Module 9-fat biochemistry

Question 1

what re edible fats and oils made of

Answer 1

Edible fats and oils are mixtures of triacylglycerols (TG), also called triglycerides, consisting of a glycerol subunit linked or esterified to three fatty acid (FA) molecules

Question 2

what is the distinction between fats and oils

Answer 2

The distinction between fats and oils is made on their state of matter at room temperature, fats are solid at room temperatures whereas oils are liquid at room temperature

Question 3

where can fats and oils be derived from

Answer 3

Fats and oils may be derived from animal or vegetable sources

Question 4

what are the principal animal fats

Answer 4

The principal animal fats are tallow, lard and butterfat which include many saturated fatty acids that can be a health concern. On the other hand, marine oils with high levels of long chain, polyunsaturated fatty acids including omega-3 fatty acids, are recommended for their health benefits

Question 5

what is glycerol

Answer 5

Glycerol, the backbone of a trigylceride is an organic trihydroxy sugar alcohol with three carbon atoms and three hydroxyl (-OH) groups

Question 6

what are fatty acids

Answer 6

Fatty acids are long chains of carbon atoms with an attached carboxyl group

Question 7

what a triglyceride form

Answer 7

The triglyceride forms when three fatty acid molecules undergo esterification with the three hydroxyl groups of the glycerol molecule producing a large triester molecule

Question 8

what would a simple triglyceride look like

Answer 8

Simple triglycerides have three identical fatty acids attached to the glycerol backbone

Question 9

what would a mixed triglyceride look like

Answer 9

in mixed triglycerides, the glycerol is combined with two or three different types of fatty acids

Question 10

what determines the physical and chemical property of a fat or oil

Answer 10

The physical and chemical properties of a fat or oil are determined by its fatty acid and triglyceride profile

Question 11

what are the properties at most concern

Answer 11

The properties of most concern are melting point, crystal form and stability

Question 12

what does the melting point determine

Answer 12

The melting point determines the hardness and spreadability of solid fats like margarine and shortening and the susceptibility of liquid oils to cloudiness when refrigerated

Question 13

what does the nature of the crystals influence

Answer 13

The nature of the crystals in solid fats influences texture sensation when the product is consumed

Question 14

what does the stability influence

Answer 14

Stability refers to susceptibility to oxidation or rancidity (spoilage).

Question 15

how many different types of fatty acids are there and what makes them different

Answer 15

Hundreds of different types of fatty acids, distinguished by number of carbons, degree of branching, and level of saturation, exist in nature

Question 16

how many of fatty acids are found in vegetable oil

Answer 16

A dozen of these fatty acids are important in vegetable oils and five are predominant in most vegetable oils.

Question 17

what is the amount carbon range that can be found in fatty acids and what is the most common range

Answer 17

Fatty acids can be 4 to 28 carbons in length but the most common are between 12 and 24 carbons long

Question 18

what is the melting point of fatty acids dependent on

Answer 18

The melting point of fatty acids increases as the number of carbons in the chain increases

Question 19

what kind of bonds does a saturated fatty acid have

Answer 19

Saturated fatty acids contain no double bonds between the carbon atoms

Question 20

what kind of bond does a monounsaturated fatty acid contain

Answer 20

monounsaturated fatty acids contain a single double bond between the constituent carbon atoms of the fatty acid molecule

Question 21

what kind of bond would a polyunsaturated fatty acid contain

Answer 21

polyunsaturated fatty acids contain more than one double bond between the constituent carbon atoms of the fatty acid molecule

Question 22

why are saturated fatty acids called saturated fatty acids

Answer 22

Saturated fatty acids are called saturated because they contain the maximum number of hydrogen atoms possible with the given number of carbon atoms

Question 23

how do double bonds impact melting points

Answer 23

The melting point of a fatty acid decreases as the degree of unsaturation or the number of double bonds increases

Question 24

what affects the melting point the most? double bonds or chain length

Answer 24

The effect of the number of double bonds on melting point is more dramatic than the effect of the chain length

Question 25

what effects oxidation stability

Answer 25

The oxidative stability of fatty acids decreases as the number of double bonds increases, saturated fats are less prone to spoilage than unsaturated fats

Question 26

what are the ways the melting point of a fatty acid decreases

Answer 26

The melting point of a fatty acid decreases as the degree of unsaturation or the number of double bonds increases

Question 27

How does oxidative stability of fatty acids correlate to number of double bonds

Answer 27

The oxidative stability of fatty acids decreases as the number of double bonds increases

Question 28

are saturated or unsaturated fats more prone to spoilage

Answer 28

saturated fats are less prone to spoilage than unsaturated fats

Question 29

is most of the fatty acids in liquid saturated or unsaturated

Answer 29

A high proportion of the fatty acids in liquid oils are unsaturated

Question 30

in most of the fatty acids in solid fats saturated or unsaturated

Answer 30

the fatty acids in solid fats are mostly saturated or a mixture of unsaturated and saturated

Question 31

what are polyunsaturated fatty acids

Answer 31

Polyunsaturated fatty acids can be conjugated, with adjacent double bonds, or non-conjugated (also called unconjugated) with double bonds separated by one or more methylene groups

Question 32

what are the most naturally occurring polyunsaturated fatty acids

Answer 32

Most naturally occurring polyunsaturated fatty acids have non-conjugated double bonds

Question 33

what is the different physiological effects of conjugated and non-conjugated polyunsatureated fatty acids

Answer 33

Conjugated and non-conjugated polyunsaturated fatty acids have different physiological effects; conjugation of double bonds may increase anti-carcinogenic effects of fatty acids and fatty acids with conjugated double bonds may have more beneficial effects on moderating cardiovascular tension

Question 34

what configuration can a conjugated fatty acids be in

Answer 34

Conjugated fatty acids can be in a cis or a trans configuration

Question 35

what is the configuration of polyunsaturated fatty acids in a trans vs cis

Answer 35

polyunsaturated fatty acids in a trans configuration are straight whereas those in a cis configuration are bent

Question 36

what does the cis and trans configuration refer to

Answer 36

The cis and trans configurations refer to the orientations of the hydrogen atoms flanking a double bond

Question 37

do trans fats occur in nature

Answer 37

Trans fats occur only in small amounts in nature

Question 38

why are most dietary trans fats produced

Answer 38

most dietary trans fats are produced when fats are partially hydrogenated to extend shelf life and increase the melting point of the fat

Question 39

are trans fats a dietary requirement

Answer 39

Trans fats are not a dietary requirement

Question 40

why arent trans fats good for the inclusion of human diet

Answer 40

the inclusion of trans fats in the human diet is associated with an increased risk of cardiovascular disease

Question 41

what actions are now taken to reduce trans fats

Answer 41

Health Canada banned the use of partially hydrogenated oils in food service establishments in 2018.

Question 42

what doe we need to indicate when describing a fatty acid

Answer 42

In describing a fatty acid, we need to indicate the number of carbon atoms, the degree of saturation and the position(s) of double bond(s)

Question 43

what does the omega nomenclature for fatty acids describe

Answer 43

The omega nomenclature for fatty acids describes the fatty acid in terms of the number of carbons in the fatty acid chain, the number of double bonds and the position of the double bond(s). Cis and trans configurations may also be included.

Question 44

what are the nutritional benefits of fats

Answer 44

Nutritionally, fats and oils are highly digestible sources of energy and essential fatty acids such as linoleic and linolenic acid. They also act as carriers for fat soluble vitamins

Question 45

how much of daily caloric intake should fat make up the diet

Answer 45

Fat should constitute no more than 30% of daily caloric intake in the human diet. Both saturated and trans fats should be limited

Question 46

what of fatty acids determines the effect on health

Answer 46

The characteristics of fatty acids determine their effect on health

Question 47

ideally what fatty acids do we and to increase and what ones do we want to decrease

Answer 47

Ideally, we want to increase high-density lipoproteins (HDL) which are considered to be beneficial cholesterols and lower low-density lipoproteins (LDL), considered to be detrimental cholesterols

Question 48

what source does most fats come from in human and livestock diets

Answer 48

The oilseeds provide a major source of fats in both human and livestock feeds

Question 49

why are fats important

Answer 49

Fats are nutrient dense sources of energy and include essential fatty acids that must be supplied in the diet.

Question 50

what is oleic acid and trans isomer

Answer 50

The trans isomer of oleic acid, a monounsaturated fatty acid with eighteen carbons (C18:1 cis), is commonly called elaidic acid (C18:1 trans); the melting point of oleic acid is 16oC whereas the melting point of the trans isomer, elaidic acid, is 45oC