5 Lipids in Foods Free Online FlashCards

What are the main molecules in food fats and oils?

Most food fats and oils consist mainly of triacylglycerols: molecules in which glycerol is joined to three fatty acids.

How are fatty acids classified by their number of double bonds?

Saturated fatty acids have no carbon-chain double bonds; monounsaturated fatty acids have one; polyunsaturated fatty acids have more than one.

How does a cis double bond affect a fatty-acid chain?

A cis double bond bends an unsaturated fatty-acid chain, making close molecular packing more difficult.

How do chain length and saturation generally affect fatty-acid melting points?

In general, longer and more saturated fatty acids pack more readily and have higher melting points than shorter or more unsaturated ones.

How does a solid-fat network affect food texture?

Solid fat crystals can form a network that traps liquid oil. This network helps determine a food’s hardness, spreadability, and melting sensation.

Why can the same fat produce different textures after processing?

Cooling rate, mixing, and other processing conditions affect fat-crystal size and arrangement, so the same fat can create different textures.

How can fat help make baked goods tender?

In baked goods, fat can coat flour particles and limit some gluten development, contributing to tenderness.

What can beaten solid fat contribute to a baked product?

When beaten with sugar, solid fat can hold small air pockets that help give a baked product a lighter structure.

How does lecithin help stabilize an emulsion?

Lecithin has a water-attracting region and an oil-attracting region, allowing it to help stabilize the boundary between the liquids in an emulsion.

Which emulsion type describes mayonnaise and butter?

Mayonnaise is an oil-in-water emulsion; butter is a water-in-oil emulsion.

What conditions promote lipid oxidation, and how can it be slowed?

Light, heat, and transition-metal ions can promote lipid oxidation. Limiting exposure to oxygen, light, and excessive heat, and using appropriate packaging and antioxidants, can slow it.

What products form as lipid autoxidation progresses?

In autoxidation, a free-radical chain reaction forms lipid hydroperoxides. These unstable products can break down into aldehydes, ketones, and alcohols that may cause undesirable odors and flavors.