Chemistry Viva

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Group member: Group member: 1. 1. Aileen See SiouNing Aileen See SiouNing 2. 2. Chiew Jin Fang Chiew Jin Fang 3. 3. Oon Khai Shian Oon Khai Shian 4. 4. Ting Shue Kien Ting Shue Kien

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Transcript of Chemistry Viva

  • Group member: Aileen See SiouNingChiew Jin FangOon Khai ShianTing Shue Kien

  • EFFICIENT METHOD TO PRESERVE THE CONTENT OF VITAMIN C IN FRUITS.Objective: determine the efficient method to preserve the content of vitamin C in three types of freshly squeeze fruit juices (orange, lime and lemon) using pH meter. comparing vitamin C content based on different temperature.

  • Different conditions (room temperature, in oven, in cold and under sunlight) can get different concentration of vitamin C content.Method: using pH meter with buffer solution.Results:

    The best way to preserve the content of vitamin C (pH value) is in cold condition

    Types of juiceOrangeLimeLemonTemperature, C171719pH value4.73.73.9

  • Ascorbic acid ( vitamin C ) is a carbohydrate-like substance involved in the metabolic functions.Vitamin C is a colourless, white or almost white crystal , odourless or almost odourless.It is water soluble which give out pH value of 2.2 2.5.Vitamin C is an essential nutrient in human diets, and necessary to maintain connective tissue and bone.Vitamin C is easily oxidized. Vitamin C can be easily destroyed under the exposure to oxygen, metals, light and heat.Experiment is carried out to find out the best way and condition to preserve and conserve the vitamin C.In this experiment, the pH value is taken as the measured unit as the vitamin C is acidic and can be measured by using the pH meter.This experiment indicates that the lower the pH value the higher the content of vitamin C and the higher the pH value, the lower the content of vitamin C.

  • 2.0 Problem Statement1 ) What is the condition that is suitable for the preserve and conserve of the vitamin C content in freshly squeeze juice?

    2 ) Does the temperature a factor that causes changes in the content of vitamin C? 2.1 Hypothesis1 ) The vitamin C content in freshly squeeze juice can be preserved and conserved in the condition of cold and dry places.

    2 ) The vitamin C content is deteriorate in the condition of high temperature in a faster rate.

  • 3.0 Material and Apparatus

  • 4.0 PROCEDURE

  • Initial pH value.Sunlight, refrigerator and heat with microwave.

  • 5.0 RESULT AND DISCUSSION

    Condition Type of fresh fruit juiceInitialReading / R.T Final reading / Temperature OvenUV lightR.TColdpHCpHCpHCpHCpHCOrange4.4286.9386.8326.5304.719Lemon4.0285.5384.8324.7303.719Lime4.7285.0385.7325.1303.917R.T Room Temperature

    Chart1

    4.444.7

    6.95.55

    6.84.85.7

    6.54.75.1

    4.73.73.9

    Orange

    Lime

    Lemon

    Sheet1

    OrangeLimeLemon

    Initial4.44.04.7

    Oven6.95.55.0

    UV light6.84.85.7

    Room Temperature6.54.75.1

    Cold4.73.73.9

    To resize chart data range, drag lower right corner of range.

  • 5.1 OBSERVATION

    The best condition to preserve the acidity of fresh fruit juice is at cold condition.

    pH value for orange juice and lime juice are 4.7 and 3.7 at 17 C.

    For lemon juice, the pH value is 3.9 at 19 C.

    Enzymes are less active at low temperature.

  • 5.2 DISCUSSION

    Thermometer is used to determine the best condition to preserve the maintenance of pH value. pH value is related to the content of vitamin C. Thus, enzyme is sensitive to pH change.pH is measured by the concentration of hydrogen ions using the formula pH = -log[H+]. For orange juice and lemon juice, the increase in temperature will directly increase the pH value. But, it has almost maintained its pH value at low temperature. For lime juice, it has a little difference in its pH value as we use the fresh lime and ripe lime which have different concentration. Thus, the pH value of lime juice is unstable if the temperature increases or decreases.low temperature (cold) is the best condition to preserve the content of vitamin C.

  • 5.3 RECOMMENDATION

    The best way to preserve the content of vitamin C (pH value) is in cold compare to oven, UV light and room temperature.

    we should store the fresh juice in refrigerator to maintain the pH value.

  • The best condition to preserve the acidity of fresh fruit juice is at cold condition.High temperature, the enzyme activity more active, the rate of reaction increase, vitamin C content deteriorate in a faster rate.The lower the temperature, the higher the maintenance of acidity in pH value.