How will distinctive species of berries (strawberry, blueberry, raspberry, blackberry, cranberry) have an effect on the breakdown of hydrogen peroxide in celery juice to supply the enzyme - catalase?

In my Biology IB Class, I was introduced to enzymes and how they work in different conditions in different conditions, as well as, what inhibits them to function. Regularly, it interests me how what we consume daily impacts our health. But also, how changing our specific diets can improve or deteriorate different aspects of our health. Being an athlete, it's important to consistently maintain a balanced diet, not only to maximise performance levels, but also, promote muscle repair and prevent injuries from occurring. Consequently, I started inquiring about the possible health benefits if we decided to increase our intake of flavonoids and if they have a significant impact upon increasing energy generation and blood glucose concentrations to improve performance output. Hence, I chose to use different types of berries; to explore the effects it has on the breakdown of hydrogen peroxide. Even though there are many health benefits attributed to berries, I wanted to investigate if it has any specific drawbacks as being an inhibitor of the enzyme Catalase.

Enzymes are globular proteins with a specific function that acts as a catalyst in living organisms, thus, they speed up the chemical reactions inside and outside the cell without being altered by the process itself. On the surface level, an enzyme has a region known as the active site, which is where substrate molecules bind and a chemical reaction is catalysed. However, each active site is adapted to one specific substrate, meaning one reaction can occur, this is known as the Lock and key model. As seen in Figure 1, the substrate entering the active site of the enzyme must alter itself slightly as the substrate binds into perfect contact. As a result, an enzyme-substrate complex is formed, and the products are released.

Consequently, the presence of inhibitors can occur; a molecule that disrupts the normal pathway between an enzyme and a substrate (Brent Cornell, 2016). In this experiment, flavonoids are considered to be a competitive inhibitor; they bind to the same active site. As seen in Figure 2, though the shape of the substrates are structurally and chemically similar, the inhibitor blocks the active site and prevents the development of an enzyme substrate complex, thus, no reaction occurs. There are various different types of enzymes in living organisms, but his experiment specifically focuses on the enzyme catalase found in the Celery. The presence of catalase, an antioxidant enzyme found in all living organisms, is integral for the decomposition of 2 hydrogen peroxide to 2 water molecules (H₂O) and 1 oxygen molecule (O₂). Most importantly, it protects the cells from oxidative damage carried out by reactive oxygen species and maintains an optimum level of the molecule in the cell for cellular signal processes. Inevitably, if there is an exorbitant volume of Catalase, a disease called acatalasemia, a genetic disease formed when catalase level is too low, is activated and the catalase deficiency becomes a potential threat to the cell and the living organisms. Accordingly, the methodology developed attempts to quantify the different effects between fruit species that contain flavonoids, used by 5 different types of berries: Blueberry containing 1100mg/100g dry weight, Raspberries and strawberries containing 500 mg/100g dry weight (Jiyun Lun), Cranberries containing 7.9mg/100g dry weight and blackberries containing 38.8mg/100g dry weight (Croge et al.). They were extracted and converted to liquid form to investigate how each of these inhibitors will affect the volume of oxygen being released. Celery Juice was used to display the breakdown of hydrogen peroxide as it is rich in catalase to sustain health and inhibit the enzymes of transcription factors important in inflammation. This experiment seeks to reciprocate the natural procedure of catalase reactions in the liver through controlled means, creating the optimum medium in which it naturally occurs. As a result, the breakdown of hydrogen peroxide as displayed by the celery juice that is rich in catalase to sustain health, Each of the berry juice was mixed with the celery juice to see to what extent it has inhibited the function of Catalase. If a prominent volume of O₂ is released, it indicates the berry used did not interfere significantly with the chemical action, conversely, if a minimal volume of O₂ is released, it indicates the berry used worked effectively on slowing down the chemical reaction.

The Alternative Hypothesis (H_a) predicts that as the concentration of flavonoids increases in different species of berries, the inhibitor will become more prominent, decreasing the volume ((cm³) of oxygen (O₂) being produced. The prediction is that blueberries will have the greatest effect on preventing the breakdown of hydrogen peroxide because they are anticipated to produce the lowest volume (cm³) of oxygen ( O₂) as it has the highest concentration of flavonoids. As a result, they act similarly to mutagens, specifically these pre-oxidants act as inhibitors that prevent release of O₂ molecules. of enzymes. Consequently, Blackberries, strawberries and raspberries should produce somewhat the same volume of oxygen as they contain similar concentrations of flavonoids. Whilst, cranberries will produce the highest volume of oxygen (cm³) as it has the lowest concentration of flavonoids. Nonetheless, a Null hypothesis (H₀)can occur, whereas there is no difference in the rate of reaction when different concentrations of flavonoids are added. The topic of interest in this investigation is the impact on different species of flavonoids (Strawberry, Blueberry, Raspberry, Blackberry, Cranberry) have on the effect on the breakdown of hydrogen peroxide in Celery juice to supply the enzyme - Catalase. In numerous previous scientific studies (Skibola and Smith), flavonoids was seen as an competitive inhibitor to several enzymatic reactions, decreasing the breakdown of hydrogen peroxide.

Independent Variable -

The Different types of berries used  ( Strawberries - Fragaria anassa, Blueberries - Vaccinium sect, Raspberry - Rubus Idaeus,  Blackberries - Rubus, Cranberries - Vaccinium subg. Oxygccous). 5cc of each berry were added each trial throughout the experiment.

Dependent Variable -

The Volume of Oxygen (cm³) measured by the Gas Syringe (2 minutes)

A preliminary experiment was done to identify if there needs to be alterations to the method. It was important to determine whether tea or berries ( liquid form ) would work better as an inhibitor for the enzyme Catalase. A control variable of Celery juice ( Hydrogen peroxide ) was used to understand the effect the independent variable had on the dependent variable, as well as, to ensure the experiment results were unskewed.

• 5 different types of tea: Green tea, Black tea, English Breakfast tea, Earl Grey tea and Pure Darjeeling tea was first used in the experiment, which did trigger a reaction to occur. However, all of the tea except the Earl Grey tea hardly worked as an inhibitor, as the volume of oxygen measured in the Gas syringe system ranged from 14 - 46 cm3 which was exceedingly high in comparison to berries that ranged from 6 - 12 cm3 . As well as surpassing the control setup of 42 cm3
• In the original method, there was no recollection of the need to stir the mixture after the inhibitor was poured into the celery juice and attracted to the Gas syringe. Yet it was found in this pre-trial, that all mixtures needed to be stirred to have a noticeable impact on enzymes and thus, 5 different peers were used to stir each mixture. This would have had a slight impact on the results as it was merely impossible to control the speed and strength of each individual. Therefore, it was decided that a magnetic stirrer would be used to maintain consistency to ensure equitable results
• At first, 20cc of hydrogen peroxide and 5cc of the inhibitor was used but this ratio was found to be too disproportionate and made it difficult for the inhibitors to have an evident effect on the enzyme. Thus, it was reduced to 10cc to maintain a proportionate ratio.

• 450cc 5% Hydrogen peroxide (H₂O₂) 
• 50cc Pure (1:1 ratio, celery to water) celery (Apium graveolens)  Juice
• 10x Synrigles of 10cc (+/-0.50cc)
• 5x 250cc beakers (+/- 10.00cc)
• 5x 25cc Conical flask (+/-0.10cc)
• 5x Retort Stands
• 2x Waste Bins
• 5x 100cc Gas Syringe (+/-0.5cc)
• 1x Electronic Balance (+/- 0.005 grams)
• 1x Blender
• 1. 1x Stopwatch (+/- 0.005 seconds)
• 5x Magnetic Stirrer
• 1x Pack of Blue tack
• 80 grams Strawberries
• 80 grams Raspberry
• 80 grams Cranberry Juice
• 80 grams Blackberry Juice
• 1x Marker pen1x Marker pen
• 5x Rubber tube with band
• 200cc Distilled Water​​​​​​​

The methodology developed attempts to quantify the effect of flavonoids on the breakdown of hydrogen peroxide using a Gas syringe to measure the volume of oxygen (O₂) released. Hydrogen peroxide, consisting of water and extra oxygen atoms tacked on, is broken down by the enzyme catalase to water and oxygen. This test is composed of a mixture of flavonoids (berries juice), hydrogen peroxide and catalase (celery juice). As all components are mixed together, the hydrogen peroxide reacts with the catalase, but is inhibited with the mixture of flavonoids. Therefore, it's expected that with a larger concentration of flavonoids added in the 2 minute intervals, the lesser volume of oxygen (O₂) wll be released.

• Measure 170g of strawberries using the electronic balance, and place the berries into the blender
• Measure 20cc of distilled water using a measuring cylinder and pour the water into the blender
• Start blending for 2 minutes by setting it to “smoothies” to ensure that the force of blending is identical
• Filter the juice using a strainer Repeat for all the other types of berries: blueberries, cranberries, strawberries and raspberries

• Collect 1 retort stand and place it on the counter.
• Attach the Gas syringe onto the clamp of the retort stand, adjust if necessary to ensure it's in place.
• Use the Blu Tack to secure the cork onto the tube to make it airtight. Then, attach the tube onto the rim of the Gas syringe.
• Place the magnetic stirrer plate next to the retort stand
• Measure 10cc of Hydrogen peroxide (1%) using a 50cc measuring cylinder  and then, pour the liquid into the conical flask.
• Using a syringe, extract 5cc of celery juice from the beaker. Repeat this step using a new syringe to measure 5 cc of the strawberry juice.
• Place the conical flask onto the magnetic stirrer plate. Once in position, add the magnetic onto the centre of the flask.
• Set the magnetic stirrer to half speed.
• First, add the strawberry juice from the syringe into the conical flask. Immediately after, add the celery juice from the syringe into the conical flask. The enzyme is added after the addition of an inhibitor because once the enzyme is added, the reaction would start.
• Place the cork onto the conical flask instantly after the liquid in both syringes were added to the mixture.
• Start the timer and measure the volume of oxygen produced (cm3) after 3 minutes
• Dispose the mixture into the waste bin.
• Record data on the volume of oxygen produced of the strawberry juice.
• Repeat steps 1-13 for the remaining berries: raspberries, blueberries, blackberries and cranberries. Ensure new beakers, conical flasks and syringes are used in each trial.
• Process the data and describe any trends or parents in the results. Discuss how the increasing concentration of flavonoids affects the inhibition of the breakdown of hydrogen peroxide.

Safety - Hydrogen peroxide can cause severe eye irritation, burns, and respiratory system when in contact with the skin, Therefore, goggles and lab coats must be worn when handling the acid to prevent any injuries. Additionally, the use of glass beakers and conical flasks must be handled with precaution to prevent any cuts to the conduct/peer. If an accident occurs, immediately rinse the contaminated skin and inform a teacher or supervisor.

Ethical - There were no ethical implications to be considered throughout the investigation as non living organisms were used in the procedure.

Environmental - The hydrogen peroxide used in this experiment was safely poured into waste bins to prevent pollution in the water supply. Furthermore, all berries used were disposed properly through composting, a conventional trash bin or rescuing the leftovers parts if possible. Only the minimum amount of each berries were used to avoid food wastage.

*All data are rounded to 2 significant figures

*cm³ = Volume of gas syringe

Qualitative Data - Throughout the experiment, there were many observations made on the amount of oxygen released by the reaction after being inhibited by berries (flavonoids).

• For Blueberries, as soon as the magnetic stirrer was on and both celery juice and blueberry juice were added to the hydrogen peroxide, it immediately changed the colour from transparent to a dark blue and brownish colour. The solution also began to slightly foam.
• For Raspberries and Cranberries, as soon as the magnetic stirrer was on and both celery juice and raspberries/cranberries juice were added to the hydrogen peroxide, it immediately changed the colour from transparent to maroon and brownish colour. The solution also began to foam.
• For Strawberries, as soon as the magnetic stirrer was on and both celery juice and strawberries juice were added to the hydrogen peroxide, it immediately changed the colour from transparent to a pinkish and brown colour. The solution also began to foam.
• For the control, as soon as the magnetic stir and the celery juice were added to the hydrogen peroxide, it immediately turned into a light green colour, with a large amount of foam

In all trials, there was never any distinctive smell that was released from the solution besides the smell of the berries. The foam foamed in all trials was created because celery contains an enzyme called catalase, as it comes into contact with hydrogen peroxide (H202), this reaction happens so quickly, the bubbles formed are pure oxygen bubbles created by catalase. In general, there was an inverse relationship because as the concentration of flavonoids increased, the amount of foam decreased.

Decision for uncertainties -  The uncertainty for the volume of oxygen released +/- 0.5cc, was used as the gas syringe used in the experiment changed by 1, not more or less, meaning, the volume oxygen released changed by 1, therefore it was unable to measure the volume of 17.6cc of 22.3 as an example. Therefore, this unit was kept constant throughout the mean and standard deviation,

*all data rounded to 0 decimal places