FOOD FLAVOR By : Mariam Gamal Amine Geris

Under the supervision of Dr/ Neveen Agamy

Food Flavor

Flavor or flavour (see spelling differences) is the sensory impression of a food or other substance, and is determined

mainly by the chemical senses of taste and smell.

The "trigeminal senses", which detect chemical irritants in the mouth and throat, may also occasionally determine flavor.

The flavor of the food, as such, can be altered with natural or

artificial flavorants, which affect these senses.

What is Flavor ?

5 Basic Tastes in Food

1- sweetness 2- saltiness 3- sourness 4- bitterness 5- umami (savory).

Taste Substances

The

sweet Taste

modality

● Sweet molecules must contain two polar groups that may be supplemented with

a nonpolar group.

● The AH/B theory for the saporous (taste eliciting) unit common to all

compounds that cause a sweet sensation: was initially viewed as a combination

of a covalently bound H-bonding proton and an electronegative orbital

positioned at a distance of about 3 Å from the proton. Thus, vicinal

electronegative atoms on a molecule are essential for sweetness. Further, one

of the atoms must possess a hydrogen bonding proton.

● Changes in the structure and stereography of a sweet molecule lead to the loss

or suspension of sweetness or the induction of bitterness.

.

SWEETENERS- Sweeteners used can be

(i) Natural Sweeteners

Carbohydrate sweeteners

Nutritive Sweeteners

(ii) Artificial Sweeteners

Synthetic Sweeteners

Non-Nutritive

They do not provide calories

Sugar is added to savoury dishes in minute amounts to improve the

flavour of the dish.

Taste Substances

The Salty and Sour

Taste Modalities

● Classic salty taste is represented by sodium chloride (NaCl), and is also

given by lithium chloride (LiCl).

● Salts have complex tastes, consisting of psychological mixtures of sweet,

bitter, sour, and salty perceptual components.

● The mechanism of salty taste perception involves the interaction of

hydrated cation anion complexes with AH/B-type receptor sites.

The Bitter Taste

Modality

● A requirement for only one polar group and a hydrophobic group.

● Bitter substances, these molecules contain AH/B sites suitable for

inducing the bitter sensation.Quinine is an alkaloid that is generally

accepted as the standard for the bitter taste sensation.

3 more flavor categories: Astringency

is a taste-related

phenomenon,

perceived as a dry

feeling in the mouth

along with a coarse

puckering of the oral

tissue. It involves the

association of tannins

or polyphenols with

proteins in the saliva

to form precipitates or

aggregates

Pungency

Certain compounds found

in several spices and

vegetables cause

characteristic hot,

sharp, and stinging

sensations that are

known collectively as

pungency. Ex:chili

peppers, black pepper,

and ginger, are not

volatile and exert their

effects on oral tissues.

Cooling

Cooling sensations occur

when certain chemicals

contact the nasal or oral

tissues and stimulate a

specific saporous

receptor. Ex: mint-like

flavors, including

peppermint, spearmint,

and wintergreen

Flavorant

is defined as a substance that gives another substance flavor, altering the characteristics

of the solute, causing it to become sweet, sour, tangy, etc.

What is Flavorant ?

WHY DO WE ADD FLAVOURING???

Add Flavor

To add an intrinsic flavour - an

example being flavoured

mineral water with citrus extracts.

To add a flavour which has been

lost or modified during

processing. Example: Fruit

flavour in yogurt.

There are three principal types of

flavorings used in foods

TYPES DESCRIPTION

Natural

flavoring

substances

Substances which are extracted from vegetable or

animal materials and are not further chemically

modified or changed. An example is vanilla extract.

Nature-identical

flavoring

substances

Substances that are chemically identical to natural

substances, but which are obtained by chemical

processes or by chemical modification of other natural

substances. An example is vanillin, which is identical

to the vanillin in vanilla, but not obtained from vanilla

pods.

Artificial

flavoring

substances

Substances obtained by chemical synthesis or

chemical modification of natural substances, but

which are not present in natural products.

Natural Flavors A natural flavor is a combination of naturally derived aroma

chemicals and/or essential oils.

Fruit flavorings are mainly generated:

● during ripening process and are produced by secondary

metabolism

● by the catabolism of small quantities of carbohydrates, lipids

and amino acids.

Also vegetables flavors are produced essentially:

by catabolic process but most of these are not due to ripening

rather to manipulation.

Vegetable and Fruit flavors

Sulfur-Containing Volatiles in Allium sp.

Sulfur-Containing Volatiles in the

Cruciferae

.

Methoxy Alkyl Pyrazine Volatiles in

Vegetables

Many fresh vegetables

exhibit green-earthy

aromas that contribute

strongly to their

recognition, and it has

been found that the

methoxy alkyl pyrazines

are frequently

responsible for this

propert

Plants in the genus Allium

have strong, penetrating

aromas, and important

members are onions, garlic,

leek, chives, and shallots.

These plants lack the

strong characterizing aroma

unless the tissue is

damaged and enzymes are

decompartmentalized so

that flavor precursors can

be converted to odorous

volatiles.

contains Brassica plants such as

cabbage, brussel sprouts, turnips,

and brown mustard, as well as

watercress,radishes, and

horseradish.

-The fresh flavors of the disrupted

tissue are caused mainly by

isothiocyanates resulting from the

action of glucosinolases on

thioglycoside precursors.

-The flavor compounds in these

plants are formed through enzymic

processes in

disrupted tissues and through

cooking.

Natural Flavors

Flavors of the

Terpene

Family

● Flavoring substances isolated

from essential oils.

● Ex:Anethol Flavor from Anise,

Fennel, Star anise.

Flavors

derived from

Amino Acids

Catabolism

● Glucosinolates present in different vegetable

.Formation of flavors in radish root.

● Flavor formation in onion and Lachrymatory

factor generation

Flavors

derived from

Lipid

Catabolism

● Production of tomatoes

flavors from linoleic acid

● The Production of pear

esters from linoleic acid

by lipooxygenase

.

Flavor Volatiles in Muscle Foods and Milk

1-Species-Related Flavors of Meats and Milk from Ruminants:

The characterizing flavors of at least some meats are inextricably associated

with the lipid fraction.

2-Species-Related Flavors of Meats from Nonruminants:

Ex.: Formation of the steroid compound responsible for the urinous aroma

associated with the swine sex odor defect of pork.

3-Volatiles in Fish and Seafood Flavors:

Trimethylamine has been associated with fish and

crab-like aromas, and alone it exhibits an ammoniacal, fishy aroma.

Trimethylamine and dimethylamine are produced through enzymic

degradation of trimethylamine oxide

Artificial Flavor ● Artificial flavor is synthesized from other chemicals rather than being

extracted from a natural source.

● Artificial flavors usually contain only a small number of the same

flavor chemicals found in the natural extract, but lack the others so

they cannot precisely duplicate the flavor of the complex mixture. So,

while someone tasting an artificially flavored food will be able to

identify the principal flavor, it may seem bland or taste like it is

“missing something.” EX: Vanilla Flavor, Grapes Flavor.

Added Flavour

Natural flavour or synthetic flavours are often added to food to

increase its acceptability. The flavour which is lost during cooking and processing can be

replaced by either of the following methods:

● Adding natural flavourings and extracts:– Eg:- Natural essence

from fruits.

● Adding synthetic flavours that consist of a blend of chemical which

smells like the original substances Eg:- Vanillin.

Favour Enhancers

● Flavor enhancers are amino acid or nucleotide

derivatives that capable of enhancing the odor of

food. Most flavor enhancers are called as savory

flavorants or umami. These are manufactured as

sodium or calcium salts. Their effects are

prominent and desirable in the flavors of

vegetables, dairy products,meats, poultry, fish,

and other seafoods.

1. Glutamic acid salts – Sodium salt of glutamic acid is called monosodium glutamate (MSG), one of the most commonly used flavor enhancers in food processing. 2. Glycine salts – A simple amino acid that is usually used in conjunction with glutamic acid as flavor enhancers.

The important types of flavor enhancing

substances are :

3. Guanylic acid salts – Nucleotide salts that are usually used in conjunction with glutamic acid as flavor enhancers. 4. Inosinic acid salts – Nucleotide salts created from the breakdown of AMP. Due to high costs of production, it is usually used in conjunction with glutamic acid as flavor enhancer.

Cont.

5. Organic acids – Organic acid are usually not considered and regulated as flavorants by law. But they can impart different sour or taste that alters the flavor of a food – (i) Acetic acid – It gives vinegar sour taste and distinctive smell (ii) Citric acid – It is found in citrus fruits and gives them their sour taste (iii) Lactic acid – It is found in various milk products and give them a rich tartness (iv) Malic acid – It is found in apples and gives them their sour or tart taste (v) Tartaric acid – It is present in grapes and wines and gives them a tart taste

Cont.

Flavourings agents are widely

used in the food industry to

● Enhance a good flavour –eg: addition of

chocolate essences to chocolate cake.

● Replace flavour lost while processing food.

● Give particular flavour to food.

● Mask some undesirable flavour in order to

increase acceptability of food.

● Eg:- adding essence to egg to mask the egg

flavour.

Flavor in different foods ● Tannin- A mixture of strong astringent acids found in plants, particularly

tea leaves, red Grape skins and the bark of trees. It has the ability to

coagulate proteins and is Responsible for the keeping quality of fine red

wines.

● Tannic acid - One of the acids in tannin used for flavoring and as a

clarifying agent in beer, Wine, cider, and other brewed drinks.

● Caffeine - Coffee owes its characteristic flavor to caffeine although by

itself caffeine without Its aroma has a faint bitter taste. Coffee also contains

alkaloids, volatile aromatic Products and substances belonging to the

phenolic series. It stimulates the central Nervous system

Flavor in different foods

● Capsaicin -contained in chilies and is responsible for their

fiery flavour.it is an oily Substance insoluble in water. The

heat of the chilly is measured in Sackville units.

● Alcohol - wine has alcohol which refers to a potable liquid

containing ethyl Alcohol (C6H5OH) it denotes a class of

organic compounds distinguished by the Presence of

hydroxyl group. Alcohol is produced as a result of

fermentation.

Methods for Flavor Analysis

● Gas chromatography combined with fast-scan mass spectrometry

(ppm, ppb and ppt)

Examples:

complexity of mixtures (e.g., over 450 volatiles identified in coffee)

Identification of flavor compounds requires initial isolation from the bulky constituents of

foods combined with substantial concentration.

● However, higher boiling compounds and some compounds present in very low

concentrations still require distillation techniques to assure adequate recovery for

identification.

Methods for Flavor Analysis

● Advances in High-performance liquid chromatography ( HPLC) have provided powerful means for separating many higher boiling compounds and precursors.

Sensory characterization of samples by skilled individuals

(experienced flavorists or researchers)

Sensory assessments are essential for the determination of

detection thresholds, which provide a measure of the

potency of flavor provided by individual compounds

Sensory Assessment of Flavors

A range of concentrations of a selected flavor compound in a defined medium (water, milk etc.) is presented to sensory panelists, and each panelist indicates whether or not the compound can be detected.

The concentration range where at least half (sometimes

greater) of the panelists can detect the compound is designated as the flavor threshold.

Sensory Assessment of Flavors cont.

Future Directions of Flavor Chemistry and Technology

-Enzymic production of flavors within foods and ingredients will

undoubtedly form a significant area of flavor technology in the future.

- With recent developments in making encapsulated

flavor enzyme systems, it is possible to maintain substrate-enzyme

proximity and to control the amounts of flavor compounds produced so

that unbalanced flavors can be avoided.

- With the increasing emphasis on high-quality formulated, complex

foods,flavor development by enzymes should find a role of increasing

importance.

Misconcepts

Of the many misconceptions used in the “natural vs. artificial”

narrative, two stand out:

(1) That artificial flavors are inherently less healthy than their

natural counterparts, and

(2) that a flavor chemical obtained from a

natural source is either different or superior to the same flavor

chemical produced in a laboratory or factory.

The truth is multiple chemicals that make up natural flavors in a

piece of fruit are not harmful. They are not toxic in natural foods for

the same reason they are not toxic in artificial ones

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Food Chemistry

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