Food Composition: Fats

What is the difference between fats and oils?

fats are solid at room temp and usually from animals but oils are liquid at room temp and usually from plant sources

What are exceptions of plant oils?

coconut and palm oil are normally solid

What are some exceptions for animal fats?

fish oil is liquid

What are high in fats?

Animal - meats poultry and dairy products Plant - avocado, seeds, nuts, olives and coconuts

What are invisible fats?

marbling in meat at higher level

What are visible fats?

white striations in bacon and outside trim on meats and also vegetable oils, lard, butter, margarine, shortening, tallow

What is lard fat from?

pork

What is tallow fat from?

beef

What is suet?

hard fat found around kidneys and other organs of cattle and sheep

What does suet provide?

deep rich flavor and color in baked goods used in british and irish cuisines for christmas dishes puddings and savory items

What are fats composed of?

Carbon Hydrogen and Oxygen

What is the difference in fats and carbs composition?

proportions and configurations

Do lipids dissolve in water?

no they don’t

What are the three edible lipids?

Triglycerides (fats and oils), phosopholipids, and sterols

What is a Triacylglycerol?

aka triglycerides and formed through a condensation reaction where the -COOH end reacts with glycerol

What make up 95% of lipids in diet?

triglycerides

What is the composition of triglycerides?

3 fatty acids attached to a glycerol molecule the fatty acids can be identical or different

How do fatty acid’s structures differ?

Length - carbon atoms or degree of saturation - # of double bonds between carbons (2-22)

Which triglyceride is more liquid at room temp?

the more unsaturated fat

Which triglyceride is more solid/firm at room temp?

the more saturated fat

What is a saturated triglyceride?

no double bonds - animal fats, coconut and palm oils

What are monounsaturated triglycerides?

one double bond - olives and canola oils

What are polyunsaturated triglycerides?

vegetable and fish oils

About how many FAs are in nature?

40

What are essential fatty acids?

cannot be synthesized by humans alpha-linolenic and linoleic acid are majorly important

Why are FAs called Omega 3 or 6?

it depends on the position of the first double bond from the methyl group and carbon on methyl end is called Omega carbon and its either 3 or 6 links away

What is the P/S ratio in foods of animal origin?

50:50

What is the P/S ratio?

ratio of polyunsaturated to saturated fats

What is the P/S ratio of plant foods?

85/15

What are animal sources of saturated fat?

butter, poultry (skin), Whole milk (products), processed meats (bacon, sausage etc) Egs - yoke, Red Meats - steak, sirloin, ground beef, ribeye

What are trans fat?

difference in configuration trans means that the Hs on the C double bond are on opposite sides so it keeps the chain straight so it acts like saturated fats

What are Cis fats?

difference in configuration the Hs on the C double bond are on the same side so it bends and is easy for body to process

How do you make trans fats?

by hydrogenation - heating liquid vegetable oils in hydrogen gas and a catalyst (metal) because it makes oils more stable and less likely to be rancid like margarine

What are phospholipids?

similar to triglycerides has fatty acids attached to glycerol but difference is one fatty acid is replaced by a phosphate group

Are phospholipids soluble in water?

the phosphate head is soluble in water but the fatty acid tails are hydrophobic so it creates the phospholipid bilayer in the cell

What fat is the ideal emulsifier?

phospholipids because the hydrophilic and hydrophobic ends disperse in either water or oil best know is lecithin

What are sterols?

large intricate molecules of interconnected rings of carbon atoms with a variety of side chain attachments and they maintain the human body

What is Cholesterol?

a very important sterol made only by animals and it plays a role in bile, sex hormones, adrenal hormones, and Vit D

What are the structure of Sterols?

carbon rings

Is dietary cholesterol different from cholesterol in blood?

sort of, a lot of it is genetics and how our bodies process dietary cholesterol with 85% of blood cholesterol being made in the liver (not the food we eat) and exercise is very important to being healthy