Shoulder more tender than sirloin
Loin is a popular muscle that is preferred by many consumers, but it is not especially tender. New studies at Nofima Mat show that topside, rump and silverside are all of similar tenderness. The most tender muscle of all comes from the shoulder of the animal.
Most people know that a beef carcass contains many muscles, but not many know the names of more than a few. This is not surprising; even meat researchers have been mainly working with only a few of them.
If you look through a list of scientific works carried out on beef, you will soon find that the muscle most often described is Longissimus dorsi, the muscle most prominent in loin. There are many reasons why this muscle has become a favourite among meat researchers. The retail price of loin is high, which makes it a financially valuable muscle. For producers, it is therefore important to know how sirloin should be handled in order to obtain optimum quality.
The muscle is also physically large. In biological terms the muscle Longissimus dorsi runs all along the upper part of the animal’s back, but is usually split when the carcass is divided and may be found in both sirloin and fore rib. Longissimus dorsi is in fact the largest muscle in the beef carcass, representing more than 5% of the total meat volume. Of course this means that almost 95% of the meat is from other muscles. In order to make the best use of the other muscles, it is important to know what properties they have.
Measured tenderness in 10 beef muscles
At Nofima Mat we have carried out a study in which 10 muscles have been analysed for tenderness and other properties. The research was carried out in collaboration with Furuseth’s abattoir at Dal. 10 bull carcasses were chosen from the line at random. Their ages ranged from 19 to 30 months. Checks were continuous right from the time of slaughter, to ensure that the quality of the meat was maintained in the best way possible. The speed of chilling the carcasses was controlled so that the temperature in the muscles did not drop below 10°C until 14 hours after slaughter – the ideal chilling speed. After ageing for 9 days, tenderness of the meat was measured by the Warner-Bratzler (WB) method. This is a standardised method, used in most meat laboratories around the world.
Chose cuts that are popular in the USA
The muscles selected were 3 from the shoulder and 6 from the hind quarter plus that from the loin; see table 1. Naming the muscles presents a problem because, not only the names, but the actual way in which the carcass is divided differs in, for example, Norway, the United Kingdom and the USA. We therefore refer to the Latin names with abbreviations. The three muscles from the shoulder are TB, IS and SS and they are often sold in Europe for stewing or braising. In the USA, infraspinatus (IS) has become a very popular muscle in restaurants. It is sold as Flat iron steak, because its shape resembles an iron. From the hind quarter the following muscles were selected: RF, VL, BF, ST, SM and AD. Again putting popular names to these is difficult, partly due to national differences and partly due to the fact that cuts from the rump/topside/flank area often contain more than one muscle. The purpose of this research was to look at individual muscles, not at beef cuts.
Tender – or shoe leather?
The results for the individual muscles are shown in Figure 1. The blue column shows the WB value, while the black line shows the variation between the 10 animals. A high value means a tough muscle, while a low value means tender. Most people would describe a piece of meat with a WB value of 50 or less as tender. Similarly, most of us would say that meat with a WB value of 75 or more was tough. If your test sample is entering the realms of 90 or more, then you are really talking about shoe leather.
Infraspinatus most tender
It is worth pointing out that the loin steak (LD) is not particularly tender, when compared with the others. In fact only BF from the hind quarter was tougher. ST is traditionally thought to be particularly tough, actually it had the same WB value as the loin. All the hind quarter muscles apart from BF were at least as tender as the loin. This should have consequences for how beef is marketed. The rump, topside and flank cuts are sold at a much lower retail price than loin. Considering that tenderness is the most important quality parameter among consumers, there is potential to increase prices of several of the hind quarter muscles.
There is certainly good reason to take note of the name Infraspinatus (IS), which was clearly the most tender muscle in this survey. In the USA it is sold at about the same price as loin. The unusual thing about Infraspinatus is that it has a thick longitudinal sinew running along its centre that must be removed before cooking. Removing this is easy, a roughly similar operation to removing the backbone from a fish fillet. Two simple cuts with a knife and the result is two very tender steaks!
Choose a reliable quality
The loin muscle shows large variation between individual animals. In our survey, only BF showed a greater variation. The part of the biceps femoris (BF) muscle closest to the back of the animal is more tender than the end down towards the hind leg. The upper part is often cut off and sold separately. The main reason for the great variation in BF in our survey was probably that some samples were from the back end and others from further down towards the hind leg.
It is easier to keep the consumer happy if the meat keeps a reliable quality each time than if it varies a great deal. The variation measured for ST was considerably less than from the sirloin (LD). For reliable quality, the ST muscle is a good candidate. TB and IS also showed little variation.