XII-A

CHEMISTRY INVESTIGATORY PROJECTCOMPARATIVE STUDY OF THE RATE OF

FERMENTATION OF VARIOUS FOOD PRODUCTS

INDEX

1. Aim2. Certificate of completion3. Declaration4. Acknowledgement5. Introduction

5.1 Fermentation5.2 Advantages5.3 Risks of consuming fermented foods

6. Experiment6.1 Objective6.2 Theory6.3 Requirements6.4 Procedure6.5 Observations6.6 Result6.7 Conclusion

7. Bibliography

AIM

COMPARATIVE STUDY OF THE RATE OF FERMENTATION OF VARIOUS

FOOD PRODUCTS

To compare the rates of fermentation of the given samples of wheat flour,

gram flour, rice and potatoes

CERTIFICATE OF COMPLETION

This is to certify that

AYUSHI SHAKYA of class XII-Ahas completed the chemistry project entitled‘COMPARITIVE STUDY OF RATE OF FERMENTATION OF VARIOUS FOOD

MATERIALS’herself and under my guidance.

Mrs. Poonam Shah(P.G.T. CHEMISTRY)

KENDRIYA VIDYALAYAANDREWS GANJ

ACKNOWLEDGEMENT

I would like to express my special thanks of gratitude to my teacher Mrs. Poonam Shah as well as our principal Mrs. Rashmi Mishra who gave me the golden opportunity to do this wonderful project on the topic comparative study of rate of fermentation of various food materials, which also helped me in doing a lot of Research and i came to know about so many new things I am really thankful to them.

Secondly i would also like to thank my parents and friends who helped me a lot in finalizing this project within the limited time frame.

Ayushi ShakyaXII-A

INTRODUCTIONFERMENTATIONFermentation is the slow decomposition of complex organic compounds into simpler compounds by the action of enzymes. Enzymes are complex organic compounds, generally proteins. There are many examples of fermentation processes which we come across in our daily life; souring of milk or curd, dosa making, jalebi making, bread making, wine making and brewing. Fermentation word has been derived from Latin (Ferver which means ‘to boil’). As during fermentation there is a lot of frothing of the liquid due to evolution of carbon dioxide, it gives the appearance as if it is boiling.

Louis Pasteur in 1860 demonstrated that fermentation is a purely physiological process carried out by micro-organisms like yeast. This view was abandoned in 1897 when Buchner demonstrated that yeast extract could bring about alcoholic fermentation in the absence of any yeast cells. He proposed that fermenting activity of yeast is due to active catalyst of biochemical origins. These biochemical catalysts are called enzymes.

Sugars like sucrose and glucose when fermented in the presence of yeast cells are converted into ethyl alcohol. Sucrose is first converted into glucose and fructose with an enzyme invertase. Enzyme zymase converts glucose and fructose to ethanol.

C12H22O11 + H2O C6H12O6 + C6H12O6

C6H12O6  2 C2H5OH + 2 CO2

During fermentation of starch, starch is first hydrolyzed to maltose by the action of enzyme diastase. The enzyme diastase is obtained from germinated barley seeds. Maltose is converted to glucose by enzyme maltase. Glucose is converted to ethanol by another enzyme zymase.

2(C12H22O11)n + nH2O n C12H22O11

C12H22O11 + H2O 2 C6H12O6

C6H12O6  2 C2H5OH + 2 CO2

Enzymes maltase and zymase are obtained from yeast.

INVERTASE

ZYMAS

Sucrose

Glucose

Fructose

Glucose orfructose

Ethyl alcohol

MALTASE

ZYMAS

Maltose

Glucose

Glucose Ethyl alcohol

Starch Maltose

DIASTASE

ADVANTAGESFermentation is a way to preserve food that has been practiced by most cultures for thousands of years. In addition, the process helps retain nutrients and prevents spoilage. Foods that are fermented typically have strong, pungent flavors.

PROBIOTIC POWERFermented foods help restore the proper bacteria balance in your intestines. Most probiotics are part of a group of lactic acid-producing bacteria, which are found in yogurt, fermented milk and other fermented foods. An article published in the "Journal of Applied Microbiology" in June 2006 noted that eating foods that contain lactic acid bacteria improves intestinal tract health, improves the bioavailability of nutrients, reduces symptoms of lactose intolerance and decreases the prevalence of allergy in susceptible people.

HEART HEALTHAlthough most people associate dairy consumption with the risk of coronary heart disease, some fermented-milk products may actually contain heart-healthy properties. An article published in "Current Opinion in Lipidology" in February 2006 noted that there is evidence that fermented milk products have a mildly decreasing effect on abnormally high blood pressure, known as hypertension. The article urged further examination of the effects of cheese on coronary heart disease risk factors.

ENHANCES IMMUNE SYSTEM

RISKS OF CONSUMING FERMENTED FOODSWhile fermented foods offer certain health perks, they also create some concerns.

SIDE EFFECTS OF FERMENTATIONMany fermented foods, such as soy sauce, contain a significant amount of alcohol. Even small amounts of alcohol affect the cells of the body. Vinegar, in the form of acetic acid, also results from food fermentation. This acid gives fermented foods their sour or sharp taste. Vinegar prevents the digestion of foods, so a food filled with vinegar andother similar byproducts would seem to be indigestible.

FERMENTED FOODS ARE LOW IN NUTRITIONAs soon as a food is tampered with in any way, nutrient loss results. The longer a food is held in storage, the lower it becomes in nutrition.

EXPERIMENT

OBJECTIVETo compare the rates of fermentation of the given samples of wheat flour, gram flour, rice and potatoes.

THEORYWheat flour, gram flour, rice and potatoes contain starch as their major constituent. Starch present in these food materials is first brought into solution. In the presence of enzyme diastase starch undergoes fermentation to give maltose.

2(C12H22O11)n + nH2O n C12H22O11

Starch gives blue violet color with iodine, whereas products of fermentation of starch do not give any characteristic color. When the fermentation is complete the reaction mixture stops giving blue- violet color with iodine solution. By comparing the time required for completion of fermentation of equal amounts of different substances containing starch, their rates of fermentation can be compared. The enzyme diastase is obtained by germination of moist barley seeds in dark at 15C. When the germination is complete, the temperature is raised to 60C to stop further growth. These seeds are crushed in water and filtered. The filtrate contains enzyme diastase and is called malt extract.

REQUIREMENTSConical flasksTest tubesFunnelFilter paperWater bathWheat flourGram flourRice flourPotatoes1% iodine solution

PROCEDURE

1. Take 5.0 g of wheat flour in a 100 ml conical flask and add 30 ml of distilled water.

2. Boil the contents of the flask for about 5 minutes.3. Filter the above contents after cooling. The filtrate obtained is the flour

extract.

Starch Maltose

DIASTASE

4. To the extract taken in a conical flask, add 5ml of 1% aqueous NaCl solution.

5. Keep this flask in a water bath maintained at a temperature 50-60C. Add 2 ml of malt extract to it.

6. After 2 minutes take 2 drops of the reaction mixture and add to diluted iodine solution. Note the color produced.

7. Repeat step 6 after every 2 minutes. When no bluish color is produced the fermentation is complete. Record the total time taken for completion of fermentation.

8. Repeat the experiment with other extracts.

OBSERVATIONS

RESULTThe rate of fermentation of starch in different substances containing starch is in the order:

Rice flour > Potato > Gram flour > wheat flour

WHEAT FLOUR10 hours

GRAM FLOUR12.5 hours

RICE FLOUR15 hours

POTATO13 hours

CONCLUSIONRice flour takes maximum time for fermentation whereas wheat flour takes minimum time for fermentation.

BIBLIOGRAPHYNCERT Chemistry class 12 (Part-2)Comprehensive Practical Chemistry

www.google.com en.wikipedia.org chemistry.about.com www.rawfoodexplained.com www.livestrong.com

Times of India