Zmiany parametrów struktury mięsa wieprzowego podczas peklowania i pasteryzacji (angielski).pdf

N auka P rzyroda T echnologie

2009

Tom 3

Zeszyt 4

ISSN 1897-7820 http://www.npt.up-poznan.net

Dział: Nauki o Żywności i Żywieniu

H ANNA G AJEWSKA -S ZCZERBAL 1 , M IROSŁAWA K RZYWDZIŃSKA -B ARTKOWIAK 1 ,

D ONATA J ARMOŁOWSKA -J URCZYSZYN 2

Chair and Section of Clinical Pathomorphology

Poznań University of Medical Sciences

CHANGES IN PORK MUSCLES STRUCTURE PARAMETERS

IN THE COURSE OF CURING AND PASTEURISATION

Summary. The aim of the study was to perform a comparative evaluation of the histological

structure of the following pork ham muscles: the semimembranosus muscle ( musculus semimem-

branosus ) and the quadriceps muscle of thigh ( musculus quadriceps femoris ) and to compare the

extent of these changes following the injection with a curing brine under the pressure of 0.5 MPa,

plasticization (massaging) in vacuum conditions and pasteurisation. Muscles for investigations

were collected from carcasses 24 h after slaughter. The injected curing brine contained, among

others, sodium chloride and polyphosphates. In order to perform histometric measurements at

each phase of the experiment, histological preparations were made which were stained with the

assistance of the HE method (hematoxylin and eosin). Measurements were conducted with the

assistance of the computer image analysis (CIA) using for this purpose MultiScan software. Mi-

croscope pictures were characterised on the basis of the following muscle fibres parameters: cell

cross-section area, cell circumference, as well as Feret’s H and V diameters. In addition, percent-

age proportion of muscle fibres and their quantity in the analysed field of vision were calculated.

The shape of the fibres cross-section was determined on the basis of the ratio of Feret’s H and V

diameters. The results of all measurements were tested for the significance level at p = 0.05.

The performed comparative analysis of structure parameters showed that the cross-section area of

cells of the quadriceps muscle of thigh was smaller than that of the semimembranosus muscle.

Its increase in the former was caused, primarily, by the pasteurisation process, while in the second

one – by the injection with brine. The massaging process resulted in more regular shapes of cells

of the quadriceps muscle of thigh than of those of the semimembranosus muscle as evidenced by

the value of the H/V quotient close to 1. Following pasteurisation, both the area and the circum-

ference of the muscle fibres of the m. quadriceps femoris increased further, while the value of

H/V in both muscles did not differ statistically significantly despite significant differences after

massaging.

Key words: computer image analysis, muscle structure, curing, plasticization, pasteurisation

1 Institute of Meat Technology

Poznań University of Life Sciences

Gajewska-Szczerbal H., Krzywdzińska-Bartkowiak M., Jarmołowska-Jurczyszyn D., 2009. Changes in pork muscles

structure parameters in the course of curing and pasteurisation. Nauka Przyr. Technol. 3, 4, #127.

Introduction

Muscle fibres parameters provide one of the basic elements of meat histological

structure associated with the quality of final products manufactured from whole muscles

(A GUILERA 2005). Their size is connected with the anatomical position of a given mus-

cle in the animal carcass. There are differences between individual animal muscles

regarding their histological structure (W IKLUND et AL . 1998), texture (S HACKELFORD et

AL . 1995) as well as in their susceptibility to the process of plasticization (M OTYCKA

and B ECHTEL 1983, S HACKELFORD et AL . 1989.). Morphological parameters of structural

muscle parameters change under the influence of after slaughter maturation (M ESTRE

P RATES et AL . 2002, S OTELO et AL . 2004), as a result of technological processes to which

meat is subjected in the course of processing as well as types of chemical compounds

making up the curing mixture. The technological and technical curing conditions (L A-

CHOWICZ et AL . 2003, S OBCZAK et AL . 2004.) and thermal treatment (P ALKA 2004, T ORN-

BERG 2005) exert a significant impact on the dynamics and direction of meat tissue struc-

ture changes. Brine which is applied intramuscularly remains in interfibrillar spaces in

quantities which depend on the type of the raw material (G AJEWSKA -S ZCZERBAL and

K RZYWDZIŃSKA -B ARTKOWIAK 2005, K RZYWDZIŃSKA -B ARTKOWIAK and G AJEWSKA -

-S ZCZERBAL 2007). The plasticization process – by loosening and destroying muscle

structures – increases the sorption of the curing brine and diffusion of intrafibrillar pro-

teins into intracellular spaces (L ACHOWICZ et AL . 2003, X ARAGA ỳ O et AL . 1998).

The aim of this study was a comparative assessment of the histological structure of

swine ham muscles, namely: the semimembranosus ( musculus semimembranosus ) and

thigh quadriceps ( musculus quadriceps femoris ) muscles and the range of its changes as

a result of the introduction of the curing brine, plasticization and thermal treatment.

Material and methods

Muscles for analyses were collected 24 h after slaughter and divided into two parts,

one of which was treated as the control, while the other – the experimental sample –

was injected with curing brine which contained, among others, 5.0% sodium chloride

and 0.5% polyphosphates converted into P 2 O 5 . The experimental samples injected with

the brine were plasticized in 95% vacuum and then pasteurised in steel cans at the tem-

perature of 72°C in the can geometric centre measuring the temperature with the assis-

tance of a thermocouple sensor. Histological preparations were prepared at each of the

four phases of the experiment staining them with the assistance of hematoxylin and

eosin (HE). Histometric measurements were performed with the aid of the computer

image analysis (CIA) using for this purpose the MultiScan software. The characterisa-

tion of the microscopic images was carried out on the basis of the following muscle

fibres parameters: cell cross-section area, their circumference and Feret’s H and V di-

ameters. The fibres cross-section shape was determined on the basis of the ratio of the

Feret’s H and V diameters. In addition, the percentage proportion of muscle fibres and

their quantity in the analysed field of vision were calculated. All the measurements were

carried out three times from 10 fields of vision of the microscope eyepiece. The ob-

tained results were tested for the significance level of p = 0.05.

Gajewska-Szczerbal H., Krzywdzińska-Bartkowiak M., Jarmołowska-Jurczyszyn D., 2009. Changes in pork muscles

structure parameters in the course of curing and pasteurisation. Nauka Przyr. Technol. 3, 4, #127.

Results and discussion

The results of parameter measurements of the porcine musculus semimembranosus

and musculus quadriceps femoris structures are presented in Figures 1-6 as well as in

Table 1. Using a visual assessment system, it was found that the scope of changes de-

pended on the evaluated muscle and the stage of experiment.

Fig. 1. Microstructure of the musculus quadriceps femoris : A – raw, B – injected with

brine, C – plasticized, D – pasteurised

Rys. 1. Mikrostruktura musculus quadriceps femoris : A – surowy, B – nastrzyknięty so-

lanką peklującą, C – plastyfikowany, D – pasteryzowany

Differences in the meat histological structure and its constitution depending on the

animal species and/or type of muscle were reported earlier by other researchers, among

others: L IU et AL . (1996), O RYL (2004), G AJOWIECKI et AL . (2001) and L ACHOWICZ et

AL . (1997). Analyzing the results obtained with the assistance of the computer image

analysis it was found that the raw semimembranosus muscle was characterised by

a greater area and circumference of muscle fibres and a fairly regular shape (H/V = 0.97)

in relation to the thigh quadriceps muscle (Table 1). Similar experiments for raw muscles

were conducted earlier and a similar correlation was obtained (G AJEWSKA -S ZCZERBAL

et AL . 2007).

The process of injection with the curing brine increased the cell capacity in the se-

mimembranosus muscle in comparison with the raw muscle (Figs. 2, 3). This is con-

firmed by the measurement results of the cross section area and circumference of mus-

cle fibres carried out in raw and injected muscles between which statistically significant

differences were observed (Figs. 3, 4).

Gajewska-Szczerbal H., Krzywdzińska-Bartkowiak M., Jarmołowska-Jurczyszyn D., 2009. Changes in pork muscles

structure parameters in the course of curing and pasteurisation. Nauka Przyr. Technol. 3, 4, #127.

Fig. 2 Microstructure of the musculus semimembranosus : A – raw, B – injected with brine,

C – plasticized, D – pasteurised

Rys. 2. Mikrostruktura musculus semimembranosus : A – surowy, B – nastrzyknięty solan-

ką peklującą, C – plastyfikowany, D – pasteryzowany

260

240

220

200

180

160

140

120

100

Raw

Injected

with brine

Plasticized

Pasteurised

Fig. 3. Changes in the surface area (CSA) of muscle fibres caused by: the injec-

tion with brine, massaging and pasteurisation

Rys. 3. Zmiany powierzchni przekroju włókien mięśniowych spowodowane

przez nastrzyk solanką peklującą, masowanie i pasteryzację

m. quadriceps femoris

m. semimembranosus

Gajewska-Szczerbal H., Krzywdzińska-Bartkowiak M., Jarmołowska-Jurczyszyn D., 2009. Changes in pork muscles

structure parameters in the course of curing and pasteurisation. Nauka Przyr. Technol. 3, 4, #127.

260

240

220

200

180

160

140

120

100

Raw

Injected

with brine

Plasticized

Pasteurised

Fig. 4. Changes in the circumference of muscle fibres caused by: the in-

jection with brine, massaging and pasteurisation

Rys. 4. Zmiany obwodu włókien mięśniowych spowodowane poprzez

nastrzyk solanką peklującą, masowanie i pasteryzację

m. quadriceps femoris

m. semimembranosus

abc

Raw

Injected

with brine

Plasticized

Pasteurised

Fig. 5. Number of muscle cells in the field of view of the examined mus-

cles: raw, injected with brine, massaged and pasteurised

Rys. 5. Liczba komórek mięśniowych w polu obrazu badanych mięśni:

surowych, nastrzykniętych solanką peklującą, masowanych i pasteryzo-

wanych

m. quadriceps femoris

m. semimembranosus

The increased area of muscle fibres in the semimembranosus muscle caused a simul-

taneous decline of their numbers in the microscopic field of vision (Fig. 5). The applied

massaging and pasteurisation processes caused shrinkage of fibres and increased the

amount of muscle cells counted in the field of vision and the area of the examined pic-

ture occupied by them. In contrast to the semimembranosus muscle, the injection of the

thigh quadriceps muscle with the curing brine caused shrinkage and decrease of the

cross-section area of its cells (Fig. 1). On the other hand, their numbers, circumference

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