Various Factors in the Preparation and cooking of Fruit and Vegetables Essay Example for Free

Various Factors in the Preparation and cooking of Fruit and Vegetables Essay Pilot Method 1. Use a syringe (or Measuring Cylinder for measuring equal amounts) and pour out 10ml of DCPIP (Solution used to detect Vit.C) into a small beaker. 2. Using a separate Syringe, draw up 10ml of solution 0.1% Vitamin C 3. Slowly add the Vit.C into the DCPIP solution beaker, swirling around a few times. (swirling helps solutions to mix) 4. Continue to add the Vit.C until DCPIP turns a permanent straw colour. 5. Note the amount of Vit.C it took to change the colour of the DCPIP. 6. Repeat steps 1-5 5 3 times and take an average. Pilot Results Strength of DCPIP X Volume = Volume of Vit.C x Strength )( x 10ml = 8.5ml x 0.1% )( = 6ml x 0.1% 10ml Strength of DCPIP = 0.06 Strength of DCPIP X Volume = Volume of Vit.C x Strength )( x 10ml = 6ml x 0.1% )( = 6ml x 0.1% 10ml Strength of DCPIP = 0.06 Strength of DCPIP X Volume = Volume of Vit.C x Strength )( x 10ml = 6ml x 0.1% )( = 6ml x 0.1% 10ml Strength of DCPIP = 0.06 Average Strength of DCPIP = 0.06 Method 1. Using a Syringe (or measuring cylinder) put 10ml of DCPIP into a small beaker. 2. Using a separate syringe, take up 10ml of Juice (Juices will change per experiment) 3. Slowly add the juice a little at a time until the DCPIP turns a permanent straw colour. 4. Make sure 1oml is used at all times as to keep it a fair test at all times. 5. Repeat experiment 5 times on each of the 4 different Juices chosen and take an average one completed. 6. Put all recordings and measurements in a chart, and using the Equation below finding the strength of the Vit. C in each Juice type (Strength of DCPIP taken from Pilot experiment) Strength of DCPIP X Volume = Volume of Vit. C x Strength Results Juice 1 = Ascorbic Acid. (Pure Vitamin C) Juice 2 = Orange Juice. (Smooth) Juice 3 = Pure Orange with Mango Pure. Juice 4 = Orange and Grapefruit. Juice Type J1 J2 J3 J4 Exp. No. 1 7.5 ml 14ml 14ml 12.5ml 2 8 ml 13 ml 14 ml 13 ml 3 8 ml 13 ml 14.4 ml 12.5 ml 4 8 ml 13 ml 14 ml 12.5 ml 5 8 ml 13.5 ml 14 ml 13 ml Average 8 ml 13.5 ml 14 ml 13 ml Ascorbic Acid (J1) Strength of DCPIP x volume = Strength of Vit. C x Volume 0.06 x 10ml = )( x 8ml )( = 0.06 X 10ml 8ml Strength of Vitamin C = 0.075 Orange Juice Smooth (J2) Strength of DCPIP X Volume = Strength of Vit. C x Volume 0.06 x 10ml = )( x 13ml )( = 0.06 x 10ml 13ml Strength of Vitamin C = 0.046 Pure Orange with Mango Pure (J3) Strength of DCPIP x Volume = Strength of Vit. C x Volume 0.06 x 10ml = )( x 14ml )( = 0.06 x 10ml 14ml Strength of Vitamin C = 0.042 Orange and Grapefruit (J4) Strength of DCPIP x Volume = Strength of Vit C x Volume 0.06 x 10ml = )( x 13ml )( = 0.06 x 10ml 13ml Strength of Vit C = 0.046 Results The graph shows that the Orange and Grapefruit Juice had the highest concentration of Vitamin C. Compared with the other Juices (excluding juice one as it is pure Vitamin C) it takes less of this Juice to turn the DCPIP straw coloured (an average of 13ml). In comparison to the others there was not much difference between them all. The Pure Orange Juice with Pure Mango took an average of 14ml to turn the DCPIP straw coloured. After doing some research on the Vitamin content on different fruits, it was seen that both mangos and grapefruits, Mangos and Oranges are excellent vitamin C sources. Fruit Latin name mg vitamin C / 100 grams mg vitamin C per average size fruit/slice* Ranking Grapefruit Citrus paradisi 34 44* excellent Mango Mangifera indica 28 57 Excelent Orange Citrus sinenis 53 70 Excellent * The values are for one whole fruit, however not many would eat a whole medium sized watermelon at a sitting, so for these larger fruit the value is for a slice, a slice being, very generally, about an eighth of a medium sized fruit, or a quarter of a smaller fruit. In the particular case of lemon and lime, the slice value is juice of one wedge. For a few small fruit, such as Kei apple, the ranking is adjusted upward where the fruit mg/100 gram analysis shows it has large amounts of vitamin C, but the small size of the fruit gives it a lower per fruit vitamin C content. You are likely to eat more than one at a serving. In the case of tiny fruit, like red or black currants, a lot more, but probably still only 20-30 raw fruit, especially if they are a bit acid.. The chart states that Mangos have a higher Vitamin C level than Grapefruits implying that the results should have been the other way around with the Orange and Mango Juice having more Vitamin C present. However it could be due to the preparation process that has taken an effect on the amount of Vitamin C present. Vitamin C is a particularly fragile vitamin and is easily destroyed when in contact with oxygen in the air or if it is exposed to light. The vitamin C content of sliced, cut or bruised fruit and vegetables diminish rapidly when such foods are left standing. Freshly squeezed orange juice will lose half of its vitamin C content by the next morning. Vitamin C is one of the least stable vitamins, and cooking can destroy much of this water-soluble vitamin from foods. Vitamin C is a weak acid and is stable in weak acids. Alkalis, such as baking soda, however, destroy ascorbic acid. It is also easily oxidized in air and sensitive to heat and light. Since it is contained in the watery part of fruits and vegetables, it is easily lost during cooking in water. Evaluation The experiment went very well in that that the investigation was carried out in a safe and efficient way. The investigation was planned to produce an out come showing the strength of Vitamin C concentrations in different Juice types. This was done and a conclusion was gathered showing what was being looked for. In hindsight it was seen that the calculation could have caused problems in the reliability of the results. All the calculation were done with one main equation. However if there was any point were the calculations were not dome properly it would mean that the given numbers would not have been correct. Also, the calculator did not round up decimals; therefore figures given would have been dependant on if the numbers were rounded up or not. Making sure that the same method was used at all stages could have rectified this. This would have ensured that all the figures were reliable. Another problem that could have caused results to be unreliable is the readings that were taken. The syringes that were used had markings that went up in 5s. Its possible that the reading were not done very accurate and not made at their actual point. If this problem were consistent all of the readings would have been inaccurate. By having the same person doing the readings and also having used a syringe that has more reading points would have made them more accurate in that the individual points would have been easier to read. Another possible problem that was seen was the fact that the aim was to look for colour changes. It would not have been able to come to a sure conclusion of what was straw colour and what was not. It would have not been able to come to a sure mark of straw coloured. There would not no real solution to this problem as it would be dependant on the person. The only solution that could minimise this problem would be to have the same person making the judgments, as their perception of Straw coloured would be the same. Apart from the above points the investigation was went well and was carried out smoothly. The team were able to conclude the investigation with the use of gained figures and reactions.