FSCN - Color & extraction

What does the natural color of food indicate?

The degree of sweetness, ripeness, decay, and flavor.

Pigment

A group of natural substances present in animal or plant tissues.

Colorant

A general term referring to any chemical compound (synthetically made) that imparts color (e.g. dye and lake).

Dye

Colorants used in the textile industry, have no place in food usage.

Lake

A food colorant is synthetically made, "referred to as certified colors.”

A classification of food colors: Natural colors

Pigments extracted from animals, vegetables, fruits, and spices used to color foods.

A classification of food colors: Artificial colors

Synthetically produced (chemicals).

Features of natural pigments

Water soluble (Anthocyanins, Betaines, Heme - myoglobin), liquid soluble (Carotenoids, Chlorophylls).

Non-enzymatic browning

Caramelization & Millard browning.

Enzymatic browning

Enzymatic browning is a chemical process, involving polyphenol oxidase, resulting in a brown color. Enzymatic browning generally requires exposure to oxygen.

Climacteric

Fruits sensitive to the plant hormone ethylene, which
causes fruit to mature.

Ripening

Hydrolytic enzymes break down pectin and starches, softening or sweetening foods.

Sweetening

Converting starches to sugar through enzyme activity.

Over-ripening

Leading to microbial growth due to available nutrients as a result of enzyme activity.

What minimizes enzymatic browning?

Lemon juice or other acids, removing copper as a cofactor, blanching, cooling, gas flushing, bisulfites or citrates.

What determines the color of meat?

1. Proteins

2. Age of animal

3. Amount of exercise

4. The storage of meat

Proteins in meat responsible for color of meat

Myoglobin, a protein, is responsible for the majority of the red color. Purplish in color, when it is mixed with oxygen, it becomes oxymyoglobin and produces a bright red color.

Age of animal responsible for color of meat

The meat from older animals will be darker in color because the myoglobin level increases with age.

How exercise affects color of meat?

Exercised muscles are always darker in color, which means the same animal can have variations of color in its muscles.

How the storage of meat affects color of meat

The color of meat can change as it is being stored at retail and in the home. When safely stored in the refrigerator or freezer, color changes are normal for fresh meat.

Myoglobin to Oxymyoglobin to Metmyoglobin Formation

It’s the color and chemical transformation sequence of muscle pigments caused by oxidation — from purple (myoglobin) → red (oxymyoglobin) → brown (metmyoglobin).

The chemical and color changes that occur in muscle pigments due to oxygen exposure and oxidation–reduction reactions.

• Reduced Myoglobin (Mb) – The form where the iron is in the ferrous state (Fe²⁺) and bound to water (FBS = H₂O), giving a purple color.

• Oxymyoglobin (MbO₂) – Formed when reduced myoglobin binds oxygen (FBS = O₂) through oxygenation, producing a bright red color.

• Metmyoglobin (MetMb) – Formed when oxymyoglobin undergoes oxidation (loss of an electron), changing iron to the ferric state (Fe³⁺) and binding to hydroxide (FBS = OH), which gives a brown color.

The process can reverse partly through reduction (electron gain), converting metmyoglobin back to reduced myoglobin.

Myoglobin

A protein found in muscle tissue that stores and carries oxygen within muscle cells.

Oxymyoglobin and metmyoglobin

Oxymyoglobin and metmyoglobin are chemical derivatives (different states or forms) of myoglobin. Oxymyoglobin is the oxygen-bound form of myoglobin, while metmyoglobin is the oxidized form (of myoglobin) in which the iron can no longer bind oxygen.

Structure of myoglobin

Myoglobin is a protein with a heme group in its center, and the iron atom is a key part of this heme group. The iron atom is crucial for myoglobin's function of attracting and holding oxygen for the muscle cells to use during activities like exercise. 

Fruit and vegetable pigments/colors

Chlorophyll, Carotene, and Flavonoids.

Chlorophyll

(Green vegetables) sensitive to heat and acid.

Carotene

(Orange-yellow vegetables) very stable.

Flavonoids

(White and red vegetables) require the presence of an acid to preserve their color.

Features of dairy color

Mostly white (Diffusion of light by fat globules), Blue (In skim diffusion by casein), Yellow (Carotenoids from feed). Brown (Maillard reaction and heat).
[Various added items (Blue cheese, ice cream, yogurts, cheeses].

Yellow and white color for dairy

Carotene: A natural milk colorant from grass. Carotene molecules scatter only the yellow-orange wavelengths of light.

What conditions affect the colors of food?

Cooking temperature, cooking time, cooking methods, use of acids, mixture of ingredients vs individual ingredients, adding colorants.

Mechanisms of seperation

Filters, centrifuges, gravity, by hand.

Extraction

The removal of soluble constituents from solid, liquids or semi solid using defined solvent (WATER). Aims to recover valuable soluble components from raw materials by primarily dissolving them in a liquid solvent, so that the components can be separated and recovered later from the liquid. E.g. oil from oilseeds, coffee from coffee beans, extraction of vitamins, pigments, flavor compounds, etc.

Types of food extractions

Coffee (water extraction), Tea (water extraction), Vanilla (alcohol extraction).

Roasting

Changes during roasting: Caramelization (Starch to simple sugar), Maillard reaction (Sugars react with proteins).

Why is grind size important?

Grind size affects extraction, and therefore the overall flavor and quality of each cup of coffee.

Process of tea

Chemical changes in tea begin immediately after the leaves are picked. During this process, chlorophyll breaks down, tannins are released, and natural enzymatic fermentation occurs. These reactions involve oxidizing enzymes that transform the leaf’s color, aroma, and flavor. Tea is one of the richest sources of tannins, which are polyphenolic compounds responsible for the beverage’s distinct bitter taste and dry, astringent sensation.