Pectin Part 2 Flashcards
Define degree of methylation and degree of esterification and degree of amidation
DM and DE in the context of pectins are used interchangably to talk about the proportion of methyl ester groups to the total number of carboxyl groups in the pectin molecule.
Degree of amidation refers to the proportion of carboxyl groups in the pectin molecule that have been converted to amide groups.
how does pectin stabilize acidified dairy products
The addition of acid to a dairy group can cause coagulation of caesin as it is not stable in acid. So pectin comes in by giving almost like a hug to prevent the protiens from getting too close and coagulating. Pectin will interact with the +ve charged groups in the protien to create a coating which stabilizes the surface. Pectins have a hydrophobic nature beacuse of the acetyl and methyl esters which allows for greate stability since they adsorb to oil water interface creating less surface energy and they increase viscosity in water phase making it so caesin cannot move and there are less interactions.
how does pectin stabilize emuslions
- surface coating: can adsorb to the surface of oil/water droplets and form a coating which acts as a barrier from droplets coming into contact with others directyl
- charge and hydrophobic interactions: because of acetyl and methyl groups being hydrophobic they have an affinity to the oil phase and the hydrophilic parts of pectin interact with the water phase which will stabilize the emulsion and reduce surface energy
- viscosity modification: increases viscosity in water phase which will reduce interaction between droplets by restricting the droplets from moving freely and coming together.
why is pectin used as a fat replacer in products?
because small hydrated particles of pectin can have a similar mouthfeel to fat droplest
What is the application of high methoxyl pectins and low methoxyl pectin and why?
HM: would be used for jams and jellies, acid dairy drinks because of its gelling properties and its role as a stabilizer
LM: low calorie, sugar, things like jams because it doesn’t need sugar to jell and also used as a fat replacement as the calcium creates a better mouthfeel that is similar to fat
- where do we get pectin from typically?
fruit peels
- what are the benefits of pectins?
- dietary fibre
1. control glycemic response
2. reduce LDL-C levels
3. prebiotic
encapsulation
- define pectinase
is a broad term for the group of enzymes responsible for breaking down pectin
- how are pectinases divided and what are the enzymes that degraded those regions
They are divided into enzymes that break down the hairy region and those who degrade the smooth region. the enzymes that break down the hairy region are hydrolases or lysases this region that is made of rhamnoglacturan so rhamanose and glutaonric acid. The smooth region is degraded by esterases and de-polymerases and this region is homogalacturonic so only made up of galacturonic acid
- define hydrolases
cataylse the hydrolysis of substrates by adding water
- define lysases
catylase the removal of groups to leave a double bond in a way other than hydrolysis
- define esterases
desterfying enzymes that remove methoxyl/acetyl residues to make polygalacturonic acid
- define depolymerases and describe two expamples
a broad term for enzymes breaking alpha 1-4 linkages
the two examples are pectate lyase and pectin lyase
- pectate lyase: cleaves glycosidic linkage in pectate which has no methylation groups to form unsaturated product of alpha 4,5-D-galacturonate
- pectin lyase: cleaves pectin to form the same product as pectate lyase but pectin has ester groups so this enzymes does the degradtion without affecting the ester content of polymer chain
