitate present
may not all are due to the sugar present in the drink.
1.
tasting
Result
of Benedict’s Test
Table showing the result of Benedict’s test
Types of
drink
The whole
system’s
Final weight
(g)
Filter
paper’s
weigh (g)
Is the filter
Average
paper holed? weight of
precipitate
(yes/no)
of the two
trials (g)
Mass of
sugar in
100ml
drinks (g)
A1
A2
1.28
1.30
1.05
1.05
No
No
0.24
6.65
B1
B2
1.35
1.25
1.05
1.05
No
No
0.25
6.92
C1
C2
1.34
1.30
1.05
1.05
No
No
0.27
7.48
D1
D2
*
1.35
*
1.04
Yes
No
0.31
8.58
E1
E2
1.45
*
1.03
1.05
No
No
0.42
11.6
Table showing the result of Benedict’s test (continued)
Types of
drink
The whole
system’s
Final
weight (g)
Filter
paper’s
weigh (g)
Is the filter
paper
holed?
(yes/no)
Average
weight of
precipitate
of the two
trials (g)
Mass of
sugar in
100ml
drinks (g)
F1
F2
1.27
1.22
1.04
1.04
No
No
0.205
5.68
G1
G2
1.43
1.32
1.01
1.05
No
No
0.345
9.55
H1
H2
1.32
1.30
1.05
1.05
No
No
0.260
7.2
I1
I2
1.26
1.29
1.02
1.06
No
No
0.650
18
J1
J2
0
0
1.02
1.03
No
No
0
0
Calculation
• Average weight of precipitate of the two trials
={ [the whole system’s final weight ( precipitate + filter paper) –
filter paper’s weight ] in trial one + [the whole system’s final weight
( precipitate + filter paper) - filter paper’s weight ] in trial two} / 2
• The molar mass of glucose ( C6H12O6)
=12x6+1x12+16x6
=180 gmol^-1
• Mass of sugar present in 100ml 1M glucose solution = 18g
• Mass of sugar present in each 100ml drink
18x (mass of precipitate in drink samples/ mass of precipitate in
glucose solution)
Discussion about the Benedicts’ test
Discussion
• Interpretation of the result
• According to the mass of sugar in each 100ml drink, we can get the trend
of sweatiness of drinks
the trend is as below:
I>E>G>D>C>H>B>A>F>J
• The higher the amount of red precipitate the drink has, the higher the
mass of sugar in each 100ml drink
• 1M glucose solution has the highest amount of sugar in 100ml of it
• Water as a control has the lowest amount of sugar in 100ml of it
• Among drinks, 100ml yakult has the highest sugar content while hung fook
tong american ginzen with honey drink has the lowest sugar content
Table comparing the sugar content in 100ml of each drink in the experiment
result and the nutrition label
Types of drink
experiment result
nutrition label
A
6.65g
6.5g
B
6.92g
6.8g
C
7.48g
9.1g
D
8.58g
10.9
E
11.6g
16.7g
F
5.68g
6.5g
G
9.55g
8.2g
H
7.2g
7.1g
Picture showing the result of the experiment ( precipitate on filter paper)
Picture showing the result of the experiment ( precipitate on filter paper)
Comparison between the nutritional label and the
experiment result
• The trend of the amount of sugar content in each 100ml drink in
nutritional label
I>E>D>C>G>H>B>F,A>F
• The trend of the amount of sugar content in each 100ml drink in
experiment result
I>E>G>D>C>H>B>A>F>J
• Generally speaking, both trends are quite similar only with three of them
( D,C,G) in the wrong order.
• The wrong order may because of the errors in carrying out the experiment
Error
• The sugar content done by the experiment and that in nutritional label is
more or less the same
• The relative error between the experiment result and the nutritional label
can be minimized by using more amount of drinks to carry out the test
( e.g. 200ml)
• There are some result cannot be done in the experiment because of the
failure of filtration of precipitate
• Some filter paper may be holed by the precipitate and thus we cannot get
the result of the amount of precipitate, hence the amount of sugar ( * in
table indicated the unknown data)
control
• In this experiment, control is set up by replacing the drinks with distilled
water.
• Having a control can know whether the result have affected by some
environmental factors like temperature.
• To show any precipitate formed is due to sugar presented in drinks
• In this experiment, another control is set up replacing the drinks with 1M
glucose solution in order to carry out a quantitative test
• Through doing quantitative test, we can calculate the amount of sugar
content in each drink
Result of the tasting test
Graph showing the sweetness tasted by different testers
Tester
Average
01
02
03
04
05
06
07
08
09
10
11
★★★
★★★
★★★
★
★★★
★
★★★
★★
★★★
★★★
★★★
★★★
★★
★★★
★★★
★★★
★★★
★★★
★
★★
★
★★★
★
★★
0
★★★
★
★★★
★★
★★★
★★
★★★
★
★★★
★★★
★★★
★★★
★★★
☆
C
Lucozade
★★★
★
★★★
★
★★★
★
★★
★
★★
★★★
★★
★★★
★★★★
★
★★☆
D
Lemon
tea
★★★
★
★★★
★★
★★★
★★★
★★★
★
★★★
★★★
★★
★★★
★
★★★
★★★
★★★
★
★★★
★★
★★★★
★★★
★☆
E
Yakult
★★★
★★★
★★★
★★★
★★★
★★★
★
★★
★★★
★★★
★★
★★★
★★★
★
★★★
★★★
★
★★★
★★★
★
★★★
★★★
★
★★★
★★★
★
★★★
★★★
F
Ginseng
drink
★★★
★
★★
★★★
★
★
★★★
★
★★
★★★
★★★
★★★
★
★★★
★★
★★★
G
Ribena
★★★
★★
★★★
★★
★★★
★
★★★
★★
★★★
★★★
★★
★★★
★★
★★★
★★★
★★★
★★★
★★
★★★
★
H
Slimilk
-
-
-
-
★
-
-
★
-
-
drink
A
Milktea
B
Coffee
@
@
@
-
-
*★ is an arbitrary value(7★= very sweet, 1★= slightly sweet, - =not sweet at all)
**☆ = 1/2 ★
***@ means that tester can state that drink is a ‘less sweet’ formula
Results of Taste test
• The sweetness tasted by testers in descending order
E>D>G>A>B>F>C>H
• The sugar content claimed by nutrition label
E>D>C>G>H>B>F,A
• By comparing two sets of data, taste of testers are not totally
reliable.
• However, we can see that the experimental trend roughly
echo with the claimed one:
E>D>G>B>F
The above trend can be found in both data
Discussion about the tasting test
Discussion – Is human taste is reliable?
The reliability is so-so.
In what way it’s reliable:
1.Most of data of the trend we get echoes with the official one
(E>D>G>B>F)
2.Although the sweetness of Yakult only worth 6stars, 2/3 of the testers agree
that Yakult is ‘7 stars sweet’, which is ‘very sweet’ !. Indeed, it contains 9.1g of
sugar per 100ml, which is very sweet in reality.
Graph showing the tasted sweetness and the actual amount of sugar of drinks
.
Degree of
sweetness
tasted by
testers
Amount of
sugar (in
g/100ml)
milktea
coffee
★★★
★
★★★
☆
6.5
6.8
lucozade
★★☆
9.1
Lemon
tea
Yakult
Ginseng ribena
drink
★★★
★☆
★★★
★★★
★★★
10.9
16.7
6.5
slimilk
★★★
★
-
8.2
7.1
Discussion – Is human taste is reliable?
in what way human taste is unreliable?
1. Comparing coffee and milk tea, the former contains more sugar
than the latter but the former taste less sweet than the latter
2. Comparing milk tea and ginzen drink, they contains same amount
of sugar. However, milk tea tastes sweeter than Ginseng drink
Graph showing the tasted sweetness and the actual amount of sugar of drinks
milktea
coffee
Degree of
sweetness tasted
by testers
★★★
★
★★★
☆
Amount of sugar
(in g/100ml)
6.5
6.8
lucozade
Lemon
tea
Yakult
Ginzen
drink
ribena
★★☆
★★★
★☆
★★★
★★★
★★★
★★★
★
-
10.9
16.7
6.5
8.2
7.1
9.1
slimilk
Discussion – Is human taste is reliable?
in what way human taste is unreliable?
3. Lucozade contains 9.1g of sugar(which is 3rd highest amount of
sugar) but it only tastes like the 2nd least degree in sweetness
4. Slimilk contains 7.1 g of sugar but surprisingly, almost no one can
find out the sweet taste.
Graph showing the tasted sweetness and the actual amount of sugar of drinks
milktea
coffee
Degree of
sweetness tasted
by testers
★★★
★
★★★
☆
Amount of sugar
(in g/100ml)
6.5
6.8
lucozade
Lemon
tea
Yakult
★★☆
★★★
★☆
★★★
★★★
★★★
10.9
16.7
6.5
9.1
Ginseng ribena
drink
slimilk
★★★
★
-
8.2
7.1
Discussion – Is human taste is reliable?
in what way human taste is unreliable?
5.Out of 11 testers, only 2 and 1 can point out the lemon tea or
Ribena they are drinking is a ‘less sweet’ formula respectively.
Graph showing the degree of sweetness of 2 drinks tasted by testers
D
Lemon
tea
★★★
★
G
Ribena
★★★
★★
★★★
★★
★★★
★★★
★★★
★
★★★
★★★
★★
@
★★★
★★
★★★
★
★★★
★★★
★★★
★
★★★
★★
★★★★
★★★
★☆
★★★
★★
★★★
★★★
★★★
★★★
★★
★★★
★
@
★★★
★
@
★★★
★★
★★★
★★★
★★
Discussion – Our interpretation
Let’s go back to the comparisons with milk tea.
Both coffee and ginseng drink contains a natural bitter
taste. Our sense of taste is kind of ‘faked’ by the bitter
Taste.
When comparison is made between bitter drinks and milk
tea (which is not bitter), those bitter ones tastes less
sweet than it supposed to be.
Graph showing the tasted sweetness and the actual amount of sugar of drinks
milktea
coffee
Degree of
sweetness tasted
by testers
★★★
★
★★★
☆
Amount of sugar
(in g/100ml)
6.5
6.8
lucozade
Lemon
tea
Yakult
★★☆
★★★
★☆
★★★
★★★
★★★
10.9
16.7
6.5
9.1
Ginseng ribena
drink
slimilk
★★★
★
-
8.2
7.1
Discussion – our interpretation
Here comes the Lucozade example.
Lucozade contains citric acid and lactic acid. Taste
buds responds to H+ groups of acid and get the sense
of sourness.
Human tongue is ‘faked’ by the sour taste again so
lucozade taste less sweet than it should be.
Graph showing the tasted sweetness and the actual amount of sugar of drinks
milktea
coffee
Degree of
sweetness tasted
by testers
★★★
★
★★★
☆
Amount of sugar
(in g/100ml)
6.5
6.8
lucozade
Lemon
tea
Yakult
★★☆
★★★
★☆
★★★
★★★
★★★
10.9
16.7
6.5
9.1
Ginseng ribena
drink
slimilk
★★★
★
-
8.2
7.1
Discussion – our interpretation
Slimilk contains 7.1g of sugar but it tastes unsweetened at
all!
The reason is, those 7.1g sugar is lactose indeed.
Lactose is a disaccharide making up 2-8% of milk
which only possesses a subtle sweet taste.
So only those supertaster (very sensitive ones) can
sense the sweetness of lactose
Graph showing the tasted sweetness and the actual amount of sugar of drinks
milktea
coffee
Degree of
sweetness tasted
by testers
★★★
★
★★★
☆
Amount of sugar
(in g/100ml)
6.5
6.8
lucozade
Lemon
tea
Yakult
★★☆
★★★
★☆
★★★
★★★
★★★
10.9
16.7
6.5
9.1
Ginseng ribena
drink
slimilk
★★★
★
-
8.2
7.1
Research – why human taste is
unreliable
• Let’s be clear about the following terms:
Flavor and Taste.
• Taste is the signal received by taste bud in
respond to chemical in the food. It will be
transmitted to the brain
• Flavor is the overall impression of how the
food ‘tastes like’, affected by smell, sight and
many other factors.
Research – why human taste is
unreliable
• Approximately 80-90% of what we perceive as
"taste" actually is due to the sense of smell.
• With out smell, we can only taste 5 basic
tastes: bitterness, saltiness, sourness,
sweetness and Savoriness, which is the taste
produced by amino acids such as glutamate
Research – why human taste is
unreliable
• The brain interprets signals from taste, smell and
even vision before turning them into an impression
of the food's taste, known as flavor.
• These senses play an important role in precepting flavor:
• Sight: an unsweeten soda water with artificial
orange color added might tastes like an genuine
orange soda
• Pain: the spicy and hot taste of chili is actually a
sense of pain
Research – why human taste is
unreliable
• Chewing helps to transfer odour from the
mouth to the back of the nose.
• The area which is sensitive to smell is located
at the back of the nose where several million
receptor cells per square centimetre respond
to thousands of chemicals in the food.
Research – why human taste is
unreliable
• To conclude, the flavor we percept is affected by a
bunch of factors including pain, smell, action of
chewing,etc.
• As our testers are in normal health status, their
sense of smell is valid. So that the sweetness of drink
they taste is affected by their own smell.
• Also, other component of taste like bitterness in
ginseng drink also affect the perception of
sweetness.
conclusion
• yakult contains the most amount of sugar,
following is vita lemontea(less sweet),
lucozade(original),ribena(less sweet),
Kowloon dairy hi-calcium slim milk,
Nescafe(rich),nestle milk tea and hung
fook tong American ginzen with honey
drink, in which nestle milk tea and hung
fook tong American ginzen with honey
drink contains the same amount of sugar.
Conclusion(2)
• Respondents find yakult(E) contains the most
amount of sugar, followed by lemon tea(D), and milk
tea(A) and ribena (G)(same value for milk tea and
ribena). Next comes coffee(B) and gizen drink(F).
Then is lucozade(C). People find slim milk(H) contains
no sugar at all.
A
B
C
D
E
F
g
h
Benedic 4
t's test
5
7
2
1
6
3
8
Tasting
6
3
2
1
8
4
5
7
Key: 7- least sweet,1- most sweet
application1
• As one cannot notice any difference between the ‘less
sweet’ formula and the ‘original flavor’ flavor of drink,
‘less sweet’ drinks are suggested to buy.
• Sugars may be added to foods to make them more
palatable and are found in calorie-rich foods, which
may lead to a higher calorie diet, excess weight and
cavities.
• This is why most nutrition experts recommend limiting
added sugars (excluding fruit and milk) to 40 grams per
day or 10 teaspoons (4 grams is in one teaspoon).
• Total sugar content is easily identifiable on the
Nutrition claim on the back of processed foods.
application2
• High intake of added sugars is implicated in numerous poor health
conditions, including obesity, high blood pressure and other risk
factors for heart disease and now it may lead to premature aging.
• sugar molecules have been shown to damage collagen. Since we
naturally lose collagen as we age, the logical idea is to do whatever
we can to prevent damaging it faster than needs be to prevent
premature aging.
• sugar contribute to deplete collagen levels in our body,
• that depletion leaves your skin more vulnerable to sun damage.
• So if you eat a lot of sugar, chances are that the molecules will stick
to your collagen fibers and bind them together, hence creating
dangerous toxins that reduce your skin’s elasticity and flexibility
which is associated with younger and healthier skin.
application3
• Sugar content should not be the only concern
while choosing drinks.
• Other ingredient, like carbohydrate, also
contribute to the energy value
• Please do concern the energy value on the
nutrition label too
Application-4
• According to our tasting test, although the
sense of human is not totally reliable, it still
roughly cohere with the true sweetness
• we can rely on our own sense to determine
the drink with least sugar in a restaurant (as
nutrition label is never provided in a
restaurant)