SHEAR FORCE MAPPING: A TOOL FOR TENDERNESS MEASUREMENT1
ABSTRACT ABSTRACTA shear mapping method (SMM) was developed and evaluated for examining objectively the effectiveness of tenderization processes for meat. One-centimeter square cross section samples were cut parallel to the muscle fiber orientation across the complete cross sectional area of cooked strip loin steaks. Each sample was assigned a coordinate reference grid code that identified (“mapped”) its location within the steak. Shear force measurements within steaks were evaluated using the SMM procedure before and after applying the hydrodynamic pressure (HDP) tenderization process. The less tender the region within a control steak, the more it was tenderized after applying HDP, and HDP tenderization resulted in improved uniformity of tenderness. The suggested SMM method has the potential to minimize variations in technique among scientists and institutions and provides a tool for screening and testing the efficiency of tenderization processes by evaluating a larger proportion.
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ABSTRACT: As a spin-off of an OECD Workshop on pork quality, held in Helsinki in 1992, a group of scientists with many years of experience in the field of meat quality assessment convened in February 1993 for the first time, and subsequently in 1994 and 1995, in Kulmbach at the German Federal Centre for Meat Research under the auspices of the OECD research project Management of Biological Resources. Three specific areas were discussed in order to develop internationally accepted reference methods: In the autumn of 1997 the methods were brought into their final form at the Meat Industry Research Institute of New Zealand (MIRINZ). They are presented in this paper.Meat Science 08/1998; 49(4):447-57. · 2.75 Impact Factor
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ABSTRACT: Data collected from 690 beef rib steaks were utilized to evaluate the methodology of beef tenderness measurements. The information obtained in this study was critically compared to existing research and evaluated in relation to sample handling procedures. Frozen storage of steaks, especially if they are unprotected from dehydration or are stored for long periods of time, has important implications if such data are to be compared to steaks which were evaluated in the unfrozen state. Cooking frozen steaks with or without thawing apparently has little effect on tenderness or cooking loss. Anatomical location of the sample should be carefully controlled to prevent spurious differences from affecting tenderness measurements. Evidence indicates that a tenderness gradient exists over the cross-section of the I. dorsi and suggests that core samples should be taken from as many and as varied positions as is feasible for existing research conditions. The use of marbling score as an indicator of the tenderness of beef rib steaks resulted in the explanation of 28 percent of the variation in average shear force requirements. The shear force value of the diaphragm muscle was only moderately related (r = 0.40) to that of the I. dorsi. Cooking loss percentages were significantly increased as a result of freezing at–34°C and storage of steaks unwrapped at −23°C when compared to unfrozen steaks and by selecting I. dorsi samples from more anterior locations in the wholesale rib.Journal of Food Science 08/2006; 34(6):612 - 618. · 1.78 Impact Factor
- Journal of The Science of Food and Agriculture - J SCI FOOD AGR. 01/1980; 31(1):62-66.
SHEAR FORCE MAPPING: A TOOL FOR
Food Engineering and Biotechnoloay
Technion, Haifa 32000, Israel
BERRY, J.S. EASTRIDGE and M.B. SOLOMON’
Food Technology and Safety Laborato y
Beltsville, MD 20705
Received for Publication January 29,2001
Accepted for Publication May 24,2001
A shear mapping method (SMM) was developed and evaluated for examining
objectively the effectiveness of tenderization processes for meat. One-centimeter
square cross section samples were cut parallel to the muscle fiber orientation
across the complete cross sectional area o f cooked strip loin steaks. Each sample
was assigned a coordinate reference grid code that identifed (“mapped’? its
location within the steak. Shear force measurements within steaks were evaluated
using the SMM procedure before and afier applying the hydrodynamic pressure
(HDP) tenderization process. The less tender the region within a control steak, the
more it was tenderized after applying HDP, and HDP tenderization resulted in
improved uniformity of tenderness. The suggested SMM method has the potential
to minimize variations in technique among scientists and institutions and provides
a tool for screening and testing the efficiency of tenderization processes by
evaluating a larger proportion.
’Mention of brand or f i r m names does not constitute an endorsement by the United Sates Department
of Agricullure over others of a similar nature not mentioned.
’Address inquiries to D r . M.B. Solomon, USDA, ARS, FTSL, Bldg 201, BARC-East, Beltsville, MD
20705. TEL: (301) 504-8400; FAX: (301) 504-8438; E-mail: firstname.lastname@example.org
Journal of Muscle Foods 13 (2002) 1-12. All Rights Reserved.
OCopyright 2002 by Food & Nutrition Press, Inc.. Tmtnbull, Connecticut.
H. ZUCKERMAN ETAL.
Tenderness is one of the most important sensory qualities of meat and ranks
among the fust quality criteria a consumer considers when making a purchase
decision for a cut of meat. It is well documented that there often exists a large
variation in the rate and extent of postmortem tenderization when meat is aged
(Alsmeyer et al. 1965; Morgan ef a2. 1991a; Shackelford ef al. 1997). Inconsistent
tenderness both within and between steaks from a given meat cut is one of the
biggest problems facing the beef industry (Morgan et al. 1991b). Most studies
provide some indication of the degree of variability associated with instrumental
measures of tenderness, but generally do not report or document tough and tender
regions within cross-sections of steaks.
AMSA (1995) guidelines provide a recommended procedure for instrumental
measurement of tenderness using core samples. At least six cores should be
obtained from each treatment regardless of species being tested (more are
acceptable as long as they are “good” cores). If a small portion is tougher t h a n the
rest of the steak, this difference may not be observed and probably would not be
statistically significant because it might be ‘diluted’ or discarded as an ‘outlier’
value when averaging the cores across the steak surface. Dransfield and MacFie
(1980) determined, that due to the variability within the longissimus muscle, ten
shear determinations were necessary to assess tenderness of that muscle.
The challenge of identifying an objective method for tenderness assessment
across the complete aredadace of a steak raised the concept of obtaining as many
samples to examine as possible from within the steak in a rapid and easy manner.
Mechanically, in using the coring technique it would be difficult to completely
assess the tenderness gradient across an entire cross-section of a steak.
Furthermore, adequate and precise information on the tenderness profile of meat
before a tenderization treatment is applied is important in assessing the
performance of the tenderization process.
Hydrodynamic pressure wave technology (HDP), which uses an underwater
detonation of explosives to generate a hydrodynamic shock wave pressure front,
has been shown to be an effective process to tenderize various muscles (Solomon
etal. 1997; Solomon 1998; Eastridge et al. 2000). However, the effectiveness of
the HDP process in reducing tenderness variability across meat cuts is not known.
Therefore, the objectives of this study were to (1) develop and evaluate a
standardized and idonnative objective technique for tenderness evaluation
according to location within a steak [shear force mapping method (SMM)]; (2) use
the SMM to determine the ability of a postharvest tenderization process, HDP, to
reduce the inconsistency in tenderness of cuts of meat.
SHEAR FORCE TENDERNESS
MATERIALS AND METHODS
SMM for Screening and Evaluating a Tenderization Process
This part of the study was performed using seven fresh boneless paired strip
loins from the lower third of the US. Select grade. The fresh U.S. Select grade
loins were removed f r o m the carcasses 3 days postmortem, vacuum-packaged and
stored at 4C. At 5 days, postslaughter the loins were equally divided into 10 cm
thick sections parallel to the rib end and loin end cut surface. The sections were
randomly assigned to either hydrodynamic pressure process (HDP) or control (C)
nontreated samples. Afier applying HDP, both HDP and C meat sections were cut
into 2.5 cm thick steaks and frozen. These steaks were thawed for 18 h at 4C,
cooked (described below) and analyzed for tenderness using the SMM procedure.
Meat samples designated for HDP treatment were fust vacuum-packaged in a
polyolefin resin bag (Cryovac/Sealed Air Corporation, Duncan, S.C.). The
packaged meat was then placed in a polymer of isoprene (rubber) bag. This outer
isoprene bag was also evacuated. The packaged meat samples were placed in a
cooler filled with ice until treating with the HDP process. The packaged meat was
placed on top of a 2 cm thick steel plate located on the bottom of water-filled
plastic containers (1 15 L volume; 5 1 cm diameter) situated below ground level as
described by Solomon et al. (1997). A binary explosive (100 g mixture) was
immersed into the plastic container to a distance of 38 cm above the steel plate
(Solomon et al. 1997) and detonated. Control samples were vacuum packaged in
polyolefin resin bags only and placed in the cooler with ice along with the samples
for HDP treatment.
Individual steaks were thawed at 4C for 18 h prior to cooking. Steaks were
broiled in a Farberware convectionhroiler oven (Model T-4850, Hanson Corp.,
Bronx, N.Y. ) to an internal temperature of 71C. Steaks were turned mid-way
between the initial temperature and 71C. Internal temperature was monitored using
iron-constantan thermocouples inserted into the center of each steak and attached
to a Speedomax multipoint recording potentiometer (Model 1650, Lee& and
Northrup, North Wales, Pa.). After cooking, all steaks were allowed to cool to
room temperature (-25C) before sampling for shear force.
Shear Mapping Method-(SMM)
Frozedthawed boneless strip loin steaks from carcasses representing the lower
H. ZUCKERMAN ETA.
third of U.S. Select quality grade were used to demonstrate the SMM. The standard
procedure (AMSA 1995) for shear force tenderness is often measured as the force
needed to shear a cylindrical core (1.27 cm diameter) of meat. Chrystall and
Devine (1991) suggested that samples with a square cross section area were better
in ensuring repeatability than a cylindrical surface. The SMM used test sample
strips with a 1 cm x 1 cm cross section in area and a 2 to 3 cm length, parallel to
the fiber axis (Boccard e f al. 1981; Honikel 1998). In the SMM procedure,
samples were removed fiom the entire area of the cooked steaks (described below)
rather than using a few representative samples f r o m different locations within the
steak. Each sample was assigned a coordinate reference grid code or index that
identified (“mapped”) its location within a steak. The matrix indices are depicted
in Fig. 1. The epimysial connective tissue (CT)
lateral (L) portion of each steak served as an anatomical reference point (arrow in
Fig. 1). Column designations ran parallel to the CT with column numbers
increasing as sampling moved towards either end of the steak, either laterally or
medially. Rows were perpendicular to columns and were numbered starting at the
subcutaneous edge of the steak. Figure 2 reflects the steak trimmed of fat before
dividing the medial (M) f r o m the
FIG. 1. “MAPPING” THE STEAK
Connective tissue dividing the medial (M) portion f r o m the lateral (L) portion labeled. Column
designations running parallel to the CT with column numbers increasing towards either end of the
steak. Rows arc perpendicular to the columns with numbers starting at the subcutaneous side
of the steak
SHEAR FORCE TENDERNESS
cutting the 1 cm2 cross-section pieces. The arrow designates the CT reference point
separating the medial (M) portion from the lateral (L). The number of
rows/columns are not fxed, but vary according to the cross-sectional area of the
steak. Each row and column extends out as far as possible in gettiug good samples.
The technique of cutting and measuring using a caliper is also depicted in Fig. 2,
that is, cutting columns followed by cutting these columns into 1 cm x 1 cm cross-
section samples. Only minor trimming was necessary due to changes in the muscle
fiber orientation. Each sample was sheared once at right angles to the fiber
orientation using a Warner-Brawler shear test cell mounted on a texture
measurement system (Model TMS-90, Food Texture Corp., Chantilly, Va.) using
a 3.18 mm thick blade, V-notch shaped, and crosshead speed of 25 cdmin.
Statistical analysis was conducted using the PROC-MIXED procedures of the
Statistical Analysis System (SAS 1996) program. The model for comparing shear
force values included location withm the cross-section of the steak (i.e., coordinate
reference codes, medial region and lateral region). The random effect of animal,
with the corresponding interaction was also included in the model.
RESULTS AND DISCUSSION
The SMM provided a minimum of 9 samples from the medial region and a
minimum of 16 samples from the lateral region of each steak totaling a minimum
of25 shear force determinations. Minor amounts of trimming were required and
generally was performed to correct for fiber orientation before the final rectangular
sample was cut. There was no need to exclude samples due to defects in fiber
orientation or sample defects for shear force assessment. Areas of marbling or
blood vessels can easily be avoided when sampling and twisting of samples or
hourglass shape problems from the coring technique was not a problem with the
SMM procedure. Slight variation in the application of the coring technique
between operators can lead to inconsistent hameter cores (Kastner and Henrickson
1969). Uniform sample size (thickness) can be verified through the use of a caliper
(Fig. 2). With the I-cm square strip section, it was easy to obtain uniform samples
parallel to the muscle fiber orientation which is an important factor in ensuring
repeatability (Boccard et al. 1981; Chrystall and Devine 1991). The timeflabor
involved for the SMM procedure does appear to be slightly longer compared to the
standard coring procedures (Zuckennan and Eastridge personal communications;
Eastridge and Solomon 1996). However, timeflabor is diminished with experience
and more shear samples are obtained with the SMM method. Furthermore, a shear