Colored fabrics (1. LF UK, NT)
From WikiLectures
Compounds that affect the color of food are called coloring substances. (Color is a visual sensation, dye is a colored substance).
Origin
Primary substances:
- Natural component of food;
- natural component of other materials (microorganisms, algae, higher plants), use as additives.
Secondary substances:
- Enzyme reactions (enzyme browning reactions);
- chemical reactions (reactive dyes).
Synthetic substances:
- Use as additives.
When evaluating the organoleptic properties of food, we can notice color defects.
Natural dyes
Notable groups:
- Tetrapyrrole dyes - vegetable, animal
- Heme dyes, chlorophyll dyes
- Betalain dyes' - vegetable
- Betacyanins
- Betaxanthins
- Flavonoid dyes' - vegetable
- Anthocyanins
- Anthoxanthins
- Phenolic and quinoid dyes' - vegetable, animal
- Phenols
- Quinones
- Carotenoid dyes - vegetable, animal
- Carotenes
- Xanthophylls
Tetrapyrrole dyes
Chlorophyll pigments
Betalain dyes
Flavonoid dyes
Anthocyanins
- Basic structure
- Pelargonidin Pg... R1 = H, R2 = H violet-red
- Cyanidin Cy... R1 = H, R2 = OH purple
- Delfinidin Dp... R1 = OH, R2 = OH blue-violet
- Peonidin Pn... R1 = H, R2 = OCH3 violet
- Petunidin Pt... R1 = OH, R2 = OCH3 dark red
- Malvidin Mv... R1 = OCH3, R2 = OCH3 blue-violet
- Carbohydrates: Glu, Gal, Xyl, Ara, Rha, always C-3, often C-3 and C-5, rarely C-7
- Acids: p-coumaric, caffeic, ferulic
Examples:
- Cyanidin-3-O-β-D-glucoside (generally known)
- (E)-petunidin-3-O-[6-O-(4-O-p-kumaroyl-α-L-rhamnopyranosyl)-β-D-glukopyranosid]-5-O-β-D-glukopyranosid
- Trivially: petanin (red potato variety)
Anthocyanins of fruits and vegetables
- Dependence of coloration on various factors:
- pH of the environment;
- Copigmentation, or transformation to other dyes;
- sulphur dioxide;
- hydrogen peroxide
pH of the medium
- Copigmentation
- Interaction with procyanidins (e.g. catechins, so-called copigments) → colour complex.
- Transformation to other dyes, colour complex → dimer (oligomer), insoluble condensation products, sediments phlobaphenes.
- Sulphur dioxide → colourless sulphonic acids.
- Hydrogen peroxide → colourless products.
Anthoxanthins
Chinoid dyes
Carotene dyes
Enzyme browning reaction
Links
- Tetrapyrrole dyes
- Chlorophyll pigments
- Betalain dyes
- Flavonoid dyes
- Anthoxanthins
- Chinoid dyes]
- Carotene dyes
Source
- ws: Látky barevné (1. LF UK, NT)
- {{#switch: web
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Incomplete publication citation. DAVÍDEK, GeorgeAlso available from <https://el.lf1.cuni.cz/p21372106/>.
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Incomplete citation of contribution in proceedings. DAVÍDEK, George. Also available from <https://el.lf1.cuni.cz/p21372106/>. {{ #if: |978-80-7262-438-6} } |article = Incomplete article citation. DAVÍDEK, George. 11. COMPOUNDS AFFECTING FOOD COLOR. also available from <https://el.lf1.cuni.cz/p21372106/>.
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DAVÍDEK, George. 11. COMPOUNDS AFFECTING FOOD COLOR [online]. [cit. 2012-03-13]. <https://el.lf1.cuni.cz/p21372106/>.
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DAVÍDEK, George. 11. COMPOUNDS AFFECTING FOOD COLOR [CD/DVD]. [cit. 2012-03-13].
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Incomplete database citation. 11. COMPOUNDS AFFECTING FOOD COLOR [database]. [cit. 2012-03-13]. <https://el.lf1.cuni.cz/p21372106/>.
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Incomplete citation of company literature. DAVÍDEK, George. Also available from <https://el.lf1.cuni.cz/p21372106/>. legislative_document = Incomplete citation of legislative document. Also available from URL <https://el.lf1.cuni.cz/p21372106/>.
