Page 4 - APN September 2017

Pork CRC digesting eating quality research findings
☛ from P3
were more tender than
those from conventional housing.
Shear force also de- clined with increasing carcass weight, but like previous studies, the re- sults differed across cuts, with housing having no effect on the shear force values for the silverside.
Drip loss was higher from deep litter housing for the loin and silverside.
Results for shear force drip loss and lightness are shown in Table 1.
The findings show that on-farm factors affect eat- ing quality and will con- tribute to the eating qual- ity model being developed by Pork CRC.
Packaging problem
Pork CRC has conduct- ed two studies comparing the effects of high oxygen modified atmosphere and vacuum packaging on the ageing and eating quality of pork.
Both were conducted by students and researchers at the University of Mel- bourne.
The first study suggest- ed that pork aged better in VAC than MAP and that the differences were detectable by consumers.
Results after seven days of ageing showed signifi- cant differences in con- sumer preferences for eat- ing quality, overall like- ness and for repurchasing intentions for the vacuum- packed pork.
The results of a larger study (Pork CRC Project 3A-118) confirmed the re- sults.
The research, led by Dr Minh Ha, looked at packaging pork loins in MAP and VAC on numer- ous objective measures of eating quality and chemi- cal changes of the loin aged for one, five and 10 days in both packaging types and loins aged for 10 days in VAC followed by a further 10 days in MAP packaging.
The bottom line was MAP, which is commonly used by retailers, adverse- ly affected most aspects of objective eating quality and this was most obvious for shear force and hard-
ness, which are indicators of tenderness and chewi- ness, respectively.
The results are shown in Figure 1.
There was little differ- ence in packaging on the indicators of tenderness and hardness up to five days.
There was a marked dif- ference in favour of VAC at day 10 and when pack- aging was changed from VAC to MAP at day 10.
At day 10, there was a 22 percent reduction in tenderness and a 33 per- cent increase in the hard- ness of the loin packaged in high oxygen modified packaging compared to vacuum packaging.
HiOxMAP had a nega- tive impact on overall col- our, shear force, texture and water holding capaci- ty of Australian pork loins compared to VAC.
The adverse effects of MAP were associated with increased lipid and protein oxidation.
The results suggest the use of hiOxMAP should be limited to pork cuts with a high turnover to
reduce storage time to less than five days.
Ideally, the results sug- gest retailers should in- crease the use of alterna- tive packaging methods such as vacuum packag- ing and the more recent innovation of vacuum skin packaging.
It seems a pity to invest, as we have, in on-farm and more costly process- ing interventions to im- prove the eating quality of Australian pork, only to have this eroded by how pork is packed and dis- played.
www.porkcrc.com.au
Carcasses from deep litter were fatter at all carcass weights.
Least square mean ± S.E
Muscle
Loin (L)
Rump (R)
Silverside (SS)
Housing (H)
Ecoshelter
Conventional
Ecoshelter
Conventional
Ecoshelter
Conventional
Shearforce kg
4.66±0.2
5.11±0.2
3.95±0.1
4.20±0.1
4.66±0.1
4.77±0.1
Drip loss (%)
6.71±0.003
5.92±0.003
3.75±0.002
3.67±0.002
3.69±0.002
3.14±0.002
L*
49.07±0.3
49.44±0.3
46.94±0.3
47.77±0.3
44.94±0.3
46.42±0.3
Table 1: Housing effects on objective meat quality measurements – shear force (kg), drip loss (percent), and colour in the loin, rump and silverside
Figure 1: Effects of high oxygen modified packaging and vacuum packaging or a combination of VAC fol- lowed by MAP on the Warner Bratzler shear force and hardness of pork loins aged for up to 20 days.
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