mf203 lecture 7 - flavour & colour (printed)

7/28/2019 MF203 Lecture 7 - Flavour & Colour (Printed)

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7.0 Flavour & Colour

Flavour

Colour

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7.1 Flavour

a. Definition of Flavour

b. Historical development of food flavourings

c. Types of flavourd. Categories of flavour

e. Functional role of flavour

f. Methods of producing flavour materials

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a. Definition of Flavour

In English, we use the term flavour in threedifferent senses.

First, we use it to describe the sensation, the

physiological and psychologicalresponse to astimulate.

Second, we use it also to refer to the stimulus itself,the properties of the substance which we perceive asthe flavour of that substance.

Lastly, it is the term for a particular category ofsubstance which causes the stimulus

Stimulus

Substance

Sensation

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Continue ..

These senses are reflected in 2 definitions.

Hall (1968) includes the sensation & stimulus:

- Flavour is the sum of those characteristics of any material

taken in the mouth, perceived principally by the sense of

taste and smell and also the general pain and tactile

receptors in the mouth, as received and interpreted by thebrain.

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STIMULUS by receptor (taste and smell)

SENSATION (sweet/sour/bitter/hot/umami?)

RESPONSE (saliva/satisfying/sweating?)

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Thats why coffee never tasted as good as we smell them. 6


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Continue .

Society of Flavour Chemists (1969) is concerned mainly

with the substance:

- A flavour is a substance which may be a single chemicalentity, or a blend of chemicals of natural or synthetic origin

whose primary purpose is to provide all or part of the

particular flavour effect to any food or other product taken

in the mouth.

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b. Historical development of food flavourings

Originally, the only flavourings available were essential oils and

other natural extracts.

Advances in chemical analysis and synthetic organic chemistry,came an increasing number of nature-identical and synthetic

flavour chemicals.

This allow improved fidelity to the original materials and greaterflavour intensity, stability and reproducibility.

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Around 1985, a range of natural flavour chemicals produced

by enzymic, microbial or mild chemical processes became

available.

This resulted in good quality flavour formulations can be

made whose composition closely resemble the analysis of

natural extracts of the fruit.

Advantages new raw materials (more cheaper and available)

can be utilised to manufacture flavours.

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c. Types of Flavour

According to EC (1988a,b), there are 3 types

of flavour:

i. Natural

ii. Nature-identical

iii. Artificial/synthetic

Flavouring Substance

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.. Continue .. (i) Natural:

- Chemical substance with flavouring properties which is obtainedby appropriate physical processes (including distillation andsolvent extraction) or

- enzymatic or microbiological processes from material ofvegetable origin either in the raw state or after processing forhuman consumption by traditional food-preparation processes(including drying, torrefaction and fermentation)

Naturally present and has been identified in nature.

Example: menthol obtained from peppermint oil.

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.. Continue .. (ii) Nature-identical:

Chemical substance with flavouring properties which is

obtained by chemical synthesis or isolated by chemical

processes and which is chemically identical to a substance

naturally present in material of vegetable or animal originas described in (i) Natural

.Limonene biosynthesis

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(iii) Artificial/Synthetic

Chemical substance with flavouring properties which is

obtained by chemical synthesis but which is not chemicallyidentical to a substance naturally present in material of

vegetable or animal origin as described in (i)

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Synthetic limonene

Octanol + Acetic acid

Octyl Acetate (CH3COOC8H17)

Another example:

ethyl vanillin

Use in ice cream, confectionery and baked goods.

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According to Regulation (EC) No 1334/2008 ,

the flavouring means:

Flavouring substance

Flavouring preparation

Thermal Process flavouring

Smoke flavouring

Natural

Synthetic

Flavouring complexes

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Flavouring Preparation Means a product, other than the substances defined in

(i) above, whether concentrated or not, with flavouringproperties, which is obtained:

by appropriate physical processes (including distillation andsolvent extraction) or enzymatic or microbiological processes

from material of vegetable origin either in the raw state orafter processing for human consumption by traditional food-preparation processes (including drying, torrefaction[roasting] and fermentation)

Flavouring preparations contain various flavouring substancesoriginating from the sources they are obtained.

Covers product such as vanilla extract and orange oil.

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Thermal Process Flavouring Means a product which is obtained:

according to good manufacturing practices by heating to atemperature not exceeding 180oC for a period not exceeding15 minutes a mixture of ingredients, not necessarilythemselves having flavouring properties, of which at least

one contains nitrogen (amino) and another is a reducingsugar.

It does not apply to the majority of commercial process

flavours, which are heated for 1-4 hours, albeit at lowertemperatures.

EC, unofficially agreed that longer times at lowertemperatures are appropriate and a doubling of the time for

each 10oC decrease in temperature is acceptable. 17


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Smoke Flavouring Means a smoke extract used in traditional foodstuffs

smoking processes.

Complex mixture of smoke obtained by untreated wood topyrolisys in a limited and controlled amount of air, drydistilled superheated steam, then subjecting the wood smoketo an aqueous extraction system or to distillationcondensation and separation for collection of the aqueousphase.

It is assumed that it refers to smoke generated by a methodsimilar to that used in traditional smoking processes that isthen condensed or absorbed in a carrier to form a smokeextract.

Flavouring compounds are carboxylic acids, compound withcarbonyl groups and phenolic compounds.

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d. Categories of Flavours Flavours may be classify in 7 different forms:

Aromatic chemicals

Condiments

Spices

Concentrated fruits & Juices

Oleoresins and solid extracts

Essential Oils

Process flavours

These multiple forms partially account for the large number

of flavour additives.

They give the technologist or flavourist alternative wayseach with its own set of technical characteristics for

achieving a particular flavour effect.

Flavouring substance

Flavouring

Preparation

Process flavouring

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e. Functional Role of Flavours

The functional role and values of flavours cover a

broad spectrum:

First, we use flavouring ingredients to create anot previously existing flavour. Eg. Coca-cola.

A secondrole is to supplement, round out, orcomplement the flavour of the basic ingredients.Eg. Salads, with a salad dressing.

Third, to enhance and extend the flavour of thebasic food. Eg. Almond flavour in a cherry cake.

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Fourth, use flavours to replace processing

losses as the top note in a juice concentrate orthe aroma in an instant coffee.

Fifth, use an artificial flavour to stimulate a

more expensive or less practical natural flavour.Eg. Common in soft drinks and desserts.

Lastly, flavours serve to cover not spoilage.Eg. Seasoning in sausage.

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a) Extraction process

b) Distillation process

c) Biotechnology production processesd) Flavour precursor

f. Methods of producing flavours material

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a) Extraction process

Example: coffee preparation

Hot water separation of flavouring substances.

Flushing them out of coffee powder.

Filter then separates the solid components from the powder. Another example: deriving vanilla extract from vanilla pods.

Alcohol and supercritical

carbon dioxide are used as

solvent.

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b) Distillation process Distillation will separate liquid mixture by heating.

The technique is based on the fact that many substances have

different boiling points.

Distillation process sees the plant or animal source material

being brought to a certain, pre-determined boiling point.

The steam is collected by cooling.

E.g. natural citral from lemon grass oil.

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c) Biotechnology production

processes

Micro-organisms such as lactic acid bacteria or enzymes

acting as biocatalysts.

By enzyme and/or fermentation reactions. Eg. Conversion of

ethanol into vinegar and enzyme-modified cheese flavours.

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d) Flavour precursor

Compounding appropriate precursor molecules,usually various sugars, amino acid sources andsulfur-containing compounds,

Heating or cooking to accelerate chemicalreactions, such as the Maillard reaction, thatform the required mixture of flavour materialscalled process flavours.

Eg. Savoury flavour.

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7.2 Colour

a. Natural colours

- Anthocyanins (blue-red)- Carotenoids (yellow-orange-red)

- Betalains (Red-purple)

- Chlorophylls (Green)

b. Artificial colours

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a. Natural Colours

Colour is one of the first characteristics perceived byconsumer and as a means of identification and, ultimately,acceptance of a food product.

Both the quality and the flavour of food are closely are closelyassociate with colour.

Natural colours are those extracted from animal, vegetable or

mineral sources.

They often lack consistency of shade, light and heat stabilityand may introduce undesirable flavours into food products.

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Anthocyanins

Anthocyanins are the intense red, purple and blue pigments

found in many fruits, vegetable and flowers such as grapes

and cranberries.

These pigments undergo reversible structural transformations

with a change in pH manifested by strikingly different

absorbance spectra.

They are suited for use in acidic foods such as preserves, fruit

toppings, pickles and dairy products.

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Colour Red, purple and blue

Source Red cabbage, Strawberries, Grape skin,

Blueberries, Raspberries

Colour pigments Cyanidin, Delphinidin, Malyidin, Peonidin,

Petunidin, pelargonidin

Solubility Soluble in aqueous solutions

Stability Each pigment has different stability

Brighter in lower pH range. Becomes blue

at higher pH

Other properties Antimicrobial properties, antioxidant

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Carotenoids

Carotenoids are the yellow, orange and red pigments in alarge variety of plants and animals, including carrots,tomatoes, paprika, annatto and red salmon.

They are very susceptible to oxidation because of theirchemical structure.

However, synthetically processed beta-carotene is protectedfrom oxidation and is extensively used in butter, margarine,processed cheese, beverages, desserts and many otherapplications.

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Colour Red, yellow and orange

Common Types Beta-carotene, alpha-carotene, -

carotene, lycopene, lutein, crpytoxanthin,

zeaxanthin and astaxanthin

Source Carrots, sweet potatoes, spinach and

tomatoes

Stability Fat and Oil

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Betalains

Betalains are found in certain plants but the most commonsource is beets and red dragon fruits.

Betalains are sensitive to pH, heat and light.

Red beet (betanin) is used in frozen or chilled dairy productssuch as ice-cream, yoghurt and flavoured milks.

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Colour Bluish-Red

Source Beet Root

Colour Pigments Betanin

Solubility Water, ethanol, propylene

glycol

Stability Stable at higher pH. Sensitive

to light and heat

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It is a rather stable colorant for products with 3.5 9.0 pHrange.

It has a mild flavour characteristics to beet root.

It is best stored in frozen form away from light and has alonger lifespan if stored under -18oC.

Acidic conditions brighten the colour and it is available inpowder as well as liquid form.

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Chlorophylls

The most abundant naturally occurring plant pigments, arethe green colour in green plants.

They are sensitive to acid and light and are not very useful as

food colours.

Application include soups, sauces, jellies, pickles and petfoods.

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Colour Natural green

Source Grass and alfalfa

Solubility Water

Application Pastas, confectionary

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b. Artificial Colours

Artificial colours are normally very pure chemicals withstandardized colour strengths.

They are available as powders, pastes, granules, and solutions.

Water solouble colours are used in a wide range of foodapplications, including desserts, confectionary, beverages,baked goods, condiments, snack foods, processed meats andcheeses, candy, pharmaceuticals and many other foods.

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They offer good stability, consistency, economical to use andare generally compatible with each other in blends.

Concern for consumers safety is a universal commonalityamong legislators as well as users of food colourant.

Colours that are considered safe in one country may not beconsidered safe in another.

It is absolutely necessary to review and understand localregulatory limitations when choosing food colours.

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Learning Outcomes

Students are able to:

Define the term of flavour

Tell the historical development of food flavouring Differentiate between the types and categories of flavour

Explain the functional role of flavour

Examine the methods can be used in producing flavour

materials

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mf203 lecture 7 - flavour & colour (printed)

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