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Eggs

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Composition of eggs

% Water Protein Fat CHO

Whole 100 74.6 12.1 11.2 1.2

White 58 88.0 10.1 0.2 0.8

Yolk 31 48.0 16.4 32.9 2.0

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Composition of Eggs -

egg white (albumen)

Water (~88%)CHO (~1%)

mainly gluose! may ause brown

"isoloration in "rie" eggs an" har" oo#e"eggs ($aillar" reation)

at (trae)

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Composition of Eggs -

egg white (albumen)

&roteins (~11%)! most are glyoproteins'hree primary proteins

ovalbumin(*%)+truture of ,a#e" &ro"uts

ovotransferrin(1%)! ,in"s metal! .isoloration

ovomucoid(11%) &rotease /nhibitor ovomucin(10%)ibrous &rotein!

ontributes to the thi#ness of the white (* 2more abun"ant than in yol#)! ontributes to

the stability of egg white foam

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Composition of Eggs -

egg white (albumen)&roteins (ont3n)

globulins (8%) inlu"ing lyso4yme! areimportant for foaming

lyso4yme ability to hy"roly4e apolysahari"e in the ell wall of some

bateria to pre5ent baterial spoilageothers o5oinhibitor! o5ofla5oprotein!o5omiroglobulin! a5i"in (bin"s biotin! but isheat sensiti5e)

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Composition of Eggs -

egg yol#&roteins (160*%)

plasma (78%) li5etin 9.9 (protein

ontent ~ 1:%)granular fration phos5itin (16%!arrier of e)! lipo5itellins (7:%) 9.9

(1%)Water (*8%)

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Composition of Eggs -

egg yol#9ipi"s (; to ;*%)

triglyerol (66%)

phospholipi" (8%) inlu"ing leithin

(has remar#able emulsifying ability)

holesterol (;%! or : mg)

'he olor of yol# "epen"s on thepresene of arotenoi"s0

2anthophylls not arotene

(9utein an" 4ea2anthin)

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Egg uality shell harateristis!shape! soun"ness! leanliness! olor

/nterior >uality si4e of the air ell!firmness of the white! the yol#("istint or flattene" "uring aging)

E5aluate" by an"ling

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Egg >uality "uring storage

'he si4e of the air ell inreaseswater e5aporates from the egg through shell

'he egg white beomes thinnero5omuin un"ergoes "egra"ation

pH of white inreases (from ~ 8 to ~?)

"ue to the loss of CO through the pores

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Egg >uality "uring storage

'he yol# enlarges an" the membrane wea#ens(water mo5es from white to yol#! 5isosity"ereases! yol# beomes flatter an" sprea"s farther)

.eterioration of o"or fla5or

/nrease" storage temperature aelerates loss of>uality

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untionality of Eggs

Coagulation

Emulsifiation

oaming

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untionality of EggsCoagulation or @elation

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&rotein Coagulation

.enaturation Aela2ation of the tertiarystruture to the seon"ary struture!aompanie" by "ereasing solubility of aprotein

&reipitation of protein as moleulesaggregate (often as a result of energyinput! suh as heating or beating)

&roess that results in a loss of solubilityor a hange from a flui" state to a soli"state0 (@elation is also use" to "esribethe proess0

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untionality of Eggs -oagulation

egg white begins to thi#en at~6oC! yol# at ~6oC0 7oC irm

'he gel firmness "epen"s on time temperature of heating @el har"ness "epen"ents on the pH

an" the onentration of protein inrease" pH or protein will inrease

gel har"ness "ilute" protein will inrease oagulation

temperature

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untionality of Eggs -oagulation

+ugar "ereases the rate of heat

"enaturation inreases theoagulation temperature

+alts promote oagulation

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untionality of Eggs

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untionality of Eggs -emulsifiation

ormation of emulsionB mehanial agitation ma#es it

insoluble an" stiff or stableB emulsifying agent (9eithin)

Egg ol# is an oil-in-water

emulsion

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untionality of Eggsoaming

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untionality of Eggs -foaming

olloi"al suspension bubblessurroun"e" by egg albumen

(protein) globulins ha5e greater foaming

ability

o5omuin stabili4es the foam

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untionality of Eggs -fators affeting foaming

$etho"! time an" temperature ofbeating

as beating time inreases! 5olume an"stability of the foam 1st inreases then"ereases

ma2imum stability is reahe" before

ma2imum 5olume room temperature 5s refrigerator

temperature

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untionality of Eggs -fators affeting foaming

Charateristis of the egg white thin white 5s thi# white

store" eggs 5s fresh eggs pH

ai"s or ai" salts inreases foam

stability but "elays foam formation

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untionality of Eggs -fators affeting foaming

Water water inreases the foam 5olume but

"ereases its stability fat

oil re"ues foam 5olume

so"ium hlori"e re"ues the foam stability! inreases

whipping time

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untionality of Eggs -fators affeting foaming

+urose "elays foam formation (so beat then a"")

pro"ues a more stable foam egg yol#

"ereases the foam 5olume

a""iti5es surfatants an" stabili4ers may re"ue

whipping time! inrease foam 5olume

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untionality of Eggs

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untionality of Eggs -fators affeting foaming

$etho"! time an" temperature ofbeating

harateristis of the egg white pH

water an" fat

so"ium hlori"e surose

egg yol#

a""iti5es

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untionality of Eggs

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&roesse" Eggs ro4en eggs

egg whites perform well after free4ing thawing

a"" 1:% (wDw) of sugar or salt to yol#sbefore free4ing to ontrol the gelation offro4en yol#

'o pre5ent syneresisF in fro4en oo#e"egg pro"utsB a""ition of gums

B a""ition of itri ai"

B a""ition of salt

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&roesse" Eggs Egg substitutes

use of egg white together with a yol#-li#e mi2ture ontaining no holesterol

fortify with fat-soluble nutrients a""ition of arotenoi" for gi5ing the

yol# olor

a""ition of arbo2ymethyl-ellulose(C$C) re"ues weeping aroma an" fla5or are not as goo" as

fresh eggs

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&roesse" Eggs .rie" eggs (spray "rying)

pro"uts whole-egg soli"s! yol# soli"s!fortifie" whole-egg soli"s an" whites

growth of miroorganisms is inhibite"

oagulation is not affete"

foaming potential is re"ue"

a"" whipping agents (surfae ati5e)

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&roesse" Eggs ll li>ui" eggs shoul" be

pasteuri4e" (61C for ;0 min) to

#ill salmonella an" other potentialpathogens0

=ltrapaseuri4e" li>ui" whole eggs retain funtional properties of fresh

shell eggs

are aseptially pa#age"

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untionality of Eggs

+ummaryoloring agent (arotenoi"s in yol#)

emulsifier

mayonnaise! hollan"aise saue! ream puffthi#ening agent (oagulation)

ba#e" (gel) or stirre" (sol) ustar"s!

foamingmeringues! foam a#es (angel! sponge!an" hiffon)

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&ro5erbs 11

'he Way of a ool

+eems right to Him,=' a Wise $an

9istens to "5ie