# 4T - Factors Responsible for Deterioration.ppt

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1. I.Respiration
II.Transpiration
III.Ethylene
IV.Mechanical damages
V.Pests & diseases
FACTORS RESPONSIBLE FOR DETERIORATION
OF HARVESTED FRUITS AND VEGETABLES

2. I. RESPIRATION
MostdeterioratingbiologicalprocessofharvestedFV–
oxidativebreakdownofcomplexmaterial(CHO/acids)
intosimplemolecules(CO
2,H
2O)withproductionof
energy.
Sincetheproductsarestillaliveafterharvest,their
livingcellsrespiretosecureenergy.
Enzymes
Stored foods + H
2O---soluble foods + O
2-------CO
2+ H
2O
+ Heat and useful energy.

3. Respiratory Quotient (RQ)
Thevacuolesofmanyfruitshavelargereserveof
organicacids–mobilizedforuseinmitochondria
asoxidizablesubstratesinTCAcycle.
CompleteoxidationofacidsgeneratemoreCO
2
thattheamountofO
2consumed.Theconceptof
RQhasbeendevelopedtoquantifythisvariation.
RQ=CO
2produced(mL)/O
2consumed(mL).
RQis>1,1&<1forthecompleteoxidationof
acids,glucose&fattyacidsrespectively.

4. Classification of FV according to their respiration rates
Class
Range at 5
0
C
(mg/CO
2/kg/hour)
Commodity
Very low <5 Nuts,dates,dryfruits&vegetables
Low 5-10 Apples,citrus,grape,garlic,onion,potato,
sweetpotato
Moderate
10-20 Apricots,banana,cherry,peach,pear,
Nectarine,fig,mango,cabbage,carrot,
Lettuce,pepper,tomato
High
20-40 Strawberry,blackberry,raspberry,
Cauliflower,limabean,avocado
Very High 40-60 Artichoke,snapbean,greenonion,Brussels
sprout
Extremely high >60 Asparagus,broccoli,mushroom,pea,
spinach,sweetcorn

5. Factors influencing respiration
•Broadly categorized into
A.Plant factors
B.Environmental factors
A) Plant Factors
1) Soluble Sugars:Directly proportional to resp.
Glucose is chief sugars
2) Proportion of living cells:Directly proportional to resp.
Living cells require constant supply of energy.
Respiration liberation the necessary energy.

6. 3)Watercontentoftheproduct:
Directlyproportionaltoresp.
Generallysucculentproductsrespiremorerapidly
thannon-succulentproducts.
Ex.Lettuceheadsrespire(deteriorate)morerapidly
thanpotatoesorsweetpotatoesorevenpeppers.

7. B) Environmental factors
1.ConcentrationofO2&CO2:MoreO
2morewillbethe
respirationrate&viceversa.
2.Temperature:Highertemp–greaterrespirationrate.

8. Itisthemaincauseofdeteriorationitresultsin
–Directquantitativelosses(lossofweight)
–Lossinappearance(wiltingandshriveling)
–Texturalqualityloss(softeninglossofcrispness)
–Lossinnutritionalquality.
II.TRANSPIRATION

9. Factors effecting Transpiration
A)Plant factors
1.Differentiationoftissues:
Plantproductsdifferindegreeofdifferentiationoftheir
tissues–differintranspirationunderthesameconditions.
Ingeneral,non-differentiatedverysucculenttissues
containmorewaterthanhighlydifferentiated,non-
succulenttissues.Underthesameconditionstissueswith
highwatercontentlosewatermorerapidlythantissues
withlowwatercontent.Ex:Highlysucculent–Asparagus
spears,spinachleaves.Highlydifferentiated–Mature
cabbageheads,onions,celeryetc.

10. 2. Outer cover
OutercoverofFVcontainepidermis&peridermtissues.
Epidermisconsistsofsinglelayeroflivingcells–a
layerofwaxonepidermisretardstranspiration.
Plantproductswithcutinizedepidermis–shrinkless
rapidlyinstoragethannon-cutinizedepidermis.

11. Welldeveloped&non-injuredperidermlosewater
lessrapidly&keeplongerinstoragethanthose
productswithapoorlydevelopedorbadlyinjuredor
bruisedperiderm.
Peridermasaoutercoverinapples,pears,citrus
fruits,rootvegetables,potatoes&sweetpotatoes.

12. B) Environmental factors
1)Temperature:
Highstoragetempinducesagreaterrateof
transpirationandgreatershrinkagethan
comparativelylowtemp.
2)Relativehumidity:
Therateoftranspirationisinverselyproportional
totheRH.InotherwordslowRHinducesahigh
rateoftranspiration&highRHinduceslowrate
oftranspiration.

13. III. ETHYLENE
EtheneorEthylene(C
2H
4)wasdiscoveredin1796,
wasoriginallydefiantgas.
Itisacolourlessgaswithsweetishodour&
taste,hasasphyxiantandanaestheticproperties
&isflammable.
Ethylenewasknowntohavephysiologicaleffects
oncrops.
Itwasfirstidentifiedasavolatilechemical
producedbyripeningapplesbyGane(1934).

14. Allfruitsproducesminutequantitiesof
ethyleneduringdevelopment.
Atripening,climactericfruitsproducemuch
largeramountsofethylenethannon-
climactericfruits.
Theinternalethyleneconcentrationof
climactericfruitsvarieswidely,butthatof
non-climactericfruitschangeslittleduring
development&ripening.
Thethresholdlevelofethylenetoinduce
ripeningis0.001microlitre.

16. Theriseinrespirationinresponsetoethylene
mayoccurmorethanonceinnon-climacteric
fruitsincontrasttothesinglerespiration
increaseinclimactericfruits.

17. Internal ethylene concentration in fruits:
Fruits Ethylene (µL/L)
Climacteric
–Apple 25-2500
–Pear 80
–Peach 0.9 –20.7
–Nectarine 3.6 –602
–Avocado 28.9 –74.2
–Mango 0.04 –3.0
–Passion Fruit 466 –530
–Tomato 3.6 –29.8
Non-climacteric
–Lemon 0.11 –0.17
–Lime 0.30 –1.96
–Pineapple 0.16 –0.40
Appliedethylenemerelyincreasestherespirationofnon-climactericfruits,the
magnitudeoftheincreasewasdependupontheconcentrationofethylene.

18. Classification of FV according to Ethylene
Class Range at 20
0
C
(ml/C
2H
4/kg/h)
Commodities
Very low< 0.1 Artichoke, asparagus, cauliflower, cherry, strawberry,
pomegranate, leafy vegetables, potato
Low 0.1 –1.0 Blue berry, cranberry, cucumber, egg plant, okra,
olive, pepper, persimmon, pineapple, pumpkin,
watermelon
Moderate1.0-10.0 Banana, fig, guava, melon, honey dew, mango,
plantain, tomato
High 10.0 –100.0 Apple, apricot, avocado, cantaloupe, feijoa, kiwi fruit,
nectarine, papaya, peach, pear, plum
Very high> 100.0 Cherimoya, apple, passion fruit, sapota

19. Ethylene Biosynthesis
L-Methionine(precursor)-------------------SAM
(S-adenosylmethionine)-------------------ACC
(1-aminocyclopropane-1-carboxylicacid)--
--------Ethylene
ACCsynthase(ACS)isratelimitingstep.
FactorsthataffecttheactivityofACS
includefruitripening,senescence,auxin,
physicalinjuryandchillinginjury.
ACSactivityisstronglyinhibitedbyAmino
oxyaceticacid(AOA)andAminoethoxy
vinylglycine(AVG)
ACCoxidase(ACO)activityisinhibitedby
anaerobiosis,temp>35
o
C&cobaltions.

20. Application of Ethylene
1.Shotsystem
2.Tricklesystem–moreefficient–betterripening.
3.Forcedaircoolingsystem–Now-a-daysfollowed
forethyleneapplicationinclosedroom.
Themethodselectedforapplyingethylenedepends
oncost,convenienceandsafetyfactors.
EthyleneisappliedasliquidasCEPA(Chloroethoxy
phosphonicacid),Ethrel,Ethephonorfromlarge
gascylindersorbyethylenegenerators.

21. Mode of Action
Ethyleneprobablyactsinconcertwithotherhormones.
Thesharpincreaseinethyleneproductionattheonset
ofclimactericphaseisconsideredascontrollingthe
initiationofchangesincolour,aroma,texture,flavour
andotherbiochemicalorphysiologicalattributes.
Tworegulatorysystemofethyleneproduction.
SystemI:operatinginclimactericandnon-climacteric
fruitaswellasvegetativetissuewouldberesponsible
forbasal&woundinducedethyleneproduction,
SystemII:wouldberesponsiblefortheupsurgeof
ethyleneproductionduringripeningofclimactericfruit.

22. Ethyleneisthoughttobindtospecificreceptors
likecoppertoformacomplexwhichthentriggers
ripening.
Patternofchangesinethyleneproductionvaries
withfruits.
1.Ethyleneconcentrationrisesbeforetheonsetof
ripeningdeterminedastheinitialrespiratory
increasee.g.,banana,tomatoandhoneydew
melon.
2.Ethylenedoesnotrisebeforetheincreasein
respiratione.g,apple,avocadoandmango.

23. Effect of Ethylene
Thesensitivityofplanttissuetoethylene
affectedbyO
2andCO
2levelsandwasvarywith
plants.
Ethylenehasprofoundeffectonripening,flavour
synthesisandcolourformationoffruits.
Besides,theyalsoplayapivotalroleindisease
tolerance,chillinginjury,sprouting,growth,
texture,respiration,nutrientcontent,abscission,
senescenceandtoxinformationofplants.

24. Effects of Ethylene on Crops
Crop Effect
Lettuce Russet sprouting, Discolouration
Carrot, BeetBitterness
Celery Blanching
Cabbage Leaf abscission, undesirable flavour
Asparagus Fibrousness
Cucumber Degreening
Strawberry Increased rotting
Brussel SproutsStem elongation (Blown)
Peas Toxin pisatin formation
Mushroom Stalk and cap development
Sweet PotatoesHard core, production of pheolics
Potatoes Suppression of sprouting
Tulips Blueing of petals
Carnation Sleepiness

25. Ethylenecausesde-greeninginoranges
&banana,itbleachesgreencolourof
leafyvegetables,celery,cabbage,
broccolietc.
InFVde-greeningrelatedtoripening
process.
Ethyleneisaninitiatoroffruitripening
orascontributortoripening.

26. Ethylene Control from Commodities
1.Ethylenecanbeabsorbedbytheuseofmolecular
sieves,activatedcharcoal,activatedcarbon,
hydratedaluminiumsilicateorzeolite.
2.Useofcatalyticconvertors.
3.Shouldstoreripeandunripeproduceinseparate
storagerooms.
4.Gaspipes,gascylindersandexhaustgasesfrom
internalcombustionenginesshouldkeptawayfrom
storageroom.
5.EthylenecanalsobedestroyedbyPotassium
Permanganate(KMnO4),astrongoxidizingagent.

27. 6.Ethylenecanbecontrolledbyusingultraviolet
radiation
7.Shouldensuregoodventilationwithairfrom
outsidethestoragecomplex.
8.ManipulatinghighCO2andO2atmosphere.
9.UseofAgNO3,SilverthiosulphateandCalcium
nitrate.
10.Useofpolyamineslikespermidine,putrezine,etc.
11.UseofAOAandAVGwhichpreventtheethylene
biosynthesis.

28. 1.Rollerbruising:
Damageoccursonfruitsurfaceduetorubbingor
vibrationagainstanothersurfaceduringhandling&
transportation.
2.Impactbruising
Productdropsontoahardsurfaceduringfillingand
handlingpackageorpalletloadsofproduce.
Impactbruisingmaynotbeseenatproductsurface–
symptomsappearasinternaldamage.
3.Compressionbruising
Itoccursfrom‘squeezing’thefreshcommoditiesinto
toosmallerspace.
IV. MECHANICAL DAMAGE

29. V. PESTS AND DISEASES
FVareattackedbymanyinsectpestswhich
renderthemunfitforconsumptionorreduce
theirmarketvalue.
Inallcases,infestationstartsinthefield.
Inmostcases,damageisvisibleinthefield
itself&suchFVdiscardedduringharvesting.
Manycasestheinfestationisinternal&not
visibleatthetimeofharvesting.Itisvisible
onlyduringstorageorhandling.