F4+Colour

Distinguish between // dye // and // pigment //:
 * Dye: ** synthetic food-grade-water-soluble colorant (substances which are added to produce color in food)
 * Pigment: ** naturally occurring colorant found in the cells of plants and animals

Explain the occurrence of color in naturally occurring pigments: Color appears from the reflections of light from an object. White light hits the object and some frequencies are absorbed, the reflected frequencies are those that are seen.

Foods have color because they have the ability to absorb different wavelengths of visible light and transmit the remaining light of the visible spectrum which has not been absorbed. The transmitted frequencies are those that are seen - the color of the food.

Describe the range of colors and sources of the naturally occurring pigments anthocyanins, carotenoids, chlorophyll and heme. Anthocyanins, carotenoids, chlorophyll and heme are pigments.
 * || ** Anthocyanins ** || ** Carotenoids ** || ** Chlorophyll ** || ** Heme ** ||
 * Occurrence || Most widespread in **plants** (fruits and vegetables) || Most widespread in **nature** (majority produced by algae)

Precursor of vitamin A synthesis

Vitamin A, Alpha carotene, Beta carotene || Found in ** green plants ** ( necessary for photosynthesis)  || Red blood cells and muscle tissue ||
 * Colors || Pink, red, purple, blue || Yellow to orange to red || Green || Purple - Red ||
 * Associated Proteins || / || Red astaxanthin gives blue/green hue to live lobsters and crabs; gives pink color to salmon || / || Myoglobin gives purplish-red color to muscle (meat)

Hemoglobin gives red color to blood ||
 * Examples in food || Cranberries, blueberries, strawberries, raspberries || Bananas, carrots, tomatoes, watermelon, peppers and saffron || Green vegetables: broccoli, green cabbage, parsley || Fresh meat ||

Describe the factors that affect the color stability of anthocyanins, carotenoids, chlorophyll and heme. Factors affecting the molecule’s structure will, in turn, affect its pigment’s ability to absorb a precise wavelength.
 * || ** Anthocyanins ** || ** Carotenoids ** || ** Chlorophyll ** || ** Heme ** ||
 * Oxidation || Affects position of equilibrium || Unsaturated carbon bonds allow for oxidation catalyzed by light, metals and hydroperoxides =**LOSS** of color (bleached)

*Loss of Vit. A activity = stinky || / || Oxygen binds to purple-red myglobin (Mb), forming red oxymyoglobin (MbO2)

*Fe2+ in MbO2 and Mb

Auto-oxidation of MbO2 and Mb = Fe2+ → Fe3+ (metmyoglobin, MMb) = brown-red color || Therefore, 50°C+ = **LOSS** of color
 * Temperature || Higher temperatures = equilibrium shifts to the right =**LOSS** of color || Stable up to 50°C

Increase heat = //trans//- isomer rearranges to //cis-//isomer || Stability depends on pH High pH (basic) – about pH 9 = thermodynamically stable

Low pH (acidic) – about pH 3 = thermodynamically unstable (**LOSS**)

Increase heat = deterioration of cell membrane = decreases pH = chlorophyll decomposition by light || / || Therefore, pH < 2 and pH > 7 = **LOSS** of color || ­ ­ ­ (refer to temperature) || / ||
 * pH levels || Low pH levels = greater color || Stable in range of pH 2 – pH7
 * Presence of metal ions || Can form complexes with Al3+ and Fe3+ (in tin cans) = **LOSS** of color of canned foods || / || Structure of chlorophyll contains porphin ring (group with 4 nitrogen atoms) which forms complex with a Mg ion

Low pH = Mg ion displaced by 2 H ions = olive-brown pheophytin color || Porphin ring forms complex with Fe ion.

Fe2+ in MbO2 and Mb ||

Discuss the safety issues associated with the use of synthetic colorants in food. Synthetic colorants = dyes

International Numbering System (INS) or E numbers = food additive identifiers

Artificial dyes are potentially carcinogenic (any substance, radionuclide, or radiation that is an agent directly involved in causing cancer) so these particular carcinogens are banned in certain countries.

Therefore in most countries, all ingredients are required to be on packaging labels.

//**__International Food Concerns:__**// Some dyes banned in certain countries but not others. Now with lots of international trade, it has become a concern with the use of these particular dyes.

__Possible solution:__ international legislation on colorant legislation Example of International Food/Colorant Concern: Sunset Yellow in M&M's
 * Banned in Finland and Norway
 * Potential carcinogen
 * Allergic reaction in people with aspirin intolerance
 * Can cause ADHD

List of common food colorants: []

Compare the two processes of non-enzymatic browning (Maillard reaction) and caramelization that cause the browning of food. Natural browning can enhance flavor and appearance of food. There are two different types of natural browning that we have to know: Top of baked egg dishes || Toffees Caramels Fudge Chocolate milk ||
 * || **Caramelization** || **Non-enzymatic browning** ||
 * **Type of Food** || Foods high in carbohydrate content (e.g. sucrose and reducing sugars) || Foods in high nitrogen ||
 * **Process** || Achieved by heating || ** Condensation reaction:
 * Involves reaction of carbohydrate (sugar) with amine group in amino acid
 * Between carbonyl group on sugar and the amine group
 * Presence of amino acid, lysine, results in most browning
 * Presence of amino acid, cysteine, results in least browning ||
 * **Products** || ** Sucrose and glucose form :
 * Acids
 * Sweet
 * Bitter derivatives
 * Volatile molecules
 * Caramel aroma
 * Brown-colored polymers
 * <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.2055in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">Volatile caramel aromas
 * <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.2055in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">Brown caramel-colored products || * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;"> Undesirable colors
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;"> Desirable colors (golden brown)   ||
 * **Affecting Factors** || ** <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.2055in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">pH:
 * <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.375in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">pH < pH3 → acid catalysis occurs
 * <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.375in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">pH > pH 9 → base catalysis occurs
 * <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.2055in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">Temperature:
 * <span style="direction: ltr; margin-bottom: 0in; margin-left: .375in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;"> Boiling does not result in caramelization because 120 ° C is needed || ** <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.2055in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">Moisture lowers temperature so heating in hot oil is:
 * <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.375in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">Good for browning meat, vegetables and flour to make stew
 * <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-bottom: 0in; margin-left: 0.375in; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;">Brings out flavors ||
 * **Examples** || Baking and roasting