SISTEM PASCAPANEN PERIKANAN

KULIAH PENGANTAR ILMU KELAUTAN DAN PERIKANAN

OLEH : D A R I U S

Fish Abt. 20.000 known species Bony fish Cod, plaice Gristle fish Ray Shellfish Shrimp, lobster Bivalves mussel

Fishes are cold blooded vertebrates.

Fish muscle is biochemically similar to mammals.

Fish proteins breakdown more rapidly than mammals.

Fish muscle have certain associated problems like endogenous enzymes, free amino acids and small peptides etc.

Lipids from fish contain high levels of polyunsaturated fatty acids.

The stability of fish lipids is short due to their polyunsaturated nature.

Composition of a fish

Water 65 – 80 %Fat 1 – 20 %Protein 14 – 20 %

VitaminsMinerals

Post-harvest changes• Quality of harvested fish depends on these

factors – Intrinsic

• Species, size, sex, composition, spawning, presence of parasites, toxins, contaminants with pollutants and cultivation

• Biochemical characteristics that influence autolysis, rapid microbial proliferation and spoilage are

– Low glycogen– High unsaturated lipids– Soluble nitrogen compds

– Extrinsic• Location of catch, season, methods of actch (gill net,

handline, longline, or trap, etc), on-board handling, hygienic conditions of f/vessel, processing and storage conditions

Extrinsic Factors• temperature

– lower temperatures retard microbial growth

• relative humidity– higher levels promote microbial growth

• atmosphere– oxygen promotes growth– modified atmosphere packaging (MAP)

• use of shrink wrap and vacuum technologies to package food in controlled atmospheres

8

Changes in eating quality of iced cod (Huss, 1976)

FRESH FLAT SWEET/ STALE PUTRID

PRE-RIGOR MORTIS• Live fish

– Cycles of chemical changes take place continuously in the muscle• these provide energy for the muscle while the fish is swimming, and also

produce substances necessary for growth and replacement of worn-out tissue.

• enzymes are compounds that bring about, and control, these changes

• Low glycogen in muscles contributes to small pH drop– pH 6.2 is maintained (fresh: pH 6.0-6.5)

– The enzymes in the flesh go on working even after the fish is dead• some of them act on those substances that normally keep the muscle

pliable and lifelike.

– During life, the muscle contract and become rigid if its two main protein components were allowed to interact and bond together

• but the bonding is prevented by the presence of substances that keep the muscle pliable

• Fish exhausted by lengthy struggle (stress prior slaughter) give meat poor texture and a low keeping quality

– Rigor mortis duration is shortened• pH remains high

• Muscle type makes maturation time shorter

• Factors highly favorable for rapid spoilage are;– Structure of muscle– Tendency to generate alkaline pH rxn in muscle– High probability of microbial infection during fishing and dressing

RIGOR-MORTIS• Rigor mortis is shorter in cold-blooded (hours-a day)

• Duration of rigor mortis depends on species, tempt, and condition of fish when caught– Stiffness is delayed when caught and put on ice immediately and stay

chilled• However freshness is extended, as bacterial spoilage only occur after rigor

mortis has passed

• Flesh that goes thru rigor mortis (stiff to relaxed muscle) has better texture and flavor

• Water-holding capacity of proteins is increased– Makes flesh juicier

• Freezing immediately after catch without chilling to allow rigor mortis results in tough texture

• Cooking fish prior to rigor mortis also result in tough texture

Factor for on set of rigor mortis• Species:

– Some species take longer than others to go into rigor, due to differences in their chemical composition. • E.g. Whiting go into rigor very quickly and may be completely stiff one hour after death, whereas redfish stored under the same

conditions may take as long as 22 hours to develop full rigor. • Trawled codling, 18-22 inches long, gutted and stored in ice, usually take 2-8 hours to go into rigor.

• Condition: – The poorer the physical condition of a fish, that is the less well nourished it is before capture, the shorter will be the

time it takes to go into rigor; this is because there is very little reserve of energy in the muscle to keep it pliable. Fish that are spent after spawning are an example.

• Degree of exhaustion: – In the same way, fish that have struggled in the net for a long time before they are hauled aboard and gutted will have

much less reserve of energy than those that entered the net just before hauling, and thus will go into rigor more quickly.

• Size: – Small fish usually go into rigor faster than large fish of the same species.

• Handling: – Manipulation of pre-rigor fish does not appear to affect the time of onset of rigor, but manipulation, or flexing, of the

fish while in rigor can shorten the time they remain stiff.

• Temperature: – The most important factor governing the time a fish takes to go into, and pass through, rigor because the temperature

at which the fish is kept can be controlled. • The warmer the fish, the sooner it will go into rigor and pass through rigor.

– E.g gutted cod kept at 32-35°F may take about 60 hours to pass through rigor, whereas the same fish kept at 87°F may take less than 2 hours.

– Tempt difference between water and storage of fish

• > difference – the shorter time of death to rigor mortis

enzymatic spoilage (rigor)

Lactic acid produced

PH decrease

Muscle becomes rigid

Muscle becomes pliable

Decompositon of fish 1) enzymatic spoilage 2) oxidative deterioration 3) bacterial spoilage

Deterioration processes in fish

Lipids Proteins

Chemical, bacterial and endogeneous enzyme reactions

Oxidation of fatty acidsHydrolysation of lipids to free fatty acids

Hydrolysation of proteins to peptides andamino acidsDeamination of amino acidsDecarboxylation of amino acids

Fungi

Molds Yeasts

16

Origin of bacteria in fish

Bacterial Number/Square cm

Before decay

Skin 100 – 10,000

Gill 1,000 – 1,000,000

Digestive tract 1,000 – 100,000,000

After decay

Skin 1,000,000 – 100,000,000

Generally, the most importantfactor affecting microbial

growth is temperature.

bacterial spoilage TMAO TMA + Formaldehyde Decomposition of proteines

18

Formation of histamine

Histidine

Histidine decarboxylase

Histamine

oxidative deterioration rancid odors colour changes

Most spoilage of fish is due to bacterial breakdown.

One spoilage characteristic found in fish and not in muscle foods is trimethylamine formation.This odoriferous amine is responsible for the fish smell associated with spoiling fish.

fish meat has high level of polyunsaturated fatty acids, which are unstable.

Chilling of fish immediately after harvest is very important part of preservation.

SUMMARY

THEREFORE:

Preservation

Preservation Salting Smoking

Preservation Salted Smoked Heated Cooled Fermented Dry

What Is Biotechnology? Using scientific methods with organisms to

produce new products or new forms of organisms

Any technique that uses living organisms or substances from those organisms to make or modify a product, to improve plants or animals, or to develop microorganisms for specific uses

What Is Biotechnology? GMO- genetically modified organisms. GEO- genetically enhanced organisms. With both, the natural genetic material of

the organism has been altered. Roots in bread making, wine brewing,

cheese and yogurt fermentation, and classical plant and animal breeding

What Is Biotechnology? Manipulation of genes is called genetic

engineering or recombinant DNA technology Genetic engineering involves taking one or

more genes from a location in one organism and either Transferring them to another organism Putting them back into the original organism in

different combinations

What Are the Benefits of Biotechnology? Medicine

Human Veterinary Biopharming

Environment Agriculture Food products Industry and manufacturing

Biotechnology Helps meet human needs Food, clothing and shelter Plants and animals are used in

manufacturing food, clothing and materials for shelter

BiotechnologyUsed to make products more

useful or desirableEx: conversion of milk into

cheese or yogurt

EfficiencyMust keep the cost of

improving products as low as possible

Biotech results in greater efficiency

Greater Production Increases yields Food with unique traits Some contain therapeutants Some designed with nutrient

enrichment Engineered to have a longer shelf

life

Safety Consumers want foods to provide

needed nutrients and in some cases, enhanced foods

Do not want side effects from those enhanced foods

34

IntroductionFood safety is becoming more prevalent today as wewitness both local and International outbreaks of foodborne diseases.• E. coli poisoning from spinage in 2006, affected 200 people in

the United States and Canada. • Dioxins poisoning from animal feed in 1999, affected

approximately 4,100 dogs and cats in United States, Canada and Mexico

• Dioxin tainted food products ranging from eggs to pork distributed form Belgium to Europe and North America, Australia and New Zealand

• Melamine tainted infant milk in 2008 affected 51,900 infants and young children were hospitalized for urinary track and kidney problems in China. Infants in Hong Kong SAR, Macao SAR Taiwan were also affected

HACCP

• System of process control used by the industry to prevent hazards to the food supply and as a tool in the control, reduction and prevention of pathogens in meat and poultry

Critical Limit

A maximum and/or minimum value to which a biological, chemical or physical parameter must be controlled at a CCP to prevent, eliminate or reduce to an acceptable level the occurrence of a food-safety hazard

Examples of Critical Limits

Hazard CCP Critical Limitbacterial pasteurizer ≥161oF for

≥15

pathogens seconds

(biological) for elimination of

pathogens from milk

Examples of Critical Limits

Hazard CCP Critical Limitbacterialdrying drying schedule:

pathogens oven oven temperature: 200oF

(biological) drying time: 120 min.

air flow rate: 2 ft3/min.

product thickness: 0.5

inches

(to achieve aw 0.85 to

control

pathogens in dried

foods )

Examples of Critical Limits

Hazard CCP Critical Limitbacterialacidification Batch schedule:pathogens product weight: 100 lbs.(biological) soak time: 8 hours

acetic acid concentration: 3.5% volume: 50 gallons(to achieve maximum pH of 4.6 to control Clostridium botulinum in pickled foods)

Structure, Function and Efficacyof Safe,Healthy High Quality Foods

Biochemistry & Molecular Biology

Microbiology

Packaging & Shelf-Life

Food Product Development

Genomics, Proteomics, Bioinformatics

Biophysical Chemistry,

Materials Science

Chemistry Quality and Functionality

Engineering (Conventional and Emerging )

Bioavailabilty Efficacy

Sensory/Consumer