Preliminary investigations on the effects of ageing and cooking on the Raman
spectra of porcine longissimus dorsi
J. Renwick Beattie
, Steven E.J. Bell
, Claus Borggaard
, Bruce W. Moss
School of Chemistry, Queen’s University, Belfast BT9 5AG, Northern Ireland, United Kingdom
Danish Meat Research Institute, 2 Magleggaardsvej, P.O. Box 57, 4000 Roskilde, Denmark
Queen’s University of Belfast, Newforge Lane, Belfast BT9 5PX, Northern Ireland, United Kingdom
Agri-Food and Biosciences Institute, AFBI Newforge, Newforge Lane, Belfast BT9 5PX, Northern Ireland, United Kingdom
Received 2 April 2007
Received in revised form 13 May 2008
Accepted 15 May 2008
The inﬂuence of ageing and cooking on the Raman spectrum of porcine longissimus dorsi was investi-
gated. The rich information contained in the Raman spectrum was highlighted, with numerous changes
attributed to changes in the environment and conformations of the myoﬁbrillar proteins.
Predictions equations for shear force and cooking loss were developed from the Raman spectra of both
raw and cooked pork. Good correlations and standard errors of prediction were obtained for both WB
shear force and cooking loss, with the raw and the cooked samples showing almost identical results
= 0.77, root mean standard error of prediction (RMSEP)% of mean = 12% for shear force; R
RMSEP% of mean = 10% for cooking loss. The Raman spectra were also able to predict the extent of cook-
ing that occurred within the pork (R
= 0.94, RMSEP% of range = 5.5%).
Raman spectroscopy has considerable potential as a method for non-destructive and rapid determination
of pork quality parameters such as tenderness. Raman spectroscopy may provide a means of determining
changes during cooking and the extent to which foods have been cooked.
Ó 2008 Elsevier Ltd. All rights reserved.
The tenderness of meat is dependent on three main factors:
content and nature of connective tissue, sarcomere length (i.e.
muscle shortening) and proteolysis (Koohmaraie & Geesink,
2006). Within a given muscle connective tissue is likely to account
for only a small amount of the variability in tenderness. Sarcomere
length is inﬂuenced by the temperature at which the muscle goes
into rigor (Locker & Hagyard, 1963) and method of carcase suspen-
sion (Thompson et al., 2006). The time the meat is held post-mor-
tem, i.e. ageing, increases tenderness due to proteolysis within the
muscle (Thompson et al., 2006).
The tenderness of meat is an important attribute to consumers
and several approaches have been used to predict tenderness.
These approaches include a number of both ultrasonic (Huang
et al., 1997) and optical techniques (Egelandsdal, Wold, Sponnich,
Neegard, & Hildrum, 2002; Park, Chen, Hruschka, Shackelford, &
Koohmaraie, 2001). Near infrared reﬂectance spectroscopy (NIRRS)
has been the most widely researched technique. Shackelford,
Wheeler, and Koohmaraie (2005) showed that measurements at
2 days post-slaughter on-line could be used to predict tenderness
at 14 days post-slaughter.
The potential of Raman spectroscopy as a rapid non-destructive
technique for the prediction of tenderness and juiciness has been
demonstrated for beef when both the spectral measurement and
the meat quality assessment were made after 21 days aging (Beat-
tie, Bell, Farmer, Moss, & Patterson, 2004a). The main beneﬁts of
Raman spectroscopy are its insensitivity to water, sampling ﬂexi-
bility (can be performed on any phase or mixture of phases) and
the fact that it is non-destructive. The insensitivity of Raman to
water represents a major advantage for application to meat com-
pared to NIRRS. Until the 1990s Raman spectroscopy was ignored
due to low efﬁciency, complex and expensive instrumentation;
however, low-cost high-performance bench top instruments are
now widely available.
Although there is little published information on the application
of Raman spectroscopy to meat, there is a considerable body of the
literature which documents the relationship of the Raman spectra
of proteins with their physical and chemical composition (Grassel-
li, Snavely, & Bulkin, 1981; Hester & Girling, 1991; McCreery, 2000;
Mossoba, 1999). Thus in principle Raman spectroscopy has the po-
tential to provide interpretation of protein structural changes in
relation to meat quality, either during aging or during cooking of
0309-1740/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
* Corresponding author.
E-mail address: email@example.com (B.W. Moss).
Meat Science 80 (2008) 1205–1211
Contents lists available at ScienceDirect
journal homepage: www.elsevier.com/locate/meatsci