Vitamin C content in fruit juices

Please read either from Hands on Pg 55 /the sample experiment plan given below :

Objective	To determine the vitamin C content in pineapple, lime and orange juice.
Problem statement	Which fruit juice contains the highest concentration /percentage of vitamin C?
Hypothesis	Lime juice contains higher concentration/percentage of vitamin C compared to pineapple juice and orange juice.
Variables	Manipulated : Types of fruit juice
	Responding : Concentration/percentage of vitamin C in fruit juices
	Constant : Volume of fruit juices/concentration of DCPIP solution/ Standard concentration of ascorbic acid solution
Apparatus and materials	Materials : freshly prepared pineapple, lime and orange juices, 0.1% ascorbic acid solution, DCPIP solution Apparatus : 5ml syringe(with needle), 1ml syringe, specimen tubes, 5ml measuring cylinder
Technique	Measure and record the volume of fruit juice needed to decolourise 1 ml DCPIP using a syringe// Calculate the % of vitamin C in fruit juice by using formula : Vol of 0.1% ascorbic acid X 0.1 Volume of fruit juice OR Calculate the content of vitamin C in fruit juice by using formula : Vol of 0.1% ascorbic acid (mgcm-3) Volume of fruit juice
Procedure	1. 1 ml of DCPIP solution is placed in a specimen tube using a 1 ml syringe. 2. 5 ml syringe was filled with 5 ml of 0.1% ascorbic acid solution. 3. The needle of the 5 ml syringe was immersed into the DCPIP solution. 4. Ascorbic acid solution was added drop by drop until the DCPIP solution, and gently stirred with the needle of the syringe. (Do not shake the tube vigorously). 5. Ascorbic acid solution is added continuously until the DCPIP solution is decolourise. 6. The volume of ascorbic acid solution used measured using a syringe and recorded. 7. Steps 1-6 are repeated using fresh orange, pineapple and lime juice. 8. The volume of fruit juices required to decolourise the DCPIP solution in each fruit juice is measured using a syringe and recorded in a table. 9. The percentage and the concentration of vitamin C in each fruit juice are calculated using the above formula. Precaution: 1. The juice must be freshly prepared. 2. Do not shake the DCPIP too vigorously.
Recording data/ result	Solution/ fruit juice Volume of solution/fruit juice needed to decolourise 1 ml of DCPIP solution (ml) Percentage of vitamin C (%) Conc. of vitamin C (mg cm-3) 1 2 3 Average 0.1% ascorbic acid Pineapple juice Lime juice Orangejuice
Conclusion	Lime juice contains higher concentration/percentage of vitamin C compared to pineapple juice and orange juice. Hypothesis is accepted.