Oils and Fats - Weebly



Oils and Fats

1- Oils and fats are members of:

a- Simple lipids. b- Compound lipids.

c- Derived lipids. d- Both a & c.

2- Waxes are:

a- Fatty acids. b- Esters of fatty acids and glycerol.

c- Esters of fatty acids and high molecular weight alcohol.

d- All of the above

3- Derived lipids are:

a- Fatty acids b- Sterols

c- Phosphoric acid and carbohydrates d- All of the above

4- Fixed oils and fats contain traces of free fatty acids due to:

a- Oxidative rancidity b- Hydrolysis in the presence of moisture

c- Heating at high temperatures d- All of the above

5- When oils and fats are heated strongly, they decompose with the production of:

a- Free fatty acids b- Glycerol

c- Acrolein d- All of the above

6- Unsaponifiable part in an oil or fat is:

a- Glyceride part or ester part b- Non-glyceride or no-ester part.

c- Ester of fatty acids and long chain alcohol. d- All of the above

7- The following are unsaponifiable part of oils and fats Except:

a- Steroids. b- Vitamins, A, D and E.

c- Hydrocarbons d- Glycerides

8- Oils and fats are:

a- Simple triglycerides b- Diglycerides

c- Mixture of mixed triglycerides d- Monoglycerides

9- The carbon atoms in fatty acids are:

a- Odd number arranged in branched chain and carboxylic group.

b- Even number arranged in straight chain and carboxylic group.

c- ester of alcohols and acids d- None of the above

10- The difference between the point of incipient fusion and complete fusion is known as:

a- Refractive index b- Melting point

c- Solidifying point d- None of the above

11- Saponification value is defined as, the number of mg of alcoholic KOH required to:

a- Neutralize the free fatty acids present in 1 gm oil or fat.

b- Hydrolize and react with the glycerides present in 1 gm oil or fat.

c- Both a and b. d- None of the above

12- Presence of mineral oil as an adulterant in vegetable oil will:

a- Decrease the S.V. b- Decrease the I.V.

c- Both a and b. d- Increase I.V. and S.V.

13- The degree of unsaturation is measured in terms of, the weight of halogen fixed by;

a- One gram of oil b- 5 gm of oil

c- 100 gm of oil. d- All of the above

14- Oils having high I.V. are classified as:

a- Non-drying oils b- Semi-drying oils

c- Drying oils d- None of the above

15- Waxes has:

a- Very small I.V. b- High I.V.

c- I.V. similar to that of vegetable oils d- None of the above

16- Animal fat and butter have:

a- High I.V. b- Zero I.V.

c- Low I.V. d- None of the above

17- Iodine and thiocyanogen are added to the double bonds present in linoleic acid as follows:

a- Both adds and saturate the two double bonds

b- Thiocynogen adds to the two double bonds, while iodine adds to one.

c- Both adds and saturate one of the two double bonds

d- Iodine saturate the two double bonds, while (SCN)2 adds to one.

18- Diene value is useful for:

a- Conjugated double bonds. b- Isolated double bonds

c- Saturated fatty acids d- All of the above

19- The glycerides of butter fat contain:

a- High % of long chain fatty acids

b- Low % of short chain fatty acids.

c- High % of short chain fatty acids d- None of the above.

20- Acetyl value equal:

a- S.V. for acetylated hydroxyl fatty acids

b- S.V. of non acetylated oil

c- S.V. for acetylated oil - S.V. of non acetylated oil

d- None of the above

True and False Statements

1- Rancidity which leads to formation of low molecular weight fatty acids results in decrease in the S.V.

2- S.V. Is useful in the identification of oils and fats.

3- Oils with high I.V. are liable to rancidity and are liquids at room temperature.

4- Thiocyanogen is obtained by the reaction of Br2 with Pb(SCN) 2 in ether.

5- I.V and Thiocynogen value are equal when determined for lenoleinic acid.

6- the glycerides of butter fat contain low percentage of short chain fatty acids and its S.V. is low.

Give reasons:

1- Rancidity increases acetyl value.

2- In the determination of S.V., Ph.Ph. is used as indicator (M.O. can not be used), when excess potassium hydroxide is back titrated with standard HCl solutin.

3- Alcoholic KOH is used for the S.V. of oils and fats, while aqueous KOH is used for saponification of oils and fats in case of Richert-Meissel value.

4- Iso-oleic acid present in hydrogenated fats, not present in natural oil or fat.

5- During hydrogenation of oils, the mixture of oil, Ni, and hydrogen, is heated just to start hydrogenation and further heating is not necessary.

Write short notes on:

1- Oxidative rancidity

2- a- Define, Polenske and Kirchener values.

b- Pro-oxidants and anti oxidants

3- Detection of hydrogenated oils in butter fat

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download