Modellingbeefmeatqualitytraitsduringageing byearlypost … · 2021. 1. 14. · Introduction MaterialandMethods Results Conclusions Modellingbeefmeatqualitytraitsduringageing byearlypost-mortempHdecaydescriptors

IntroductionMaterial and Methods

ResultsConclusions

Modelling beef meat quality traits during ageingby early post-mortem pH decay descriptors

C. Xavier1 U. Gonzales-Barron2 A. Muller1V.A.P. Cadavez2

1Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança

2Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto

69th EAAP Annual Meeting, Dubrovnik 2018

C. Xavier, U. Gonzales-Barron, A. Muller, V.A.P. Cadavez Modelling beef meat quality traits


ResultsConclusions

Outline

1 IntroductionMeat qualityMeat tenderness is a complex trait

2 Material and MethodsData collectionData analysis

3 ResultspH/temperature decay descritorsEffect of animal/carcass descriptorsModelling meat tenderness

4 Conclusions



ResultsConclusions

Meat qualityMeat tenderness is a complex trait

Meat tenderness

Inconsistency in the eating-quality characteristics of meatIs one problem faced by the meat industry worldwide

Meat tenderness - Most important sensory quality attributeIf the beef is tender- We are able to evaluate the Juiciness andFlavour

Consumers are even willing to pay more for beef of higher orguaranteed tenderness



ResultsConclusions


Meat tenderness






ResultsConclusions


Meat tenderness






ResultsConclusions


Meat tenderness






ResultsConclusions


Meat tenderness

Depends on various physiological factorsProteolytic degradationMuscle contractionIntra-muscular connective tissueMarblingetc



ResultsConclusions


Meat tenderness

Depends on various physiological factorsProteolytic degradationMuscle contractionIntra-muscular connective tissueMarblingetc



ResultsConclusions


Meat tenderness

Critical periods for meat tendernessImmediately pre-slaughterDuring slaughterImmediately post-slaughter

Interaction between the pH and temperature declineIdeal window



ResultsConclusions


Meat tenderness

Critical periods for meat tendernessImmediately pre-slaughterDuring slaughterImmediately post-slaughter

Interaction between the pH and temperature declineIdeal window



ResultsConclusions


Ideal window



ResultsConclusions


Objectives

1 to model the decrease in temperature and pH during chillingof beef carcasses early post-mortem

2 to evaluate the extent of influence of live-animal/carcasscharacteristics (i.e., sex, weight, age, breed, class, fat cover,conformation, and transport and lairage time) on the pH andtemperature decline rates

3 Classification of beef carcasses into optimal quality (OQ) andcold-shortened (CS) taking into account the ideal window rule

4 Assess the combined effects of early post-mortempH/temperature decline and animal/carcass characteristics onmeat tenderness

5 The ultimate aim is to build practical models that can be usedto predict the minimum ageing period of a beef carcass



ResultsConclusions

Data collectionData analysis

Animals

Study 1: Modelling pH/temperature decline126 beef animals (74 cross-breed and 52 Mirandesa breed)

85 males and 41 femalesAverage age of 10.1 ± 2.32 months

Study 2: Modelling meat quality51 Mirandesa breed animals

34 males and 17 femalesHot carcass weight: 209.7 ± 65.60 kg



ResultsConclusions


pH/temperature measurements

Study 1 and 2pH and temperature were recorded

Intervals of 10 min during 24 h of carcass chillinglongissimus thoracis muscle at 4th rib levelOMEGA wireless receiver/host (UWTC-REC1)



ResultsConclusions


Meat tenderness

Study 2: Meat sampleslongissimus thoracis et lumborum muscle from the 12ththoracic vertebrae to the 3rd lumbar vertebraeMeat blocks were vacuum packed (1, 2 or 3) and randomlyassigned to one of three ageing periods (3, 8 and 13 days)Tenderness

Cooked at 70°C until the sample reached an internaltemperature of 70°C1-cm cork-borer to give the maximum number of sub-samplesTen to fifteen replicates of 1 cm2 cross-sectional areaTA.XTPlus texture analyser - Warner-Bratzler



ResultsConclusions


Modelling of pH/temperature decline

Exponential Decay function proposed by Hwang andThompson (2001)

Y(t) = A(u) + (A(i) − A(u)) × e−k×t

where:Y(t)is the pH or temperature at time tA(u) is the final pH or temperatureA(i) is the initial pH or temperaturek is the exponential constant of decayt is the time in hours after slaughtering



ResultsConclusions


pH/temperature descriptors

pH: 1.5, 3.0, 4.5, 6.0 and 24 hoursTemperature: 1.5, 3.0, 4.5 and 6.0 hourstimepH6.0: time at pH = 6.0TemppH6.0: Temperature at pH6.0kpH : exponential decay parameter for pH declinekTemp: exponential decay parameter for temperature decline



ResultsConclusions


Animal/carcass characteristics considered as regressors

sex, age, breedhot carcass weight (HCW)transport time (tTransport), lairage time (tLairage)animal class: Calf, Vealer or Yearling



ResultsConclusions


Modelling shear force during ageing

Linear mixed-effects modelSFij = β0j + β1j × Ageingij + β2 × Ageing2

i + β3 × pHep + β4 ×kpH × Ageingi + β5 × Sex + εijβ0j = β′0 + ujβ1j = β′1 + vj

Random-effects terms uj and vj were added to the mean of theintercept β0 and time slope β1 to account for random shifts due tocarcass j .



ResultsConclusions

pH/temperature decay descritorsEffect of animal/carcass descriptorsModelling meat tenderness

pH/temperature decay modelling



ResultsConclusions


Mean, median and range of pH/temperature declinedescriptors



ResultsConclusions


pH at 3 hours



ResultsConclusions


pH decay rate - kpH



ResultsConclusions


Time to pH6.0 and Temperature at pH6.0



ResultsConclusions


Temperature decay date - kTemp



ResultsConclusions


Compliance discrimination



ResultsConclusions


Compliance discrimination



ResultsConclusions


Sex effect on meat tenderness



ResultsConclusions


Class effect on meat tenderness



ResultsConclusions


Compliance



ResultsConclusions

Conclusions I

1 Considerable variation in:1 rigor time: 1.5 – 20.2 hours2 rigor temperature: 2.0 – 35.0ºC

2 Quality of meat tenderness could be either optimal (~61%) orcold-shortened (~39%)

3 A two-dimensional principal component analysis showed thatfive variables – HCW, kpH , kT , pH3.0 and T3.0 hourspost-slaughter - can be used to distinguish the beef meatquality into cold-shortened and optimal quality

4 The rate of tenderisation is higher in the early post-mortemcarcasses and slows down as ageing time elapses for thecarcasses



ResultsConclusions

Conclusions II

5 Carcasses of low final pH produced the least tender meatthroughout the ageing period but with a sharp decline in shearforce attained tenderness levels at 13 days post-mortemcomparable to those of high pH meat

6 This study clearly shows that a quality control system can beimplemented based on the pH/temperature descriptors



ResultsConclusions

THE END! I

Thank You for Your Attention

Obrigado pela Atenção

Hvala na Pozornosti


Documents

Modellingbeefmeatqualitytraitsduringageing byearlypost … · 2021. 1. 14. · Introduction MaterialandMethods Results Conclusions Modellingbeefmeatqualitytraitsduringageing byearlypost-mortempHdecaydescriptors