LABORATORY 4

LABORATORY REPORT

SBK3033 FOOD SCIENCE

TITLE OF EXPERIMENT: LABORATORY 4 VITAMIN C ANALYSIS

LECTURER: DR HASIMAH ALIMON

GROUP: A

GROUP MEMBERS:

MOHAMAD HARITH BIN SULAIMAN	D20141067083
SHARIFAH AWANIS BINTI SYED MOHD ASWAD	D20141067053
MAUREEN SANTIH ANAK AMBANG	D20141067070

RESULTS

Tube	Liquid	Volume needed to decolourize DCPIP (ml)
1	0.1% ascorbic acid	1 drop x 0.05     = 0.05
2	Fresh lemon juice	3 drops x 0.05   =0.15
3	Orange squash	2 drops x 0.05   =0.10
4	Canned or bottled orange juice	4 drops x 0.05   =0.20
5	Pineapple	3 drops x 0.05   =0.15
6	Pumpkin	43 drops x 0.05 =2.15
7	Papaya	2 drops x 0.05   =0.10
8	Orange juice that has stood in an open beaker for 3 days	3 drops x 0.05   =0.15

DISCUSSION

The juices is added until the blue colour of DCPIP  disappear, and the volume needed to decolourize DCPIP is noted. This volume is equivalent to the amount of Vitamin C present in the solution. When DCPIP is added into vitamin C solution, the vitamin C reduces the DCPIP, then, decolorizes the blue colour of DCPIP. The decolourization of DCPIP indicates the presence of Vitamin C.

0.1% ascorbic acid has the most Vitamin C because it only required a drop or 0.05 ml of ascorbic acid to decolourize the DCPIP solution. Then, it is followed by orange squash and papaya which required only 2 drops or 0.10 ml of each solution to decolourize the DCPIP. Fresh lemon juice, pineapple and orange juice that has stood in the open beaker for 3 days required 3 drops or 0.15 ml each to decolourize the DCPIP. Another liquid that we used is canned or bottled orange juice which required 4 drops 0r 0.20ml of the solution to decolourize the DCPIP. Lastly, pumpkin solutions need the most volume to decolourize the DCPIP which are 43 drops or 2.15ml. But, the DCPIP does not decolourize completely as they turned to yellow in colour. This is because the pumpkin has low amount of Vitamin C.

The higher the concentration of vitamin C, the less volume is needed to fully decolourise the DCPIP solution. Ascorbic acid has a very high level of vitamin C, so the concentration is sufficient to react fully with DCPIP in small volumes. Pumpkin solutions contain much less vitamin C, so we need more to decolourize the DCPIP. Note that some solutions may be very acid, in which case the colour of the DCPIP becomes pink or magenta such as fresh lemon juice, orange squash and pineapple.

CONCLUSION

The higher the concentration of vitamin C in the solutions, the less volume is needed to  decolourise the DCPIP solution. Ascorbic acid has very high concentration of Vitamin C, followed by orange squash, papaya, fresh lemon juice, pineapple and canned or bottled orange juice. Pumpkin has the less amount of Vitamin C.