3/3/

2004

ITU

FO

OD

EN

G.

DEP

.1

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

LECT

URE

5

PRACT

ICAL

TECH

NOLO

GY

(Cha

pter

s 8-

12)

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.2

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

1 H

EAT

PRES

ERVA

TIO

N A

ND

PRO

CESS

ING

PRACT

ICAL

TEC

HNOLO

GY

2 CO

LD P

RESE

RVA

TIO

N A

ND

PRO

CESS

ING

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

5 FE

RMEN

TATI

ON

PRO

CESS

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.3

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

1 H

EAT

PRES

ERVA

TIO

N A

ND

PR

OCE

SSIN

G(Ch

.8)

Hea

t pr

eser

vati

on o

f fo

od r

efer

s to

con

trol

led

proc

esse

s th

at a

re p

erfo

rmed

com

mer

cial

ly, s

uch

as

blan

chin

g, p

aste

uriz

ing,

and

can

ning

.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.4

1 H

EAT

PRES

ERVA

TIO

N A

ND

PRO

CESS

ING

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

Deg

rees

of

pres

erva

tion

:

Ster

iliza

tion

–Re

fers

to

com

plet

e de

stru

ctio

n of

m

icro

orga

nism

s. T

his

freq

uent

ly r

equi

res

a tr

eatm

ent

of

at le

ast

121°

C of

wet

hea

t fo

r 15

min

or

its

equi

vale

nt.

Com

mer

cial

ly s

teri

le–

Deg

ree

of s

teri

lizat

ion

at w

hich

al

l pat

hoge

nic

and

toxi

n fo

rmin

g or

gani

sms

have

bee

n de

stro

yed

as w

ell a

s al

l oth

er t

ypes

of

orga

nism

s wh

ich

coul

d gr

ow in

the

pro

duct

and

pro

duce

spo

ilage

und

er

norm

al h

andl

ing

and

stor

age

cond

itio

ns. T

hey

may

co

ntai

n a

smal

l num

ber

of h

eat

resi

stan

t ba

cter

ial

spor

es b

ut t

hese

will

not

nor

mal

ly m

ulti

ply

in t

he f

ood

supp

ly(m

ost

cann

ed a

nd b

ottl

ed f

ood

prod

ucts

)

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.5

Past

euri

zati

on–

Invo

lves

a c

ompa

rati

vely

low

orde

r of

he

at t

reat

men

t, g

ener

ally

at

tem

pera

ture

bel

ow t

he

boili

ng p

oint

of

wate

r. T

hese

pro

cess

es a

re s

peci

fica

lly

desi

gned

to

dest

roy

path

ogen

ic m

icro

orga

nism

s an

d to

ex

tend

pro

duct

she

lf-li

fe f

rom

a m

icro

bial

and

en

zym

atic

poi

nt o

f vi

ew.

Blan

chin

g-

A k

ind

of p

aste

uriz

atio

n ge

nera

lly a

pplie

d to

fr

uits

and

veg

etab

les

prim

arily

to

inac

tiva

te n

atur

al

food

enz

ymes

. Thi

s is

com

mon

pra

ctic

e wh

en s

uch

prod

ucts

are

to

be f

roze

n. D

epen

ding

on

its

seve

rity

, bl

anch

ing

als

o de

stro

ys s

ome

mic

roor

gani

sms.

1 H

EAT

PRES

ERVA

TIO

N A

ND

PRO

CESS

ING

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.6

1 H

EAT

PRES

ERVA

TIO

N A

ND

PRO

CESS

ING

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

How

ever

, hea

t su

ffic

ient

to

dest

roy

mic

roor

gani

sms

and

food

enz

ymes

als

o af

fect

s ot

her

prop

erti

es o

f fo

ods

nega

tive

ly, t

here

fore

the

re is

nee

d fo

r “o

ptim

isat

ion”

. Fo

r ch

oosi

ng o

ptim

al h

eat

trea

tmen

t pa

ram

eter

s, t

he

follo

wing

poi

nts

shou

ld b

e ev

alua

ted:

Tim

e-te

mpe

ratu

re c

ombi

nati

ons

requ

ired

to

inac

tiva

te

the

mos

t he

at-r

esis

tant

pat

hoge

n an

d sp

oila

ge o

rgan

ism

s in

a p

arti

cula

r fo

od(t

he m

ost

heat

-res

ista

nt p

atho

gen

in

cann

ed f

oods

is

Clos

trid

ium

bot

ulin

um).

0.78

minut

es a

t 12

7C=1

0 minut

es a

t 11

6C=3

6minut

es a

t 11

0C

Hea

t pe

netr

atio

n ch

arac

teri

stic

s in

a p

arti

cula

r fo

od,

incl

udin

g th

e ca

n or

the

con

tain

er i

f it

is p

acka

ged.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.7

1 H

EAT

PRES

ERVA

TIO

N A

ND

PRO

CESS

ING

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

2 A

lter

nati

ve T

echn

ique

s in

volv

ed:

1. H

eati

ng f

ood

in c

onta

iner

s(Fi

g.8.

8-12

):

Still

or

agit

atin

g re

tort

s

Hyd

rost

atic

coo

ker

or c

oole

rs

Dir

ect

flam

e st

erili

zati

on

In-p

acka

ge p

aste

uriz

atio

n

2. H

eati

ng f

ood

prio

r to

pac

kagi

ng:

Hig

h Te

mpe

ratu

re S

hort

Tim

e (H

TST)

pas

teur

izat

ion

follo

wed

by “a

scep

tic

pack

agin

g”(H

ot p

ack

or H

ot f

ill)

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.8

2 CO

LD P

RESE

RVA

TIO

N A

ND

PR

OCE

SSIN

G(Ch

.9)

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

Cool

sto

rage

gen

eral

ly r

efer

s to

sto

rage

at

tem

pera

ture

s ab

ove

free

zing

, fro

m a

bout

16°

C do

wn t

o -2

°C.

Com

mer

cial

and

hou

seho

ld r

efri

gera

tors

are

usu

ally

op

erat

ed a

t 4

-7°C

. M

ost

food

s wi

ll no

t be

gin

to f

reez

e un

til a

bout

-2°

C or

lowe

r.Fr

ozen

sto

rage

ref

ers

to s

tora

ge a

t te

mpe

ratu

res

that

mai

ntai

n fo

od in

fro

zen

cond

itio

n.Go

od f

roze

n st

orag

e ge

nera

lly r

equi

res

tem

pera

ture

s of

-18

°C o

r be

low.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.9

2 CO

LD P

RESE

RVA

TIO

N A

ND

PRO

CESS

ING(

Fig.

9.1)

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

60°C

51,7

°C

37°C

15,6

°C

4,4°

C

0°C

-17,

8°C

Man

y ba

cter

ia s

urvi

ve a

nd s

ome

may

gro

w

Body

tem

p. id

eal f

or b

acte

rial

gro

wth

Tem

p. in

thi

s zo

ne a

llow

rapi

d gr

owth

of

bact

eria

and

pro

duct

ion

of t

oxin

s by

som

e ba

cter

iaBa

cter

ia c

ausi

ng f

oodb

orne

illn

ess

may

gro

wRe

frig

erat

ed t

emp.

per

mit

slo

w gr

owth

of

bact

eria

Free

zing

tem

p. s

top

the

grow

th o

f ba

cter

ia b

ut a

llow

man

y to

sur

vive

.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.10

2 CO

LD P

RESE

RVA

TIO

N A

ND

PRO

CESS

ING

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

The

prin

cipa

l req

uire

men

ts f

or e

ffec

tive

ref

rige

rate

d st

orag

e ar

e:

Cont

rolle

d lo

w te

mpe

ratu

re

Air

cir

cula

tion

Hum

idit

y co

ntro

l

Mod

ific

atio

n of

gas

atm

osph

eres

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.11

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GYSto

rage

req

uire

men

ts a

nd p

rope

rties

of p

erisha

ble

food

s

94,7

2-5

week

s85

-90

12-2

5To

mat

oes

01

year

-1,

5O

il(ve

geta

be

sala

d)

-9-

12 m

onth

s90

-95

-18-

(-23

)M

eat

froz

en62

-77

1-6

week

s88

-92

0,5-

1,0

Beef

, fre

sh62

-85

8-10

mon

ths

90-9

5-1

8-(-

23)

Fish

fro

zen

62-8

55-

20 d

ays

90-9

50,

5-4,

5Fi

sh f

resh

678-

9 m

onth

s85

-90

-1Eg

g (s

hell)

-Se

vera

l m

onth

s-

4-5

Skim

milk

(d

ried

)

32-3

7Se

vera

l we

ek-

-18

Brea

d

Wat

er %

Sto

rage

life

RH%

Sto

rage

te

mp

(°C)

Commod

ity

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.12

2 CO

LD P

RESE

RVA

TIO

N A

ND

PRO

CESS

ING

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

Ther

e ar

e th

ree

basi

c fr

eezi

ng m

etod

s in

com

mer

cial

us

e(Fi

g. 9

.4-1

0):

Free

zing

in a

ir

Free

zing

by

indi

rect

con

tact

wit

h a

refr

iger

ant

Free

zing

by

dire

ct im

mer

sion

in a

ref

rige

rati

ng

med

ium

: Im

mer

sion

fre

ezin

g is

don

e wi

th c

ryog

enic

liq

uids

: (liq

uid

nitr

ogen

and

liqu

id c

arbo

n di

oxid

e -

196°

C an

d -7

9°C)

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.13

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

(Ch.

10)

Food

deh

ydra

tion

ref

ers

to t

he n

earl

y co

mpl

ete

rem

oval

wat

er f

rom

foo

ds b

y dr

ing

unde

r ar

tifi

cal a

nd

cont

rolle

d co

ndit

ions

tha

t ca

use

min

imum

or

idea

lly n

o ot

her

chan

ges

in t

he f

ood

prop

erti

es (D

ried

milk

and

eg

gs, p

otat

o fl

akes

, ins

tant

cof

fee

etc.

)

Proc

esse

s t

hat

rem

ove

only

par

t of

the

wat

er f

rom

fo

ods

(pre

para

tion

of

syru

ps, e

vapo

rate

d m

ilk,

cond

ense

d so

ups)

are

no

tco

nsid

ered

“foo

d de

hydr

atio

n” b

ut a

re c

alle

d “c

once

ntra

tion

”

(Fig

. 10.

7-22

)

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.14

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

Reas

ons

of d

ehyd

rati

on:

Pres

erva

tion

Reta

inin

g si

ze a

nd s

hape

Prod

ucti

on o

f co

nven

ienc

e it

ems

In f

ood

dehy

drat

ion,

eve

ry e

ffor

t sh

ould

be

mad

e to

sp

eed

heat

and

mas

s tr

ansf

er r

ates

. The

fol

lowi

ng

crit

eria

hav

e to

be

opti

miz

ed f

or t

his

aim

:

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.15

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

Surf

ace

area

:Foo

d to

be

dehy

drat

ed is

sub

divi

ded

into

sm

all p

iece

s or

thi

n la

yers

to

spee

d he

at a

nd m

ass

tran

sfer

Tem

pera

ture

:The

gre

ater

the

tem

pera

ture

dif

fere

nce

betw

een

the

heat

ing

med

ium

and

the

foo

d th

e gr

eate

r wi

ll be

the

rat

e of

hea

t ta

nsfe

r in

to t

he f

ood.

Air

-vel

ocit

y: A

ir in

mot

ion

swee

ps m

oist

ure

away

fro

m

the

dryi

ng f

ood’

s su

rfac

e, p

reve

ntin

g th

e cr

eati

on o

f sa

tura

ted

atm

osph

ere.

Hum

idit

y:W

hen

air

is t

he d

ryin

g m

ediu

m, t

he d

rier

the

ai

r, t

he m

ore

rapi

d is

the

rat

e of

dry

ing.

Moi

st a

ir is

cl

oser

to

satu

rati

on s

o a

bsor

bs le

ss a

ddit

iona

l moi

stur

e.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.16

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

Atm

osph

eric

pre

ssur

e an

d va

cuum

:At

a pr

essu

re o

f 1

atm

, wat

er b

oils

at

100°

C. A

s th

e pr

essu

re is

lowe

red,

th

e bo

iling

tem

pera

ture

dec

reas

es. L

ower

dry

ing

tem

pera

ture

s an

d sh

orte

r dr

ying

tim

es a

re im

port

ant

in

the

case

of

heat

-sen

siti

ve f

oods

.

Tim

e an

d te

mpe

ratu

re:W

ith

few

exce

ptio

ns, d

ryin

g pr

oces

ses

that

em

ploy

hig

h te

mpe

ratu

res

for

shor

t ti

mes

do

less

dam

age

to f

ood

than

dry

ing

proc

esse

s em

ploy

ing

lowe

r te

mpe

ratu

res

for

long

er t

imes

.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.17

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

Conc

entr

atio

n ca

n be

a f

orm

of

dehy

drat

ing

or a

pr

elim

inar

y st

ep in

foo

d dr

ying

but

onl

y fo

r so

me

food

s.

Conc

entr

atio

n re

duce

s we

ight

and

vol

ume

and

resu

lts

in im

med

iate

eco

nom

ic a

dvan

tage

s.

Nea

rly

all l

iqui

d fo

ods

to b

e de

hydr

ated

are

co

ncen

trat

ed b

efor

e th

ey a

re d

ried

bec

ause

in t

he

earl

y st

ages

of

wate

r re

mov

al ,

moi

stur

e ca

n be

mor

e ec

onom

ical

ly r

emov

ed in

hig

hly

effi

cien

t ev

apor

ator

s th

an in

deh

ydra

tion

equ

ipm

ent.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.18

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

The

mor

e co

mm

on c

once

ntra

ted

food

s in

clud

e:

Evap

orat

ed a

nd s

weet

ened

con

dens

ed m

ilk

Frui

t an

d ve

geta

ble

juic

es a

nd n

ecta

rs

Suga

r sy

rups

and

fla

vore

d sy

rups

Jam

s an

d je

llies

Tom

ato

past

e

Frui

t pu

rees

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.19

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

3 FO

OD

DEH

YDRA

TIO

N A

ND

CO

NCE

NTR

ATI

ON

Met

hods

of

conc

entr

atio

n:

Sola

r co

ncen

trat

ion

Ope

n ke

ttle

s

Flas

h ev

apor

ator

s

Thin

-film

eva

pora

tors

Vacu

um e

vapo

rato

rs

Free

ze c

once

ntra

tion

Ult

rafi

ltra

tion

and

rev

erse

-osm

osis

dev

ices

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.20

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS(

Ch. 1

1)

Food

irra

diat

ion

is u

sed

prim

arily

as

a pr

eser

vati

on

met

hod.

Mic

rowa

ve e

nerg

y,on

the

oth

er h

and,

is b

eing

em

ploy

ed e

spec

ially

to

prod

uce

rapi

d an

d un

ique

he

atin

g ef

fect

s, o

ne a

pplic

atio

n of

whi

ch c

an b

e fo

od

pres

erva

tion

.

Ohm

ic h

eati

ngis

the

new

est

and

leas

t us

ed o

f th

e th

ree

tech

nolo

gies

. Ohm

ic h

eati

ng c

an p

rese

rve

food

s by

the

app

licat

ion

of h

eat

and

has

the

abili

ty

to v

ery

rapi

dly

heat

foo

ds w

ith

min

imal

des

truc

tion

.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.21

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

In 1

983

the

FDA

(Foo

d A

nd D

rug

Adm

inis

trat

ion)

ap

prov

ed ir

radi

atio

n as

mea

ns o

f co

ntro

lling

m

icro

orga

nism

s on

spi

ces.

In 1

985

FDA

wid

ened

the

allo

wed

uses

of

irra

diat

ion

to a

ddit

iona

l foo

dssu

ch a

s st

rawb

erry

, pou

ltry

, gro

und

beef

, and

por

k.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.22

Irra

diat

ion

is u

sed

for

thre

e pu

rpos

es:

Cont

rol i

nsec

ts in

foo

d su

ch a

s pi

ces,

fru

its

and

vege

tabl

es (a

s an

alt

erna

tive

to

chem

ical

fum

igat

ion)

Inhi

bit

spro

utin

g or

oth

er s

elf-

gene

rati

ng

mec

hani

sms

of d

eter

iora

tion

Des

troy

veg

etat

ive

cells

of

mic

roor

gani

sms

Incr

ease

in s

afet

y an

d sh

elf-

life

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.23

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

Ult

ravi

olet

ligh

t–

espe

cial

ly w

ithi

n th

e wa

vele

ngth

ra

nge

of 2

00-2

80 n

m, i

s em

ploy

ed t

o in

acti

vate

m

icro

orga

nism

s on

the

sur

face

of

food

s. I

t ha

s lo

w de

gree

of

pene

trat

ion.

Tre

atm

ent

of e

quip

men

t su

rfac

es, w

ater

and

air

use

d in

foo

d pl

ants

are

ad

diti

onal

app

licat

ions

.

X-r

ays

-ha

ve g

reat

er p

enet

rati

ng p

ower

tha

n U

V lig

ht. B

ut t

hey

cann

ot e

asily

be

focu

sed

lead

ing

to lo

w ef

fici

ency

of

use

with

cur

rent

equ

ipm

ent.

App

licat

ions

ha

ve b

een

expe

rim

enta

l rat

her

than

com

mer

cial

.

Alf

a, b

eta

and

gam

ma

rays

are

als

o us

ed

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.24

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

Dos

e de

term

inin

g fa

ctor

s:

Safe

ty a

nd w

hole

som

enes

s of

tre

ated

foo

d

Resi

stan

ce o

f fo

od t

o or

gano

lept

ic q

ualit

y da

mag

e

Resi

stan

ce o

f m

icro

orga

nism

s

Resi

stan

ce o

f fo

od e

nzym

es

Cost

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.25

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

Mic

rowa

ve e

nerg

y in

foo

d ap

plic

atio

ns is

use

d fo

r it

s he

atin

g pr

oper

ties

.

Whe

n m

icro

wave

s pa

ss in

to f

oods

, wat

er m

olec

ules

an

d ot

her

pola

r m

olec

ules

ten

d to

alig

n th

emse

lves

wi

th t

he e

lect

ric

fiel

d. T

he e

lect

ric

fiel

d re

vers

es

915

or 2

450

mill

ion

tim

es p

er s

econ

d ge

nera

ting

in

term

olec

ular

fri

ctio

n, w

hich

qui

ckly

cau

ses

the

food

to

hea

t.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.26

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

Mic

rowa

ve f

ood

appl

icat

ions

:Ba

king

Conc

entr

atin

g

Cook

ing

Curi

ng

Dry

ing

Blan

chin

g

Fini

sh-d

ryin

g

Free

ze-d

ryin

g

Hea

ting

Past

euri

zing

Prec

ooki

ng

Puff

ing

and

foam

ing

Solv

ent

rem

oval

Ster

ilizi

ng

Tem

peri

ng

Thaw

ing

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.27

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

4 IR

RAD

IATI

ON

, MIC

ROW

AVE

AN

D O

HM

IC

PRO

CESS

ING

OF

FOO

DS

Ohm

ic h

eati

ng:

Cons

ider

able

hea

t is

gen

erat

ed w

hen

an a

lter

nati

ng

elec

tric

cur

rent

is p

asse

d th

roug

h a

cond

ucti

ng

solu

tion

suc

h as

a s

alt

brin

e.

Prod

ucts

in a

con

duct

ing

solu

tion

are

con

tinu

ousl

y pa

ssed

bet

ween

the

se e

lect

rode

s, e

ach

of w

hich

ra

ises

the

tem

pera

ture

.

The

solid

pie

ces

and

the

liqui

d ar

e he

ated

nea

rly

sim

ulta

neou

sly.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.28

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

5 FE

RMEN

TATI

ON

PRO

CESS

(Ch.

12)

Ferm

enta

tion

s oc

cur

when

mic

roor

gani

sms

brea

k do

wn f

ood

mac

ro-c

ompo

nent

s (i

.e. C

arbo

hydr

ates

lik

e su

gars

) int

o ne

w pr

oduc

ts (i

.e. a

lcoh

ol, C

O2,

lact

ic

acid

). It

enc

oura

ges

the

mul

tipl

icat

ion

of

mic

roor

gani

sms

and

the

prod

ucti

on o

f th

eir

prod

ucts

of

met

abol

ic a

ctiv

itie

s in

foo

ds.

But

only

sel

ecte

d m

icro

orga

nism

s ar

e en

cour

aged

, si

nce

while

the

ir m

etab

olic

act

ivit

ies

and

end

prod

ucts

are

hig

hly

desi

rabl

e, t

here

are

oth

ers

whic

h pr

oduc

e un

desi

rabl

e an

d to

xic

met

abol

ites

.

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.29

5 FE

RMEN

TATI

ON

PRO

CESS

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

Som

e in

dust

rial

fer

men

tati

ons

in f

ood

indu

stri

es:

Lact

ic a

cid

bact

eria

:Cu

cum

bers

–di

ll pi

ckle

s, s

our

pick

les

Oliv

es –

gree

n ol

ives

, rip

e ol

ives

Vege

tabl

e an

d m

ilk –

tarh

ana

Mea

ts –

saus

ages

suc

h as

sal

ami

Milk

–yo

ghur

t, c

hees

eLa

ctic

aci

d ba

cter

ia w

ith

othe

r m

icro

orga

nism

s:D

airy

pro

duct

s wi

th m

ould

–Ch

eese

s(I.

e. r

oque

fort

, ca

mam

bert

)D

airy

pro

duct

s wi

th y

east

–ke

fir

Vege

tabl

e pr

oduc

ts w

ith

mou

ld –

soya

sau

ceA

ceti

c ac

id b

acte

ria:

Win

e, c

ider

, mal

t, h

oney

, vin

egar

Yeas

ts: B

eer,

win

e, b

rand

y, w

hisk

ey, b

read

etc

.

5 FE

RMEN

TATI

ON

PRO

CESS

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

The

term

fer

men

tati

on r

efer

s to

bre

akdo

wn o

f ca

rboh

ydra

te

and

carb

ohyd

rate

-like

mat

eria

ls u

nder

eit

her

aero

bic

or

anae

robi

c co

ndit

ions

. In

wine

, bee

r an

d br

ead

ferm

enta

tion

s,

the

yeas

ts f

erm

ent

gluc

ose

:

C 6H

12O

6

2C

2H5O

H+2

CO2

Lact

ose

lact

ic a

cid

Stre

ptoc

occu

s la

ctis

Und

er a

naer

obic

cond

itio

ns -

true

fer

men

tati

on.

Ethy

l alc

ohol

ace

tic

acid

Ace

toba

cter

ace

tiU

nder

aer

obic

con

diti

ons

–ox

idat

ion

rath

er t

han

ferm

enta

tion

3/3/

2004

ITU

FO

OD

EN

G.

DEP

.31

5 FE

RMEN

TATI

ON

PRO

CESS

INTRO

DUCT

ION T

O F

OOD S

CIEN

CE A

ND T

ECHNOLO

GY

In a

ddit

ion

to p

rovi

ding

var

iety

to

the

diet

, fe

rmen

tati

on a

lso

aids

in

pres

erva

tion

of

food

s si

nce

end

prod

ucts

of

acid

s an

d al

coho

ls a

re

inhi

bito

ry t

o th

e co

mm

on p

atho

geni

c m

icro

orga

nism

s Fa

ctor

s fo

r co

ntro

lling

fer

men

tati

on:

Aci

dA

lcoh

olU

se o

f st

arte

rsTe

mpe

ratu

reLe

vel o

f ox

ygen

A

mou

nt o

f Sa

lt