U4 - a + b
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properties of a fat are a function of…
• fatty acid composition 2. fatty acid distribution
difference and similarity between lard and vegetable oil
similar fatty acid content different distribution, causing lard to be solid due to configurations of GS3 and GS2U in lard
characteristic of lard texture
grainy. fixed by interesterification
what is G2SU
glyceride with 2 saturated and 1 unsaturated fatty acid oleopalmitostearin. forms large crystals and causes a grainy texture
when is crystal modified lard formed (CML)
intraesterification conditions
when is partially modified lard (PML) formed
random distribution conditions
when is direct interesterified lard (DIL) formed
directed interesterification (GS3)
what is interesterification
exchange of fatty acids on the glycerol backbone via heat and a catalyst. occurs between triglycerides
potential catalysts for interesterification
tin, lead, zinc, alkali earth metals
difference between interesterification and hydrogenation
both change the physical and chemical properties of the lipid, but interesterification doesn’t produce trans fats
interesterification v intraesterification
inter - between TGs intra - within a TG
what happens when interesterification is undergone at lower temperatures ?
more saturated long-chain glycerides fractionally crystallize out
random esterification
interesterification carried out to equilibrium, assuming random distribution. occurs at low temperatures
directed interesterification
interesterification is directed away from its usual random end-point, allowing the fat to crystallize (GS3 crystallizes first)
is chemical interesterification random or directed?
random
is enzymatic interesterification random or directed?
directed - produces lipids with highly specific compositions for functional uses and mono/diglycerides for emulsifiers
catalyst used at high temperature
KOH and NaOH
catalyst used at low temperature
NaOCH3
cocoa butter melting point
sharp and at body temp
can other fats and oils be modified to produce cocoa butter?
yes! good because this reduces the amount of expensive cocoa butter needed
what can be formed as a byproduct from interesterification
mono and di glycerides used as emulsifiers
4 analytical methods for modified triglycerides
Iodine value saponification value gas chromatographic analysis liquid chromatogroaphy
definition of iodine value
mass of iodine in g absorbed by 100g of a fat sample
what 2 things does IV tell us
degree of unsaturation and source of oil