Food Processing Food Processing PrinciplesPrinciples

Chapter 4: Meat ProcessingChapter 4: Meat Processing

Louis LagrangeLouis Lagrange

Lecture StructureLecture Structure

SA Meat Processing MarketSA Meat Processing Market What is muscle/meat?What is muscle/meat? Conversion of muscle into meatConversion of muscle into meat Meat Processing categoriesMeat Processing categories Meat Processing flow diagramsMeat Processing flow diagrams Equipment requiredEquipment required Additives and ingredientsAdditives and ingredients

SA Meat Processing MarketSA Meat Processing Market

750 000 metric tons750 000 metric tons R 5 billionR 5 billion Abattoir sizesAbattoir sizes

What is meat?What is meat?

Skeletal muscle and fatSkeletal muscle and fat Can include organsCan include organs Can include bloodCan include blood

Excellent source of:Excellent source of:– protein, amino acids, zinc, B12, protein, amino acids, zinc, B12,

Selenium, phosphorus, niacin, B6, iron, Selenium, phosphorus, niacin, B6, iron, riboflavinriboflavin

Blend with cheaper productsBlend with cheaper products Red meat (myoglobin) vs white meatRed meat (myoglobin) vs white meat

Composition of meatComposition of meat

3 muscle types3 muscle types– Skeletal muscle (40 % of carcass Skeletal muscle (40 % of carcass

weight) – used for processingweight) – used for processing– Smooth muscleSmooth muscle– Cardiac muscleCardiac muscle

Composition of meatComposition of meat

Meat typically consist of the Meat typically consist of the following:following:– Water 75 %Water 75 %– Protein 20 %Protein 20 %– Fat 3 %Fat 3 %– Soluble non nitrous ingredients 2 %Soluble non nitrous ingredients 2 %

Meat Protein:Meat Protein:– Water soluble (sarcoplasmic)Water soluble (sarcoplasmic)– Salt soluble (myofribrillar)Salt soluble (myofribrillar)– Insoluble protein (connective tissue)Insoluble protein (connective tissue)

Functional Functional characteristicscharacteristics

Water absorption and water Water absorption and water bindingbinding

Gel formationGel formation Cohesion and adhesionCohesion and adhesion Fat content and emulsification Fat content and emulsification

– Fat content variableFat content variable– Leads to oxidation and rancidity Leads to oxidation and rancidity

Meat Processing Meat Processing PrinciplesPrinciples

1. Convert muscle to meat1. Convert muscle to meat– Muscle consists of water, protein & Muscle consists of water, protein &

fatfat

2. Convert meat into high quality, 2. Convert meat into high quality, attractive processed productattractive processed product

Muscle to meatMuscle to meat

Stun animalStun animal Kill animalKill animal Homeostasis (attempt to sustain life)Homeostasis (attempt to sustain life) Blood escapeBlood escape

– 50 % blood is removed50 % blood is removed– 50 % remain in vital organs50 % remain in vital organs– Remove microorganisms breeding Remove microorganisms breeding

groundground– Appearance of the meatAppearance of the meat

Muscle to meatMuscle to meat

Homeostasis (attempt to sustain life)Homeostasis (attempt to sustain life)– Oxygen in muscle exhausted after slaughterOxygen in muscle exhausted after slaughter– Anaerobic reactions take placeAnaerobic reactions take place– Energy from converting glycogen to lactic Energy from converting glycogen to lactic

acidacid– Lactic acid causes pH dropLactic acid causes pH drop– Final pH depend on glycogen present Final pH depend on glycogen present – pH 7 to 5.5 – 5.7 in 6 to 8 hourspH 7 to 5.5 – 5.7 in 6 to 8 hours– pH 5.3 – 5.5 after 24 hourspH 5.3 – 5.5 after 24 hours

– Processor – Processor – final pHfinal pH as well as as well as rate of rate of changechange

Problems!Problems!

Dark Firm Dry (DFD)Dark Firm Dry (DFD)– Animal stress before slaughteringAnimal stress before slaughtering– Absence of glycogenAbsence of glycogen– Reduces lactic acid formationReduces lactic acid formation– pH lowers to > 6.2pH lowers to > 6.2

Unsuitable for prosessor – colour & Unsuitable for prosessor – colour & microbial activitymicrobial activity

ButBut good water binding & good water binding & emulsificationemulsification

Problems!Problems!

Pale, soft and Watery (PSW)Pale, soft and Watery (PSW)– Increase of glycogen and conversion to Increase of glycogen and conversion to

lactic acidlactic acid– Low pH < 5.5Low pH < 5.5– Higher temperature of meat – protein Higher temperature of meat – protein

damagedamage

Prosessor: protein denaturation (not Prosessor: protein denaturation (not soluble, cannot bind water)soluble, cannot bind water)

Lower emulsion propertiesLower emulsion properties

Heat lossHeat loss

Circulation lostCirculation lost Muscle and internal temperature riseMuscle and internal temperature rise pH lowerspH lowers Protein is denaturised (water binding Protein is denaturised (water binding

capabilities is reduced)capabilities is reduced)

Processor: remove heat through coolingProcessor: remove heat through cooling keep at 15 keep at 15 °C until rigor mortis is °C until rigor mortis is

completedcompleted

Rigor mortisRigor mortis

After slaughtering stiffening:After slaughtering stiffening: Cattle 12 – 24 hoursCattle 12 – 24 hours Sheep 12 – 18 hoursSheep 12 – 18 hours Relaxing and softening starts after rigor Relaxing and softening starts after rigor

mortismortis Muscles cut before rigor complete - Muscles cut before rigor complete -

shrinkageshrinkage

Processor: the higher the rigor mortis, the Processor: the higher the rigor mortis, the tougher the meat and the greater the tougher the meat and the greater the water losswater loss

Processor: start curing only after rigor Processor: start curing only after rigor mortismortis

Electrical stimulationElectrical stimulation

Electrical current at specific Electrical current at specific frequencyfrequency– Increase onset of rigor mortis (4 hours)Increase onset of rigor mortis (4 hours)– Increase pH lowering (tender meat)Increase pH lowering (tender meat)– Cut carcass earlierCut carcass earlier– Less dripping lossesLess dripping losses– Prevents cold crimping (0 – 10 Prevents cold crimping (0 – 10 °C)°C) – Prevents defrosting rigor (freeze before Prevents defrosting rigor (freeze before

rigor complete)rigor complete)

PausePause

Processing CategoriesProcessing Categories

Whole meat productsWhole meat products– Muscle tissue is still recognizableMuscle tissue is still recognizable– Bacon, Ham, Corned meatBacon, Ham, Corned meat

Minced meat productsMinced meat products– Hamburger patties, salami, sausagesHamburger patties, salami, sausages

Emulsified meat productsEmulsified meat products– French polony, frankfurters, meat French polony, frankfurters, meat

loavesloaves

Generic flow diagramsGeneric flow diagrams