Quality Control of Fish and Fishery Products

5/25/2018 Quality Control of Fish and Fishery Products

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Quality Assessment of Fish and

Fishery Products

Dr.A.Surendraraj


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Fish Production

World Fish Production-144.59

(Capture 88.9, Culture 55.7)

Indian Fish Production-8.42 (Inland5.2, Marine 3.22

Tamil Nadu Fish Production 6,14,000tonnes


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Post Mortem Changes in Fish


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Summary of PMC


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Sampling Scale


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Sensory Evaluation of Seafood (Raw)


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EIA Raw Material Evaluation


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Objective Methods of Quality

Evaluation

Introduction

Spoilage of fish

Steps in spoilage

Method of Quality Evaluation

1.Subjective , 2.Objective

Objective Methods

Setting stds, Eliminate subjective error,Assessing marginal quality


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Objective Methods

Characteristic Requirements ofObjective quality test

a.Costb.Skill

c.Facilities

d.Correlatione.Process effect


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Objective Methods

Objective Quality Indices:

a.Volatile Compounds

b.Lipid deterioration

c. Biogenic amines

d. Enzymes etc

e. Physical methods

f. Microbial methods

g. Nucleotide catabolites

h.Miscellaneous


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Volatile Compounds as Quality

Indices

Total Volatile Bases

Trimethyl amine

Dimethyl amine

Ammonia


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TVB-N and TMA-N

TVB-N Widely used

Includes TMA, DMA, NH3and other bases

Later stages of spoilage

Limits

Disadvantage- Source not known

TMA-N

Source Correlation with TPC

Limit


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DMA and Ammonia

DMA:

Source

RoleAmmonia:

Source


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Indices

Determination of TVB-N and TMA-N Steam Distillation method

Conways Micro diffusion Method

Anthno copoulos Method Picrate Method for TMA-N

KOH, Toluene, Picric acid

Simultaneous Determination of TMAOand TMA

Picric acidTMA

TMAOTiCl3 - TMA


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TMA-N and TVB-N

Other Methods:

1.cis-Aconitic acid method,

2.Automated Method3.Enzyme Method

4.TMA-Specific Electrode

5.Chromatographic methods


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Indices Determination of DMA

a.Colorimetric Method

Copper dimethyl dithio carbamate

b.Simultaneous determination of TMA&DMA

Picric acid-TMA, K2Co3-TMA+DMA

c.Chromatographic methods

Determination of Ammonia

a.Glutamate dehydrogenose (430nm)b.Enzyme kits (Sigma, Boehringer,Merck)


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Indices

Volatile Reducing Substances:

Not for early stages

Good for raw, frozen, canned, etc

Method:

Pottasium permanganate (610nm)


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Changes in Lipid as Quality Indices

Oxidative Changes

Primary Changes:

i.Change in reactantsii.Changes in unsaturation

iii.Weight gain

iv.Hydroperoxides


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v.Peroxide value

a.Iodometry b.Spectrophotometry

c.Electrochemical tech e.Flourescent methodd.Chromatography (HPLC, GC)

vi.Conjugated dienes


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Secondary Oxidative Changes:

i.TBA ii.Oxirane value

iii. Totox value iv.p-Anicidine value

v.Carbonyls vi.Hydrocarbons

vii.Kries test

Hydrolytic deterioration

Free fatty acid


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Biogenic Amines as Quality indices

Biogenic amines and their formationGood quality indicesHistamine Limit

i.Column chromatography assay

Sample Extract,Column separation (Amberlite resin, Hcl),Assay (Diazonium reagent, 495nm)

ii.HPLCSample preparation,Injection, Detection.

iii.TLC densitometric methodiv.HISTAMARINE (ELISA) France


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Enzymes as Quality indices

Adenosine Triphosphate

Lactate dehydrogenase

Lysosomal and Mitochondrial enzymes Creatine

Phenol oxidase

Tryptophanase

Succinic dehydrogenase


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Adenosine Triphosphate:Glycolysis

Good- Chill storage, Frozen StorageAssay with Magnesium chloride

Lactate dehydrogenase:GlycolysisCorrelation in ice storageSpecific activity values

Assay with dinitrophenyl hydrazine (520nm)


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Lysosomal and Mitochondrial enzymesFresh and Freeze thawed fish

Lipoamide reductase, 5AMP deaminase

Assay : cumbersome Creatine

Chill storage- good correlation

Phenol oxidaseLobster and shrimp

Tyrosine-----Melanin


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Tryptophanase

Shrimp-Tryptophan---Indole

Max- 25 mg%

Sensory and Chemical quality good

Succinic dehydrogenase

Oysters rapid method with TTC

TTC-----Triphenyl formozon


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Physical MethodsQuality evaluation

Water binding capacityDrips

TextureProtein denaturation, autolytic changes

Measurement using shear or compression cell.i. Instron Model TMii.Universal Testing Machineiii.RHEO-TEX

iv.Compressive deformabilityv.Shear force measurement


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Physical MethodsQuality evaluation

Refractive index

Frozen storage- drip rises

OpacityOpaque and yellow

PHand Eh

Electrical propertiesi.GR Torry meter ii.RT Freshness Tester

iii.Intelectron fish tester


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Microbial Changes as Quality indices

Total Plate CountCommon method (PCA)

Rapid methods:

a.Employment of readymade media

b.Microscopic examination-Phase contrast

c.DEFT

d.ATP measurement

e.Endotoxin-LAL

f.Other method

(Microcalorimetry, Dye reduction, Conductance)


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Microbial Changes as Quality indices

Examination of specific spoilage bacteria

a.H2S producers

b.Vibrionaceae spoilers

c.Pseudomonasd.Photobacterium phosphorium

e.Immunological and gene probes

Determination of Spoilage bacterial countIn terms of TMA, Eh decrease, PH increase etc


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Nucleotide catabolites as quality

indices

Nucleotide degradation:Both autolytic and Bacterilogical

Hypo xanthin:

Good index in fresh, chill storage, also in frozenstorage

Limit

Abnormality

Methods: Silver salt method Enzymatic method

Enzyme test stips, enzyme coated oxygen electrode


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Nucleotide catabolites as quality

indices

K-Value:

Good Correlation

Method:Enzyme sensors

Readymade lit (KV101 Freshnessmeter,Microfish)

HPLC:

Quality Control of Fish and Fishery Products

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