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

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DIETETICS

P A Judd, University of Central Lancashire, Preston,

Lancashire, UK

Introduction

0001 This article briefly relates the history of the develop-

ment of dietetics and the role of the dietitian and

describes the current roles of dietitians in some gen-

eral and specialist areas of practice. The increasingly

important roles of the dietitian in research and

education are also discussed.

Definition and History of Dietetics

0002 Dietetics is defined as ‘the application of the science

of nutrition to the human being in health and disease.’

However, the term ‘dietitian,’ used to describe a prac-

titioner of dietetics, was in use long before the science

of nutrition had become an accepted discipline. Al-

though Florence Nightingale has been described as

the first dietitian because of her insistence, during

the Crimean war, that the sick men in her charge

would not recover if not well fed, the first use of the

title of dietitian was recorded in 1899 in the USA. The

dietitian was then described as a person working in a

hospital who provided nutritious meals to patients

and the earliest dietitians were primarily home econo-

mists. The role of the dietitian expanded greatly

during the 20th century and is no longer seen simply

as the provision of food. The dietitian is seen as the

expert in the planning and evaluation of nutritional

care for patients requiring therapeutic dietary regi-

mens as well as for the population in general and

this is reflected in the breadth of knowledge and

skills required for qualification and registration as a

dietitian.

0003 The profession of dietetics is a relatively young one,

first formalized in the USA in 1917 when the Ameri-

can Dietetic Association (ADA) was founded. In the

UK the first dietitians were nurses and the first diet-

etic department was started in the Edinburgh Royal

Infirmary in 1924. Several of the pioneers of British

dietetics were able to visit the USA in the 1920s to

study the work of established dietetic departments

there and after several abortive attempts the British

Dietetic Association (BDA) was established in 1936.

Other countries followed and in 2000 there were

more than 30 dietetic associations throughout the

world registered with the International Committee

of Dietetic Associations (ICDA).

Dietetics Qualifications

0004It is now accepted that the practice of dietetics

requires a wide range of knowledge and skills. As

the scope of dietetic practice has expanded over the

years, training programs have continually adapted to

insure that the practitioner has the current knowledge

and skills required. The education and training of a

dietitian usually comprises a degree program (either

BSc or MSc), based in a university, including or

followed by a period of practical training based in a

recognized hospital dietetic department.

0005Preregistration programs include coverage of basic

and applied sciences (chemistry, biochemistry, physi-

ology, nutrition, microbiology) as well as social sci-

ences (psychology and sociology). In addition, as

dietetics is concerned with feeding people, a knowl-

edge of the food habits of populations together with

detailed knowledge of food composition and food

preparation is essential. To this basic foundation is

added knowledge of medicine, pathology, and the

therapeutic uses of dietary treatment. Increasingly

the development of skills required to communicate

with all types of people is emphasized, whether

counseling individuals or teaching groups.

0006During the practical training or internship the stu-

dent dietitian learns to apply the theory learned at

university with individuals or groups of people. The

training covers all aspects of dietetic practice and the

students spend time in different settings, including

community care and, in some countries, in large-

scale catering establishments. In order to become a

registered practitioner students must demonstrate

that they have both good theoretical knowledge and

are competent practically.

0007In the USA, UK, Canada, Australia, New Zealand,

South Africa, The Netherlands, and many other coun-

tries, training programs are regulated by bodies exter-

nal to the educational establishments and successful

completion of such a regulated training allows regis-

tration as a dietitian. In the USA regulation of courses

and training programs is carried out by the ADA. In

the UK, the former Dietitian’s Board of the Council

for Professions Supplementary to Medicine (CPSM)

has been replaced by the Health Professions Council,

set up to regulate the 12 professions previously over-

seen by the Boards of the CPSM. In the UK only state-

registered dietitians may be employed in the National

Health Service. The registration body, in each case,

1886 DIETETICS

produces a statement of conduct which describes the

role and responsibilities of the registered dietitian and

failure to work within this statement of conduct may

result in disciplinary action and removal from the

matically mean that a dietitian can work elsewhere in

the world as levels of education and training are not

always comparable from country to country. Each

registering body will therefore consider applications

from dietitians from other countries and suggest fur-

ther training if appropriate.

0008 Continuing education and demonstration of con-

tinuing competence to practice is increasingly being

seen as vital in this rapidly changing profession; in the

USA there has long been a requirement to demon-

strate continuing education and continuing registra-

tion is dependent on this. In the UK it is not yet a

registration requirement to demonstrate continued

competence to practice, although this was considered

as part of the recent review of the Act of parliament

defining Professions Supplementary to Medicine and

is likely to become mandatory now that the Health

Professions Council has succeeded the CPSM. How-

ever, the BDA, the professional association for diet-

itians, has recently introduced a Diploma in

Advanced Dietetic Practice, which has as part of its

remit the recognition of continuing education.

The Role of the Dietitian

0009 The first dietitians (with the exception of those con-

cerned mainly with food service provision) worked

mainly in hospitals. Clinical dietetics and the acute

hospital service still claim a large proportion of the

graduates from dietetics training but other areas of

work are increasingly becoming more important. In

the UK changes in the emphasis of health care, par-

ticularly the change of emphasis from acute (hospital)

care to care in the primary health care setting, has

resulted in a marked increase in the number of ‘com-

munity-based’ dietitians and the Community Nutri-

tion Group of the BDA has been the fastest-growing

specialist group in recent years.

0010 Dietitians also have many other roles outside the

health services. In industry they may work as advisors

to food companies, wholesale and retail suppliers of

food, and companies producing specialized dietary

products. They also work with government agencies,

e.g., in dietary surveys of the population, in evalu-

ation of intervention programs, and advising on the

practical application of policy. In addition dietitians

are increasingly working independently as consult-

ants, e.g., in private practice, journalism, and sports

nutrition. Whatever aspect of work a dietitian

chooses, one of the primary roles will be that of an

educator, whether in assisting individuals to under-

stand and apply a therapeutic regimen, teaching

doctors, nurses, or other health professionals about

nutrition and dietetics to help them carry out their

functions, teaching groups of people about aspects of

preventive nutrition, or writing an article for the

scientific or lay press. The ability to communicate is

therefore central to every dietitian’s role.

The Dietitian’s Role in Food Service

0011In the USA and countries which follow the US model,

hospital dietitians work in either administrative or

clinical (therapeutic) areas. Administrative dietitians

manage the provision of food services for all patients

and staff. They are responsible for food production

and quality control in the delivery of the hospital

meal service as well as insuring their nutritional ad-

equacy. They are also often responsible for budgeting

and staffing of the dietary departments and usually

relate to other administrators and managers, having

little or no direct contact with patients or medical

staff. The clinical dietitian is the person who has

direct contact with patients and the medical and

paramedical staff involved in their care.

0012In the UK the practice of dietetics has evolved along

a different route and dietitians do not usually have

overall responsibility for food service. However, there

is usually close liaison between dietitians and the

catering manager to insure the provision of nutrition-

ally sound selective menus. The dietetic manager will

also be consulted on matters of policy such as the

implications of changes in food preparation systems

or the introduction of healthy eating policies. It is

acknowledged now that many patients (especially

elderly people) are malnourished when they enter

hospital and that this often becomes worse during

their stay. Dietitians are therefore very much involved

in attempts to insure that every patient has a nutri-

tionally adequate diet.

Clinical or Therapeutic Dietetics

0013The term ‘therapeutic dietetics’ is used to describe the

work of the dietitian in his or her direct dealings with

patients who require special diets, for various

reasons, as outlined in Tables 1 and 2. The role of

the clinical dietitian has broadened in the last decade,

both with respect to the range of conditions which are

encountered and the setting in which the work is

done. In the past the role of the therapeutic dietitian

was to calculate, teach, and facilitate compliance to a

range of dietary regimens prescribed by medical or

surgical practitioners for specific disorders. These

functions are still important and, indeed, are

DIETETICS 1887

extending as improvements in medicine enable

patients who would previously have died in child-

hood to survive to adulthood with continuing needs

for nutritional care. For example, patients with cystic

fibrosis require nutritional support as their lungs

deteriorate and women with hyperphenylalaninemia

need dietary advice in order to help them achieve

successful pregnancies.

0014 In addition to these roles, however, dietitians are

increasingly involved in the assessment and support

of patients not traditionally seen as requiring a thera-

peutic diet. Planning and implementing feeding for

patients who are nutritionally compromised as a

result of trauma, surgery, or chronic illnesses such as

cancer or acquired immunodeficiency syndrome

(AIDS) has become an important part of the work-

load of the dietitian working in both acute and

community settings.

0015 Clinical dietitians are increasingly involved in deci-

sions about the appropriateness of particular dietary

regimens or the type of nutritional support required

and in many institutions are responsible for prescrib-

ing the patient’s diet in consultation with the phys-

ician or surgeon, who recognizes the dietitian as the

expert. In acute care a dietitian is an important

member of the nutrition support team, working

alongside nurses, pharmacists, and medical staff to

advise on the feeding of all patients who need nutri-

tional support. (However, in the UK at least, the

medical practitioner is ultimately responsible for the

patient and any therapeutic regimen, including

dietary treatment.)

0016 As new advances occur in clinical practice, the

dietitian must be aware of these, and many dietitians

are now involved both in research into the develop-

ment of new treatments and in evaluating current

practice. There has been a rapid increase in the

numbers of dietetic practitioners with research quali-

fications and dietitians are increasingly initiating

their own projects, working alongside experienced

investigators rather than acting as technicians in

other people’s projects, as sometimes happened in

the past. These advances are contributing in some

part to a reevaluation of dietetic practice and result

in a need for dietitians to justify the evidence-base for

therapies and to set priorities in their work. As dietet-

ics has developed it has become more specialized and

this has resulted in the formation of practice groups

within the dietetic associations. These groups have

become a forum where advances in practice in par-

ticular areas can be shared and are often a focus for

continuing education, both formally (by running

courses) and informally. Some of the more specialized

roles in which dietitians are working are described

below.

Pediatric Dietetics

0017The pediatric dietitian has a unique role in that he or

she has to combine the metabolic requirements of

the disease process or condition with the normal

requirements for growth and development. With the

advances in early diagnosis of many complex meta-

bolic conditions, children may require complicated

diets which are very different from the rest of their

family and peers, which need constant modification

as the child grows and which may be lifelong. The

dietitian is responsible for modifying the diet as

necessary to take account of the patient’s metabolic

tbl0001 Table 1 Examples of the use of therapeutic diets to alleviate symptoms of disease

Symptoms Condition Therapeutic diet

Dysphagia Disease of mouth or esophagus Semisolid diet, with thickeners

Weight loss Trauma, surgery, carcinoma, severe burns High-energy

Constipation Diverticular disease, irritable bowel syndrome. High-fiber

Diarrhea Pancreatic insufficiency Low-fat

Lactose intolerance Lactose-free

Polyuria, polydipsia Diabetes Controlled energy; high-complex-carbohydrate and low-fat

tbl0002 Table 2 Examples of therapeutic diets used to correct disturbances in physiological or metabolic function

Condition Cause Therapeutic diet

Uremia Renal failure Moderate-protein, high-energy, low-phosphate

Edema Liver or renal diseases Salt restriction

Malabsorption Pancreatic disease Low-fat plus MCT

Cows’ milk protein intolerance Exclude milk and dairy products

Eczema Food allergy Remove identified foods, e.g., cows’ milk, eggs

Villous atrophy Celiac disease Gluten-free

High blood phenylalanine Phenylketonuria Controlled phenylalanine intake plus amino acid supplements

1888 DIETETICS

requirements, any feeding difficulties, whether mech-

anical or physiological, and the patient’s food prefer-

ences and dislikes as he or she grows. The dietitian is

an essential part of the support system for children

with inborn errors of metabolism such as phenyl-

ketonuria and cystic fibrosis, conditions such as

renal or heart disease, food allergies, diabetes, and

many others, being able to tailor the diet to the pa-

tient’s specific needs and having access to the infor-

mation about special foods and products of which the

carer might be unaware or have difficulty in locating.

0018 The pediatric dietitian also has an important role as

an educator, often teaching the child’s parents initially

and later the child him-/herself how to cope with the

constraints of a special diet, both at home and in

school. As is the case with adult patients, the dietitian

will often be able to put the child and family in

contact with support groups where newly diagnosed

patients or parents will be helped by others with first-

hand experience of the disease and its treatment.

Renal Dietetics

0019 Renal dietitians are usually attached to specialized

renal units and are an integral part of the team in-

volved in the treatment of people suffering from vary-

ing degrees of renal impairment, whether acute or

chronic. In the USA there is a legal requirement re-

lated to funding of patient care which states that a

qualified dietitian must be part of the professional

team which develops long- and short-term care

plans for renal patients. The dietitian, together with

the nephrologist, has responsibility for nutritional

assessment, the diet prescription, and for monitoring

responses to treatment. In addition, he or she must

be able to devise appropriate individualized dietary

plans, taking into account any other ongoing disease

processes or conditions (e.g., diabetes mellitus) and

will teach the patient and family how to manipulate

the diet. The dietitian will also monitor dietary com-

pliance. A thorough knowledge of physiology and the

pathological processes involved in the various kidney

diseases and an ability to interpret the patient’s

biochemical data are therefore essential for the renal

dietitian.

0020 Some disorders may resolve with treatment but

others may become chronic and result in permanent

kidney failure. In progressive renal disease, patients

may initially be managed using diet and drugs alone

but as the kidneys fail they will require replacement

therapy such as peritoneal dialysis, hemodialysis, or

transplantation. Each of these stages requires differ-

ent dietary treatment. The dietitian will deal with a

variety of patients with different types of disease

and at different stages of progression, with different

needs with respect to diet and will also have to

teach the patient how to cope with changes in diet

which follow as he or she changes from one treatment

to another.

Nutritional Support

0021Nutritional support of patients who are unable to

feed themselves adequately by the normal oral route

is now an important area practice. The dietitian’s

involvement here ranges from simply advising on

and providing supplements for the patient who

cannot eat enough to designing and advising on com-

plete parenteral nutrition regimens for the uncon-

scious patient in intensive care. Between these two

extremes will be patients who need enteral feeds to

provide complete or supplementary nutrition for a

variety of reasons and for periods varying from a

few days to a lifetime.

0022Patients requiring nutritional support may be

acutely ill or may require long-term feeding, some-

times at home. The dietitian must be able to assess

the nutritional requirements of each individual and

design appropriate feeding regimens under all circum-

stances. Many patients will be sent home whilst

still being tube-fed, either enterally or parenterally,

and the community dietitian as well as the dietitian in

the acute hospital will both be closely involved in the

patient’s care and in monitoring progress.

Diabetes Care and Education

0023Traditionally the dietitian always had an important

role in the treatment of patients with diabetes melli-

tus, and the radical changes in dietary treatment over

the last 15–20 years have emphasized this role. Since

the early 1980s there has been a move away from

diets low in carbohydrate and the basis for the

treatment of all people with diabetes mellitus,

whether young and insulin-dependent, or older and

treated by diet alone or diet and hypoglycemic drugs,

is now the supply of an appropriate amount of energy

as a low-fat diet with at least 50% of energy from

foods rich in complex carbohydrates and nonstarch

polysaccharides. In addition, the recognition that

similar amounts of carbohydrate from different

foods have different effects on blood glucose levels

has led to less stress on absolute intakes of carbo-

hydrate and a move towards a qualitative approach

to the diet.

0024Many established diabetics found the change in

dietary treatment confusing and have needed help in

switching to the new regimen. Newly diagnosed pa-

tients also need help in learning to manipulate and

control this lifelong disorder. Many dietitians have

also been involved in the research which has under-

pinned the progression of dietary treatment and are

now evaluating its effects.

DIETETICS 1889

HIV and AIDS

0025 The dietetic care of patients with human immuno-

deficiency virus (HIV) and AIDS has become increas-

ingly important in the last decade. Dietitians may

work with people who are HIV-positive to help

them optimize their nutritional status and resist the

opportunist infections which eventually cause death

in the patient with frank AIDS. Once the person

develops AIDS, the dietitian’s role becomes both

therapeutic and palliative, devising and implementing

with the patient regimens to satisfy nutritional re-

quirements when, for example, disease of the gastro-

intestinal tract results in multiple malabsorption or

cancer results in weight loss and anorexia. The advent

of new multidrug regimens which require careful

planning of meals to match their absorption charac-

teristics and which have side-effects affecting nutri-

tional status has made the dietitian’s role even more

important.

Other Areas of Specialization

0026 There are many other areas of clinical dietetics in

which individuals may specialize, including oncology,

liver disease, gastroenterology, eating disorders,

gerontology, and care of the mentally ill or mentally

handicapped. Many of the activities in these areas and

those described in the sections above are not confined

to the hospital but require input from the dietitian in

the community.

Dietetics in the Community

0027 Community dietitians fulfill a variety of roles which

may range from working mainly in clinical dietetics in

the community setting, e.g., advising a variety of

patients in a general practitioner’s clinic, to that

of public health nutritionist advising the local health

or social services on aspects of food policy. In recent

years, due to the changing emphasis in health care,

the numbers of community dietitians in the UK have

increased markedly. The main increase has been in

supplying clinical (therapeutic) care to the primary

health care setting and about 21% of UK community

dietitians surveyed in 1997 stated that this was their

only role. About half of the respondents to the survey

were involved in health promotion activity as well as

clinical work but only 9% worked solely in health

promotion.

0028 Many of the dietitians working in health promo-

tion achieve their objectives by educating other

professional groups, such as doctors, nurses, health

visitors, and midwives, who will then pass the specific

knowledge on to the individual or groups of patients.

Prevention of diseases which may be diet-related has

recently become a much more important issue, and

dietitians are working with schools, health education

departments and industry to try to educate the public

towards consuming a healthier diet. Dietitians also

work as advisors in government departments and are

therefore involved in planning nutrition policies for

the country as a whole.

Dietitians in Research and Education

0029The advances in all areas of nutritional knowledge,

both in terms of achieving optimal health and preven-

tion of disease as well as in therapeutic nutrition, have

led to an increasing number of dietitians working in

research. The combination of nutritional and medical

knowledge and the ability to translate these into terms

of foods eaten means that the dietitian has a unique

role to play. Dietitians often approach research from a

deductive perspective in order to understand or solve

difficulties observed in practice, and the results of this

research will often have practical significance and can

be incorporated into treatments. Evaluation of prac-

tice can also be considered as part of this deductive

process and is essential in the current health care

climate when increasing reliance is put on measuring

effectiveness and the use of evidence-based medicine.

In addition, dietitians are increasingly involved in

basic experimental and analytical scientific research

which is essential for nutrition and dietetics to ad-

vance in both clinical and nonclinical areas. Involve-

ment in research has led to registration for higher

degrees and the number of dietitians with masters’

degrees or doctorates is now considerable in countries

such as the USA, UK, Canada, and Australia.

0030Research is also seen as an important part of the

role of those dietitians employed in universities and

colleges to teach dietetic and other students. In the

UK and other countries, there is a requirement that

each dietetic training course has registered dietitians

on the staff and in many cases these people also work

in the National Health Service in order to keep up to

date with current practice. Dietitians are also in-

volved in the education of many other professional

groups, including nurses, midwives, and pharmacists.

Recently, advances have been made in convincing

those in charge of medical education at undergradu-

ate and postgraduate level of the importance of nutri-

tion in medical education and this is also seen as an

important area where dietitians should be involved.

See also: Children: Nutritional Requirements; Nutritional

Problems; Community Nutrition; Diabetes Mellitus:

Treatment and Management; Problems in Treatment; HIV

Disease and Nutrition; Renal Function and Disorders:

Nutritional Management of Renal Disorders

1890 DIETETICS

Further Reading

American Dietetic Association (1993) The American Dietetic

Association Research Agenda for Dietetics: Conference

Proceedings. Chicago, IL: American Dietetic Association.

American Dietetic Association (1994) Position of the

American Dietetic Association: nutrition: an essential

component of medical education. Journal of the

American Dietetic Association 94: 555–557.

Bateman EC (1986) A History of the British Dietetic

Association. The Second Twenty-five Years 1936–1986.

Sunderland, UK: Edward Thompson.

Chernoff R (1983) The dietitian in the hospital setting. In:

Schneider HA, Anderson CE and Coursin DB (eds)

Nutritional Support in Medical Practice, pp. 70–

78.Philadelphia: Harper & Rowe.

Department of Health (1994) Targeting Practice: The Con-

tribution of State Registered Dietitians. Health of the

Nation. London: HMSO.

Department of Health (1994) Nutrition Core Curriculum

for Nutrition Education of Health Professionals.

London: HMSO.

Fox C (1999) Community Dietetics: Supporting the Future.

Community Nutrition Group of the British Dietetic

Association. Birmingham, UK: BDA.

Judd PA (1996) Educating the dietitians of the future.

Journal of Human Nutrition and Diet 9: 333–338.

Judd PA (1997) Pre-registration training for dietitians –

report of the Dietitians Board/BDA working group on

pre-registration training. Journal of Human Nutrition

and Diet 10: 157–162.

Disinfectants See Cleaning Procedures in the Factory: Types of Detergent; Types of Disinfectant; Overall

Approach; Modern Systems

Distilled Beverage Spirits See Vodka; Gin: The Product and its Manufacture; Composition and

Analysis; Whisky, Whiskey, and Bourbon: Products and Manufacture; Composition and Analysis of Whisky;

Rum; Vermouth

Distribution See Transport Logistics of Food

Down Syndrome See Developmental Disabilities and Nutritional Aspects: Down Syndrome; Prader–

Willi Syndrome

DIETETICS 1891

DRESSINGS AND MAYONNAISE

Contents

The Products and Their Manufacture

Chemistry of the Products

The Products and Their

Manufacture

S C Yang and L S Lal, Providence University, Taiwan,

Republic of China

Introduction

0001 Salad dressings are liquid or semiliquid products used

to flavor, moisturize, and enrich salads. In addition,

they may be used as spreads for sandwiches or as

ingredients in a variety of cold and hot recipes.

0002 A two-phase emulsion may consist of oil droplets

in water phase (i.e. oil-in-water emulsion) or water

droplets in oil phase (water-in-oil emulsion), as

shown in Figure 1. Traditional salad dressings are

oil-in-water emulsions. Droplets of oil, the dispersed

phase, are suspended in a continuous aqueous acidic

phase such as vinegar or lemon juice. Other ingredi-

ents are added to modify the flavor or texture. Nor-

mally oil and water do not combine well, but separate

into layers. However, the two phases must remain

evenly dispersed in an acceptable salad dressing.

(See Colloids and Emulsions.)

0003 Salad dressings can be divided into four categories

on the basis of their formulations and stability:

0004oil and vinegar dressings (most are temporary

emulsions);

0005emulsified dressings (most are permanent emul-

sions);

0006cooked salad dressings (most are emulsions

containing a starch thickener);

0007low-fat/diet products (most are emulsions contain-

ing hydrocolloids for viscosity and texture charac-

teristics).

Each type of salad dressing must conform to certain

specifications; in the USA each has a standard of

identity established by the Food and Drug Adminis-

tration (FDA).

Typical Examples and Their Uses

Oil and Vinegar Dressings

0008Basic French dressing and variations such as mustard

French, herbed French, Italian, piquante, chiffonade,

and avocado dressings are examples of temporary oil

and vinegar emulsions. The ingredients include vin-

egar, oil, and various dry ingredients. In these prod-

ucts the liquid phase separates after mixing, although

dry ingredients, such as mustard and paprika, collect

at the oil–water interface to give limited stability to

the emulsion. These dressings should be mixed thor-

oughly immediately before they are used. The harder

the mixture is beaten or shaken, the longer it takes for

it to separate again.

Emulsified Dressings

0009The classic example of an emulsified dressing is may-

onnaise, a permanent oil-in-water emulsion. Mayon-

naise is made from a vegetable oil, vinegar and/or

lemon juice, and whole egg or egg yolk. Additional

seasonings such as mustard, paprika, and salt are

usually added. By legal definition in many countries

(e.g., the USA), commercial mayonnaise must contain

either egg yolk or whole egg and must have an oil

content of not less than 65% by weight. Whole

egg or egg yolk functions as an effective emulsifier

and creates a permanent emulsion. The rather high

percentage of oil contributes significantly to the vis-

cosity of the dressing. The viscous nature of permanent

Oil

Water

(a) (b)

fig0001 Figure 1 A two-phase emulsion may consist of (a) oil droplets

in water (o/w) or (b) water droplets in oil (w/o).

1892 DRESSINGS AND MAYONNAISE/The Products and Their Manufacture

emulsions makes it difficult for the oil drops to come

into direct contact and coalesce. (See Emulsifiers:

Organic Emulsifiers.)

0010 Emulsified French dressing is similar to basic

French dressing, except that egg yolk is added to

prevent the oil and vinegar from separating. Its prep-

aration is similar to that of mayonnaise. Mayonnaise

is sometimes used by itself as a salad dressing but

more often serves as the base for a variety of other

dressings. Thousand Island, Lousis, Russian, Chan-

tilly, and blue cheese dressings are all mayonnaise-

based. These dressings are generally thick and

creamy, and many of them contain sour cream.

Cooked Salad Dressings

0011 Cooked salad dressings resemble mayonnaise in

appearance but differ in some of the ingredients and

in the method of preparation. The basic ingredients

are vegetable oil, vinegar or lemon juice, whole egg or

egg yolk, milk or water, and a cooked starch paste.

Homemade cooked salad dressings are usually

thickened with starch and/or egg. Very little, if any,

oil is used in these dressings. However, a commercial

salad dressing, labeled as such, must meet the stand-

ard of identity of the FDA and contain by weight no

less than 30% vegetable oil and no less than 4%

liquid egg yolk or the equivalent. Although these

dressings are often very similar in appearance to may-

onnaise, they cannot be labeled mayonnaise because

of the lower oil and egg yolk content, plus the fact

that they may contain cooked starch. The reduced oil

content has the advantage of making this product

lower in calories than mayonnaise.

Low-Fat/Diet Products

0012 The recent change in dietary consciousness has

affected the type of food consumers select at super-

markets and in restaurants. In 1985, the size of

reduced-fat or reduced-calorie sauces and dressings

grew faster than the total market. In 1986, this

category of food grew at an annual rate of 6% but

reduced-calorie products achieved 23% growth. The

driving forces were the increased interest in nutritious

foods and dietary fiber, less consumption of choles-

terol, and a marked increase in vegetarianism.

0013 By moving low-calorie/reduced-fat out of the

diet section of supermarkets and repositioning them

with regular, standard products, producers improved

the image of these products. The low-calorie/reduced-

fat products are now recognized by consumers not as

diet foods but as nutritious, lower-calorie counter-

parts to the standard products, with good sensory

properties.

0014 Reduced-fat dressings and mayonnaise require pro-

cessing similar to traditional products and a one-third

reduction of oil content. The oils are the same as for the

full-fat products. Generally, soya bean oil is used.

Gums, particularly xanthum and alginates, are incorp-

orated to stabilize the formula, and water replaces the

fat removed. These products rely totally on hydrocol-

loids for viscosity and texture characteristics.

0015Food technologists have developed ingredients that

can be used to replace or lower the fat content of food

products. One such ingredient is Simplesse, a physic-

ally modified combination of milk and egg-white

proteins processed by an internationally patented

heating and blending procedure called microparticu-

lation. Simplesse possesses fat-like characteristics

while providing significantly fewer calories than fat

for such items as mayonnaise and salad dressings.

Other recently developed fat substitutes include Oles-

tra, a sucrose polyester, and Veri-Lo, a creamy white

emulsion containing milk fat. All substances must

undergo review and gain official approval before

they can be used. (See Fats: Fat Replacers.)

0016Reduced-sodium mayonnaise and salad dressings

are also of interest to health-conscious consumers.

The market has grown steadily since 1980, and is

expected to make up 23% of the total sauces and

dressings market by 1995. Reduced-sodium mayon-

naise is made with salted egg yolk containing potas-

sium chloride rather than sodium chloride. Frozen

salted egg yolk made with potassium chloride is less

viscous than that containing sodium chloride. How-

ever, viscosity and stability of mayonnaise made from

10% salted (potassium chloride) egg yolk are accept-

able. (See Hypertension: Hypertension and Diet;

Sodium: Physiology.)

0017Continued growth in the area of low-calorie, re-

duced-fat and reduced-sodium mayonnaise and salad

dressings is anticipated. The aging population, com-

bined with increased nutritional awareness, will

create a market for such modified products.

Formulations

Oil and Vinegar Dressings

0018French dressing is prepared from edible vegetable oil

and the following acidifying and flavoring ingredients:

0019salt;

0020nutritive carbohydrate sweeteners, such as sucrose,

dextrose, corn syrup, glucose syrup, or honey;

0021mustard, paprika or other spices, spice oils or

spice extracts;

0022any suitable, harmless food seasoning or flavoring

(other than imitation);

0023tomato paste, tomato pure

e, catsup, sherry wine;

0024any vinegar or vinegar diluted with water to an

acidity of not less than 2.5% by weight calculated

DRESSINGS AND MAYONNAISE/The Products and Their Manufacture 1893

as acetic acid, or any such vinegar or diluted vin-

egar mixed with an additional optional acidifying

ingredient such as citric acid, weighing no more

than 25% of the weight of the acids of the vinegar

or diluted vinegar calculated as acetic acid (lemon

juice is another acidifying ingredient which may be

used in place of vinegar).

French dressing contains not less than 35% by weight

of vegetable oil. The ratio of oil to vinegar in basic

French dressing is 3:1. Some chefs prefer a 2:1 ratio.

Less oil makes the dressing more tart, while more oil

makes it milder in flavor and oilier. For emulsified

French dressing, eggs or other emulsifiers (vegetable

gum, propylene glycol esters of alginic acid, methyl

cellulose, pectin, xanthan gum, etc.) may be added,

the total content being no more than 0.75% by

weight. Eggs used for French dressing can be fresh,

frozen, or dried.

0025 Formulae for commercially prepared dressings and

mayonnaise vary according to the specific plant and

equipment employed. Also, taste preference is differ-

ent from region to region. Herein, typical formulae

for certain commercial products are presented.

0026 A typical commercial French dressing formula may

contain:

Water 12.0%

Vinegar (cider) 5% 22.0%

Sugar 8.8%

Salt 3.5%

Worcestershire sauce 3.5%

Paprika 4.5%

Mustard, garlic, onion 4.7%

White pepper 0.3%

Vegetable oil 40.0%

Gum tragacanth 0.4%

Dried egg-yolk solids 0.3%

In this formula, the total solids of commercial liquid

egg yolk is about 44%. Dried egg yolk may be substi-

tuted for commercial liquid egg yolk on a total solids

basis. French dressing may be mixed and packed in an

inert atmosphere in which air is replaced totally or in

part by carbon dioxide or nitrogen.

Emulsified Dressings

0038 Mayonnaise and mayonnaise dressing are emulsified

semisolid food products prepared from edible vege-

table oil, egg yolk-containing ingredients and the

following acidifying and flavoring ingredients:

0039 salt;

0040 nutritive carbohydrate sweeteners, such as sucrose,

dextrose, corn syrup, glucose syrup, or honey;

0041 mustard, paprika or other spices, spice oils or

spice extracts, except turmeric or saffron, and

no spice oil or spice extract which imparts to the

mayonnaise a color simulating that imparted by

egg yolk;

0042any suitable, harmless food seasoning or flavoring

(other than imitations), provided it does not

impart to the mayonnaise a color simulating that

imparted by egg yolk;

0043monosodium glutamate;

0044acidifying ingredients, which may be any vinegar

of not less than 2.5% acetic acid, or frozen,

canned, concentrated or dried lemon or lime

juice with a total acidity of no less than 2.5%

calculated as acetic acid; citric or malic acid may

be used in a proportion not to exceed 2.5% of the

acid of the vinegar calculated as acetic acid.

A typical commercial mayonnaise formula may contain:

0045Vegetable oil 78.5%

0046Vinegar, white (10%) 3.8%

0047Water 11.6%

0048Sugar 1.8%

0049Salt 1.2%

0050Spices (mustard, onion, etc.) 0.3%

0051Dried egg yolk solids 2.8%

This formula provides a mayonnaise with medium

viscosity. For a heavier viscosity, vegetable oil may

be increased to 80.5% and water decreased to 9.6%.

Mayonnaise may be mixed and packed in an inert

atmosphere in which air is replaced totally or in part

by carbon dioxide or nitrogen. Dried egg-yolk solids

may be substituted for liquid egg yolk on a total solids

basis.

Cooked Salad Dressings

0052Salad dressing is the emulsified semisolid product

prepared from ingredients such as those of mayon-

naise plus cooked (or partially cooked) starch paste

prepared with a food starch, tapioca, wheat or rye

flour, or any two or more of these. Salad dressing

under the FDA standards of identity resembles may-

onnaise in that it is an emulsion of oil in vinegar with

egg as an emulsifier. It differs from mayonnaise in that

it also contains starch paste as a thickener. Salad

dressing may be flavored with one or more of the

following ingredients:

0053salt;

0054nutritive carbohydrate sweeteners;

0055mustard, paprika or other spices, spice oils or any

suitable harmless food seasoning or flavoring in-

gredient providing they do not impart a color

simulating that imparted by egg yolk;

0056monosodium glutamate.

1894 DRESSINGS AND MAYONNAISE/The Products and Their Manufacture

Salad dressing contains not less than 30% by weight

of vegetable oil and no less egg yolk-containing ingre-

dient than is equivalent to 4% by weight of the yolk

solids of liquid egg yolk. Salad dressing may also

contain not more than 0.75% by weight of any of

several polysaccharide gums or their cellulose deriva-

tives, methylcellulose and sodium carboxymethylcel-

lulose; gums are not permitted in mayonnaise. The

acidifying ingredients may be any vinegar or frozen,

canned concentrated or dried lemon juice. Citric or

malic acid may be used in a proportion not to exceed

25% of the total acid of the vinegar calculated as

acetic acid. A typical commercial salad dressing for-

mula may contain:

0057 Vegetable oil 30.0%

0058 Starch paste mixture 68.2%

0059 Dried egg-yolk solids 1.8%

Dried egg-yolk solids may be substituted for liquid

egg yolk on a total solids basis.

0060 The starch paste is made by cooking and cooling a

combination of ingredients in the following propor-

tions:

0061 Vinegar (10%) 17.2%

0062 Salt 4.0%

0063 Starches 7.7%

0064 Sugar 15.0%

0065 Spices (mustard, celery, etc.) 1.1%

0066 Water 55.0%

The starch may be a food starch, modified food

starch, tapioca, wheat, rye flour, or any two or more

of these. Water may be added in the preparation of

the paste. Salad dressing may be mixed and packed in

an inert atmosphere in which air is replaced in total or

in part by carbon dioxide or nitrogen.

Low-Fat/Diet Products

0067 The Nutrition Labeling and Educational Act (NLEA)

of 1990 standardized the nutrient content claims on

food labels in the USA. Additionally, the NLEA

standardized the serving sizes for each product. The

US regulations for foods are published in Code of

Food Regulations 21 CFR Part 101 each year. The

three claims of particular interest here are ‘reduced,’

‘low,’ and ‘free’ as applied to calories, sodium, fat,

saturated fat, and cholesterol. In the USA, the term

‘reduced’ refers to a nutritionally altered product that

contains at least 25% less of a nutrient or 25% fewer

calories than a reference food. The term ‘low’ refers

to a reference amount (or 50 g of food, if the reference

amount is small) that contains 40 calories,

140 mg sodium, 3 g fat, 1 g saturated fat, and

15% of calories from saturated fat, or 20 mg of

cholesterol. The term ‘free’ refers to a serving and the

reference amount contains no or physiologically in-

consequential amount, specifically, < 5 cal, < 5 mg

sodium, < 0.5 g fat, < 0.5 g saturated fat and < 0.5 g

trans fatty acids, < 2 mg cholesterol, or < 0.5 g sugars.

Standards may vary by country.

0068Various fat-replacers, including starch-derived fat

mimetics, fiber-based fat mimetics, microparticulated

proteins, hydrocolloid gums, and synthetic fat

mimetics, have been successfully applied to reduced-

fat, low-fat, and fat-free salad dressings. Formulation

of a low-fat salad dressing containing 5% oil may

contain:

0069Microcrystalline cellulose 3.2%

0070Vegetable oil 4.3%

0071Xanthan gum 0.3%

0072Modified starch 3.6%

0073Sugar 5.8%

0074Egg yolk 4.0%

0075Vinegar 4.5%

0076Lemon juice 0.5%

0077Salt 1.8%

0078Water 72.0%

The reduced-fat, low-fat, and fat-free salad dressing

formulations are generally designed to impart a full-

fat organoleptic profile, including texture, appear-

ance, mouth feel, and body.

Major Ingredients in the Formulae

0079Vegetable oil Oil is the major ingredient contribut-

ing to the viscosity and body of mayonnaise. The

rigidity of the emulsion depends partly on the size of

the oil droplets and partly on how tightly they are

packed. The more oil that is dispersed in the emul-

sion, the stiffer it will be. The choice of oil is governed

by quality and local preference. It should be bland.

Strongly flavored oils can make excellent dressings

but are not appropriate with every food. Today,

soya bean, cottonseed, sunflower, and corn oils are

used commercially. They may be used singly or in

combination. Deodorized, winterized oil should be

used with dressings that are to be refrigerated. (See

Soy (Soya) Beans: The Crop.)

0080Vinegar The functions of vinegar are as a preserva-

tive and a flavoring. Acid is the main preservative

against microbial spoilage in mayonnaise. The indus-

try makes use primarily of two types of vinegar,

namely cider vinegar and distilled vinegar. The ideal

vinegar for salad dressing and mayonnaise is one

which is mild in odor and taste. Vinegar strength is

measured by ‘grain’, 100 g equalling 10% acetic acid.

Most salad vinegars range from 3 to 5% and should

be standardized by dilution with water before meas-

uring out for a recipe. (See Vinegar.)

DRESSINGS AND MAYONNAISE/The Products and Their Manufacture 1895