In September of 1997, the OVA and the University of Guelph began an important research project that would determine the effects of carcass weight class and ageing on carcass characteristics and sensory attributes (eg. flavour, tenderness, juiciness, etc.) for grain fed veal.
The goal of this project was to dispel the myth that only small veal calves could produce meat that was tender and juicy. Many retailers, consumers and producers alike believe that veal must come from only small calves in order to maintain the sensory attributes (eg. flavour, tenderness, juiciness, etc. ) that veal is well known for.
It is important to examine the effects of carcass weight on sensory attributes of veal as the current definition of veal terminates on January 1, 2001, at which time a new definition of veal must be developed. In Ontario, approximately 70% of producers target their calves for a dressed weight range of 400 to 450 lb (hide on). While carcass weights (hide on) under 450 lbs (205 kg) can be legally marketed as veal, only carcass weights that are 363 lbs or less (165 kg or less) can be graded and stamped as veal. Heavy weight veal can be paper graded if less than 401 lbs (368 kg) or else can only be marketed as ungraded veal.
The study was conducted by Dr. Tanya MacLaurin, School of Hotel and Food Administration; Dr. Ira Mandell, Department of Animal and Poultry; and Susan Buttenham of the Sensory Evaluation Centre. The results of this study are not only crucial to the viability of veal production in Ontario but also serve as another building block towards the OVA’s marketing plan. Funding for this study was provided by OVA and Grow Ontario.
The Management of the Calves
Prior to the calves being delivered to the University of Guelph, 36 Holstein bull calves were randomly assigned to one of three carcass weight categories including:
Calves were purchased from local producers by a commercial grain fed veal producer in southwestern Ontario and placed on a milk replacer diet with access to a dry ration (71% whole shell corn and 29% pellets). All calves were group fed in pens that contained 50 to 60 animals. The calves continued on this dietary regimen for approximately 6 to 10 weeks or until 180 to 200 lb (82 to 91kg) live weight.
Calves were weaned from the milk replacer and placed directly on the whole shell corn and pelleted concentrate diet when calves were consuming 4 lb (1.8 kg) of dry feed. At 400 lb (182 kg), calves were placed on a 14% protein ration (80% corn and 20% pellets) which was offered until individual animals attained live weights of 450 to 500 lb (204 to 227 kg). Calves were then switched to an 11.5% to 12% protein ration (86% corn and 14% pellets). This continued until specific targeted slaughter weights were achieved.
All calves were slaughtered at the University of Guelph meat abattoir over a six week period. Hides were removed and weights recorded. The hot carcass weights were recorded with and without the kidneys and kidney fat prior to overnight chilling at 2 C. After two days hanging, the carcasses were re-weighed and graded. The rib eye and the top round roast muscles from both sides of the carcass were removed from each animal. Each muscle was cut into 3 roasts and each of these 3 roasts were allocated to one of three postmortem ageing times (2, 7, or 14 days). The roasts that were cut from the left side of the carcass were used for colour evaluation and shear determination, while roasts from the right side were used for sensory evaluation. The roasts were vacuum packaged prior to storage at 1.5 C for the appropriate postmortem ageing times.
The rib eye and the top round roasts from all 36 calves were used to evaluate the palatability or sensory attributes of grain fed veal. A nine member trained taste panel was used to evaluate these attributes using a linear scale:
The taste panel team conducted tests 4 days per week over a five week period for each of the rib eye and the top round cuts. In order to eliminate any bias or errors from the research, the roasts were prepared and presented to the members of the panel in a consistent and uniform fashion.
Results: Carcass Weight Class
While carcass weights differed between carcass weight class (light, medium, heavy), dressing percentage was similar for all three classes.
Carcass shrink was also similar across all weight classes and ranged from 2.4% to 3.1%. Hide weight increased, as expected, with the corresponding increase in the carcass weight class from light to heavy. Hide weight as a percentage of the live weight, however, was not significantly different across the weight classes.
The grading of veal uses an objective measurement of colour to differentiate veal from beef. Veal colour is measured on the carcass at grading using an instrument that measures the amount of light reflectivity from the brisket. The research indicates that there were no differences between the weight classes for luminosity, a measurement of how light or dark the meat is. While measures of redness/greenness and yellowness/blueness increased as carcass weight increased, these differences would not be noticed by the consumer when selecting veal to purchase.
Results: Sensory Evaluation
Statistically, nine times out of ten, carcass weight did not affect any of the tenderness attributes evaluated including softness, tenderness, chewiness, breakdown rate, and the Warner-Bratzler shear test, an instrumental measure of tenderness. Interestingly, tenderness data for the medium carcasses tended to be lower than other carcass weight classes implying less “tender” meat. In contrast, Warner-Bratzler shear force tended to be lower in the medium carcass weight class as compared to the other weight classes, implying a more “tender” meat.
Flavour was not affected by carcass weight class. This was not surprising to the researchers as previous studies have not found flavour differences comparing grain fed versus milk fed veal. Both initial and overall juiciness tended to be greater in veal from the light carcass weight class versus the medium and heavy carcass weight classes. The medium and heavy weight classes had higher cooking losses which can be attributed to weight class differences in meat juiciness.
Two contrasts were designed to evaluate postmortem ageing. The first contrast was designed to compare 2 days versus 7 and 14 days. The second contrast was designed to compare 7 versus 14 days. Ageing veal to 7 or 14 days increased the luminosity and the yellowness in both cuts of veal. The colour of the veal, however, had stabilized by 7 days and therefore there were no significant changes at 14 days ageing.
For the rib eye roasts, all tenderness attributes increased by ageing the veal for 7 days. There were no differences, however, in veal that was aged for 14 days. This data does not agree with many beef studies that suggest 14 days ageing is the optimal length for improving tenderness and quality. Veal flavour also increased with 7 days of ageing which may be similar to beef where postmortem ageing helps develop meat flavour.
For the top round roasts, ageing for 7 days tended to improve softness, tenderness, breakdown rate, and chewiness as compared to 2 days ageing. Ageing the veal for 14 days did not improve any tenderness attribute as compared to 7 days ageing. Previous research for beef suggests ageing muscles from the round for 21 days in order to obtain optimal meat quality. Postmortem ageing did not affect any juiciness or flavour attribute or cooking losses for this muscle.
- All carcass weight classes for grain fed veal were similar in carcass characteristics.
Carcass characteristics cannot be used to single out a specific weight class of grain fed veal
- All carcass weight classes for grain fed veal were similar in palatability attributes and Warner-Bratzler shear for both the rib eye and the top round muscles.
A specific weight class of grain fed veal could not be singled out by the sensory attributes evaluated in this study. Grain fed veal from the light, medium, and heavy carcasses all have similar sensory characteristics.
- Ageing the veal rib eye roasts for 7 days improved all tenderness and flavour attributes as compared to 2 days ageing. Ageing the top round roasts tended to improve some tenderness attributes. There was no further improvement in veal palatability by increasing the postmortem ageing from 7 to 14 days.
Ageing veal for 7 days should be considered in order to improve meat quality.
The OVA would like to thank the dedicated researchers of this project and OMAFRA for the Grow Ontario funding.