Real World: Vitamin C Concentration in Orange Juice and Grapefruit

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Cannot be stored in
body, needs to be
replenished regularly
 Promotes healthy cell
development, normal
tissue growth and
repair, and helps in
absorption of calcium.




Vitamin C is lost in
foods easily, so it is
best to eat fruits and
vegetables in raw form
Scurvy -disease
caused by lack of
vitamin C
It’s an antioxidant,
helps protect body
against contaminants





DCPIP(2,6 – dichlorophenol-indophenol) can be used
as an indicator for ascorbic acid.
DCPIP turns clear when it is oxidized by the orange
juice. When there is excess DCPIP, it no longer turns
clear and dyes the sample purple.
1% DCPIP solution added to juice until color change
occurred
The amount of DCPIP added was recorded
Taking into account the amount of vitamin C there
should be in the juice based on daily value, the
theoretical and actual values of Vitamin C were
calculated

Theoretical
› Total volume of
container
› Amount of servings
› 100% daily value
› Volume of juice
used

Experimental
› 1% DCPIP solution
› mL of DCPIP added,
gives grams of
DCPIP
› 1:1 mol ratio
Theoretical:
Theoretical grams of Vitamin C X Servings= grams vitamin C per bottle
Fresh Squeezed Orange Juice:
0.124g X 2 servings=0.248g vitamin C per bottle
Experimental:
Total volume in bottle/volume added=theoretical grams vitamin
C/grams vitamin C in sample
Fresh Squeezed Orange Juice:
473mL/10.31mL=0.248g/x
X=0.0055g
Juice
Juice
Orange
Orange Juice
Juice Conc.
Conc.
(10
mL)
(10 mL)
Orange
Orange Juice
Juice Freshly
Freshly
Squeezed
Squeezed
(10
(10 mL)
mL)
Grapefruit
Grapefruit Juice
Juice Conc.
Conc.
(25
(25 mL)
mL)
Grapefruit
Grapefruit Juice
Juice Freshly
Freshly
Squeezed
Squeezed
(25
(25 mL)
mL)
Average
Average (mL)
(mL)
Vitamin
Vitamin C
C
Theoretical
Theoretical (g)
(g)
Vitamin
Vitamin C
C
Actual
Actual (g)
(g)
0.90
0.90
0.00254
0.00254
0.00591
0.00591
3.40
3.40
0.01310
0.01310
0.02230
0.02230
2.33
2.33
0.00630
0.00630
0.01530
0.01530
2.53
2.53
0.00990
0.00990
0.01660
0.01660
In all juices, there was almost double the
theoretical amount of vitamin C
 Reason?

› Companies want to make sure that they
have at least the amount of vitamin C in
their juice that they claim
› Too much is not a bad thing

25mL of juice samples were titrated with an iodine
solution until the endpoint was reached. A 1% starch
indicator was used as the indicator

The amount of vitamin C was calculated and
compared based on daily values for each juice
Fresh Squeezed Orange Juice
Trial One
Trial Two
Trial Three
Total mL iodine
added
10.41mL
10.27mL
10.24mL
Grams of
vitamin C
0.0055g
0.0054g
0.00537g
Orange Juice from Concentrate
Trial One
Trial Two
Trial Three
Total mL iodine
added
7.11mL
7.19mL
7.34mL
Grams of
vitamin C
0.00180g
0.00182g
0.00186g
Fresh Squeezed Grapefruit Juice
Trial One
Trial Two
Trial Three
Total mL iodine
added
7.14mL
7.24mL
7.33mL
Grams of
vitamin C
0.00283g
0.00287g
0.00291g
Grapefruit Juice from Concentrate
Trial One
Trial Two
Trial Three
Total mL iodine
added
7.38mL
7.11mL
7.24mL
Grams of
vitamin C
0.00187g
0.00181g
0.00184g
Fresh squeezed orange juice has the
highest Vitamin C concentration
 Fresh squeezed juices have a higher
vitamin C concentration than juice from
concentrate

3 samples of each juice were titrated
with standardized NaOH
 pH level were measured each addition
of NaOH
 Calibration curve were made
 pH calculated for each juice

› Used the curve to estimate equivalence
point
› Another way: change in volume vs. pH
mL of base added vs. pH
Orange Juice (conc.) Trial #1
11.5
10.5
9.5
pH
8.5
7.5
6.5
5.5
4.5
3.5
0
3
6
9
12
15
18
21
24
Amount Added (mL)
27
30
33
36
39
mL of base added vs. pH
Orange Juice (Freshly Squeezed) Trial #1
11.5
10.5
9.5
pH
8.5
7.5
6.5
5.5
4.5
3.5
0
3
6
9
12
15
18
21
24
Amount added (mL)
27
30
33
36
mL of base added vs. pH
Grapefruit Juice (conc.) Trial #1
10.5
9.5
8.5
pH
7.5
6.5
5.5
4.5
3.5
2.5
0
4
8
12
16
20
24
28
mL NaOH added
32
36
40
44
mL of base added vs. pH
Grapefruit Juice (Freshly Squeezed)
Trial #1
11.5
10.5
9.5
pH
8.5
7.5
6.5
5.5
4.5
3.5
0
4
8
12
16
20
24
28
32
mL NaOH added
36
40
44
48
Orange Juice
(Conc.)
Orange Juice
(Fresh Squeezed)
pH
Total
Acidity
E.P.
(mL)
pH
Total
Acidity
23.26
8.00
-
23.50
8.25
-
Trial 2
23.60
8.40
-
22.50
8.10
-
Trial 3
23.40
7.50
-
22.80
7.82
-
Average
23.42
7.97
0.0963M
22.93
8.06
0.0943M
E.P.
(mL)
Trial 1
Grapefruit Juice
(Conc.)
Grapefruit Juice
(Fresh Squeezed)
E.P.
(mL)
pH
Total
Acidity
E.P.
(mL)
pH
Total
Acidity
Trial 1
35.50
7.00
-
38.00
8.36
-
Trial 2
36.50
7.20
-
37.40
8.60
-
Trial 3
37.20
6.90
-
37.40
8.50
-
Average
36.40
7.03
0.1497 M
37.60
8.49
0.1546M

Freshly squeezed juices had a higher pH
than the juices from concentrate

Grapefruit juice more exaggerated
relationship

Freshly squeezed juices are more acidic
 All
experiments showed that
freshly squeezed juices had more
vitamin C
 Two
of three: orange juice had
most
DCPIP
Juice
Average (mL)
Vitamin C Theoretical
(g)
Vitamin C Actual
(g)
Orange Juice Conc. (10 mL)
0.90
0.00254
0.00591
Orange Juice Freshly Squeezed
(10 mL)
3.40
0.01310
0.02230
Grapefruit Juice Conc. (25 mL)
2.33
0.00630
0.01530
Grapefruit Juice Freshly Squeezed
(25 mL)
2.53
0.00990
0.01660
Iodine Titration
Juice
Average (mL)
Vitamin C Theoretical
(g)
Vitamin C Actual (g)
Orange Juice Conc.
7.21
0.00180
0.001827
Orange Juice Freshly
Squeezed
10.31
0.0055
0.00542
Grapefruit Juice Conc.
7.24
0.00187
0.00184
Grapefruit Juice Freshly
Squeezed
7.24
0.00283
0.00287




http://www.fitnesshealthzone.com/vitaminssupplements/importance-of-vitamin-c/
http://www.practicalbiology.org/areas/advan
ced/health-and-disease/whats-in-ourfood/measuring-the-vitamin-c-content-offoods-and-fruit-juices,53,EXP.html
http://en.wikipedia.org/wiki/Dichlorophenolind
ophenol
http://www.google.com/#sclient=psy&hl=en&
q=Determination+of+the+Total+Acidity+in+Ora
nge+Juice&aq=f&aqi=&aql=&oq=&gs_rfai=&p
bx=1&fp=fae64975a117d0cd

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