Canning for food preservation is very important technique

canning method for food preservation

1. UIBT, Chandigarh UniversityDr. Nikita Goswami
Canning
Dr. Abhishek Kumar Singh
Assistant Professor
UIBT, CU

2. UIBT, Chandigarh UniversityDr. Nikita Goswami
Objectives
Toexplainwhatiscanning
Toexplaindifferentstagesofcanning
UIBT, CU

3. UIBT, Chandigarh UniversityDr. Nikita Goswami
Introduction
Canningaimstodestroyallmicro-organismsandtheirsporesthroughthe
applicationofheat.
Thisisachievedbysterilisingthefoodwithinair-tightcontainerstoprevent
re-contamination.
UIBT, CU

4. UIBT, Chandigarh UniversityDr. Nikita Goswami
The stages of canning
Thestagesofcanningare:
Cleaningofrawmaterials;
SizeReduction;
Blanching;
Filling;
Sealing;
Washing;
Sterilisation;
Cooling;
Drying;
Labelling.
UIBT, CU

5. UIBT, Chandigarh UniversityDr. Nikita Goswami
Cleaning of raw materials
Allfoodstobecannedmustbewashedthoroughlytoremovecontaminants
andinediblematter.Forsomeproductsthisisaone-stepprocess.Forothers,
suchasstews,allseparateingredientsmustgothroughthisprocess.
Certainingredients,suchasvegetables,needtobeslicedordicedinorderto
fitintocans.However,somevarietiesofcarrotaregrownespeciallysothat
theyfitintothecanwhole.
Size reduction
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6. UIBT, Chandigarh UniversityDr. Nikita Goswami
Blanching
Productswhichcontainfruitsandvegetablesneedtheseingredientsblanched
(i.e.immersedinboilingwater)beforetheycanbepackaged.Thisprocess
helpswithfillingthecan.Blanchingmusttakeplace,quickly,topreventany
enzymaticreactionssuchasdiscolouration.
UIBT, CU

7. UIBT, Chandigarh UniversityDr. Nikita Goswami
Filling
Thecansarefilledautomaticallywithameasuredweightorvolumeofproduct.
Asolutionofbrine,savourysauce,fruitjuiceorsugarsyrupisusuallyadded.
Aspaceisleftatthetoporthecanwilldistortwhensterilised.
Foodisalsopackagedinplasticcontainers.
Theseareknownasplasticcans,e.g.ambientreadymeals.
UIBT, CU

8. UIBT, Chandigarh UniversityDr. Nikita Goswami
Sealing
Thecansaresealed,undervacuum,usingadoubleseamonthecanrim.A
vacuumisappliedtodrawouttheairatthetopofthecanandsealthelid.
Atthisstagesomeproductmayseepout.
Washing
Oncesealed,cansarewashedtoremoveanyexternalparticles,andarethen
readytobesterilised.
UIBT, CU

9. UIBT, Chandigarh UniversityDr. Nikita Goswami
Sterilisation
Batchesofcansareplacedinaretort,whichworkslikea
largepressurecooker.Thetimetakentosterilisethe
contentsatboilingpointwouldberelativelylong.By
canningunderpressurelesstimeisneededasthe
temperaturerisesto121ºC.
Theretortissealedandstemisinjected.Thiscausesthe
temperaturetoriseandeventuallyresultsinairbeingdriven
outoftheretort.
UIBT, CU

10. UIBT, Chandigarh UniversityDr. Nikita Goswami
Sterilisation
Thetypeofproductbeingcannedisofimportanceatthisstage.
‘Solidpack’contents,e.g.cannedmeat,needmoretimeastheheatneedsto
penetratetheproductbyconduction.
‘liquidpack’contents,e.g.soups,needfarlesstimeastheliquidpresent
helpstransfertheheatbyconvection.Thiswilldictatethepressureandtime
neededtosterilisetheproductthroughout.
UIBT, CU

11. UIBT, Chandigarh UniversityDr. Nikita Goswami
Cooling
Afterthecanshavebeensterilised,theyarecooledtopreventovercookingof
thecontents.Thisisachievedbysprayingcoolwateroverthecansanda
gentlereductioninpressure.
Anysuddendropintemperaturewouldcausethecanstodistortanddamage
thecanseams.Whilestillwarm,thecansareremovedandpassedthrougha
coolingtanktoreducethetemperaturefurther.
UIBT, CU

12. UIBT, Chandigarh UniversityDr. Nikita Goswami
Drying
Theremainingheatfromthecanevaporatesanywaterleftonthesurface.
Thisisimportanttopreventrustingduringstorageandtheriskofintakeof
dirtywaterifthereisaseamdefect.
Labelling
Finally,cansarecodedthenlabelledwitha‘bestbefore’date.
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13. UIBT, Chandigarh UniversityDr. Nikita Goswami
Outcome
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Thestudentswillgainknowledgeaboutcanning&differentstagesof
canning.

14. UIBT, Chandigarh UniversityDr. Nikita Goswami
REFERENCES
CanningbyC.PArora,TATAMcGrawHill.
FoodPackagingbyShanK.Wang,TATAMcGrawHill
FoodbyP.LBallaney,KhannaPublishers.
FoodBiotechnologybyK.Shetty,G.Paliyath,A.Pometto,R.E.Levin,
Taylor&Francis
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