Use of Marination by Injection to Improve the Palatability of Bison Top Round

J.S. Dhanda, R.B. Pegg and P.J. Shand
Saskatchewan Specialty Livestock Value-Added Program
Department of Applied Microbiology and Food Science
University of Saskatchewan
51 Campus Drive, Saskatoon, Sask. S7N 5A8

Further processing is the key to improve bison meat acceptability.

Background 

In Canada, the demand for bison meat is increasing faster than its rate of production. With regard to bison meat, the main concern is inconsistency, in terms of both the quantity and quality available in the market. There is a general perception that bison meat is leaner but less tender than beef. So, further processing may be desirable to improve the sensory characteristics and to make bison meat more acceptable, or at least an attractive red meat alternative, to consumers. This is particularly true for under-utilized or lesser-value meat cuts (e.g., chuck and round). Injection of various salt and phosphate formulations into primal meat cuts is now routinely practiced to enhance the tenderness and juiciness of fresh meat products.

The present study was conducted to investigate the effects of sodium chloride and sodium tripolyphosphate injection on the palatability of bison top round.

Methodology

Twenty paired top round (semimembranosus muscle only) were obtained from 10 intact male bison between 24 to 30 months of age and having carcass grades from A1 to D1. Each semimembranosus muscle was divided into two sections. Using a multi-needle injector, one section was injected with a chilled brine solution to 110% of its original weight to contain 0.5% sodium chloride and 0.3% sodium tripolyphosphate, while the other was kept as a non-injected control. Muscle samples were sliced to obtain four 1.5″ thick steaks, two 0.5″ thick steaks, and two roasts from the remaining edges. The 0.5″ steaks were stored in a retail display case at 3.0±1oC under 24 hour fluorescent lighting (975 lx). HunterLab colour values (L* - lightness, a* - redness and b* - yellowness) of meat samples were read daily for 5 days.

Steaks (1.5″ thick) were broiled in a conventional oven at 260oC, while the roasts were cooked in a vacuum-sealed cook-and-ship bag in a water bath to two endpoint temperatures i.e., 71oC and 77oC. Warner-Bratzler shear force values were determined to assess the tenderness of these samples. An 80-member consumer panel evaluated the steaks, which were grilled to 71oC or 77oC. Steaks were scored for tenderness, flavour, juiciness, and overall acceptability using a 6-point hedonic scale, where 1 = dislike very much and 6 = like very much.

Results

As expected, the bison meat was very lean. The proximate chemical composition of control non-injected trimmed bison semimembranosus muscle was: 74.5% moisture, 22.0% protein, 0.77% fat and 2.1% ash.

Injected steaks were slightly darker in colour (lower L* values) than control steaks but did not differ in Hunter a* and b* values. In total, the change in colour was monitored for 5 days (Fig. 1). Both control and marinated bison steaks held a bright red colour for 2 days, but after that discolouration became evident and by day 5 all steaks were grossly discoloured. Thus, colour stability of bison meat was very short.

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Fig. 1. Effects of storage in a retail display case on Hunter values of bison top round steaks

The cooking yield for the steaks and roasts obtained from the injected muscle sections was significantly higher compared to the steaks from control non-injected sections when cooked to an internal temperature of either 71oC or 77oC (Fig. 2). This may be due to the slightly higher pH of injected steaks achieved with marination.

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Fig. 2. Effects of injection treatment, cooking method and cooking temperature on cook yield of bison top round steaks/roasts

Control samples from bison semimembranosus muscle were not very tender and there was a high variability in shear values between animals. Marination by injection was able to markedly improve the tenderness of semimembranosus muscle (Fig. 3); injected steaks and roasts had significantly lower shear force values (64 ± 14 N) compared to controls (102 ± 21 N).

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Fig. 3. Effects of injection treatment, cooking method and cooking temperature on shear force values of bison top round steaks/roasts

Furthermore as shown by the lower standard deviation, the range in shear values of control samples was reduced by almost 35% with injection. As bison meat is very lean, cooking steaks and roasts to a medium level of doneness (71oC) is more suitable than cooking to an internal temperature of 77oC. When steaks and roasts were cooked to 77oC, they appeared very dry/grainy and had higher shear force values compared to those cooked to 71oC.

Consumer acceptance scores (i.e., tenderness, juiciness, flavour and overall acceptability) for injected steaks were higher compared to control steaks (Fig. 4). It was interesting to note that consumers preferred injected steaks cooked to 77oC endpoint over other combinations. The acceptability scores for non-injected and injected steaks cooked to 71oC were almost similar, whereas non-injected steaks cooked to 77oC had the lowest acceptability. Hence, injection seems to be protecting against moisture loss at high end-point cooking temperatures.

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Fig. 4. Effects of injection treatment and cooking temperature on consumer acceptability (TEND, Tenderness; JUIC, Juiciness; FLAV, Flavour; OA, Overall acceptability)

Conclusions

The findings of the present study suggest that bison semimembranosus muscle is very lean and high in protein but not very tender. There was also high variability in shear values of semimembranosus muscle between animals. Marination by injection had a significant effect in addressing these issues by improving the tenderness and by decreasing the variability in tenderness found amongst bison top round obtained from different animals.

In the present study, only salt and phosphate were used for marination in order to prevent masking/overlapping of the distinct flavour of bison; however, the opportunities can be further widened by using combinations of different herbs, spices and flavours. Processors could successfully use this technology to produce value-added meat products from lesser-value cuts of bison.

Acknowledgement

Financial support for this research project by the Saskatchewan Agri-Food Innovation Fund is gratefully acknowledged.

For more information on the Saskatchewan Specialty Livestock Value-Added program visit their website at www.ag.usask.ca/sfpip or contact:

J.S. Dhanda, Ph.D.
Saskatchewan Specialty Livestock Value-Added Program
Department of Applied Microbiology and Food Science
University of Saskatchewan
51 Campus Drive, Saskatoon, SK S7N 5A8
Phone: (306) 966-5030; Fax:(306) 966-8898

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