LIPIDS

A water insoluble compounds, but soluble in ether, benzena, acetone and chloroform Consists of glicerol & 3 fatty acids. Forms: solid lipid liquid fat Energy contents 2.25 times higher than carbohydrate…….WHY??

ENERGY OF LIPIDS H:O higher than carbohydrate They have higher Oxidation potential Ex. Butiryic acid C 3 H 7 COOH (4:1) Glucose C 6 H 12 O 6 (2:1)

Classifition: 1.Simple lipids: esther, fatty acids and glicerol 2.Mixed lipids: simplelipid + other molecules such as N, S, P etc 3.Lipids obtained from hydrolysis

LIPID SYNTHESIS CH 2 OH HOOC-R CH 2 -OOC-R CHOH + HOOC-R  CH-OOC-R + 3H 2 O CH 2 OH HOOC-R CH 2 -OOC-R Glicerol fatty acid fat water

Triacylglycerol Triglycerides R-COO-CH 2 R-COO-CH R-COO-CH 2 Triglycerides found in seeds and animal adipose. Diglycerides found in plant leaves, one fatty acid is replaced by sugar (galactose).

PROPERTIES Determined by structure of fatty acids: 1.Saturated (C n H 2n O 2 ) 2.Unsaturated (C n H 2n-x O 2 )

SATURATED FATS Ex. Acetic acid CH 3 COOH Butyric acid C 3 H 7 COOH Caproic C 5 H 11 COOH Caprylic C 7 H 15 COOH Capric C 9 H 19 COOH Lauric C 11 H 23 COOH etc

UNSATURATED They have double bounds Ex. Palmitoleic acid C 15 H 29 COOH Oleic acid C 17 H 33 COOH Linoleic acid C 17 H 31 COOH Linolenic acid C 17 H 29 COOH Arachidonic acid C 19 H 31 COOH

Most Common Fatty Acids in Di- and Triglycerides Fatty acidCarbon:Double bondsDouble bonds Myristic14:0 Palmitic16:0 Palmitoleic16:1 Cis-9 Stearic18:0 Oleic18:1 Cis-9 Linoleic18:2 Cis-9,12 Linolenic18:3 Cis-9,12,15 Arachidonic20:4 Cis-5,8,11,14 Eicosapentaenoic20:5 Cis-5,8,11,14,17 Docosahexaenoic22:6 Cis-4,7,10,13,16,19 CH 3 (CH 2 ) n COOH

Fatty Acid Isomers

Lipid Content of Feeds Forages Fat content is low: 1 to 4% of dry matter High proportion of linolenic acid (18:3) Diglycerides in fats of leaves Grains Fat content variable: 4 to 20% of dry matter High proportion of linoleic acid (18:2) Triglycerides in oils of seeds

CHEMICAL REATION OF FAT 1.HYDROLISIS A.ENZYMATIK (in GIT) B.WITH ALKALI (SAPONIFICATION) Lipid+alkaline glicerol salt alkaline fatty acid

2. ANALYSIS a.Saponification score- No.of mg KOH needed to form 1 gr fat b.Fatty acids score- No.of mg KOH needed to neutrilise free fatty acid from 1 gr of fat c.Polenske score- No.of mg KOH neede to neutralise insoluble fatty acids from 5 gr of fat CHEMICAL REACTION (CONT...)

d. Iodine score (unsaturation level) - gr iodine absorbed by 100 gr lipid (each double bounds of fat can take 2 iodine atoms) e. Ranacidity Test (level of rancidity) - Peroxida score (using KI) - Tiobarbiturate test - Oven Schaal test CHEMICAL REACTION OF FAT

RANCIDITY 1.HYDROLITIC Presence of lipase causes this reaction to form fatty acid+glicerol NV of feed is not affected 2.OXIDATIVE Occured by the presence of oxigen Energi value of fat reduced

PREVENTION 1.ANTIOXIDANT Compund preventing the occurence of lipid oxidation (rancidity) # PRIMER (to stop chained reaction of free radical formation to release H) # SEKUNDER (to prevent the action of prooxidant) 2.HYROGENISATION ---- lessreaktve 3. Good storage