Effect of pretreatments on convective and vacuum drying characteristics and quality of shrimp

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Effect of pretreatments on convective and vacuum drying characteristics and quality of Shrimp.

Presented by :RAM VINOD KR. SAHU

(12AG65R04)

Agricultural and Food Engineering DepartmentIndian Institute of Technology Kharagpur

Under the guidance of PROF. P. S. RAO

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ContentsIntroductionReview of literatureObjectivesMaterials and MethodWork s and planResults and DiscussionReference

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INTRODUCTIONDried shrimp is an important domestic and export

seafood product. Its price largely depends on its quality dryness,

color (especially its redness) and size. The production of dried shrimp can be mainly

divided into two steps: pretreatment and drying.

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Review of literatureTreatment Sampl

eFindings Reference

Drying Shrimp Drying methods and quality of shrimp dried in a jet-spouted bed dryer

Tapaneyasin et al., 2004

Drying Shrimp Desorption isotherms and Drying characteristics of Shrimp in superheated Steam and hot air

Prachayawarakorn et al., 2002

Shrimp drying

Shrimp Modelling coupled transport phenomena and mechanical deformation of shrimp during drying in a jet spouted bed dryer

Niamnuy et al., 2008

Shrimp drying

Shrimp Shrimp Drying Characterizes Undergoing Microwave Treatment

Farhang et al., 2011

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Objectives:To study the effect of pretreatements on

convective and vacuum drying characteristics of shrimp.

To optimize the drying conditions for convective and vacuum drying of shrimp based on quality parameters.

To compare the quality and storage stability of convective and vacuum dried shrimp.

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Factors affecting the drying process

Type, variety and size of the materialsAir temperatureAir velocityAir humidityExposure timeInitial moisture contentDepth of drying layer

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Works and plan

Pretreatment i) Hot Water Blanching ii) Steam Blanching iii) Microwave BlanchingOne particular temperature for tray dryer. 60 oC , 70 oC and 80 oC for each temperature air velocity at 0.5 m/s, 1 m/s

and 1.5 m/s.Drying combination of convective and vacuum dryer.Rehydration ratio, Shrinkage (%), color and water

activityTo optimize the drying conditionsquality and storage stability convective and vacuum

dried shrimp.20-Sep-13

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Materials and method

Convective tray dryer (1) Air flow regulator(2) Blower(3) Heater (Inside)(4) Temp. Control(5) Heating chamber(6) Temperature

sensor

Vacuum dryer

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PretreatmentsTo reduce the drying time of samples, three

different pre-treatments are testing: a. Hot water blanchingb. Steam blanching c. Microwave blanching

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Control

After pre treatment

Steam blanching

Hot water blanching Microwave blanching

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Control

After drying

Steam blanching

Hot water blanching Microwave blanching20-Sep-13

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Shrinkage The percentage of shrinkage of the shrimp will be

determined by measuring its volume before and after it dried, and calculated using.

Where Zo and Zf are the volume of each group of shrimps at the beginning and at the end of each drying experiment, respectively.

Rehydration Ability The percentage of rehydration will be calculated using:

Where mo and mg are the weights of dry and boiled shrimps, respectively.

Materials and methods

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Moisture Ratio The moisture ratio (MR) was calculated using the following

equation:

Where MR is moisture ratio (dimensionless); Mt is moisture content at t (kg[H2O]/kg[DM]); Me is equilibrium moisture content (kg[H2O]/kg[DM]); and Mo is initial moisture content (kg[H2O]/kg[DM]).

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ColorThe color of the dried shrimp will be evaluated by a

color meter. The Hunter color system has used to illustrate the value of L, a and b.

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Results and DiscussionDrying rate vs. Drying time

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Drying rate constantExperiment Drying rate

constant(k), 60oC

Drying rate constant(k),

80oC

Control -0.0091 -0.009

Hot water blanching -0.0147 -0.013

Steam blanching -0.0220 -0.020

Microwave blanching -0.0117 -0.007

0 100 200 300 400 500 600

-16

-14

-12

-10

-8

-6

-4

-2

0

ControlLinear (Control)MicrowaveLinear (Microwave)Hot water blanchingLinear (Hot water blanching)Steam blanching

Drying time (min)

ln(M

ois

ture

rati

o)

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Shrinkage (%)Experiment Shrinkage (%), 60 oC Shrinkage (%), 80 oC

Control 78.13 78.17

Hot water blanching 74.38 77.50

Steam blanching 82.75 80.51

Microwave blanching 83.89 80.00

Experiment Percentage rehydration ratio, 60 oC

Percentage rehydration ratio, 80

oC Control 78.13 78.17

Hot water blanching 74.38 77.50

Steam blanching 82.75 80.51

Microwave blanching 83.89 80.00

Percentage rehydration ratio

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Water Activity

Experiment Water activity, 60 oC Water activity, 80 oC

Control 0.716 0.463

Hot water blanching 0.721 0.437

Steam blanching 0.690 0.384

Microwave blanching 0.672 0.428

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References Farhang, A., Hosainpour, A., Darvishi, H. and Nargesi, F. (2011).

Shrimp Drying Characterizes Undergoing Microwave Treatment. Journal of Agricultural Science, 3(2): 157-164.

 Kaur, B,P., Kaushik, N., Rao, P.S. and Chauhan, O.P. (2013). Effect of High-Pressure Processing on Physical, Biochemical, and Microbiological Characteristics of Black Tiger Shrimp (Penaeus monodon), Food Bioprocess Technol, 6: 1390–1400.

 Mousa, N, and Farid, M. (2002). Microwave vacuum drying of banana slices. Drying Technology, 20(10): 2055–2066.

 Namsanguan, Y., Tia, W., Devahastin, S. and Soponronnarit, S. (2004). Drying kinetics and quality of shrimp undergoing different two-stage drying processes. Drying Technology, 22(4): 759–778.

 Niamnuy, C., Devahastin, S., Soponronnarit, S. And Raghavan G.S.V. (2008). Modelling coupled transport phenomena and mechanical deformation of shrimp during drying in a jet spouted bed dryer, Chemical Engineering Science, 63: 5503 – 5512.

Prachayawarakorn, S., Soponronnarit, S., Wetchacama,S. and Jaisut, D. (2002). Desorption isotherms and Drying characteristics of Shrimp in superheated Steam and hot air. Drying Technology, 20(3): 669–684.

Ramaswamy, H.S., Lo, K.V. and Stalet, L.M. (1982). Air Drying Of Shrimp. Can. Agriculture Engineering, 24: 123-128.

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