Chapter 10: Lipids: Nature's Flavour Enhancers Part 1

C, H, O

• Triglycerides

• Phospholipids

• Sterols

Glycerol molecule and fatty acid(s)

Glycerol molecule with 3 hydroxyl groups that readily react with other compounds

Carbon chains with a carboxyl group (COOH) at one end

Carboxyl group of a fatty acid will react with the hydroxyl group of a glycerol producing a lipid and water
They are both charged (COOH+, OH-) and polar, but will become nonpolar after combining

Mono and diglycerides are partially soluble in water and soluble in fat
They are added to processed foods to keep mixtures of water and fats stable (emulsion)

A glycerol base + 2 fatty acids (diglyceride) + phosphorus-containing acid attached

Fatty acid dissolves in fat (nonpolar)

Phosphorus-containing acid dissolves in water (polar)

• Part of cell membranes, help transport fats in and out of cells (phospholipid bilayer)

• Help fats stay mixed in water-based solutions (emulsifying agents)

Vitamin D, steroid hormones, cholesterol

How saturated the carbon chains are with Hatoms (0, 1 or many double bonds)

Fatty acids that have max nb of H atoms (no double bonds)

Do not have the max number of H atoms (double bonds present)

Olive and canola oils, almonds, walnuts

Safflower, sunflower and corn oils

The number of carbon and hydrogen atoms

Double bonds

The temperature at which all the different fats and oils it contains are liquid

The process of adding hydrogen atoms to an unsaturated lipid to increase its saturation levels

• H is bubbled through liquid oil in the presence of a nickel catalyst

• Double bonds in the fatty acid chain break and pick up extra H atoms

• Longer shelf life than oil or lard (less oxidation)

• Greater stability and lower production cost than lard

• Faster dissolving and setting properties in chocolate production

Contain short chain fatty acids and come from cows, goats and sheep

Lipids found in the oils of fruits and seeds from tropical palm trees, low melting point, most saturated of the oils found in plants

Come from seeds of tropical plants (ex: cocoa butter)

Corn, peanuts, sunflowers, olives, cottonseed: largest group of triglycerides and contain less than 20% saturated fatty acids

Soybeans, wheat germ

Linolenic acids

More marbling = more animal fat
High marbling = good quality cut
Marbling is an indicator of flavour and tenderness and higher fat content

Unsaturated oils from fish

Because of the mixture of fatty acids

Temperature at which all lipids in a mixture are in a solid state

The more saturated the fatty acid and the longer the length of the carbon chain, the higher the melting point

Since they are nonpolar and water is polar.

| Nonpolar: equal or balanced sharing of electrons

Complex chain reaction that starts when lipids are exposed to oxygen and results in deterioration

Form of food spoilage that poses no short term health risk

Vacuum sealing (removing O or replaced with N or CO2) or adding antioxidants (interact with O before the lipids do)

1) Lipids transfer heat quickly, evenly, and at high T
2) Lipids tenderize baked products
3) Lipids aerate batters
4) Lipids enhance flavours of other foods
5) Lipids lubricate food components
6) Lipids serve as liquids in emulsions

T at which fatty acids break apart and produce smoke

T at which lipids will flame (grease fire), cannot put out with water

fat to flour ratio

Fats shorten flour's protein strands (which causes chewiness and toughness)

With high melting point (solid fats - butter, regular margarine, lard, shortening)

Oils

Allow tiny air pockets to form when beaten

Creaming fat and sugar together

Butter, margarine, mayonnaise

Fats dissolve and disperse flavour compounds

Cottonseed, vegetable shortening, soybean, canola

• Greasy texture feels slick and smooth, making foods seem moister

• Spreads like butter, margarine and mayonnaise make sandwiches seem moister without the soggy bread