Effects of goat milk or milk replacer diet on meat quality and fat ...

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S. Bañón et al. / Meat Science 72 (2006) 216–221 219 the mean content <strong>of</strong> all the main fatty acids in the perirenal adipose tissue. The percentages were higher in GM fat f<strong>or</strong> C10:0, C14:0, C15:0, C16:0 and C18:0, whilst they were higher in MR fat f<strong>or</strong> C12:0, C16:1, C17:0, C18:1, C18:2, C18:3, C20:0 and C20:4. The main fatty acids in GM fat were C16:0, C18:1, C18:0 and C14:0, and the SFA/UFA ratio was 2.27. The main fatty acids in MR fat were C18:1, C16:0 and C18 and the SFA/UFA ratio was 0.94. Milk <strong>or</strong> <strong>milk</strong> <strong>replacer</strong> <strong>diet</strong> had a pronounced eVect on the composition <strong>of</strong> depot fat. GM fat was m<strong>or</strong>e saturated than MR fat. Sh<strong>or</strong>t-chain C4–C12 fatty acids were minimal causing an increase in the relative percentages <strong>of</strong> other fatty acids with m<strong>or</strong>e carbon atoms. This eVect was m<strong>or</strong>e pronounced in MR fat, since the <strong>milk</strong> <strong>replacer</strong> contained m<strong>or</strong>e than 40% sh<strong>or</strong>t-chain fatty acids, as opposed to the 10% in <strong>goat</strong> <strong>milk</strong>. 3.3. Sens<strong>or</strong>y quality <strong>of</strong> cooked meat Table 4 shows the mean values and standard deviations <strong>of</strong> the sens<strong>or</strong>ial sc<strong>or</strong>ing <strong>of</strong> cooked meat acc<strong>or</strong>ding to <strong>diet</strong>. In general, the sens<strong>or</strong>y attributes were perceived by the members <strong>of</strong> the panel with low-medium intensity, with the exception <strong>of</strong> the odour and Xavour characteristic <strong>of</strong> freshly cooked <strong>goat</strong> kid meat and tenderness. Milk odour was slightly m<strong>or</strong>e intense than <strong>milk</strong> Xavour. The meat was practically free <strong>of</strong> acid and cooked liver odour and Xavour. The meat was considered to be s<strong>of</strong>t and juicy, leaving little residue after chewing. Statistically signiWcant diVerences (P < 0.01) were found between GM Table 4 Sens<strong>or</strong>y attributes <strong>of</strong> cooked meat from suckling kids fed with <strong>goat</strong> <strong>milk</strong> <strong>or</strong> <strong>milk</strong>-<strong>replacer</strong> <strong>diet</strong> GM a MR a P b Odour c Liver 2.28 § 0.21 2.65 § 0.22 *** Milk 2.16 § 0.07 2.70 § 0.15 *** Acid 1.32 § 0.13 1.31 § 0.12 Freshly cooked <strong>goat</strong> meat 3.28 § 0.12 3.93 § 0.06 *** Flavour Liver 1.97 § 0.19 2.01 § 0.15 Milk 1.90 § 0.16 1.53 § 0.07 *** Acid 1.46 § 0.12 1.24 § 0.06 ** Metallic (blood) 2.40 § 0.09 3.08 § 0.13 *** Freshly cooked <strong>goat</strong> meat 3.22 § 0.16 3.75 § 0.10 *** Metallic persistence 2.62 § 0.09 2.78 § 0.09 ** Texture Tenderness 3.26 § 0.19 3.58 § 0.11 *** Graininess 2.53 § 0.11 2.47 § 0.15 Juiciness 2.89 § 0.08 3.42 § 0.13 *** Chewiness 2.77 § 0.15 2.63 § 0.09 Residual 2.02 § 0.13 1.65 § 0.08 *** a GM, <strong>goat</strong> <strong>milk</strong>; MR, <strong>milk</strong> <strong>replacer</strong>. Mean and standard deviation. N D 18. b Mean values are signiWcantly diVerent: ¤ (P
220 S. Bañón et al. / Meat Science 72 (2006) 216–221 protein. However, acc<strong>or</strong>ding to Marichal et al. (2003), both the composition (protein, fat, collagen and ash), and the quality (pH, colour, shear f<strong>or</strong>ce and water retention capacity) <strong>of</strong> raw meat are similar in kids slaughtered at 6 kg and 10 kg live weight. Acc<strong>or</strong>ding to this, it seems improbable that a little age diVerence might causes diVerences in the composition <strong>of</strong> the meat. In fact, the type <strong>of</strong> suckling did not aVect other attributes <strong>of</strong> the meat such as intramuscular fat, cholesterol, collagen, muscular pigments, pH <strong>or</strong> water retention capacity. The greatest eVect <strong>of</strong> <strong>diet</strong> was on the fatty acid composition <strong>of</strong> fat depots. ArtiWcial suckling using <strong>milk</strong> <strong>replacer</strong>s rich in coconut fat gave a m<strong>or</strong>e unsaturated fat. The SFA/UFA Wgures found were diVerent from the references consulted. The SFA/UFA ratio in kid fat ranges from 1 to 2 <strong>or</strong> 1.4 to1.8, f<strong>or</strong> natural suckling (Potchoiba et al., 1990; Rojas et al., 1994; Todaro et al., 2002; Zygoyiannis et al., 1992) and feeding <strong>milk</strong> <strong>replacer</strong> (Rojas et al., 1994; Yeom et al., 2003), respectively. The fat composition <strong>of</strong> depots can aVect the appearance, colour and odour <strong>of</strong> raw meat. Milk <strong>replacer</strong> gave a m<strong>or</strong>e unsaturated, s<strong>of</strong>ter and m<strong>or</strong>e oxidable fat consistent with Weld observations. DiVerences in the contribution <strong>of</strong> sh<strong>or</strong>t-chain fatty acids through <strong>diet</strong> strongly aVected fat composition. Compared to fatty acid proWle <strong>of</strong> <strong>diet</strong>, no noticeable levels <strong>of</strong> C4–C8 and other sh<strong>or</strong>t-chain fatty acids were found in kid fat. This agrees with other auth<strong>or</strong>s (Rojas et al., 1994; Todaro et al., 2002; Yeom et al., 2003; Zygoyiannis et al., 1992). Acc<strong>or</strong>ding this, sh<strong>or</strong>t-chain acids are metabolised in kids so there is little accumulation in the adipose tissue. This increased the relative percentages <strong>of</strong> the long-chain fatty acids in the adipose tissue with respect to their <strong>diet</strong>ary prop<strong>or</strong>tion, especially in the case <strong>of</strong> C18:1, the maj<strong>or</strong> fatty acid in kid fat (Rojas et al., 1994; Todaro et al., 2002; Yeom et al., 2003; Zygoyiannis et al., 1992) and <strong>goat</strong> fat (Banskalieva, Sahlu, & Goetsch, 2000). If the <strong>diet</strong> is very rich in C12:0 and po<strong>or</strong> in C18:0, this eVect was even m<strong>or</strong>e pronounced, increasing still further the level <strong>of</strong> C18:1 and other unsaturated acids in the adipose tissue. Although there may be a certain endogenous synthesis <strong>of</strong> C18:1 and other acids, the level <strong>of</strong> the C18:2 and C18:3 essential acids found in the fat suggests that they are accumulated progressively in the adipose tissue, since they cannot be synthesised by the suckling <strong>goat</strong>. Rojas et al. (1994) observed that a <strong>diet</strong> with 15.5% C12:0 deposited 3.5% C12:0 in the adipose tissue, where C18:1, at 36%, was the main fatty acid, just as was found in the present study. The same auth<strong>or</strong>s maintain that the fat levels <strong>of</strong> C15:0, C17:0 and C17:1 are higher in kids fed with <strong>milk</strong> and that they allow diVerentiation <strong>of</strong> natural and artiWcial suckling. The results <strong>of</strong> this study call this claim into question, especially in the case <strong>of</strong> C17:0, which was found to have a higher percentage in artiWcially suckled kids, despite the fact that the <strong>milk</strong> contained m<strong>or</strong>e fatty acids with odd numbers <strong>of</strong> carbons. Suckling kid fat appears to be practically free <strong>of</strong> those fatty acids related to <strong>goat</strong> odour, such as C6:0, C8:0 and C10:0 (Rojas et al., 1994; Todaro et al., 2002; Yeom et al., 2003; Zygoyiannis et al., 1992). Diet also aVected the sens<strong>or</strong>ial quality <strong>of</strong> freshly cooked kid meat. Milk <strong>replacer</strong> <strong>diet</strong> gave the cooked meat a m<strong>or</strong>e intense characteristic odour and Xavour, and improved the texture <strong>of</strong> the meat. The diVerent sc<strong>or</strong>es rec<strong>or</strong>ded f<strong>or</strong> odour and Xavour could be related to variations in the degree <strong>of</strong> unsaturation <strong>of</strong> the fat. The development <strong>of</strong> odour and Xavour in cooked meat is a complex process in which diVerent various components react to produce intermediate <strong>or</strong> Wnal aromatic and taste compounds. The thermal degradation <strong>of</strong> lipids plays a key role in f<strong>or</strong>ming the odour <strong>of</strong> cooked meat, especially in the case <strong>of</strong> unsaturated lipids, which are m<strong>or</strong>e reactive to heat and can, theref<strong>or</strong>e, generate m<strong>or</strong>e aromatic compounds (Mottram, 1998). It is not clear, however, that intense odour and Xavour actually improve the quality <strong>of</strong> kid meat (Dhanda, Tayl<strong>or</strong>, & Murray, 2003), especially f<strong>or</strong> a market where consumers do not habitually eat <strong>goat</strong> meat. All other fact<strong>or</strong>s being equal, meat with a higher water content is perceived as m<strong>or</strong>e tender and juicier, and leaves fewer residues after chewing. The meat <strong>of</strong> kids fed with <strong>milk</strong> <strong>replacer</strong> may be preferable from the nutritional point <strong>of</strong> view due to its higher levels <strong>of</strong> oleic acid and other health related unsaturated fatty acids. References Banskalieva, V., Sahlu, T., & Goetsch, A. L. (2000). Fatty acid composition <strong>of</strong> <strong>goat</strong> muscles and fat depots: a review. Small Ruminant Research, 37(3), 255–268. Bonnet, M., & Kopp, J. (1984). Dosage du collagene dans les tissus conjonctifs, la viande et les produits carnes (Vol. 5, pp. 19–30). Cahiere Technologie Institute National Recherche Agronomique. Cayuela, J. M., Bañón, S., Ros, J. M., & Garrido, M. D. (2003). Simultaneous HPLC analysis <strong>of</strong> α-tocopherol and cholesterol in fresh meat. Journal <strong>of</strong> Agriculture and Food Chemistry, 51, 1120–1124. Dhanda, J. S., Tayl<strong>or</strong>, D. G., & Murray, P. J. (2003). Part 1. Growth, carcass and meat quality parameters <strong>of</strong> male <strong>goat</strong>s: eVects <strong>of</strong> genotype and liveweight at slaughter. Small Ruminant Research, 50(1– 2), 57–66. Folch, J., Lees, M., & Stanley, G. H. S. (1957). A simple method f<strong>or</strong> the isolation and puriWcation <strong>of</strong> total lipids from animal tissues. Journal <strong>of</strong> Biology and Chemistry, 226, 497–509. Garrido, M. D., Pérez, A. D., & Sanchez-Ferrer, A. (1994). Meat pigment determination by phase partitioning in triton X114 and oxidation with sodium nitrite. Journal <strong>of</strong> Science Food and Agriculture, 64, 327–329. Granados, M. V. (2000). InXuencia del genotipo y la <strong>diet</strong>a sobre la calidad de la canal y de la carne p<strong>or</strong>cina. Efecto de a-toc<strong>of</strong>erol acetato sobre la estabilidad a la oxidación de la carne. Ph Dr. Thesis. University <strong>of</strong> Murcia. 2000. Grau, R., & Hamm, R. (1957). Über das wasserbindungsvermogen des saugetier muskels. Zeitschrift Lebensmittel Untersuchung. F<strong>or</strong>schung, 105, 446. Hellín, P., López, M. B., J<strong>or</strong>dán, M. J., & Laencina, J. (1998). Fatty acids in Murciana-Granadina <strong>goat</strong>’s <strong>milk</strong>. Lait, 78, 363–369.
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