FOOD CHEMISTRY

Module 13. Beverages

Lesson 28
CLASSIFICATION, COMPOSITION AND GRADATION

28.1 Introduction

A beverage is any product that is used as a drink, for the purpose of relieving thirst and introducing fluids in the body, nourishing the body and stimulating or soothing the individual.

28.2 Classification

The beverages can be classified as follow

1. Carbonated beverages

• Alcoholic: Contains alcohol. e.g. beer
• Non-alcoholic: Contains no alcohol. e.g. soft drinks

2. Non-carbonated beverages

• Alcoholic: Contains alcohol. e.g. wine
• Non-alcoholic: Contains no alcohol. e.g. tea, coffee, cocoa

Alcoholic beverages

Alcoholic beverages are, in essence, flavored solutions of ethanol. The flavors may come from grains (e.g. Beer) or from grapes and other fruit (e.g. Wine) or from any source of carbohydrates, grains, sugar, or grapes (e.g. whiskey, rum, and brandy).

Non-alcoholic Beverages

These types of beverages include the fruit juices, tea, coffee, cocoa/chocolate drinks etc. In order to enhance their thirst quenching and refreshing properties, some drinks are carbonated. Carbonated fruit based drinks are new age beverages which provide nutritional elements of the fruit along with natural colour and flavour in addition to carbonation effects.

Beverages may also be classified according to their function in the body. A particular beverage may have more than one function.
1. Refreshing

i) Plain water

ii) Carbonated beverage containing no fruit juice
iii) Buttermilk with spices

2. Nourishing

i) Milk and milk shakes
ii) Fruit juices
iii) Glucose, lemonade-it refers to noncarbonated soft drink made of a mixture of lemon juice, sugar and water.

3. Stimulating

i) Egg nogs

ii) Coffee or tea
iii) Cocoa or chocolate beverages

4. Soothing

i) Warm milk

5. Appetizing

i) Soups

ii) Fruit juices

28.3 Composition and Gradation of Tea

28.3.1 Composition of tea

A representative analysis of fresh leaf flush is presented in Table given below. Compositional data referring to fresh leaf are based on dry-leaf solids, since leaf moisture varies from 75 to 80%.

Table 28.1 Composition of green tea

Constituents	% (on dry weight basis)
Flavanols	25.0
Flavonols and flavonol glycosides	3.0
Polyphenolic acids and depsides	5.0
Other polyphenols	3.0
Caffeine	3.0
Theobromine	0.2
Amino Acids	4.0
Organic acids	0.5
Monosaccharide	4.0
Polysaccharides	13.0
Cellulose	7.0
Protein	15.0
Lignin	6.0
Lipids	3.0
Chlorophyll and other pigments	0.5
Ash (mineral matter)	5.0
Volatiles components	0.1

28.3.2 Grades of tea

The numerous grades of tea found in the trade are defined by their origin, climate, age, processing method and leaf grade. They can be classified as follows:

1. According to the leaf grade: tea with intact leaves

• Flowery Orange Pekoe and Orange Pekoe: leaf buds and the two youngest leaves.
• Pekoe: It includes leaf buds and the three youngest leaves.
• Pekoe souchong: includes up to coarsest sixth leaf in the young twig.

2. Broken tea: are those with broken or cut leaves similar to above grades in which the fine broken or cut teas with the outermost golden leaf tips are distinguished from the coarse, broken leaves. Broken tea is the preferred product in world trade.
3. Fannings: Small fragments of the broken leaves. It is freed from stalks and stem. Used preferentially for manufacture of tea bags.
4. Tea dust:
5. Brick tea: The tea dust is compressed into a molded brick by sifting, steaming and pressing in the presence of a binder into a stiff, compact tea bricks and portions of it are broken off for us

28.4 Composition of Roasted Coffee

The composition of roasted coffee varies depending on the variety and extent of roasting. Several new flavouring constituents are generated during this process.

Table 28.2 The composition of coffee arabica after normal roasting

Constituents	Content (%)
Lipids	13.0
Protein	9.0
Polysaccharide, water insoluble	24.6
Polysaccharide, water soluble	6.0
Saccharose	0.2
Glucose, Fructose, Arabinose	0.1
Chlorogenic Acids	3.7
Caffeine	1.2
Trigonelline	0.4
Nicotinic Acid	0.92
Volatile Aroma Compounds	0.1
Formic Acid	0.1
Acetic Acid	0.25
Non-Volatile Acids(lactic, pyruvic, oxalic, tartaric and citric)	0.4
Minerals (ash)	4.0
Unidentified constituents	35.0
Moisture	2.5

28.4.1 Grading of coffee beans

Quality of Green Coffee is based on the odor and taste assays as well as on the size, shape, colours, hardness and cross-section of the beans. The plantation grades of cured coffee are:
1. Pea Berry (oval shaped beans)
2. O or A (first size in flats – bold, heavy and well formed)
3. B (slightly smaller than O or A)
4. C (slightly smaller than B)
5. Triage (pale, discolored beans)

A. Composition of CACAO Beans

The compositions of fermented and air-dried cacao nib, cacao shell and germ are presented in Table

Table 28.3 Composition of the fermented and air dried cacao nib or beans

Constituents	Content (%)
Lipids	54
Caffeine	0.2
Theobromine	1.2
Polyhydroxyphenols	6.0
Crude protein	11.5
Mono & oligosaccharides	1.0
Starch	6.0
Pentosans	1.5
Cellulose	9.0
Carboxylic acids	1.5
Ash	2.6
Moisture	5
Other components	0.5