Osmotic dehydration-Dr.M.M.Molla (BARI).ppt

Insects
Insects of different kinds are found to cause serious problems to okra crop. Fruit borer is
found to be the major insect which causes severe damage to okra pods in Comilla. Higher
doses of the insecticides are applied with shorter intervals to control insect pests by the
growers.
Diseases
Diseases, namely yellow mosaic, rots and leaf curl are found to cause serious damage to
okra crop. However, the most serious problem of okra cultivation is due to the infection by
Yellow Mosaic Virus according to 96% of the growers of the surveyed Upazillas of
Comilla. In Chandina Upazilla of Comilla, leaf curl (viral disease) is found to cause
significant damage to okra crop.
Control measures
Most of the growers use chemicals for controlling insect and disease attacks. The
commonly used insecticides and fungicides in the surveyed Upazillas are Dursban, Suntap,
Sumithion and Carrate (insecticides), and Bavistin, Knowin Power, Indofil and Redomil
(fungicides). Amongst the pesticides, Dursban, Bavistin and Knowin Powder are mostly
used. The growers of the surveyed Upazillas are found to apply pesticides at the rates
varied from 10-20 g/10-16 L of water (≈ 1-2 g/L water). The recommended doses of some
important pesticides are: 2 mL/L (Dursban 20EC), 2.4 g/L (Suntap 50SP), 1 mL/L
(Carrate 2.5 EC), 2.24 ml/L (Sumithion 50EC), 1 g/L (Bavistin 50WP), 2 g/L (Knowin
50WP) and 2 g/L (Redomil Gold) (Rahman 2008). The findings of the survey suggest that
generally the growers use the recommended doses of pesticides except for the fact that the
growers often use cocktail of pesticides with shorter interval to ensure total control of
pests and diseases.In papaya, red mite and fruit fly are found to be the predominant insect pests in Pabna.
Papaya mosaic and leaf curl are also found to be the most serious diseases in the papaya
plantation in Ishurdi of Pabna, one of the leading papaya growing zones in Bangladesh.
3.7 Pest and diseases of orange
Different types of bugs and beetles are found to cause damage to orange plants in
Moulvibazar. Die back is observed to be the most serious disease in orange plantation in
the Juri and Borolekha Upazillas of Moulvibazar.
3.8 Pest and diseases of brinjal
Insects
Insects of different kinds are found to cause serious problems to brinjal crop. The most
serious insect of brinjal is shoot and fruit borer. To control insect damage, higher doses of
insecticides with shorter intervals are very often practiced by the growers.
Diseases
In the case of brinjal, the major disease is wilt (64% in Raipura and 52% in Shibpur
Upazillas of Norshingdi district).
Control measures
All the brinjal growers use pesticides to grow brinjal. The growers use insecticides and
fungicides along with PGRs as cocktail. The major insecticides are of the Cypermethrin
(Superthion) and Dimethoate (Tafgor 40EC) groups, whereas the major fungicides are
Dithane M 45, Thiovit, Minicaper and Redomil. Presently, the consumers are re

1. Presenter
Dr. Mohammad Mainuddin Molla
Senior Scientific Officer
Postharvest Technology Division
BARI, Joydebpur, Gazipur-1701
E-mail: [email protected]
WELCOME
Food Osmotic Dehydration
1

2. Presentation Outline
Osmotic dehydration versus terminologies
What is osmotic dehydration
Why osmotic dehydration
Advantages of osmotic dehydration
How osmotic dehydration preserve foods
Before osmotic dehydration what's need
Employee/workers hygiene and sanitary during osmotic
dehydration
Basic requirements during osmotic dehydration
Factors affecting osmotic dehydration process
Chemical treatments for preventing enzymatic browning
Flow chart for osmotic dehydration of foods
BARI developed osmotic dehydrated foods
Research Results
2

3. 3
In Agricultural Sector, the country’s Challenges
Self sufficiency in food production
Reduce rural poverty
Foster sustainable economic development
Safe food
Value added food
Nutrition security

4. ThefoodprocessingindustryinBangladeshrepresents
oneofthemajorpotentialsectorswithintheindustrial
segmentsintermsofcontributiontovalueadditionand
employment.
Thesectoraccountsforover22%ofallmanufacturing
productionandemploysabout20%ofindustriallabor
forces.
Allfoodprocessingenterprisesaccountfor2%ofthe
nationalGDP.
Agro-processors/manufacturers:370
ActivemembersofBAPA:233
Number of agro-processed products:90
Number of exported countries:70
Present status of Food processing
4Source: www.bapabd.org

5. 5
0.2
0.4
0.8
1.6
3.2
6.4
12.8
25.6
51.2
Bangladesh India Vietnum China Thailand
Export value (B.US$)
Export status of processed food

6. 6
Methods for food processing and preservation
1.Osmotic dehydration
2.Drying
3.Freezing
4.High pressure
5.Brine solution
6.Sugar solution
7.Jam, jelly, marmalade etc.
8.Pickle, chutney, sauce tec.
9.Juice and beverage
10.Jam and jelly
11.Candy preparation

7. Osmotic dehydration vs. Terminologies
7

8. Osmotic dehydration Vs Dehydration
Osmotic dehydration Dehydration
•Removalofwaterby
immersingthefoodinasalt
orsugarssolution.
•Wateristransferredfrom
foodtothesolutionbyvirtue
ofthedifferenceinosmotic
pressure.
Conversionofaliquid
producttoadry(solid)
product
Involvespartialremovalof
water.
Involves(almost)complete
removalofwater.
8

9. Dehydration Vs. Evaporation
Dehydration Evaporation
Conversionofaliquid
producttoadry(solid)
product
Concentrationofaliquid
producttoaliquid
product
Involves (almost)
completeremovalof
water
Involvespartialremoval
ofwater
Itdoesstopthegrowth
ofmicrobes.
Itdoesnotstopthe
growthofmicrobes
9

10. Dehydration Vs. Drying
Dehydration Drying
Dehydrationinvolvescomplete
(almost)removalofwater
Dryinginvolvescomplete
removalofwater
Itconvertsliquidproducttodry
product
Itusuallyinvolverisein
temperatureoftheproduct
Itisneartodrying Itisbonedrying
Itcanconsumedirectly Itneedstorehydration
beforeconsumption
10

11. What is Osmotic dehydration
Osmoticdehydration
Osmoticdehydrationisactuallyacombinationof
simultaneouswaterandsolutediffusionprocess(fig.1).
Itisconventionaldryingmethod
Water
Product
Fig.1. Mass transport in osmotic dehydration
11
Sugars
Sugars (Hypertonic solution)
Product soluble (organic soluble,
sugars, salts-----

12. 12
Why Osmotic dehydration?
Fruitsareimportantsourceofdigestibleand
indigestibleminerals,carbohydratesandcertain
vitamins(vitaminAandC).
Themoistureinmostofthefruitsabove75%.
Therefore,fruitsarepronetospoilagebymoldsand
yeast(Janisiewiczetal.,1999).
Inglutseason,fruitsandvegetablescometomarket
together.
Themarketbecomeoverstockedduetolackof
preservationandstoragefacilities

13. Waterdiffusesfromdilutesolution(hypotonic
solution)toconcentratedsolution(hypertonic
solution)throughasemi-permiablemembrane.
Reducingwateractivity
Reductioninrateofmicrobialgrowth
Possiblesavingsenergy
Possiblesavingsinpackagingcosts(packaginga
solidproductasopposedtoaliquidproduct)
Reductionintransportationandstoragecost
Principles of osmotic dehydration
13

14. 14
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0
5
10
15
20
25
30
35
40
45
T2 T3 T4 T5 T6 T7
Water activity Moisture (%)
Treatment
Moisture content
Water activity
Water activity versus moisture content of the food

15. Qualityimprovementintermsofcolor,flavor,oraroma
andtexture.
Energyefficientascomparedtootherdehydration
techniquesnamelyair,vacuumandtraydrying.
Itcanbeconductedatambientorlowtemperatures
Reducesenzymaticbrowning
Flavorretentionismorewhensugarorsugarsyrupis
usedasanosmoticagent
Thereisminimumlossofcolor,flavorandnutrientasitis
lowtemperatureprocess.
Doesnotrequireanysophisticatedequipment(Nazaneen
etal.,2017).
Advantages of osmotic dehydration
15

16. How osmotic dehydration preserve foods
Foodscanbespoiledbyfoodmicroorganisms
orthroughenzymaticreactionswithinthefood.
Bacteria,yeast,andmoldsmusthavea
sufficientamountofmoisturearoundthemto
growandcausespoilage.
Reducingthemoisturecontentoffood
preventsthegrowthofthesespoilage-causing
microorganismsand
Slowsdownenzymaticreactionsthattake
placewithinfood.
Thecombinationoftheseeventshelpsto
preservefood.
16

17. 17
Osmotic dehydration effective ways of food
preservation
Duringosmoticdehydration,aproductcontinuously
immersedintheosmoticsolution
Makingtheprocessoxygenfree
Therefore,noneedtousesulfuredioxideand/or
blanchingforprotectionagainstoxidativeandenzymatic
discoloration.
Alsotheprocesstakesplaceundermildheattreatment
(50ºC)whichfurtherimprovecolor,flavorandnutrient
retention

18. 18
Fruits/VegetablesFruits/Vegetables
Banana Jackfruit
Pineapple Watermelon
Guava Citrus fruits
Carrot Potato
Mango Cherry
Papaya Appricot
Plum Apple
Application of Osmotic dehydration process

19. Before dehydration what's need
19

20. Sanitizingandhygiene
Adequatehandwashingfacilities
Adequateventilationoftheprocessingroom
Adequatestoragefacilities
20

21. Employee/workers hygiene and sanitary
Protectiveclotheshouldbeworn
Allemployeesshouldshareresponsibilitiesto
maintainwashroomsinacleanandorderly
manner.
Glovesarerequiredforindividualsthat
directlyhandledfoodingredients
21

22. Usefresh/sanitizewater
Nevertouchfoodbyhand
Neversmokeneartothe
processingplace/room
Neversneezing/coughingduring
processing
Basic requirement as good employee during dehydration
22

23. Factors affecting Osmotic dehydration process
23

24. The influence of main process variables:
1.Osmoticagent
Thecommonosmoticagentaresalt,sugar,honey,sucrose,
glucose,fructose,sorbitol,glycerol,glucosesyrup,corn
syrup,maplesyrup,starch,fructo-oligosaccharides,
maltodextrinandethanol.
Sugarandsaltsolutionsprovedtobethebestchoicesbased
oneffectiveness,convenienceandflavor.
Sugarsolutionreducesbrowningbypreventingoxygen
entrance,providesstabilitytopigmentsandhelpsretain
volatilecompoundsduringdryingofosmoticallytreated
materials
2.Concentrationofosmoticsolution
Increaseofsolutionconcentrationresultsintheincreasein
waterlossandsolidgainrates(Phisut,2012).
Lessconcentratedsucrosesolutionleadstominimallossof
waterandsolidgainratios(Tortoe,2010).
24

25. 3.Temperature
Temperaturesabove45°Ccancauseundesirable
changesincolor,flavorandaroma,aswellas
changesinthefoodcellwall.
Initially,thewaterlossandsolidgainincreasesas
temperatureincreasesupto50°C.
4.Immersiontime
Theincreaseinimmersiontimeleadstohigherloss
ofmoistureduringosmoticdehydration(Ispirand
Toğrul,2009;Mundadaetal.,2011).
Solidgainandweightlossoftheproduceduring
osmosisattainequilibriumstatewithrespecttotime
(IspirandToğrul,2009;Phisut,2012).
25

26. 26
5.Agitation
Highlyconcentratedviscoussugarsolutions
createsmajorproblemssuchasfloatingoffood
pieceshinderingthecontactbetweenfoodmaterial
andtheosmoticsolution,causingareductionin
themasstransferrates(Phisut,2012).
Soagitationorstirringprocesscanbeapplied
duringosmoticdehydration.

27. 6.Ratioofosmoticsolutiontosample
Mostofresearchersusedthesampletosolution
ratiorangingfrom1:1to1:5inordertostudythe
masstransferkineticsbyfollowingchangesin
concentrationofsolutionandotherfactors.
Aratioof1:2or1:3isoptimumforpractical
purposes(Tiwari,2005).
27

28. 28
7.Reuseofosmoticsolution
Thesolutionremainedafterosmotictreatmentof
fruitshasbeensuggestedtobeappliedforother
foodpreparationssuchas:
Jams
Syrupforfruitcanning
Mixingwithfruitjuices
Fruitysoftdrinks
Pharmaceuticalandfoodindustriesasanatural
additivesand
Animalfeedproduction.

29. 29
Effect of temperature and time on % weight reduction
Weight loss increases with duration of osmosis

30. 30
Effect of concentration of osmotic solution on weight
reduction
Weight reduction increases with increase in sucrose solution

31. Prevention of Enzymatic Browning
31

32. Particulars Chemical agents Time/
Temp.
Results
Egg plantCalcium ascorbate or
citrate (0.4%)
1 min/60°CBesttoinactivateenzyme
WatermelonSodium chloride (2%)2 min/RTPreservationofthefirmnessof
freshcuttissuethroughout
storage
Mango 3% sodium chloride 2 min/10°CSignificantdecreaseoftheloss
oftissuefirmness
Longan 0.01%sodiumchlorite10 min/RTReduce browning
MushroomDETANO(2,2
hydroxynitrosohydrazino
)bisethnamineat1mM
10min/20°CSufficienttomaintainahigh
leveloffirmness,todelay
browning.
Potato 1%Sodiumacidsulfate+
1%citricacid+1%
ascorbicacid
10 min/RTReduce browning and
polyphenoloxidaseactivity.
Apple,
guava
Ascorbic acid 0.3mM 10 min/RTDecrease of the browning
Apple,
papaya
1%sodiumchloride+
1%citricacid
1-2 min/RTPrevent browning
Studiesonchemicaltreatmentsusedtopreventionenzymaticbrowning
32

33. Flow chart for osmotic dehydration process
33

34. Takingfruit,washing,sorting,gradingandpeeling
Cutintosuitablesize
Dippinginto25°Brixsolutioncontaining1%KMSwith0.5%
citricacidfor1.5hrs
Heatinggraduallyandturneditfrom25°Brixto50°Brix
Takeouttheproductfromsyrupsolution
Transferringittotray
Dehydratingat50°C
StoringatHDPE/PPpouchatambientcondition/refrigeration
temperature
Osmo-dehydrated foods
34

35. 35
Manyresearchershavebeenusedseveralmethodsand
systemsduringosmoticdehydration
Agitation(centrifugalforce)
Applicationofvacuum(pulsedvacuum)
Heating(microwaveandthermalappliance)and
Useofultrasoundtechniques.
Amongthedifferentmethods
Useofultrasoundallowedshorteningthetimeofosmotic
dehydrationfrom30to120min
Additionally,ultrasound-assistedosmoticdehydration
minimizedthelossofL-ascorbicacid(retention:79.7-84.4
percentcomparedto63.4-72.3percentinundehydrated
frozensamples)
Improvecolourretentionandfirmnessduringrefrigerated
storagefor6months(Xinetal.2013).
Recent developments in osmotic dehydration methods

36. 36
Itisoneofthebestmethodforpreservationbecauseit
doesnotdestroymuchnutritionalparameterscolor,
flavorandtextureetc(Rastogietal.,2002).
Theprocessisquitesimple,economical(energy
requirementis2-3timeslessascomparedtothe
conventionaldryingand
Forproducingsafe,stable,nutritious,tasty,economical
andconcentratedfruitproducts.
Improvementoftheoverallqualityofthefoodproduct.
Economical benefits of osmotic dehydration

37. BARI developed osmotic dehydrated products
37

38. JackfruitCandy
(Dipping1kg matured jackfruit bulb+ 1g
KMS for 1 hras pre-treatment)
(1 kg sliced bulb+25% sugar+0.5% CA)
Mango candy
Pineapple candy
38

39. Star fruit candy
Watermelon candy
Aonla(Amloki) candy
39

40. Papaya candy
Coconut candy
(50% coconut milk+ 25%
sugar+ 25% rice malt)
Banana (Dehydrated)
40

41. Osmo-dehydrated jackfruit
Osmo-dehydrated mango
(Amchur)
41
Mango bar/leather

42. Research Results
42

43. Effect of dehydration temperature on water loss and solid
gain content
Temperature (°C)°BrixWater loss (g/g solid)Sugar gain (g/g initial solid)
30 30 0.063 0.041
40 0.075 0.042
50 0.084 0.046
40 30 0.074 0.043
40 0.078 0.045
50 0.086 0.058
50 30 0.080 0.093
40 0.083 0.115
50 0.088 0.119
The rate of water loss and sugar gain during osmotic dehydration of the
fruit was directly related to the sugar concentration and temperature.
43

44. Physico-chemical composition of fresh and osmo-dehydrated fruit
44

45. Osmoticdehydrationmethodisveryusefulfor
preservationoffoodintermsofhighqualityproductby
retainingflavor,colorandothervolatiles
Itinhibitsthebrowningofenzymesanddecreasesthe
energycosts.
Itlowertheoperationcostsofthefruitdryingprocess
Thisprocesscouldbeusedonsmallscalefor
developmentofself-entrepreneursandhomescale
industries.Consumptionofsuchnutritionalandvalued
productscouldbepopularizedthroughexhibitionand
media.
Conclusion
45

46. Challenges of osmotic dehydration technology
Theuseofhighlyconcentratedsugarsolutionscreates
threemajorproblems.
Thesyrup’sviscosityissogreatthatagitationis
necessarytodecreasetheresistancetothemass
transferonthesolutionside.
Thedifferenceindensitybetweenthesolution(about
1.3kg/litre)andfruitandvegetables(about0.8
kg/litre),makestheproductfloat.
Compositionofthesolutionandrecyclingshouldtake
intoaccountthemicrobiologicalsafety.
46

47. There is no end of learning
47