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CHE2810 - Food Chemistry > Food Microstructure > Flashcards

Flashcards in Food Microstructure Deck (82)
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What are the 8 structures of food?

Plant Cell Wall
Meat Fibre
And Mixtures of Above


What part of the plant do we eat?

We eat the fleshy tissue cell.
It is a source of dietary fibre and some sources even have starch.


What type of structure does the fleshy plant cells and their walls have?

They have an open cellular structure.
Whereas the walls have a lamella (sandwich) structure


What are the parts of a lamella plant cell wall?

A lamella cell wall has a plasma membrane, a lamella and a primary cell wall.


What is the plant cell walls made from?

These three molecules are good examples of fibre to be introduced into the diet.


What is Cellulose?

It is a Biopolymer/macromolecule which is a polymer of D-glucose connected by Beta(1-4) linkages.


What is Hemicellulose?

It is a long change biopolymer containing different sugar monomers including Xylose, mannose, galactose rhamnose and arabinose.
This makes it way more complicated molecule than cellulose!


What are the two components of starch?

Amylose - D-Glucose alpha(1-4) glycosidic bonds
Amylopectin- D-Glucose but becomes branched due to alpha(1-6) glycosidic bonds


Where are the crystalline and amorphous regions on amylopectin?

The branching point (alpha 1-6 linkage) is the amorphous structure due to the chaos.
The crystalline structure occurs where the straight forks line up side by side (alpha 1-4 linkage).


What are the three levels of fractal muscle

1) muscle tissue is fascicles surrounded by epimysium
2) fascicles are muscle fibres surrounded by perimysium
3) muscle fibres are myofibrils surrounded by sarcolemmas


What is the connective tissue surrounding muscle fibres + fascicles made from?

Collagen and Elastin
Elastin is more for ligaments.


What type of structure does collagen have?

It has a fibrous fractal structure like meat.


What are the main amino acids of collagen?

Glycine, proline and hydroxyproline.


What are sarcomeres?

They are the units that make up myofribrils,
They consist of a thin part and a thick part.
The thin part is made from actin, troponin or topomyosin
The thick part is made from myosin


What are the structures of Actin, Troponin and Tropomyosin?

Actin is a family of globular multi-functional proteins
Tropomyosin is a two stranded alpha-helical coiled protein.
Troponin is a trimeric proetin composed of troponin subunits.


What is the thick myosin structure made from?

A super family of proteins, they have both filamentous and globular structures with the chain components being amino acids.


What is Pectin?

It is a polymer of D-galacturanic acid residues which are largely esterified by methoxy groups.


What are some reason for using structuring agents?

1. Introduce texture
2. Stabilise food structure
3. Enhance shelf life
4. To structure water or other liquids so that they don't "move"


What are some common polysaccharide based food structuring agents?

1. Plant and Plant cell wall based: Starch, cellulose
2. Seed and Sap based: Guar Gum and Gum Arabica
3. Seaweed based: Agar and carrageenan
4. Bacterially produced: Xantham gum


What is the structural application of starch?

It is a secondary gelling agent, it also works as a stabiliser and a thickener.


What sources do we get starch from? what are the benefits for using it?

We get starch from wheat, potato, rice, corn and tapioca. We use it because it is very cost effective.


What sources do we get cellulose from?

Plant cell wall material


What are the structural applications of cellulose?

It can be used as a thickener, suspending aid(emulsions), lubricant and film former.
It also inhibits the production of ice crystals.


what are the sources of pectin?

The are derived from the cell wall of elevated plants and fruit, particularly orchard fruit. eg orange skin.


What are the structural applications of pectin? what two forms can it appear in?

Pectin can either be high methoxyl (highly esterified) or low methoxyl (Low esterification).
The high methoxyl pectin gels in the presence of high sugar
The low methoxyl gels within the presence of cations (Ca2+)


How is starch bonded?

Amylose is alpha D-Glucose (1-4) glycosidic linkages
Amylopectin is Alpha D-glucose (1-6) glycosidic linkages


How is cellulose bonded?

It is Beta D-Glucose (1-4) glycosidic linkages


How is Pectin bonded?

It is a linear polymer of partially esterified alpha -(1-4) Galacturonic acid and mannuronic acid


What are the structural applications of guar gum?

It is typically used as a gel or thickener for products such as pastries, yoghurt and sweet desserts.


What is the source of guar gum?

It is extracted from the endosperm guar plant.