To what extent does the Iodine value, and the acid value of the oil, and oxidative stability affect the hydrolysis rate of fatty acids in oil?

•  Be careful while handling water baths and while heating chemicals
•  Avoid contact with corrosive and irritant chemicals.
•  Wear a lab coat, safety glasses, and gloves all the time.
• Be careful while handling flame and do it under the supervision of a lab attendant.
• Handle different vegetable oils with care and store them under proper conditions.
• Make sure to repeat average experiment values and note everything you see.
• For the use of the I'm at, get a group of people to determine if the oil is rancid, to avoid bias.

The following is a commonly used procedure for measuring the rate of hydrolysis.

1. Prepare 0.5 g of solid lipase in 10 cm³ of water with 0.01 mol/dm³ of NaOH solution, 0.1 g of calcium chloride to activate, and 5% sodium lauryl sulphate detergent. preserve the oil you usually hydrolyze as well.
2. Take the enzyme solution, and using drops of NaOH, adjust the pH to 8
3. Place equal volumes of sodium lauryl sulphate detergent and the oil into a beaker and shake vigorously.
4. Adjust the pH to 8, using drops of NaOH
5. Place 20cm³ of the emulsion and add another 10cm³ of sodium lauryl sulphate detergent into a beaker, and stir vigorously with a magnetic stirrer.
6. Place a pH electrode into the mix, and measure the ph. Carefully adjust the pH to 8, using drops of NaOH, and start a stopwatch.
7. Add NaOH for 5 minutes at regular intervals of around 30 seconds to maintain the pH at 8.
8. Add 2cm³ of water to the mixture carefully, adjust the pH to 8 using NaOH, and start a stopwatch.
9. At regular time intervals, add NaOH to adjust the pH to 8.
10. Continue for about 5 minutes.
11. The experiment has to be repeated by substituting 2cm³ of enzyme for the water.
12. The initial rate of reaction in cm³ will be 0.01 mol/dm³ of alkali/second when you draw a graph of the volume of alkali injected against time.
13. This can also be converted to moles of acid produced per second
14. Repeat this experiment to get an average.

Iodine value, acid value, hydrolysis rate, and induction time are dependent variables.

Types of vegetable oils and phenolphthalein addition volume are independent variables.

Helianthus annuus (sunflower oil), Arachis oil (peanut oil), Brassica napus (canola oil), Cocos Nucifera (coconut oil), and Soybean oil (Glycine Max).

I've always loved to cook, and I could make both Indian and Western food rather well. One day, though, when I was preparing a dish and heating oil, I observed that after letting the oil heat for a while, it began to give out a very unpleasant smell, which made me wonder what had occurred. Naturally, I instantly realized that the oil had turned rancid, and this got me thinking about the various elements that affect the shelf life of fats and how different vegetable oils have varying expiration dates.

Vegetable oil's shelf life is the period of time during which it is still safe to eat or sell. Vegetable oils frequently have a short shelf life, which is a severe issue because there is only so much time before they lose their value.

There are many different reasons why this process happens. The iodine content of vegetable oils is one aspect that affects how long they last. The amount of iodine that is eaten per 100 grammes of a material is measured by its iodine value in grammes. The amount of C-I bonds and H-I bonds, which can be broken under the influence of sunlight or extremely high heat to form new bonds, and which significantly aid in the completion of the oxidation process of oils, are what is meant by the term "iodine value" to describe the amount of iodine in vegetable oil. The acid value is another element that may influence an oil's shelf life. The amount of potassium hydroxide needed to neutralize the free fatty acids in 1 gramme of oils or fats is the acid value of oil, often known as acidity. Triglycerides typically result in the production of free fatty acids. The quantity of free fatty acids reveals how well vegetable oils have been hydrolyzed. Vegetable oils have several hydrolyses already, therefore the more of them there are, the lower the oxidative power. The oxidative stability of oils is another element that significantly prolongs the shelf life of oils. The more resistant the vegetable oil molecules are to oxidization, the more energy is needed to carry out the oxidation process under specified conditions, such as a particular temperature or pressure. The rate of hydrolysis of particular oils is the last aspect taken into account here. The type of oil in question, the plant it comes from, how it is stored before being used by a consumer, and the type of plant it comes from all influence whether the oil expires at a specific time.

Rancidification is the term for the process by which vegetable oils completely or partially oxidize when exposed to air, light, moisture, or bacteria. This process is frequently referred to as hydrolysis. Below is the general chemical equation for this:

• EFFECT OF ACID AND IODINE VALUES
• UNCERTAINTY
• OXIDATIVE STABILITY GRAPH
• GRAPHICAL EVIDENCE AND FINAL PROOF

• EFFECT OF EACH OF THE INDIVIDUAL VARIABLES

1. Dissolve 1 gram of phenolphthalein in 100 cm³ of ethyl alcohol.
2. Mix the oil thoroughly before weighing
3. Add 50 cm³ of hot ethyl alcohol and about 1 cm³ of phenolphthalein indicator solution.
4. Heat the mixture for 15 minutes in a water bath (75-80 degrees Celsius).
5. Titrate against Potassium hydroxide solution, and keep adding known volumes of 0.1 M KOH solution until there is a colour change from colourless to light pink (persisting for 15 minutes)
6. The total volume of added titrant is used to measure the acid value of said oil sample.
7. After doing this with the indicator and recording the volume of KOH dropped/ remaining in the pipette, we can repeat this experiment without the indicator by adding exactly that amount of acid.
8. The acid value of the oil can then be calculated using this:

Acid Value = (56.1V* N)/W

 V = Volume in cm³ of standard potassium hydroxide

N = Normality of potassium hydroxide solution

W = Weight in grams of the sample

9) Repeat this experiment 5 times, and get the average

molarity of Potassium Hydroxide is 11.7 M(mol/dm³), where normality is the concentration of a solution.

Weighing the oil samples in the Rancimaat with an 892 professional Rancimaat and multiple disposable plastic Pasteur pipettes can be done to test oxidative stability.

1. The heating block is warmed up to a temperature.
2. The measuring vessel is filled with 60cm³ deionized water and placed on the Rancimaat with the vessel cover.
3. For longer evaluation, an increased volume has to be used; this is to compensate for the evaporation of certain oils.
4. The electrode must be immersed in the solution at all times so as to produce accurate results.
5. Each new determination requires the use of a fresh reaction vessel, which can be air-cleaned inside and out while weighing in fresh samples and removing any unwelcome particles with a strong jet of nitrogen.
6. It should be adequate to use 3 grammes of the sample, but if the water content is higher than 40%, it is critical to use a larger amount of oil, and the air inlet of the Rancimaat must always be submerged in oil.
7. The induction time, secondary product generation, odour, colour, and other modifications can all be securely determined by a group.

•  METHOD
• SAFETY PRECAUTIONS
•  RESULTS

This demonstrates that, rather than the addition of various preservatives, as the majority of oil companies do, such as with Saffola and corn oils, which may affect different properties of the oil unrelated to the two above, it is actually the inverse relationship between the acid value of the oil and the iodine value of the oil that is crucial to its hydrolysis. The findings of this analysis may be used to inform decisions about how much money to invest in and how to spend on various vegetable oils by both producers and consumers. The sorts of oil producers who invest may change as a result of the discoveries on the correlation between iodine value, acid value, and hydrolysis rate.

• BACKGROUND KNOWLEDGE
• A VARIETY OF OILS CONSIDERED
• RESEARCH QUESTION
• VARIABLES- CONTROLLED VARIABLES, DEPENDENT VARIABLES, INDEPENDENT VARIABLES
• IMPLICATIONS, APPLICATIONS, AND SCOPE
•  APPARATUS REQUIRED

1. Add 10 cm³ of sodium hydroxide dissolved in 10 cm³ of methanol
2. A Bromonium Intermediate will form:
3. The unused bromine will be reduced to bromide with Iodide(I-)
4. \(Br_2 + 2I^-\rightarrow 2Br^- + I_2\)
5. Determine the amount of iodine present, using back-titration, with 10 cm³ of sodium thiosulfate solution
6. The reaction must be carried out in the dark, as the formation of bromine radicals is stimulated by light.
7. The amount of iodine in moles can be converted into mass by multiplying the number of moles by the molar mass (126.90g).

This gives iodine value by processing the amount that would be present in 100grams of oil.