U3

oil seeds

• crushing 2. heating - destroy enzymes

exposing the lipid to enzymes, oxygen and other reactive agents. now many deteriorate reactions can occur

catalyze lipolysis hydrolyzes the ester linkage between glycerol and fatty acids

catalyze direct oxidation of polyunsaturated fatty acids with methylene group between 2 cis double bonds (cis,cis-1,4-pentadiene group)

heat denaturation

• hydraulic pressing • expelling • solvent extraction

use of a screw press to apply pressure and crush the oilseed to force oil out

slow and ineffiecient. due to time factor, the oil is subject to degenerative reactions

virgin olive oil - no chemical treatment

expeller is used - archimedes screw in a barrel increases pressure and squeezes the oil out. it is a mechanical, continuous version of hydraulic pressing

follows expelling since there is still some oil in the cake. organic solvent (hexane) extracts the residual oil from the oilseed cake

advanced, expensive technology required. scale of production must be worth it to purchase the equipment

animal and fish sources. usually waste by-products from meat and fish processing

animal and fish fats have high levels of moisture so a hydrophobic solvent is inefficient

ground fish/meat is heated with steam in a large, high pressure vessel. lipids melt and are released from tissue, allowing fat to be further processed

false - due to each source’s unique properties, a unique process is needed for each

residual press cake after being desolventized

dark brown, smelly, contains a lot of particles, liquid

• free fatty aicds • oxidative breakdown products • phospholipids • metal ions • flavor components work in conjunction to decrease quality and value of oils, so further processing must be done

• settling and degumming • refining • bleaching • deodorization

adding water to the oil. constant centrifuging and steam injection to the tank (increase hydration rate). hydophobic substances - proteins, phospholipids, carbs - hydrate and associate and eventually separate from the oil

soybean oil used as a commercial emulsifier

remove free fatty acids