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Volume 47, 1914
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Art. L.—The Chemistry of Flesh Foods—Part II.—(4.) The Composition and Nutritive Value of the Retail Cuts of Mutton and Lamb.

[Read before the Philosophical Institute of Canterbury, 2nd December, 1914.]

Introduction.

This investigation is a continuation of the research published in the Transactions of 1912.* The present study covers the results of an investigation concerning the composition and nutritive value of the various retail cuts of mutton and lamb.

Slaughter Tests.

In connection with this investigation ten average quality sheep and ten average quality lambs were taken from a line received at the Christ-church Meat Company's Islington works, and after being fasted for twenty-four hours were weighed alive and immediately slaughtered. In Table I will be found the weights and the percentages of the carcases and of the various by-products, based on the live weights.

Table I.—Results of Slaughter Tests.
Ten Sheep. Ten Lambs. Sheep. Lambs.
lb. lb. Per Cent. Per Cent.
Live weight 1,097.0 675.0
Dressed carcase (warm) 565.0 368.0 51.4 54.5
" (cold) 554.0 364.0 50.5 54.0
Wool 68.2 72.0 6.2 10.7
Pelt 51.8 30.0 4.7 4.4
Blood 47.0 24.5 4.3 3.6
Head 33.4 21.8 3.0 3.2
Feet 16.5 13.4 1.5 2.0
Fat (caul, kidney, and intestinal) 66.5 32.5 6.0 4.8
Diaphragm (skirt) 4.1 2.4 0.4 0.4
Tongue 4.0 2.9 0.4 0.4
Kidneys 2.7 1.7 0.3 0.3
Sweetbreads (thymus gland) 0.7 0.1
Brains 2.1 1.9 0.2 0.3
Heart 5.4 3.3 0.5 0.5
Lungs 12.4 8.2 1.1 1.2
Liver 16.9 8.3 1.5 1.2
Trachea (windpipe) 1.9 1.8 0.2 0.2
Spleen 1.9 1.0 0.2 0.1
Gall-bladder and contents 0.7 0.5 0.1 0.1
Small intestine 15.0 11.0 1.4 1.6
Large intestine 1.0 10 0.1 0.1
Other intestines 25.0 120 2.3 1.7
Stomach 37.0 18.0 3.4 2.7
Contents of stomach and intestines 104.5 35.5 9.5 5.5
Loss in dressing 14.0 2.6 1.3 0.4

[Footnote] * Wright, Trans. N.Z. Inst., vol. 45, pp. 1–17.

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Retail Cuts.

On the day following a carcase of mutton weighing 55 lb., and a carcase of lamb weighing 35 lb. (cold weights), were selected from the twenty carcases from the slaughter test for the purpose of the main investigation. These carcases were split, and the left half of each, weighing 28 lb. and 18 lb. respectively, were cut into the joints usually offered for sale in the retail shops. In addition each cut was separated into lean meat, visible fat, and bone. In order to compare the various cuts as to their relative amounts of lean, fat, and bone the weights have been calculated to percentages. These figures, which represent the untrimmed cuts, are shown in Table II.

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Table II.—Weights and Percentages of Lean Meat, Visible Fat, and Bone in the Retail Cuts.
Lean Meat. Fat. Bone. Lean Meat Fat. Bone. Left Half.
Mutton— lb. lb. lb. Per Cent. Per Cent. Per Cent. lb. Per Cent.
  Leg 5.4 1.3 1.2 68.4 16.4 15.2 7.9 28.4
  Loin 4.7 2.4 1.5 54.8 27.8 17.4 8.6 30.8
  Shoulder 5.2 0.9 1.0 73.2 12.7 14.1 7.1 25.4
  Neck and breast 2.0 0.6 1.8 45.5 13.5 41.0 4.4 15.4
280
Lamb—
  Leg 3.4 1.1 1.0 61.8 20.0 18.2 5.5 306
  Loin 2.1 20 0.9 42.0 40.0 18.0 5.0 27.8
  Fore quarter 4.7 0.9 1.9 62.6 12.0 25.4 7.5 41.6
180

Relative Cost of the Retail Cuts.

Throughout New Zealand the prices of the various cuts differ considerably, and are liable to frequent fluctuation, so that absolute figures for the market retail price of the cuts would serve little purpose. It has been found, however, that by taking the cheapest cut as 1 the retail market prices bear relation to one another as follows:—

Mutton—Neck and breast 1.00
" Shoulder 1.50
Lamb—Fore quarter 1.67
Mutton—Leg 1.83
", Loin 2.00
Lamb—Leg 2.17
" Loin 2.17

Thus, with the price of neck and breast of mutton at 3d. per pound, the other cuts in the above order will be 4½d., 5d., 5½d., 6d., 6½d., and 6½d. per pound.

The Chemical Composition of the Boneless Meats.

The right half of the carcases used in the previous determinations was sampled for chemical analysis, the total boneless meat (lean and fat) of each cut being used for this purpose.

Moisture.—The moisture found in the various cuts ranged from 57.92 per cent. in the leg cut of the lamb to 40.12 per cent. in the loin cut of the same carcase; in general, the higher percentage of fat is found associated with the lower moisture-content.

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Ash.—The percentage of ash or mineral salts varied from 0.89 per cent. in the leg cut of the lamb to 0.49 per cent. in the loin cut of the same carcase. The ash is chiefly composed of the chlorides and phosphates of potash, soda, lime, and magnesia, which contribute largely towards the structure of the bone and other tissues. They also aid the digestive functions, and increase the palatability of the cooked meats. There is no evident relation between market prices and the palatability of the different cuts as indicated by the amounts of mineral salts, the cheaper cuts showing as much ash as the more expensive.

Fat.—This varies from 48.38 per cent. in the lamb loin cut to 22.60 per cent. in the mutton leg cut. As indicated above, it is noted that in general the higher the fat the lower will be found the moisture-content. The amounts of fat bear no relation to the market price of the meats.

Protein.—Protein is the most important food constituent of meat, and varies in the cuts from 16.75 per cent. in the lamb leg to 9.56 per cent. in the lamb loin. The market prices charged for the cuts are not in proportion to the protein-contents.

Meat Bases.—These, while possessing but slight food-value, are of importance because of their influence on the palatability of the meat. They aid in giving cooked meat its flavour, and serve in part as stimuli to the digestive glands. No relation between the market price and the amount of meat bases seems to exist; indeed, one of the highest-priced joints, the lamb loin, contains 0.52 per cent., while the lowest-priced meat, the neck and breast of mutton, contains the same amount.

The results of the chemical analyses of the bone, less meat of the various retail cuts, are shown in Table III.

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Table III.—Chemical Composition of the Boneless Meat of the Retail Cuts.
Mutton. Lamb.
Leg. Loin. Shoulder. Neck and Breast Leg Loin. Fore Quarter.
Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent.
Moisture 4908 46.64 55.94 43.35 57.92 40.12 44.42
Ash 0.87 0.67 0.76 0.55 0.89 0.49 0.64
Fat 22.60 37.48 27.66 4256 24.08 48.38 40.54
Total nitrogen 2.956 2.394 2.495 2.112 2.742 1.688 2.283
Cold-water extract—
  Total solids 4.75 3.49 3.65 3.06 4.39 2.47 3.31
  Ash 0.75 0.52 0.56 0.44 0.71 0.43 0.51
  Organic extractives 4.00 2.97 3.09 2.62 3.68 2.04 2.80
  Nitrogen 0596 0.430 0.485 0.375 0.566 0.311 0.421
  Coagulable proteids 1.72 1.31 1.36 1.18 1.66 0.86 1.21
  Non-coagulable proteids 0.18 0.12 0.23 0.11 0.22 0.11 0.16
  Total soluble proteids 1.90 1.43 1.59 1.29 1.88 0.97 1.37
  Meat bases 0.92 0.62 0.72 0.52 0.78 0.52 0.63
Insoluble protein 14.74 12.24 12.55 10.79 14.87 8.59 11.62
Total protein 16.64 13.67 14.14 12.08 16.75 9.56 12.99
Crude protein 18.48 14.94 15.56 13.18 17.11 10.56 14.27

Conclusion.

While some of the cuts are less tender and are therefore more difficult to prepare for use than others, yet the constituents (mineral salts and meat bases) which give flavour to cooked meats show little difference in the various cuts, and since the digestibility of the protein is independent of

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the cut or the method of cooking* it is evident from a study of the figures presented above that the retail market prices charged for the various cuts are not governed by the relative food-values or by the palatability of the meats.

For permission to publish these results the author desires to express his thanks to the Christchurch Meat Company (Limited), in whose laboratory the work has been carried out.

[Footnote] * Grindley and Emmett, Bulletin 162, U.S.A. Dept. Agric. O.E.S.; also Grindley, Monjonnier, and Porter, Bulletin 193, U.S.A. Dept. Agric. O.E.S.