Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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Columbus and other early explorers arrived in

America, they found the natives using tobacco much

in the same manner as it is used today. They used it in

their religious ceremonies. The Indians believed that it

possessed medicinal properties, and that was the chief

reason for its introduction in Europe. Indians used it as

a remedy for aches and pains, snakebites, abdominal

and heart pains, chills, convulsions, epilepsy, skin dis-

eases, fatigue, hunger, wounds, sores, and numerous

other ailments. From Europe, tobacco culture practic-

ally spread to the rest of the world. Jean Nicot, the

French ambassador at Lisbon port, in whose honor

the generic name ‘Nicotiana’ wasnamed,issaidto

have sent the seeds of N. tabacum to the queen of

France, Catherine de Medici. Blessed with medical

virtues and a quality to induce trance, smoking became

very popular. Some of the factors that have contributed

to its popularity include income from excise duty, auto-

matic manufacturing machines, which lowered its

price, advertising campaigns, and, above all, social

acceptability. All this led to an increase in the number

of smoking addicts. But at present, the world is turning

away from cigarette smoking, following the American

lead. The decline in smoking in the USA was initially

triggered by the Surgeon General’s reports on smoking

and health. These reports were first published in 1964

and thereafter almost every year. Extension programs

through mass media communications have led to a

decline in smoking throughout the world. But now

the challenge is to sustain this decline. Recent studies

have shown that smoking is on the increase among

teenagers and youths.

Composition

0006 The cigarette burns at about 880



C, and this burning

of the cigarette produces smoke. The lit cigarette

has a steep temperature gradient, 880 to 40



C, which

can be demarcated into three zones: (1) high-tempera-

ture zone (900–600



C); (2) oxygen-depleter pyrolysis

zone (600–100



C); and (3) low-temperature zone

(< 100



C). Cigarette smoke consists of a heteroge-

neous mixture of gases, condensed vapor, and minute

particles. Approximately 4000 chemicals have been

detected in the mixture of gases and tarry droplets

that comprise the cigarette smoke. The major com-

ponents in the tobacco smoke are listed in Table 1.Of

these, over 30 components have been suspected to be

responsible for various health hazards, and of these,

the major components causing or promoting various

diseases are nicotine, carbon monoxide, and tar.

0007 The gas phase accounts for about 60% of the

total cigarette smoke. At least 11 of the gases have

been found to be harmful to lung tissue. These are

formaldehyde, carbon monoxide, acetaldehyde,

acrolein, menthol, acetone, methyl ethyl ketone,

ammonia, nitrogen dioxide, hydrogen cyanide, and

hydrogen sulfide. Carbon monoxide makes up about

3–5% of the cigarette smoke.

0008Nicotine is a dense, oily alkaloid. Pipe tobacco con-

tains 0.6–1.43% nicotine by weight. Cigars and cigar-

ette tobacco have 0.75–3% and 0.9–1.96% nicotine,

respectively. Nicotine has been reported to stimulate

the release of adrenaline (epinephrine) and noradren-

aline (norepinephrine), which have direct influences

on the nerve centers controlling blood pressure and

heart rate. It has been found to raise the tissue lipid

levels and stimulate platelet adhesion.

0009The particulate phase contains a vast number of

compounds, of which more than 250 have been isol-

ated from cigarette smoke. About 30 metals are pre-

sent in the tobacco smoke particulate phase. Several

of these have been found to be carcinogenic. Tar is a

dark brown viscous material composed of condensed

particles from cigarette smoke after moisture and

nicotine have been removed. Strong carcinogens

like polycyclic aromatic hydrocarbons, nitrosamines,

phenols, fatty acids, and their esters, etc., are some of

the constituents that have been detected in tar. The tar

component of cigarette smoke consists of all the par-

ticulate phase and much of the condensable compon-

ents of the gas phase. The burning of an average-sized

cigarette produces 3–40 mg of yellowish brown tar

and about 1–2 mg of nicotine.

tbl0001Table 1 Major components in tobacco smoke

Acetaldehyde

Acetone

Acrolein

Ammonia

Anabaisine

Antabine

Arsenic

Benza(a)antracine

Benzo(a)pyrene

Cadmium

Carbon dioxide

Carbon monoxide

Copper

Cotinine

Formaldehyde

Hydrogen cyanides

Hydrogen sulfide

Menthol

Mercury

Methyl ethyl ketone

Nickel

Nicotine

Nitrogen dioxide

Nitrogen oxides

Nitrosamines

Nornicotine

Polynuclear aromatic hydrocarbons

SMOKING, DIET, AND HEALTH 5317

Why do People Smoke?

0010 This habit stems mainly from psychological and social

drives. It is a psychological tool, helping the smoker to

relieve their stress, to relax, and to be at ease in social

situations. Nicotine is the only psychoactive ingredi-

ent in tobacco smoke. It stimulates the production of

powerful chemical messengers such as epinephrine,

norepinephrine, dopamine, etc. The net effect is a

temporary improvement in brain chemistry that is

experienced by the smoker as enhanced pleasure, de-

creased anxiety, and a state of alert relaxation.

Second-hand Smoke, Environmental

Tobacco Smoke (ETS), and Passive

Smoking

0011 The term ‘passive smoking’ describes the inhalation

by a nonsmoker of the smoke of tobacco products

from a smoke-filled atmosphere. The Journal of the

American Medical Association has reported measur-

able levels of cotinine in the blood of 88% of all

nontobacco users. Cotinine, is a metabolite of nico-

tine, and its presence is proof of a person’s exposure

to tobacco smoke.

0012 The chemical constituents of ETS are derived from

two main sources: (1) mainstream smoke and (2) side-

stream smoke. The mainstream smoke emerges from

the tobacco product during puffing. The side-stream

smoke is produced during smoldering of the cigarette

at the peak temperature inside the glowing cone. The

chemical compositions of the side-stream and main-

stream smoke are different. The temperature of

combustion of the tobacco is different during puffing

and smoldering. The substances are partially absorbed

from the mainstream smoke by the smoker, depending

on the characteristics of the substance, filter, additives,

and depth of inhalation by the smoker. Analysis of the

side-stream smoke has shown that it contains more

combustion products of tobacco than mainstream

smoke. In fact, it contains five times more carbon

monoxide, three times more tar and nicotine, and

four times more benzopyrine. Concentrations of ni-

trosamines can be up to 50 times higher in side-stream

smoke than in mainstream smoke. The smoke in a

smoke-filled atmosphere is mainly from side-stream

smoke, which is a great threat to the health of the

nonsmokers, especially children.

0013 In 1992, the US Environmental Protection Agency

(EPA) studied the respiratory health effects of environ-

mental tobacco smoke. Their report, a compilation of

30 epidemiological studies, concluded that there is a

strong association between ETS exposure and lung

cancer. Scientists estimate that ETS is responsible for

approximately 3000 lung cancer deaths per year

among nonsmokers in the USA. On the basis of the

health hazards of ETS, the EPA has classified second-

hand smoke as a Group A carcinogen. ETS has also

been linked with eye and nasal irritation in adults and

middle ear infections in children, it also affects the

cardiovascular system and causes acute and chronic

coronary heart disease. ETS has also been linked with

other cancers, including those in the nasal sinus cavity,

cervix, breast, and bladder. Animal experiments sup-

port the view that second hand smoke can induce

tumor formation.

0014In adults, ETS can worsen existing pulmonary

symptoms for people with asthma and chronic bron-

chitis, as well as for people with allergic conditions.

Even individuals who are not allergic can suffer eye

irritation, sore throat, nausea, and hoarseness. Con-

tact lens wearers can find tobacco smoke very irritat-

ing. Pregnant women, newborn children, and asthma

sufferers have an increased vulnerability to cigarette

smoke. It affects the development of the fetus and

causes impaired growth, low birth weight, and

sudden infant death syndrome (SIDS). Children are

at particular risk from passive exposure to cigarette

smoke, since they are more vulnerable to air pollu-

tants and respiratory pathogens. Moreover, an infant

or toddler has little opportunity to move away from

the smoking parent.

Effects of Smoking on the Body

0015There is now an extensive body of evidence – includ-

ing epidemiological, experimental, pathological, and

clinical studies – to demonstrate that smoking

increases the smoker’s risk of death and illness from

a wide variety of diseases.

Tongue

0016The pollution begins from the tongue. The surface of

the tongue of a smoker who smokes on average 50

cigarettes per day results in a loss of taste. Inflamma-

tions are also found in the mouth cavity. The smoke

causes pathological changes in the lingual papillae and

adversely affects the mucous membrane of the mouth.

Ears

0017Smoking weakens hearing too. Even 20 cigarettes per

day can weaken normal reception of speech.

Eyes

0018Researchers at the Johns Hopkins University have

found evidence linking cigarette smoking and forma-

tion of cataracts. The eyes are quite sensitive to nico-

tine. Within a few seconds of the first puff, irritating

gases (formaldehyde, ammonia, hydrogen sulfide and

5318 SMOKING, DIET, AND HEALTH

others) begin to work on sensitive membranes of the

eyes. Adverse ophthalmic effects of active smoking

include glaucoma, cyanide-induced optic neuritis, cor-

neal arcus, and vascular changes in the retina. The

associated problems include a restriction to visual

field, impaired reactions to dazzling light, etc. Smokers

tend to have a deficiency of vitamin B

. This defi-

ciency is responsible for a disease called amblyopia.

Tobacco amblyopia can produce dimming of vision in

the central part of the visual field. Sufferers find it

difficult also to distinguish between red and green.

Nose

0019 Heavy smoking causes chronic inflammatory swell-

ing of the nasal mucosa and damages the receptor

cells, thus impairing the sense of smell. There is also

an increase in the risk of nasal carcinoma in heavy

smokers. Chronic exposure leads to damage of the

olfactory cells, causing insensitivity to odors.

Lungs

0020 Smoking directly irritates and damages the respiratory

tract, and the respiratory rate increases. Irritating

gases can damage the tissues of the lungs, and the

airways leading to the lungs. This speeds up the

production of mucus and leads to an increased ten-

dency to cough up sputum. The excess mucus serves

as a breeding ground for microbes. The lining of the

bronchi begins to thicken and predisposes to cancers of

the bronchi. The smoke weakens the free moving scav-

enger cells that remove foreign particles from the air

sacs of the lungs, and continued smoke exposure leads

to a variety of symptoms, including bad breath, cough,

sputum production, wheezing, and respiratory infec-

tions such as bronchitis and pneumonia.

0021 Many compounds that are inhaled are deposited as a

layerof tar onthelining of thethroat and bronchiandin

the delicate air sacs of the lungs. This tar is rich in

carcinogenic compounds. Lung cancer accounts for

nearly 30% of all cancer deaths in the USA, and

smoking accounts for nearly 90% of cancer deaths.

The risks of dying from lung cancer are 23 times higher

for male smokers and 13 times higher for female

smokers than for nonsmokers. Additionally, smokers

areatincreased riskfor cancer ofthelarynx and theoral

cavity, and smokingcausesafivefold increase intherisk

of dying from chronic bronchitis and emphysema.

Cardiovascular System

0022 The effect of smoking on the heart and blood include

an increased blood clotting rate, increased level of

catacholamines, increased heart rate, decreased

oxygen supply to the heart muscle, increased irritabil-

ity to the electrical conducting system of the heart,

and increased blood pressure. Blood pressure in-

creases by 10–15%. Smoking increases the risk of

vascular diseases of the extremities. Carbon monox-

ide from the blood binds competitively to the oxygen

receptor sites of blood cells. Hemoglobin bound to

the carbon monoxide is converted to carboxyhemo-

globin, and so, less oxygen reaches the brain and

other vital organs.

0023Cigarette smoking is now recognized as a major

risk factor for atherosclerosis. A number of studies

have indicated a close association between cigarette

smoking anddevelopment of arteriallesions. Increased

levels of tissue and serum cholesterol, triacylglycerols,

and low-density lipoproteins (LDL), and low levels of

high-density lipoproteins (HDL) have also been

reported. A greater concentration of very-low-density

lipoprotein cholesterol and a lower concentration of

apoprotein 1 and HDL-C with a predominant decrease

in the subfraction HDL2 have been observed in

smokers. Alterations in the lipid profile have also

been reported in the offspring of dams exposed to

cigarette smoke. Lipid peroxidation and associated

lipoprotein oxidation caused by cigarette smoke also

accelerate the development of cardiovascular prob-

lems. Oxidized LDL is selectively taken up by mono-

cytes/macrophages, unlike native LDL, resulting in the

formation of cytokine-producing foam cells.

Skin

0024Smoking constricts the blood vessels of the skin, thus

decreasing the delivery of oxygen. Hence, a smoker’s

skin becomes more susceptible to wrinkling. Smokers

are at a particular high risk for a medical syndrome

called smoker’s face, which is characterized by deep

lines around the corners of the mouth and eyes, a

gauntness of facial features, a grayish appearance of

the skin, and certain complexion abnormalities.

Male Reproductive System

0025Impotency has been observed in male smokers. Re-

searchers have concluded that decreased potency

might result from the detrimental effect of smoking

on the blood vessels leading to the reproductive

organs. Smoking can cause erection problems, de-

creases in sperm count and sperm motility, and

impaired sperm morphology.

Female Reproductive System

0026Women who smoke experience gender-specific health

consequences, including an increased risk of various

adverse reproductive outcomes. A decline in fertility

and earlier menopause have also been observed in

women smokers, and smoking has been consistently

associated with an increased risk for cervical cancer.

SMOKING, DIET, AND HEALTH 5319

Smoking alters the level of estrogens and other hor-

mones and interferes with hormone-related disorders.

Some studies have suggested that cigarette smoking

might alter menstrual function by increasing the risks

for dysmenorrhea, secondary amenorrhea, and men-

strual irregularity.

Fetus

0027 Scientific literature published in the twentieth century

has indicated that cigarette smoking during preg-

nancy adversely affects the fetal development and

the development of the baby. A variety of mechanisms

have been suggested, whereby maternal smoking

habits could influence fetal health. These include the

underlying constitution of the smoker, changes in

nutrition, and impaired oxygen delivery, as well as

specific effects of nicotine and polycyclic aromatic

hydrocarbons upon the parents, uterus, and fetus.

Placental transfer of nicotine has been observed.

Nicotine has also been detected in the breast milk of

female smokers. Fetal hemoglobin has a stronger af-

finity for carbon monoxide than maternal hemo-

globin. In addition to this, nitrogen oxides oxidize

hemoglobin iron in the ferrous form to the ferric

form, to produce methemoglobin. Cyanide combines

with methemoglobin, forming cynomethemoglobin.

Cyanide also inhibits cytochrome oxidase. The com-

bined effect of all of these leads to a hypoxia condi-

tion and affects fetal growth and delivery process.

Infants born to women exposed to environmental

tobacco smoke during pregnancy have a small decre-

ment in birth weight and a slightly increased risk

of intrauterine growth retardation compared with

infants of nonexposed women. The risk for perinatal

mortality – both stillbirth and neonatal deaths – and

the risk for SIDS are increased among the offspring of

women who smoke during pregnancy.

Paternal Smoking

0028 A few studies have revealed the effects of paternal

smoking and genetic damage to the fetus. The to-

bacco smoke containing carcinogens may reach the

gonads through the blood. Since spermatogenesis

continues throughout the male’s reproductive period,

these carcinogens may genetically alter the sperm.

There is an increased risk of genetic defects to the

offspring of fathers who smoked at the time the

child was conceived.

Immune System

0029 Cigarette smoking weakens the immune system by

depressing the antibody response and decreasing

cell-mediated reactions to foreign invaders.

Brain

0030A reduced level of oxygen carried to the brain can

produce lethargy, confusion, and difficulty in think-

ing clearly.

Oxidative Damage and Pathogenesis

0031One of the major mechanisms for smoke-induced

injury is the oxidative damage. Five per cent or

more of the oxygen is converted to reactive oxygen

species (ROS) such as O



,and

OH. This

process can be represented as

Super oxide anion Hydroxyl radical

−

0032The super oxide radical is formed in almost all aer-

obic cells by three ways:

0033Normal oxidative metabolism.

0034Microsomal cytochrome P

450

activity that is indu-

cible by a variety of foreign compounds.

0035Respiratory burst of stimulated phagocytes.

Free radicals have an odd electron intheir outer orbital,

and so they tend to be hyperactive to attain a stable

form. They either abstract electrons from, or donate

their odd electrons to, other molecules in their proxim-

ity. In this process, they modify and damage biomole-

cules. Metal ions like cadmium, iron, and copper are

powerful promoters of free-radical generation.

0036The gaseous and tar phases of cigarette smoke con-

tain high levels of carbon and oxygen-centered free

radicals as well as NO

and NO

(which are capable

of attacking compounds with >C

—

C< bonds), which

can directly initiate and propagate the process of lipid

peroxidation of membrane lipids both in vivo and

in vitro. Their approximate concentrations in the

gaseous and tar phases are, respectively, 10

per puff

and 10

per puff. Cigarette smoke also contains traces

of metal ions – cadmium, copper and iron – that are

powerful promoters of free-radical generation. They

can react with H

to form OH

, the most reactive

oxygen radical known. Cellular antioxidants (vitamin

C, E, glutathione, selenium, etc.) and free-radical scav-

engers (super oxide dismutase, glutathione peroxid-

ase, catalase, etc.) normally protect a cell from the

toxic effects of ROS, but when the balance between

ROS production and antioxidant defenses is lost, oxi-

dative stress results, which, through a series of events,

deregulates the cellular activity leading to various

pathological conditions. These reactions can alter the

intrinsic membrane properties like fluidity, ion trans-

port, and loss of enzyme activity, protein cross-linking,

inhibition of protein synthesis, DNA damage, and,

5320 SMOKING, DIET, AND HEALTH

ultimately, cell death. This is the underlying mechan-

ism of the formation of various diseases, including

cardiovascular dysfunction, neurodegenerative dis-

eases, gastroduodenal pathogenesis, metabolic dys-

function of almost all vital organs, cancer, and

premature ageing. Polyhydroxyl aromatic compounds

present in tar have been proposed to bind to genetic

material, leading to the generation of H

, which in

turn causes DNA strand breakage via a hydroxy rad-

ical-dependent mechanism.

Other Forms of Smoking

Cigar Smoking

0037 Cigar smoking is increasing in the USA, since it is

considered to be a safer alternative to cigarettes, but

this is not so. It is a risk factor for cancer of the

mouth, throat, larynx, esophagus, and lungs.

Beedi Smoking

0038 In India, Beedi (tobacco wrapped in tendu (Diospyros

melanoxylan Roxb.; Fam: Ebenaceae) leaf) is used for

smoking, mostly by people belonging to lower socio-

economic strata. Other forms of smoking are chutta,

a type of homemade cigar smoked with the lit end

placed inside the mouth, hookahs (or water pipes),

and pipes. Contrary to the belief that traditional

forms of smoking are less dangerous than smoking

cigarettes, it was found that the relative risk of cancer

and cardiovascular problems were higher in the users

of beedi, chutta, or hookhas.

Strategies to Keep Healthier

0039 Quitting cigarette smoking is the best measure to

keep healthy, but some may find it difficult to give

up the habit. A reduction in the number of cigarettes

smoked, and a change in the life pattern may provide

some protection from smoke-induced toxicities.

Exercise

0040 In addition to the psychological benefits, a few stud-

ies have suggested that smokers who begin exercising

regularly may also obtain a small degree of protection

against the health risks of of smoking.

Nutrition

0041 It is widely accepted that smoking tends to reduce

nutrient intake, but it is not known for sure whether

it acts directly upon the satiety centers, affects the

sense of taste or smell, or operates less directly

through psychological mechanisms. Smoking itself

reduces the intake of vitamins such as ascorbate,

tocopherols, and folate. Smokers have low levels of

vitamin C and carotene. An in-vitro study showed

that a wide spectrum of lipophilic micronutrients

(retinal, carotene, vitamin E) undergo degradation

when exposed to the gas phase of cigarette smoke.

Experimental and epidemiological studies have found

some deficiencies of antioxidants in smokers.

0042The toxicities caused by smoking are mediated

through ROS. Hence, a diet rich in vegetables and

fruits is especially beneficial in reducing the toxicities

induced by smoking. Their beneficial effects are due

to the presence of antioxidants and anticancer nutri-

ents (vitamins A, C, and E, selenium, isothiocyanates,

indoles, calcium, fiber, vitamin B

, etc.). Many

human studies have supported this view. There is a

fivefold decrease in risk ratio for cataracts in persons

consuming 1.5 servings of fruits and/or vegetables.

Vitamin B

helps to detoxify the cyanide found in

tobacco smoke. Smokers excrete more of this vita-

min. This condition is treated with large doses of

vitamin B

. Hence, supplementation of antioxidants,

either through increased intake of vegetables and

fruits or through supplements, is essential in a

smoker’s diet.

0043Smoking is an independent risk factor for athero-

sclerosis. It increases the lipid content of tissues and

serum, and so a low-fat diet rich in fiber is ideal.

See also: Antioxidants: Natural Antioxidants; Synthetic

Antioxidants; Synthetic Antioxidants, Characterization

and Analysis; Role of Antioxidant Nutrients in Defense

Systems; Ascorbic Acid: Properties and Determination;

Cancer: Carcinogens in the Food Chain; Diet in Cancer

Prevention; Diet in Cancer Treatment; Carcinogens:

Carcinogenic Substances in Food: Mechanisms;

Coronary Heart Disease: Etiology and Risk Factor;

Antioxidant Status; Intervention Studies; Prevention;

Minerals – Dietary Importance

Further Reading

Bendich RJ and Deckelbaum J (eds) (1997) Preventive Nu-

trition: The Comprehensive Guide for Health Profes-

sionals. Totowa, NJ: Humana Press.

Ferguson T (1987) The Smoker’s Book of Health. New

York: G.P. Putnam’s Sons.

Halayya M (1992) Stop Smoking and Start Living.

Calcutta: Rupa & Co.

Kumar A (1999) Environmental tobacco smoke: A big

threat. In: Environmental Problems Protection and Con-

trol, vol. 2. New Delhi: Anmol.

Rana Sastry BV and Janson VE (1995) Smoking, placental

function and fetal growth. In: Ramasastry PV (ed.) Pla-

cental Toxicology. Boca Raton, FL: CRC Press.

SMOKING, DIET, AND HEALTH 5321

SNACK FOODS

Contents

Range on the Market

Dietary Importance

Range on the Market

A S Bawa and J S Sidhu, Guru Nanak Dev University,

Amritsar, India

Introduction

0001 The term ‘snack’ or ‘snack food’ is difficult to define

or categorize. The dictionary meaning of snack is a

‘titbit’ which is a small meal in the broadest sense.

Snacking can be described as the problem-free con-

sumption of easy-to-handle, miniature-portioned, hot

or cold products in solid or liquid form which need

little or no preparation and are intended to satisfy the

occasional pangs of hunger. Thus snacks should be in

convenient manageable portions satisfying short-

term hunger. The different categories of snack foods

are given in Table 1.

0002 Snacks can be sweet or savoury, light or substan-

tial, and they may be endowed with attributes such as

healthy or just for fun. In European markets the word

‘food’ is omitted. This article deals with various

aspects of different snack foods and the quality

checks involved.

0003 Snack foods are a significant part of the food indus-

try. The dominant leader is still potato chips (crisps),

followed by extruded snacks, corn chips, nuts, meat

snacks, pretzels, and popcorn.

Potato-Based Products

0004Potato-based snacks can be made either exclusively

from fresh, sliced potatoes or from potato dough. The

chips in the latter case are called simulated potato

chips. The steps involved in potato chip processing

include selection, procurement and receiving, storage

under optimum conditions, peeling and trimming of

potato tubers, slicing, frying in oil, salting, or the

application of flavored powders and packaging. (See

Potatoes and Related Crops: Processing Potato

Tubers.)

0005Potato must be of high specific gravity in order to

obtain superior yield, low oil absorption, and low

reducing sugar content. Peeling should remove only

a very thin layer of potato, leaving no eyes, blemishes

or other material for later removal by hand trimming.

The chips from peeled and unpeeled potatoes are

similar in appearance, flavor, and shelf-life. The

chips from unpeeled potatoes have higher oil contents

but omission of the peeling step results in a 7%

increase in potato solids and a reduction in waste.

0006The peeled potatoes are cut into slices 10–17 mm

thick by rotary slicers. Slices must be very consistent

in thickness in order to obtain uniformly colored

chips. Slices with torn surfaces lose excess solubles

from the ruptured cells, and absorb large amounts of

fat. Starch and other materials released from cut cells

are washed away prior to frying and the surface of the

tbl0001 Table 1 Snack food categories and examples of products in each category

Category Product

Hot snacks Minipizzas, pizza baguettes, etc., toasts au gratin, cup noodles, spring rolls, filled croissants

Cold snacks

Milk and dairy products Yogurt, plain or with fruit, mini cheese cubes

Bakery products Cake bars, minitarts, biscuits

Bars Granola or muesli bars, chocolate bars, minibreak bars, energy bars

Savory products Chips (crisps), sticks, crackers, pretzels, salt sticks

Other products Popcorn, puffed cereals, rice snacks, fruit sticks, dip sticks, tortilla chips, fruit snack bar

Confectionery Plain cookies, deposit cookies, macaroons, wire-cut cookies

Extruded snacks Potato sticks, cereal-based tubes with cheese filling, corn pellets and chips

Low-pressure extruded fried snacks Sev, omumbadi, murukku

Nut-based snacks Roasted peanuts, fried peanuts, coated and fried peanuts, toasted and salted pecans, roasted

and salted almonds, sugared and spiced nuts, flavored nuts and nut mixtures

Legume-based Indian snacks Fried green peas, chick peas, lentils, dhals, fried products from bengalgram meal

Meat-based snacks Expanded pork rinds or skeen, jerky, chimni

From Tettweiler P (1991) Snack foods worldwide. Food Technology 45: 58.

5322 SNACK FOODS/Range on the Market

slices dried; this step shortens the frying time and

increases the capacity of the cooking unit.

0007 The rinsed and dried potato slices are conveyed

directly to the frier. The fried slices are removed from

the tanks and drained on mesh belts. The temperature

of oil in friers is held within a narrow range. Tempera-

tures normally used are 176–190



C at the receiving

end and 160–173



C at the exit end of the frier.

0008 The oil used for deep-fat frying of potato chips has

two functions: (1) it serves as a medium for transfer-

ring heat from a thermal source to the tuber slices;

and (2) it becomes an ingredient of the finished prod-

uct. The oil should be highly refined. The flavor and

appearance of chips are affected both by the amount

of oil absorbed and its characteristics as it exists in the

chips. The amount of oil absorbed by potato slices is

affected by: (1) the solids content of the tuber; (2) the

temperature of the fat; (3) the duration of frying; and

(4) the thickness of slices. Fat pick-up by potato chips

is 10–15% lower when the chips are fried in liquid oil

as compared to fat which is solid at room tempera-

ture. Reducing slice thickness increases the oil content

of chips. A hot-air blast at the point where the slices

emerge from the fat reduces fat absorption, and

partial drying of sliced potatoes before frying also

reduces the oil content of chips. Leaching raw slices

with hot water results in an increased uptake of oil.

The treatment of slices with glucose oxidase produces

a chip of higher uniform color and lower oil absorp-

tion, without off-flavors.

Baked Snacks

Soda Crackers

0009 Soda crackers and variants, suck as saltines, oyster

crackers, etc., are themselves used as snacks, and also

serve as a basis for combination snack foods either

made in the home (crackers and cheese) or by manu-

facturers (cheese crackers, peanut butter and cracker

sandwiches, etc.) The soda cracker is made from a

lean, fermented dough. It does not contain much

shortening, sugar, or milk. (See Biscuits, Cookies,

and Crackers: Nature of the Products; Methods of

Manufacture; Wafers.)

0010 Flour constitutes 80% or more of finished crackers.

Its qualities are important in determining the machin-

ing qualities of the dough, as well as the texture of the

end product. Weak flours and lengthy fermentation

times combine to yield flat, tender crackers. Flour for

thick saltines should be stronger than for thin

crackers. Thin saltines require a weaker flour; salt

may be added at a rate of 2–5% to the dough.

0011 Sprayed crackers are rich crackers, round in shape,

and usually made from chemically leavened dough.

Many of the representatives of this class could be

considered a cross between crackers and cookies be-

cause they are not only leavened but also sweeter than

saltines. The leavening system for these is adjusted so

that the pH of the finished products is below neutral-

ity. A pH of 6.5 is regarded as desirable. Sprayed

crackers are coated with 20–25% (w/w) of a blend

shortening. Coconut oil is preferred, but peanut oil or

even hydrogenated vegetable shortening can be used.

The oil is applied either by spraying at 65–71



C, or

by a device similar to an enrober, in which the

crackers pass through a flowing curtain of oil. The

oil must be applied when the crackers are still hot.

The crackers may be salted very lightly on the cutting

machine.

Cheese Crackers

0012Cheese crackers are usually made from fermented

dough and they must be on the acid side of neutrality

to yield a typical cheese flavor. The formulation is

based on the soda cracker, except that fat and mois-

ture added in the fresh cheese have to be compensated

for. Paprika (0.25%) and a very small amount of

cayenne are added to Cheddar cheese crackers to

intensify the color and to add a flavor which is com-

plementary to cheese crackers to impart certain desir-

able characters. Natural cheese should be finely

ground before being placed in the mixer. Sometimes

a premix of ground cheese and shortening, kept pre-

viously in the fermentation room for 24 h, is added at

the doughing stage. This holding stage encourages the

development of more flavor, and leads to a better

dispersion of cheese in the dough. Artificial Cheddar

and blue cheese flavors are also used whenever

required.

Pretzels

0013Pretzels are considered to be the world’s oldest snack

food, and may have originated around ad 610 on the

borders of France and Italy. Pretzels then become a

popular snack food in Germany and Austria, where

they were called ‘pretzel,’ later to be altered to today’s

pronunciation, ‘pretzel.’ Originally, all pretzels were

soft, like unleavened bread. Accidentally, some pret-

zels were left in a cooling oven and the remaining heat

dried them, removing the moisture and giving them a

hard crisp texture and a golden coating. This led to

the introduction of hard pretzels.

0014Soft pretzels today are baked, not dried, and have a

texture resembling that of a fresh, soft roll, as well as

a high moisture content. Soft pretzels are popular as a

snack purchased at street vendors’ stands. Hard pret-

zels have an extremely long shelf-life, especially when

stored in airtight containers. Hard pretzels can be thin

or thick, and shaped as twists, sticks, nuggets, logs, or

SNACK FOODS/Range on the Market 5323

rings. They can be buttered, wholewheat, sesame-

coated, chocolate-dipped and ‘teething.’ It is the

drying which gives the hard pretzels their distinctive

crunch, and this crunchiness is fundamental to the

appeal of hard pretzels.

0015 Pretzel doughs are made very stiff so that they can

withstand the punishment of machining without be-

coming sticky or misshapen. The sponge is fermented

for a shorter time than with cracker dough. Doughs

receive a short proof stage but machinery steps,

including formation of the pretzel, are handled

automatically in all but a very few small plants. The

characteristic gloss of the pretzel is the result of a lye

dip. The lye dip solution contains about 0.5% sodium

hydroxide or 2% sodium carbonate and is main-

tained at about 100



C. The immersion time is about

10 s. The solution may also be applied by spraying.

Immediately after the pretzels leave the caustic solu-

tion they are salted. The general aim is to achieve 2%

salt in the finished product, but it is necessary to keep

the initial application rate at 8–10%, to allow for

losses in processing. A long drying time is required

to reduce the moisture content to 2–2.5%, and

temper the pretzel so that it does not break too easily

during packaging. The long pretzels can be twisted or

stick-type. Stick pretzels are extruded using a group

of five extruding heads having 10–12 holes each. Logs

and nugget-type pretzels are made in a similar manner

to that used for the sticks, except that they are cut into

short lengths at the extruded head. The stick pretzels

can be made from almost any flour, but the choice of

flour used in twisted pretzels is critical.

0016 Filled pretzel sticks or nuggets are also available.

These are produced by drilling a hole in the com-

pletely baked pretzel stick, and then inserting a

paste-like filling of peanut butter and cheese, along

with oil and sugar or a nonsweet agent such as lactose

or dextrin.

Confectionery (Sugar-Rich Products)

0017 Plain cookies are the cookies made in one operation,

and this group does not include filled, coated, sand-

wiched, and other multiple-component cookies. The

continuous structure of a cookie arises from the flour,

and this basic framework is tenderized with sugar,

invert sugar, egg yolk, ammonia, soda (or baking

powder), and shortening. It is firmed or toughened

with water, cocoa, egg white, whole egg, milk solids,

and the leavening acids. Shortening is one of the

principal agents for increasing tenderness, at least as

far as rich, sweet biscuits are concerned. Too much

shortening leads to a greasy smeary cookie which is

susceptible to rancidity because of the free fat, while

too much sugar results in hard and excessively sweet

cookies.

0018A wide variety of flours can be used, varying from

a soft cookie flour to a rather strong sponge flour.

The stronger the flour, the more shortening and sugar

are required to obtain an acceptable texture. High

protein contents lead to hardness of texture and

coarseness of internal grain and surface appearance.

Chlorine-bleached flours should not be used for soft

cookies where relatively large amounts of tenderizing

and moisture-retaining ingredients, such as sugars,

shortening, and egg yolk, are used. Cookies may

become fragile if the quantity of flour is decreased

too much.

Deposit Cookies

0019Deposit cookies are machine-made counterparts of

the ‘hand-bagged’ cookies. They contain about 35–

40% sugar, 65–70% shortening, and 15–25% liquid

whole egg. The flour should be from soft wheat,

unbleached with 8–8.5% protein and 0.35–0.40%

ash. It should have a viscosity of 40 Ns/m

and a

spread factor of 79–80. The flour should be able to

carry sugar and shortening without too much spread,

so that the top design is preserved through baking.

The flour or other ingredients must contribute

enough adhesive properties to the dough so that it

will adhere to the band and pull away from the main

column of the dough in the deposit stage.

0020Macaroons are made by a cold, or hot syrup

cooking process, but they should not be made by the

cold process unless they are to be consumed within 3

days.

Wire-Cut Cookies

0021The dough composition varies over a wider range for

wire-cut cookies than for any other type. Thus the

dough material should be sufficiently cohesive to hold

together as it is extruded through an orifice, and yet

be nonstick and short enough so that it separates

cleanly as it is cut by wire. These cookies can be

further subdivided as follows: (1) drop-type, which

are used in sandwich cookies filled with a marshmal-

low or imitation cream, and usually containing equal

amounts of sugar and flour; (2) sugar cookies,

molasses cookies, coconut, raisin, date and honey

varieties; (3) shortbreads, in which the shortening

content is usually 50–70% of the flour content; and

(4) macaroons, with little flour and large proportion

of sugar.

Nut-Based Snacks

0022Nuts are often used to upgrade popcorn-based

snacks, and are also themselves sold for snacks either

as the individual variety or as mixed nuts.

5324 SNACK FOODS/Range on the Market

Peanuts

0023 The chemical composition of peanut is approxi-

mately 46% fat, 26% protein, 18% carbohydrate,

6% water, 2% ash and 2% fiber.

Roasted Peanuts

0024 Peanuts are sorted, blanched, roasted, and salted.

Blanching for peanuts and other nuts means removal

of the skin or testa. During roasting, the kernels

become dehydrated, and browning reactions occur

throughout the kernel. The texture, flavor, and ap-

pearance change markedly. Toasting can be continu-

ous or batch-type, and dry or in oil. The unique

nutty flavor of roasted peanuts results from

browning reactions of the Maillard type. The type

of roasting affects the course of browning reactions

because of variations in the rate of heat penetration

and exposure to high temperature in different parts

of the nut. Adhesion of salt to dry-roasted nuts is

achieved by adding about 2% (w/w) coconut oil as a

dressing to the warm nuts, and immediately apply-

ing the salt. The salt must have small particles

of irregular configuration to obtain maximum

adherence.

Fried Peanuts

0025 Peanuts are fried at different temperatures depending

on the flavor the customer wants to impart. Most

peanuts are fried at temperatures around 140–

160



C but some customers prefer a slightly higher

temperature in order to impart a roasted-burnt flavor

into the peanut.

0026 After the peanuts are removed from the frier, it is

essential to reduce their temperature rapidly as they

retain a lot of heat and will continue to darken as the

Maillard reaction continues to occur with elevated

temperatures. When they are cooled glazing oil can

be applied to allow salt or flavoring to adhere to the

peanuts. When nuts are fried in hydrogenated fat,

the salt is applied before they are cooled to room

temperature and while the fat on the surface is still

molten. As the fat cools and sets, the salt granules are

held firmly.

Coated and Fried Peanuts

0027 A typical process would involve the peanuts being

placed into a coating pan with a small quantity of

starch. The peanuts will be roasted to insure they are

completely coated. An adhesive solution will be

placed on to the edge of the coating pan and the

drum rotated. Starch is added on top of the peanuts

and they are again rotated to insure the coating is

smooth. This process is repeated until the desired

coating thickness is achieved.

0028When the peanuts are deposited into the frying

system, the starch contained within the coating will

begin to gelatinize. This causes the exterior of the

product to become sticky and the peanuts must be

agitated to prevent them from sticking together. The

peanuts are fried at a temperature of approximately

145



C. The frying time varies due to different types

and levels of coating on the peanuts. Peanuts that are

completely coated require a longer fry time and lower

temperature than peanuts that are only partially

coated. The recommended frying temperature is

lower than the temperature at which caramelization

of sugars begins (i.e., 160



C). This limits the color

development of the coating and allows the moisture

to be removed from the center of the peanut before

the outside coating darkens. The moisture content of

the interior of the peanut needs to be reduced to

below 2.0% to produce a shelf-stable product. After

frying the peanuts are cooled and can be flavored if

desired. (See Peanuts.)

Pecans

0029Toasted and salted pecans are used directly as snacks.

Blanching is never required in pecans. Pecans can

either be dry-toasted or cooked in oil. Much less

heat treatment is required than for peanuts, because

the initial moisture content of pecans is lower, and

the development of a true roasted flavor is seldom

desired. Frying gives a more uniform roast and causes

less mechanical damage. Roasting is performed, on

an average, for 12–15 min at 190



C. After roasting,

the kernels are quickly cooled in tunnels or perforated

bins, with forced air circulation to remove any

undesirable odors. The cooled product is cleaned to

remove any debris, foreign matter, and scorched nuts.

The roasted kernels are coated with about 1% (w/w)

finely ground salt. Pecans may be coated with cinna-

mon, sugar, barbecue-flavored powders, etc. Since

toasted pecans have a very limited storage life, they

are vacuum-packed.

Almonds

0030Almonds are a common constituent of mixed-nut

packs, and are popular as the roasted and salted

variety. The kernels are not generally blanched for

the production of salted almonds. For blanching, the

nuts are soaked in hot water until the skin loosens

sufficiently to be removed by rubbing. Almonds may

be dry-roasted or fried, but oil roasting is the more

common method. In dry roasting, hot air is passed

through rotating perforated cylinders or a fluidized

bed to reduce the moisture content to 1%. Oil

roasting is carried out by immersing the nuts in oil,

preferably coconut oil, and heating to between 121

and 176



C. After frying, they are cooled, salted, and

SNACK FOODS/Range on the Market 5325

dressed with oil. They can also be coated with smoke-

flavored salt, cinnamon, sugar, or similar flavored

powders. (See Almonds.)

Sugared and Spiced Nuts

0031 Sugared and spiced nuts are prepared by adding nuts

and spices to water and sugar heated to 115



Cina

revolving pan. After coating, the nuts are dried for 1 h

at 48



C, or 2 h at room temperature, and packed

in hermetically sealed containers, preferably under

vacuum. The nuts must be dried to below 4%

moisture before coating. This product should be

refrigerated if not consumed within a month.

Extruded Snacks

0032 Single- or twin-screw extruders are used to get ex-

truded snacks. There are three types of extruded

snacks: (1) direct expanded snacks, (2) coextruded

snacks, and (3) indirect expanded snacks.

Direct Expanded Snacks

0033 This category gets its name from the fact that prod-

ucts expand directly out of the extruder die and

require no further processing, such as corn curls,

both baked and fried, onion rings, and potato sticks.

The puffing of direct expanded snack products is

created by heating the ingredients to temperatures

over 100



C. Inside the extruder the water in the

dough mass remains a liquid because the dough is

under pressure. When the dough exists the extruder

through the die opening, the superheated water is

exposed to atmosphere. The vaporization of water

into steam during this rapid pressure loss causes

stretching and expansion of the starch matrix. The

equipment used to make such products ranges from

simple collect extruder to twin-screw extruders.

Potato sticks are made from 65% potato starch and

35% corn meal. Blend is extruded to cook and puff.

The high level of potato starch gives this product a

unique flavor. The baked collet is then coated with

oil, salt, and other seasoning.

Coextruded Snacks

0034 Coextrusion technology became popular in the snack

food industry around 1984. A coextrusion process is

a technique where two materials (usually dissimilar in

nature) are combined in an extrusion die. The two

materials can come from two extruders or from an

extruder and a pump. This process gives the manu-

facturer the ability to make a product which has two

textures, or two colors or two different flavors. In

snack food industry the most common form of

coextrusion is the extrusion of a cereal-based outer

tube with a cheese filling pumped into the center

of the tube.

Indirect Expanded Products

0035Indirect expanded snack products are also referred

to as ‘third-generation snacks’ and ‘half-products.’

These products are not expanded directly through

the die. The additional process steps which contribute

to the appearance or texture include frying or hot-air

puffing to remove moisture and achieve the final

texture. There are two subcategories of indirect

expanded products: (1) pellets; (2) fabricated chips.

Pellets

0036Snack pellets are products cooked in an extruder and

forced through a die at temperatures below 100



The shape of the dough at low temperatures prevents

the puffing forces of water turning into steam, thus

intricate shapes can be made in pellets which would

normally be destroyed in the direct expanded extru-

sion process. Snack pellets are extruded at 25–35%

moisture and then dried to around 12% moisture for

stability. Since the snack pellet is unexpended and

dense in this stage, drying must be done at low tem-

peratures and high humidity to allow the moisture to

migrate out of the pellet. So snack pellets can be held

for longer periods, shipped to long distances, or

distributed to the snack food manufacturers or

consumer directly. The pellets are characterized by a

translucent appearance, due to above 90% level of

starch gelatinization. Then pellets can be expanded

by heating them rapidly to cause the water in the

pellet to turn into steam in an explosive manner

which puffs the pellet. This can be accomplished by

frying, baking, or microwaving, then coating with

seasoning and packing. Frying is the most common

method because it is less expensive and works well.

Frying conditions depend on the pellet thickness,

shape and composition. Frying temperatures usually

range between 170 and 210



C for 10–60 s. For low-

oil snack products, baking and microwaving have

been explored. Due to rapid heat transfer rates

required to expand a pellet uniformly, the ordinary

snack dries and a baking oven will not puff a pellet.

Microwaving of pellets also requires a rapid heat

transfer rate, therefore high-powered continuous

microwave expanders are commercially used.

Expanded pellets have a moisture content of 1–2%.

They are usually flavored in coating drums as for

direct expanded products.

Fabricated Chips

0037There are many fabricated chip products (FCP) made

through a wide variety of processes. One of these

5326 SNACK FOODS/Range on the Market