Lipids (1. LF UK, NT)

They are natural non-polar compounds that are insoluble in water, but are soluble in non-polar solvents.

Importance of lipids

 * they are one of the basic components of food, they serve as a source and reserve of energy (38kJ/g)
 * structural function - they are part of biomembranes (eg: double layer of phospholipids -> form micelles)
 * protective function - they cover some organs and thus protect them from shock
 * thermal insulation
 * solvents of non-polar vitamins (A, D, E, K)
 * precursors

Simple
they contain only the lipid part - triacylglycerols are the most abundant in the human diet
 * acylglycerols - are esters of VMK and glycerol (fats and oils)
 * waxes (animal, vegetable)



Composite
obsahují lipidovou a nelipidovou část - are part of plant membranes - their molecule is amphipathic - they are further divided into sphingomyelins containing ceramide and choline, these include cerebrosides and gangliosides containing carbohydrate and sialic acid - they are amphipathic and are found in the brain and nerves
 * they contain a lipid and a non-lipid part
 * glycoacylglycerols - contain a carbohydrate component
 * phosphoacylglycerols - are part of biological membranes and lipoproteins
 * sphingolipids - their basis is a compound that contains the 18-carbon amino alcohol sphingosine

Derived

 * terpenes
 * steroids

Higher fatty acids
They are the basic component of lipids. They have a high number of C, a high number of non-polar bonds and only one functional group - COOH, which is polar. They are unbranched, have a hydrophobic character and a cis arrangement that is natural in nature and our body can break it down.

Glycerol
=propane-1,2,3-triol, glycerin

It is a sweet viscous liquid, infinitely miscible with water.

Source of dietary fat
extraction of crude fats and oils, sources
 * vegetable – pressing, extraction
 * animal – smelting, extraction

Vegetable fats and oils
Refining
 * slime removal (hydration), vegetable slimes, proteins, their complexes - lecithin
 * deacidification (neutralization) – acid salts
 * whitening – carotenoids, chlorophylls
 * deodorization – tocopherols, sterols

Classification
By consistency
 * oils (liquid)
 * drying - linen
 * semi-drying - sunflower/soybean
 * non-drying - olive
 * fats (plastic, mushy) – lard
 * waxes (hard, non-greasy) – beeswax

By structure
 * 1) fatty acids and their soaps R-[CH2]n-COOH
 * 2) homolipids (esters of fatty acids with alcohols)
 * 3) monohydric alcohols (waxes)
 * 4) * aliphatic (cerides)
 * 5) ** CH3-[CH2]25-OH... ceryl alcohol (beeswax)
 * 6) ** H3-[CH2]15-OH... hexadecan-1-ol, cetyl alcohol (cetaceum)
 * 7) * alicyclic (steroids) - esters of sterols (cholesterol), triterpene alcohols
 * 8) dihydric alcohols (glycols), Alkoxylipids: 1-Alkoxypropane-2,3-diols Chimyl alcohol [[File:ether-glycerolu.jpg]] [[File:tuk_žraloka.jpg]]
 * 9) trihydric (glycerol)  Soubor:glycerol-3syt.jpg tuky a oleje
 * 10) polyhydric alcohols:
 * 11) * sugers – glycolipids
 * 12) ** galactose, galactosides, digalactosides, diacylglycerogalactoside (diacylgalactosylglycerol)[[File:glykolipidy.jpg]]
 * 13) * sacrose (1–3 MK emulsifiers, 6–8 MK low-energy fats (OLESTRA))
 * 14) * sorbitol (sugar alcohols) emulsifiers
 * 15) heterolipids 0.5–2%


 * 1) * glycerol, MK, další složka
 * 2) * fosfolipidy (estery MK) Soubor:fosfolipidy.jpg
 * 3) * sulfáty lipidů (estery MK) Soubor:sulfátylipidu.jpg
 * 4) * sulfolipidy Soubor:sulfolipidy.jpg
 * 5) * lipamidy (amidy MK) Soubor:lipamidy.jpg
 * 6) * serinol Soubor:serinol.jpg, ceramidy Soubor:ceramidy.jpg, cerebrosidy Soubor:cerebrosidy.jpg
 * 7) komplexní lipidy
 * 8) * proteolipidy (lipoproteiny)
 * 9) * glykolipidy (cerebrosidy)
 * 10) * mukolipidy (sialoglykosfingolipidy = gangliosidy)

Související články

 * Mastné kyseliny
 * Odbourávání lipidů a metabolismus ketolátek