“Citric Acid Levels in Commercial & Freshly Squeezed Lemon Juice” BY: SERENA GOVENDER Yr10 Question: To investigate the citric acid levels in commercial and freshly squeezed lemon juice Change: Type of Lemon Juice Why I Chose This Topic: I chose this topic because I was interested in investigating the level of citric acid in commercial and freshly squeezed lemon juice in order to compare results and suggest theories and ideas about what increases or decreases the acidity of the lemon juice and why?? (Temperature, adding chemicals/preservatives etc…) Reasons that might affect the acidic levels: -Temperature -Adding chemicals/ preservatives -Same amount of lemon juice each REPEAT 3X-TRAILS Measuring: Citric acid- Digital Ph Scale & Tapes *5-8 types of lemon juice -3: freshly squeezed -3-6: commercial Lemon Juice: -commercial -freshly squeezed “Citric Acid Levels in Lemon Juice” -FRESHLY SQUEEZED -COMMERCIAL Relevant Information: * Freshly squeezed lemon juice contains about 1. 44 and 1. 38g/oz * Commercial lemon juice contains about 0. 03 to 0. 22g/oz * Lemon contains about 5-6% *
Reasons that affect the acidity of the lemon juice: Temperature (boiling or freezing <storage> -decrease) -Adding chemicals/preservatives (depends on what chemicals added)-result: decrease -Adding water (decreases and dilutes the acidity) -Depending how ripe the lemon is (riper the lemon=less sour therefore it would be higher (less acidic), lemon not ripe=sour therefore the acidic level would be lower (more acidic) -How old/time?? -If the commercial lemon juice was opened and left out -light (not a huge decrease) -ascorbic acid (higher content of vitamin C) -Material the lemon juice is contained in -Storage (room temperature, heat, freezer etc…) added different acidic liquids e. g. vinegar, lime etc… * Measuring: Acidic levels –Digital pH scale + tapes * http://www. livestrong. com/article/296959-what-are-the-benefits-of-lemon-juice-on-the-skin/ -Usefulness Other Ideas to Investigate: * Investigating how temperature affects the acidity of the liquid/lemon juice?? * How light affects the acidity?? * By adding chemicals does it increase or decrease the acidity?? & why?? * Investigating what liquid has the highest or lowest acidity & why?? -test: vinegar etc… * How to decrease the acidity of the liquid/lemon juice?? E. . water, adding chemicals * How does lemon juice react with other chemicals?? * How does the time or how old it is affect the acidity of the liquid/lemon juice?? *
Investigate the acidic levels between a lemon and a lime * Investigate the acid levels of lemons which are ripe and not Aim: To investigate the citric acid levels in commercial and freshly squeezed lemon juice Hypothesis: The acidity in the freshly squeezed lemon juice will have a lower pH as it is more acidic than the commercial lemon juices. Equipment/Materials: * 3 lemons * 5 commercial lemon juices -PLJ Lemon Juice Golden Crown Lemon Juice -ReaLemon, 100% lemon Juice -Berri Lemon Juice -Sunshine Lemon Juice * Digital pH Scale and Tapes * Labels * 8 Drinking Glasses * Safety Glasses Variables : * Independent Variable : lemon juice (Commercial and Freshly Squeezed) * Dependent Variable : Citric acid levels which will be measured by a Digital pH Scale and Tapes * Controlled Variables : Same amount of lemon juice into each glass, same pH scale and tapes Method: 1) Collect Equipment 2) Set up equipment 3) Label each glass according to the type of lemon juice that is going to be poured in.
Example: G1: Berri Lemon Juice etc… 4) Pour equal amount of lemon juice into each glass (about 15ml) but make sure each glass consists of different brands or types of lemon juice (commercial and freshly squeezed). 5) Place the Digital pH Scale into glass 1 and record the result. This will tell you the power/strength of the acid in that certain type of lemon Juice and how acidic it is. 6) Then insert a pH tape into the same lemon juice. Ensure the tape is placed in the lemon juice. Finally, remove the tape and record the colour that appears.
This would confirm it is an acid as it would be closer to 0 and would give an average of where it sits on the pH scale and how acidic it is. 7) Remove the Digital pH scale and rinse/wash it in order to prepare for the next test and to make it a fair test. | Trail 1:| Trail 2:| Trial 3:| | | | | Type/Brand:| PH:| Colour:| pH:| Colour:| pH:| Colour:| Average pH & colour:| Acid:Yes/No| Higher pH=Less acidicLower pH=more acidic:| Ranking:| G1: Berri Lemon Juice| | | | | | | | | | | G2: Sunshine Lemon juice| | | | | | | | | | | G3: PLJ Lemon Juice| | | | | | | | | | |
G4: Golden Crown Lemon Juice| | | | | | | | | | | G5:ReaLemon (100% lemon juice)| | | | | | | | | | | G6: Lemon 1| | | | | | | | | | | G7: Lemon 2| | | | | | | | | | | G8: Lemon 3| | | | | | | | | | | 8) Complete the same method for each type/brand of lemon juice and record the results in the table below 9) Complete experiment trails, 3 times and record results for an accurate and fair test G6: Lemon 1 G5: Realemon Juice G4:Golden Crown Lemon Juice G3: PLJ Lemon Juice G2:Sunshine Lemon Juice G1: Berri Lemon Juice Method set up: Pure/Freshly Squeezed Lemon Juice Commercial Lemon Juice Labels Digital pH Scale Drinking Glass pH tapes 5ml of Lemon Juice in each glass (each glass contains a different type/brand of lemon juice-commercial and freshly squeezed) G8: Lemon 3 G7: Lemon 2 Pure/Freshly Squeezed Lemon Juice Predicted results: I predict that the freshly squeezed lemon juice will have a lower pH therefore it will be more acidic than the commercial which will have a higher pH therefore it will be less acidic and closer to neutral. I think this because by adding chemicals/preservative to the lemon juice and storing in the freezer for a long time, it would drop the acidity whereas a fresh lemon would be higher as it is fresh and chemicals are not added to it. Trail 1:| Trail 2:| Trail 3:| | | | | Type/Brand:| pH:| Colour:| pH:| Colour:| pH:| Colour:| Average pH & Colour:| Acid/Base/Neutral:| Higher pH=Less acidic (Approx 3-4)Lower pH=more acidic (approx 2-3):| Ranking (most acidic to least acidic):| G1: Berri Lemon Juice| 3. 8| light orange| 3. 8| light orange| 3. 8| light orange| 3. 8Light orange| ACID | HIGHER-Less acidic| 7| G2: Sunshine Lemon Juice| 3. 3| Medium light orange| 3. 3| Medium light orange| 3. 3| Medium light orange| 3. 3Medium light orange| ACID| HIGHER-Less acidic| 5| G3: PLJ Lemon Juice| 3. | light orange| 3. 7| light orange| 3. 7| light orange| 3. 7LightOrange| ACID| HIGHER-Less acidic| 6| G4: Golden Crown| 4. 1| Light light orange| 4. 1| Light light orange| 4. 1| Light light orange| 4. 1LightLightOrange| ACID| HIGHER-Less acidic| 8| G5: Realemon, 100% Lemon Juice| 2. 9| Dark orange| 2. 9| Dark orange| 2. 9| Dark orange| 2. 9Dark orange| ACID| HIGHER-Less acidic| 4| G6: Lemon 1| 2. 6| Dark Orange/red| 2. 6| Dark Orange/red|
2. 6| Dark Orange/red| 2. 5Dark Orange/red| ACID| LOWER -More acidic| 3| G7: Lemon 2| 2. 2| Dark Orange/red| 2. | Dark Orange/red| 2. 2| Dark Orange/red| 2. 2Dark Orange/red| ACID| LOWER-More acidic| 2| G8: Lemon 3| 2. 1| Dark Orange/red| 2. 1| Dark Orange/red| 2. 1| Dark Orange/red| 2. 0Dark Orange/red| ACID| LOWER-More acidic| 1| Results: Amount of lemon Juice Results: Conclusion: I was successful in investigate the citric acid levels in commercial and freshly squeezed lemon juice and as my results have confirmed that the freshly squeezed lemon juice had a lower pH therefore it is more acidic than the commercial lemon juices, which had a higher pH. Usefulness: Its useful to chefs as it lets them know how acidic commercial and freshly squeezed lemon juice are and therefore they can use it appropriately in order to give flavour or sourness to their foods and how much would be required to give them that taste. Also they need to know how acidic it is because if it is too strong they would need to dilute it. -People would be able to identify the difference between commercial and freshly squeezed lemon juice and also how pure the lemon juice is. This is vital in getting the right number of vitamins and minerals from the lemon juice. -If it is too strong, it needs to be diluted. You would be able to see how pure the lemon juice is due to its pH and if any artificial preservatives or chemicals have been added. -You would be able to identify the difference between commercial and freshly squeezed lemon juice. -It is useful to people who have acne as it dries the excess oils in the skin therefore reducing the amount of acne breakouts on the surface of the skin. It can also reduce redness and can brighten your skin tone -Medical benefits as it is high in vitamin C and potassium -Lemon juice can take away the bitterness from a bitter melon -You can remove callouses with lemon Juice -Useful for bleach for clothing It helps neutralize odors -It kills head lice -It reduces bloating -Diffuses boils and abscesses -It may be helpful to the liver -It reduces Cholesterol as it burns the fat -Lemon juice is good for menopause -It can cure the common cold, viruses and bacteria -It removes blackheads -it removes or fades freckles naturally -It treats constipation -It helps to refresh your breath – It shrinks swollen tissue in the throat. Difficulties Faced: -Reading the pH tapes as there were some that were the same colour or they were in the middle of two colours. Due to this problem I was not able to get a fair and accurate result.
I overcame this problem by giving an educated guess about the colours and decided to improve and make my experiment more accurate therefore I decide to use a Digital pH scale as well. This allowed me to get an accurate pH of the lemon juice therefore giving me the ability to compare my results. Improvements: -More Tests -More Types/Brands of lemon Juice to test -Accurate readings of the colour that the pH tapes have changed to as some were lighter than others or were in the middle of two colours Completed By student: The whole investigation was completed by student except for the usefulness of lemon Juice as more research was needed.
Website used: http://www. livestrong. com/article/296959-what-are-the-benefits-of-lemon-juice-on-the-skin/ Date & Time:| Work Completed:| 10/2/201215/02/20127-8/5/201214/5/201216/5/201221/5/201223/5/201228-31/5/20124-6/6/20128/6/201217/6/201220/6/201220-21/6/201230/6/2012-1/7/2012| Searched Project ideasDecided on A project-“Acidic Levels In Commercial & freshly squeezed lemon juice”Found information and researched different methods of carrying out this investigationStarted planning my experimentCompleted Aim, Method, Hypothesis and EquipmentCompleted Method and Diagram(shows how to set up the experiment)Drew up the results table and
