Transcript Tuesday Lecture – Spices, Herbs, Perfumes

Thursday Lecture –Vegetable
Oils and Waxes
Reading: Textbook, Chapter 9
A Plethora of Peppers
“Black Pepper” – Piper nigrum (Asia)
“Red Pepper” – Capsicum spp. (Mexico/South America)
“Melegueta Pepper” – Aframomum (Africa)
“Brazilian (or Pink) Pepper” – Schinus
Drupe of member of Anacardiaceae – some people exhibit
allergic reaction
Quiz
1. Two different plants both give us a spice called “pepper” –
Chili pepper (Capsicum) and Black pepper (Piper) – which
is native to the Old World and which to the New World?
2. Name a major vegetable oil crop. Where is it originally
native?
Vegetable Oils
Plant oils – mostly acylglycerides
Glycerol – 3-carbon “backbone”
Figure 9.3, p. 221
Vegetable Oils
Plant oils – mostly acylglycerides
Figure 9.3, p. 221
Glycerol – 3-carbon “backbone”
Acyl groups – mostly fatty acids = chain of carbon atoms
Triacylglyceride structure
Figure 9.3, p. 221
Vegetable Oils
Plant oils – mostly acylglycerides
Figure 9.3, p. 221
Glycerol – 3-carbon “backbone”
Acyl groups – mostly fatty acids = chain of carbon atoms
Properties of acyl groups:
1. Length – longer = higher melting point
Vegetable Oils
Plant oils – mostly acylglycerides
Figure 9.3, p. 221
Glycerol – 3-carbon “backbone”
Acyl groups – mostly fatty acids = chain of carbon atoms
Properties of acyl groups:
1. Length – longer = higher melting point
2. Unsaturation – the presence of double-bonds between carbons
Vegetable Oils
Plant oils – mostly acylglycerides
Figure 9.3, p. 221
Glycerol – 3-carbon “backbone”
Acyl groups – mostly fatty acids = chain of carbon atoms
Properties of acyl groups:
1. Length – longer = higher melting point
2. Unsaturation – the presence of double-bonds between carbons
- monounsaturated = has 1 double bond
Vegetable Oils
Plant oils – mostly acylglycerides
Figure 9.3, p. 221
Glycerol – 3-carbon “backbone”
Acyl groups – mostly fatty acids = chain of carbon atoms
Properties of acyl groups:
1. Length – longer = higher melting point
2. Unsaturation – the presence of double-bonds between carbons
- monounsaturated = has 1 double bond
- polyunsaturated = has 2 or more double bonds
Vegetable Oils
Plant oils – mostly acylglycerides
Figure 9.3, p. 221
Glycerol – 3-carbon “backbone”
Acyl groups – mostly fatty acids = chain of carbon atoms
Properties of acyl groups:
1. Length – longer = higher melting point
2. Unsaturation – the presence of double-bonds between carbons
- monounsaturated = has 1 double bond
- polyunsaturated = has 2 or more double bonds
Double bonds  generally lower melting point of compound
Triacylglyceride structure
Figure 9.3, p. 221
Vegetable Oils – The Plant View
Why do plants produce oils?
Vegetable Oils – The Plant View
Why do plants produce oils?
Answer: high energy content (caloric value)  compact way to
store energy
Vegetable Oils – The Plant View
Why do plants produce oils?
Answer: high energy content (caloric value)  compact way to
store energy
Where do plants produce and store oils?
Vegetable Oils – The Plant View
Why do plants produce oils?
Answer: high energy content (caloric value)  compact way to
store energy
Where do plants produce and store oils?
Answer: seeds, particularly endosperm or cotyledon(s)
Vegetable Oils – The Human
View
Why do people consume vegetable oils (and other fats)?
Box 9.1, p. 222
Vegetable Oils – The Human
View
Why do people consume vegetable oils (and other fats)?
Answer: high energy content – we retain a craving for fats that was
an advantage for our ancestors at a time when it was difficult to
obtain fats
Box 9.1, p. 222
Vegetable Oils – The Human
View
Why do people consume vegetable oils (and other fats)?
Answer: high energy content – we retain a craving for fats that was
an advantage for our ancestors at a time when it was difficult to
obtain fats
What has changed?
- widespread availability of fats/oils
Box 9.1, p. 222
Vegetable Oils – The Human
View
Why do people consume vegetable oils (and other fats)?
Answer: high energy content – we retain a craving for fats that was
an advantage for our ancestors at a time when it was difficult to
obtain fats
What has changed?
- widespread availability of fats/oils
- increase in human lifespan
 Revealing health issues in high consumption of fats
Box 9.1, p. 222
Acylglycerides – Health Issues –
Consumption Increasing
World Consumption Projected to be up
16% - 1998-2001
Figure 9.2, p. 220
Acylglycerides – Health Issues –
Consumption Increasing
World Consumption Projected to be up
12% - 2006-2011
Figure 9.2, p. 220
Acylglycerides – Health Issues
– 25% of deaths in U.S. due to heart disease (2007) - #1 cause
Box 9.1, p. 222
Acylglycerides – Health Issues
– 25% of deaths in U.S. due to heart disease (2007) - #1 cause
– Correlation between blood cholesterol & heart disease
Box 9.1, p. 222
Acylglycerides – Health Issues
– 25% of deaths in U.S. due to heart disease (2007) - #1 cause
– Correlation between blood cholesterol & heart disease
– Plants do not produce cholesterol
Box 9.1, p. 222
Acylglycerides – Health Issues
– 25% of deaths in U.S. due to heart disease (2007) - #1 cause
– Correlation between blood cholesterol & heart disease
– Plants do not produce cholesterol
– Correlation – saturated dietary fats  arterial plaque formation
Box 9.1, p. 222
Acylglycerides – Health Issues
– 25% of deaths in U.S. due to heart disease (2007) - #1 cause
– Correlation between blood cholesterol & heart disease
– Plants do not produce cholesterol
– Correlation – saturated dietary fats  arterial plaque formation
Conclusion: exchange saturated for unsaturated fats in foods
Box 9.1, p. 222
Acylglycerides – Health Issues
– 25% of deaths in U.S. due to heart disease (2007) - #1 cause
– Correlation between blood cholesterol & heart disease
– Plants do not produce cholesterol
– Correlation – saturated dietary fats  arterial plaque formation
Conclusion: exchange saturated for unsaturated fats in foods
Problem: polyunsaturated fats  linked to production of free
radicals, which are carcinogenic
Recommendation: mono-unsaturated fats appear best for health,
based on currently available information
Box 9.1, p. 222
Acylglycerides – Health Issues
– 25% of deaths in U.S. due to heart disease (2007) - #1 cause
– Correlation between blood cholesterol & heart disease
– Plants do not produce cholesterol
– Correlation – saturated dietary fats  arterial plaque formation
Conclusion: exchange saturated for unsaturated fats in foods
Problem: polyunsaturated fats  linked to production of free
radicals, which are carcinogenic
Recommendation: mono-unsaturated fats appear best for health,
based on currently available information
Problem: saturated fats “taste” better
Box 9.1, p. 222
Trans Fats
Saturated fats (animal fats, tropical vegetable fats)  link to
heart disease
Trans Fats
Saturated fats (animal fats, tropical vegetable fats)  link to
heart disease
Polyunsaturated fats  vegetable oils, liquid at room temp.
Trans Fats
Saturated fats (animal fats, tropical vegetable fats)  link to
heart disease
Polyunsaturated fats  vegetable oils, liquid at room temp.
Hydrogenation – bubble hydrogen gas through vegetable oil,
increases the saturation
Trans Fats
Saturated fats (animal fats, tropical vegetable fats)  link to
heart disease
Polyunsaturated fats  vegetable oils, liquid at room temp.
Hydrogenation – bubble hydrogen gas through vegetable oil,
increases the saturation
Completely saturated  hard, like wax – not useful
Trans Fats
Saturated fats (animal fats, tropical vegetable fats)  link to
heart disease
Polyunsaturated fats  vegetable oils, liquid at room temp.
Hydrogenation – bubble hydrogen gas through vegetable oil,
increases the saturation
Completely saturated  hard, like wax – not useful
Partial saturation  creamy consistency, useful for spreads
also more chemically stable, longer shelf life
Trans Fats
Saturated fats (animal fats, tropical vegetable fats)  link to
heart disease
Polyunsaturated fats  vegetable oils, liquid at room temp.
Hydrogenation – bubble hydrogen gas through vegetable oil,
increases the saturation
Completely saturated  hard, like wax – not useful
Partial saturation  creamy consistency, useful for spreads
also more chemically stable, longer shelf life
Problem – creates trans type of bonds – health problems
Omega 3, Omega 6 fats
“Omega n” – refers to position of double bond relative to
methyl end of fatty acid
Required in human diet – omega 3, omega 6 types
Associated with health benefits
Extraction of Vegetable Oils
Basic Approaches
I.
Figure 9.6, 9.7, p. 227
Mechanical Extraction
- cold pressing means no heat applied
- hot pressing means external heart is applied
Note: screw press now widely used – allows
continuous processing and separation of
residual “cake”
Extraction of Vegetable Oils
Basic Approaches
I.
Figure 9.6, 9.7, p. 227
Mechanical Extraction
- cold pressing means no heat applied
- hot pressing means external heart is applied
Note: screw press now widely used – allows
continuous processing and separation of
residual “cake”
II.
Solvent Extraction
- organic solvent (e.g. hexane)
Notes: more efficient (less oil left behind) but
requires processing because solvent must be
removed
Processing of Vegetable Oils
Figure 9.8, p. 229
Refining: use alkali to remove free fatty acids
Degumming: extraction with water to remove mucilaginous material
Bleaching: removal of pigments that produce color
Deodorizing: removal of aromatic compounds through steam heating
Winterizing: removal of particles by precipation at low temperature +
filtering
Hydrogenation: increasing the saturation of fatty acids (use hydrogen
gas + catalyst)  raise melting point
Common Sources of Vegetable Oils
Polyunsaturated
- linseed oil (Linum usitatissimum - seeds)
- tung oil (Aleurites fordii – seeds)
Unsaturated
- Safflower (Carthamus – 1-seeded fruits)
- soybean (Glycine max – seeds)
- sunflower (Helianthus annuus – 1-seeded fruits)
- corn oil (Zea mays – germ)
- sesame oil (Sesamum indicum – seeds)
- cottonseed oil (Gossypium – seeds)
- canola oil (Brassica – seeds)
Moderately saturated
- peanut oil (Arachis hypogaea – seeds)
- olive oil (Olea europea – fruit pulp)
Table 9.4, p. 230-1
2005
2007
Traditional Vegetable Oil Plants
Linseed Oil - Flax
Sesame Oil
Traditional Oil Crop - Olive
Cold Pressing of pulp after seeds removed
“extra-virgin” – first press, low oleic acid level – not processed further
Traditional Oil Crop - Olive
Cold Pressing of pulp after seeds removed
“extra-virgin” – first press, low oleic acid level – not processed further
“virgin” – first press, higher acid level – not processed further
Traditional Oil Crop - Olive
Cold Pressing of pulp after seeds removed
“extra-virgin” – first press, low oleic acid level – not processed further
“virgin” – first press, higher acid level – not processed further
“refined” – refining methods used  odor/flavor altered
“pure” – mixture of refined and virgin oils
Figure 9.21, p. 240
Major Oil Crops - Palm
Palm plantation - Thailand
Vegetable fat – solid at room temp
Major Oil Crops - Soybean
Major Oil Crops - Sunflower
Figure 9.12, p. 234
Major Oil Crops - Canola
Brassica napus – “rapeseed”  rape
Canada: Canadian oil = Canola
Vegetable Oils and Soaps
Figure 9.5, p. 223
Hydrolysis of acylglyceride  fatty acids + glycerol
Triacylglyceride + alkali (e.g. NaOH – lye)  sodium salt of fatty
acid + glycerol + water
Soap molecules connect oils
with water
Soaps versus Detergents
Detergents – formed from hydrocarbons, connected with sulfonic
acid (SO3), a cation, or a non-ionic polar group
Figure 9.5, p. 223
Detergents: less harsh than soaps (less strongly basic in pH)
Also their salts are more soluble than those of soap  no “bathtub ring”
Thursday Lecture – Medicinal Plants
Reading: Textbook, Chapter 11