belly softness and yield: Possible impacts of inherent factors

By: Soladoye Olugbenga Philip Supervisors: Prof. Phyllis Shand Dr. Manuel Juarez

http://www.dailytelegraph.com.au/travel/holiday-ideas/cant-look-away-12-cruise-ship-passengers-to- http://huntleysthebutchers.weebly.com/store/p45/Belly_of_Pork_(1.5kg-3kg).html watch-out-for/story-fnjjv4qx-1226852854540?nk=81e1d7e75d65612e37c1a7dbe615d155-1462290254 Introduction

• is the raw material for side bacon

• Pork belly is one of the most valuable primal cut of pork carcass (Correa et al, 2008), representing about 12 – 16.7% of chilled carcass weight (Soladoye et al, 2015).

• Its defect may affect product quality and processors profitability.

Introduction

• Consumer yearning for lean meat has led to:

• Thin Belly

• Soft belly Introduction

• Thin belly resulted in about $97million unrealized revenue in the US in 2003 (Person et al, 2005) due to

• Reduced processing yield • Increased inferior products

• Soft belly also leads to reduced profitability due to:

• Poor sliceability • Unattractive packaged bacon • Reduced shelf life

http://urbanpaleochef.com/2013/12/04/hormel-natural-choice-original-uncured-bacon/ http://www.sunjournal.com/files/imagecache/medium/2012/05/22/BSECeatsfgate08P052712.jpg Introduction

• Objective assessment is done industrially by iodine value (< 70 is good).

IV = [16:1] × 0.95 + [18:1] × 0.86 + [18:2] × 1.732 + [18:3] × 2.616 + [20:1] × 0.785 + [22:1] × 0.723

• However, this analysis is criticized because of:

• Its destructive nature • Its time consuming nature • Difficulty in selecting unique sampling site

• It does not fully reflect compositional variation http://www.seatons-uk.co.uk/images/layout/seatons/2011/testTubeAndFlask.jpg • 14% of variation in belly firmness (Whitney et al. 2006)

Objectives

To develop a multiple regression model with both dimensional and compositional factor that can account for more than 80% of the pork belly softness variation

• Secondary objectives:

• To assess the effects some inherent factors on variation belly softness

• To assess the possibility of replacing the iodine value with a more non- invasive predictive model to predict belly softness with higher accuracy

Materials and Methods (198 )

Landrace X

Lacombe Genotype Iberian Duroc • population (n = 198) varies with breed, sex, diet and Sex Barrow Gilt Barrow Gilt Barrow Gilt slaughter weight

• This inherent Diet Flaxseed Canola Flaxseed Canola Flaxseed Canola variation was (High linolenic) (High Oleic) (High linolenic) (High Oleic) (High linolenic) (High Oleic) included to

Control represent the Control Control large portion of pork market Slaughter 120 140 120 140 120 140 place weight Materials and Methods

• Pigs were slaughtered according to the conventional slaughtering process over a period of 10 weeks

• Left side bellies were collected for belly softness measurements Materials and Methods

Belly flop angle measurement • Pictures were analysed using ImageJ software.

• The angle between the two edges were measured.

• Belly flop measurement represents the objective measure of belly softness

Materials and methods

Subjective measure of belly softness scale

1 Firm fat, no finger depression, almost horizontal

2 Firm fat, no finger depression, partly flabby 1.5

3 Soft spongy fat, finger depression remains, flappy, roll over with resistance 3.5 https://adventureswiththepig.files.wordpress.com/2011/09/dscf0444.jpg

4 Soft spongy fat, finger depression remains, very flappy, roll over easily 4 .5

5 Soft spongy fat, finger depression remains, very

flabby, roll over easily, oily. ROI Latissumus dorsi Intermuscular fat layer Subcutaneous fat layer Cutaneous trunci Materials and Methods

• 53 parameters included in regression models

Compositional Factors Dimensional Factors

• Moisture content • Belly weight • Iodine value • Belly length • Percent total fat From three • Width midpoint and shoulder end • MUFA belly layers • Thickness of Latissimus dorsi • SFA (lean, sub • Thickness of subcutaneous and intermuscular fat • PUFA and • Belly side thickness at midpoint • N-6 intermuscu • N-3 lar fat (Uttaro and Zawadski, 2010) • N-6/n-3 • SFA/PUFA • Fat hardness

Results R2 = 0.85 • Stepwise regression equation output for objective belly flop measurement Step Intercept C18:2 Subq 2 C16 Width Belly Belly Sln Fat Moistur R2 Intermus sucutane Midpoint weight length firmness e cular ous content

1 201.25** -17.88** 0.504 2 101.58** -11.45** 36.30** 0.628 3 -80.67* -8.77** 34.61** 6.79** 0.682 4 15.66 -7.76** 32.86** 6.21** -3.37** 0.723 5 24.29 -5.01 ** 19.54** 5.27** -5.48** 6.91** 0.765 6 278.51** -5.76** 8.73* 4.00** -6.47** 13.36** -3.35** 0.826 7 288.58** -4.95** 4.98 4.25** -5.86** 13.08** -3.48** -10.60** 0.841 8 310.09** -5.18** 4.17** -6.09** 13.99** -3.66** -11.35** 0.839 9 295.58** -4.36** 3.43** -6.01** 14.18** -3.63** -11.30** 0.27** 0.844 10 261.30** -2.78* 3.95** -5.53** 13.35** -3.51** -6.48* 0.34** -0.47** 0.850 Results R2 = 0.77 • Stepwise regression equation output for subjective belly score

Steps Interce n-6 Subq2 Width Belly Belly C18 Moisture C16 C18 MUFA R2 pt Inter midpoint Weight Length Subcutaneou content Subcutaneou Lean Lean s s

1 -2.06** 0.60** 0.550 2 1.02* 0.41** -1.11** 0.651 3 -1.36 0.37** -1.06** 0.10** 0.685 4 -0.74 0.27** -0.62** 0.17** -0.23** 0.726 5 -4.48** 0.28** -0.43** 0.18** -0.34** 0.06** 0.743 6 -3.35* 0.26** -0.46** 0.18** -0.32** 0.06 ** -0.09** 0.752 7 -3.68** 0.22** -0.31 0.16** -0.31** 0.06** -0.09** 0.02* 0.759 8 -4.86** 0.23** 0.18** -0.36** 0.07** -0.09** 0.02** 0.755 9 -2.16 0.19** 0.16** -0.33** 0.06** -0.06 0.02** -0.09* 0.762 10 -2.10 0.19** 0.16** -0.33** 0.06** 0.02** -0.12** 0.758 11 -1.21 0.18** 0.17** -0.34** 0.06** 0.02** -0.11** -0.09* 0.763 12 4.45 0.15** 0.16** -0.31** 0.06** 0.03** -0.11** -0.17** - 0.08** 0.774 Belly Flop = 261.30 - C18:2Int (2.78) + C16sub (3.95) - Widthmidpoint (5.53) + Results Bellywt (13.35) - Bellylgt (3.51) - Sln (6.48) + fatfirm (0.34) - Moisture (0.47)

2 Side lean (SLn) R = 0.85 Side thickness Side thickness Dimensional factor alone, R2 = 0.82 Latissimus dorsi without rib (SThk) with rib (SThk1) Compositional factors alone, R2 = 0.67 IV alone, R2 = 0.33 – 0.45

Subjective score = 4.45 + n-6Int (0.15) + widthmidpoint (0.16) – bellywt (0.31) + Bellylgt (0.06) + moisture (0.03) – C16sub (0.11) – C18lean (0.17) – Cutaneous trunci MUFAlean (0.08) Cutaneous trunci thickness at midpoint thickness at shoulder (CuTr2) 2 Side fat (SFt) end (CuTr1) R = 0.77 Dimensional factor alone, R2 = 0.66

Compositional factors alone, R2 = 0.70 IV alone, R2 = 0.37 – 0.45

Results • What inherent factors affect belly softness perception? Objective belly flop Subjective Belly score

Effect Pr > F Effect Pr > F breed <.0001 breed <.0001 sex <.0001 sex <.0001 breed*sex 0.0096 breed*sex 0.0735 diet <.0001 diet 0.0001 breed*diet 0.2425 breed*diet 0.7061 sex*diet 0.3726 sex*diet 0.7707 breed*sex*diet 0.0106 breed*sex*diet 0.0082 sw <.0001 sw <.0001 breed*sw <.0001 breed*sw <.0001 sex*sw 0.1549 sex*sw 0.8407 breed*sex*sw 0.0005 breed*sex*sw <.0001 diet*sw 0.7803 diet*sw 0.2477 breed*diet*sw 0.0143 breed*diet*sw 0.0087 sex*diet*sw 0.2646 sex*diet*sw 0.1416 breed*sex*diet*sw 0.7260 breed*sex*diet*sw 0.9567 Results: Interaction of breed, sex and diet

120 4.5

a ab abc abcd abcd abcd a bcde cde 4 100 de de ef ab a 3.5 fg 80 c gh ghi 3 ghi bc c hij ij cd j 2.5 60 de ef 2 fgh efg fgh fgh gh 40 gh gh gh h 1.5 1 20 0.5 score Subjective Belly flop angle (o) angle flopBelly 0 0 Canola Canola Canola Canola Canola Canola Control Control Control Control Control Control Flaxseed Flaxseed Flaxseed Flaxseed Flaxseed Flaxseed Barrow Gilt Barrow Gilt Barrow Gilt Iberian Duroc Lacombe Belly flop Subjective score Results • Pork belly softness and bacon yield

Slice yield Smokehouse Cook loss Total yield Belly softness Belly flop angle appeared to be Pearson -0.05 0.62 0.76 0.25 poorly related to correlation slice and total P value 0.76 0.0001 <.0001 0.1053 yield but strongly related to Subjective belly score measurements smokehouse yield Pearson -0.07 -0.53 -0.73 -0.32 and cook loss. correlation P value 0.6634 0.0003 <.0001 0.0325 Conclusion

• Belly softness can be assessed non-invasively with some dimensional parameters with higher precision compared to frequently used iodine value

• Animal breed, sex, diet and slaughter weight can interact to affect belly softness measure

• This provided a proof of concept procedure whereby image analysis or robotic technology can be programmed for belly softness sorting in the pork industry.

Acknowledgements Results: correlation with compositional factors

Layer C16 C18 C18:2 IV MU SFA PU n-6 n-3 n-6/ PUFA/ FA ǂ FA n-3 SFA Belly flop angle measurements Lean 0.56 0.20 -0.62 -0.58 0.27 0.46 -0.62 -0.60 -0.46 0.24 -0.63 (Latissimus dorsi) Intermuscular 0.48 0.32 -0.69 -0.62 0.07 0.45 -0.65 -0.70 -0.38 0.18 -0.66 fat Subcutaneous 0.54 0.32 -0.72 -0.67 0.05 0.50 -0.68 -0.72 -0.35 0.17 -0.71 fat

Subjective belly softness score Lean -0.56 -0.27 0.64 0.61 -0.27 -0.49 0.65 0.62 0.50 -0.26 0.66 (Latissimus dorsi) Intermuscular -0.43 -0.34 0.72 0.64 -0.10 -0.44 0.68 0.73 0.40 -0.19 0.69 fat Subcutaneous -0.48 -0.37 0.70 0.67 -0.06 -0.49 0.68 0.70 0.37 -0.19 0.70 fat Results: correlation with dimensional/physical factors

Belly MC Fatfirm Fat Wdt Wdt Lgt Wgt Lean Sln Sft Ctr1 Sthk Sthk Ctr2 Seam Seam Subq Subq softness hSh 1 1 2 1 2 measures Belly -0.70 0.48 0.70 0.15 -0.43 0.14 0.58 -0.70 -0.59 0.71 -0.44 0.75 0.76 - 0.31 0.67 0.69 0.72 0.70 flop angle

Subject- 0.71 -0.43 -0.71 -0.12 0.40 -0.24 -0.58 0.71 0.53 -0.71 0.43 -0.73 -0.75 0.28 - 0.66 - 0.70 - 0.71 - 0.69 ive belly softness

MC: Moisture content; Lgt: length; Wgt: Weight; Lean: Total lean; Fat: Total fat, Wdt; width at midpoint of the belly, Wdthsh; Width at shoulder end of the belly, SLn; thickness of Latissimus dorsi, SFt; thickness of subcutaneous + intermuscular fat at the shoulder end, CuTr 1 &2; Cutaneous trunci at shoulder end and mid-point respectively, SThK & SThK1; Belly side thickness at the midpoint with and without rib respectively, Seam 1 & 2; Thickness of intermuscular fat below the rib and just in front of the same rib after the tail end of Latissimus dorsi respectively, Subq 1 & 2; Thickness of subcutaneous fat just above and below Cutaneous trunci respectively