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Processing and nutritional characteristics of value added ostrich products
Meat Science 55 (2000) 251±254
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Technical note
Processing and nutritional characteristics of value added ostrich products P. Fisher*, L.C. Homan, F.D. Mellett Department of Animal Sciences, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa Received 13 May 1999; received in revised form 4 October 1999; accepted 10 October 1999
Abstract Two types of processed products, chopped hams (0.15% and 0.30% phosphate on ®nal yield) and viennas (27 and 32% fat extension) were manufactured from ostrich fan ®llets (M. ilio®bularis) to determine the suitability of ostrich meat for processing purposes. Cooking losses diered signi®cantly (P<0.10) between the two types of ham-like products (0.15% phosphate=1.59 and 0.30% phosphate=0.78%), indicating that an increase in phosphate addition reduced cooking loss. Cooking losses did not dier (P>0.10) between the two types of ostrich viennas. Colour evaluation (L ; a ; b ) of the fresh ostrich meat and processed ostrich products (chopped hams and viennas) indicated signi®cant dierences between the dierent types of viennas. Chemical composition (moisture, ash, protein and fat content) of the ostrich meat, processed ostrich products and similar types of commercially available products suggested that processed ostrich products can be formulated to compete successfully with similar types of products derived from other meat species. # 2000 Elsevier Science Ltd. All rights reserved.
1. Introduction Ostrich meat is perceived and marketed as a healthy alternative to other red meats due to a favourable fatty acid pro®le (intramuscular ostrich fat contains 16.50% polyunsaturated o-3 fatty acids) and a low intramuscular fat content (Mellett, 1992; Sales, 1998). However, published data on value added ostrich products are limited. BoÈhme, Mellett, Dicks and Basson (1996) proved that ostrich meat can be used successfully in Italian style fermented sausage with the use of speci®c starter cultures. The relatively high ultimate pH value of ostrich meat (Sales, 1994) makes it an ideal processing meat, since the natural water binding capacity is high, which in turn can reduce the use of moisture retaining agents, such as phosphates when processed. The aim of this investigation was to determine the processing and nutritional characteristics of certain ostrich meat products, and to compare them with other commercially available products. 2. Materials and methods Ostrich meat was obtained from 12 to 14 months old birds (n 12) that were slaughtered at a local European * Corresponding author. Tel.: +21-808-4916; fax: +21-808-4750. E-mail address: [email protected] (P. Fisher).
Union approved abattoir using industrial slaughtering techniques. This included electrical stunning and cutting of the neck for exsanguination, where after the feathers and skin were removed. The intestines were then removed and, together with the carcass, inspected by a government health ocial. The carcasses were then chilled at 2 C for 24 h till the following day. The fan ®llets (M. ilio®bularis) were removed from the carcass 24 h after slaughter, shrink wrapped, boxed and frozen at ÿ40 C prior to processing. After thawing, the ®llets were chopped by hand into smaller pieces, mixed (to avoid possible inter animal eects), minced using a 32 mm diameter mincing plate and chilled to 0 C. The minced meat was then subdivided into four batches for the manufacturing of a chopped ham-like product and thin diameter emulsi®ed and smoked products (viennas). The chopped ham-like products were manufactured with two dierent levels of phosphate inclusion (0.30 and 0.15% on ®nal yield) to determine level of water binding in the product. Brine ingredients, expressed as a percentage in the brine, consisted of 10% salt, 0.25% sodium ascorbate, 1% NaNO2, sodium tripolyphosphate (1.5 and 0.75% respectively) and water (87.25 and 88% respectively). The brine mixture (addition: 20% [by weight] of meat) for each treatment was then added to the meat and the latter tumbled for 20 min. After tumbling, the ham mixtures were stued into
0309-1740/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0309-1740(99)00139-4
252
P. Fisher et al. / Meat Science 55 (2000) 251±254
plastic casings (500 g, 10 casings per treatment). Each stued casing within each treatment was weighed and cooked to a core temperature of 68 C. After cooking, the products were immersed in cold water for approximately 15 min, and then chilled (2 C) for 24 h. After chilling, the products were removed from the casings, touch dried with absorbent paper, and casing weights recorded, separate from product weights. Cooking loss was expressed as follows: cooking loss (%)=[(raw weight-cooked weight)/raw weight]100. Note that the raw weight refered only to the raw mixture, since the weights of the casings were subtracted from both fresh and cooked values. Two dierent types of viennas (32 and 27% fat extension) were also manufactured to determine the eect of the level of fat inclusion on water binding and chemical composition. Ingredients (expressed as kg/kg lean ostrich meat) were: (for the 32% fat extended viennas) 0.81 kg pork fat, 0.63 kg ice water, 0.05 kg salt, 0.005 kg NaNO2, 0.0015 kg ascorbic acid, 0.0012 kg seasoning and (for the 27% fat extended viennas) 0.607 kg pork fat, 0.55 kg ice water, 0.044 kg salt, 0.0044 kg NaNO2, 0.0013 kg ascorbic acid, 0.0011 kg seasoning. The pork fat and lean meat for each treatment were minced separately through a 13 mm plate and chilled to 0 C. The lean meat, spices and two-thirds of the water were placed in a bowl cutter and cut at high speed, where after the fat and remaining water were added and cut till the mixture resembled a ®ne paste. The emulsion temperature was constantly monitored and maintained below 6 C. The emulsion was then placed into a Handmann sausage ®ller (model FA 30) calibrated to ®ll links into 65 g portions. Collagen casings (Devro Teepak1) were used to minimize the risk of case rupturing during the manufacturing process. After completion, the sausages were divided into bundles of 10 sausages/bundle. The bundles were weighed individually (raw weight) and hung on a smoke rack. The viennas were dry smoked (using Meranti wood chips) for 60 min at 60 C. After smoking the viennas were cooked to a core temperature of 68 C, and allowed to dry before chilling (2 C) for 24 h. The bundles were weighed (cooked weight) and percentage cooking loss determined. Two commercially available types of viennas (smoked viennas and low-fat viennas) were purchased to compare with the ostrich viennas for colour and chemical composition. The declared contents of the smoked viennas and the low-fat viennas were: meat (pork and poultry for the smoked viennas, beef and poultry for the low-fat viennas), water, starch, soya protein, spices, dextrose, salt, potassium chloride, phosphates, ¯avour enhancers, stabilisers, antioxidants and sodium nitrite as preservative. Re¯ectance and hue were evaluated using a Colorgard System 2000 colorimeter (Paci®c Scienti®c, Silver Spring, MD, USA) to determine CIELAB values (L ; a and b values) on the processed ostrich products (chopped
ham-like products and viennas) and both the smoked and low-fat pork/poultry viennas. The following chemical constituents were determined (Association of Ocial Analytical Chemists, AOAC, 1997) on the minced samples of the lean meat and processed ostrich products: moisture content, by drying 2.5 g sample at 100 C to constant weight, ashing at 500 C for 5 h, protein content by the block digestion method and ether-extractable fat content by solvent extraction. All samples were analyzed in triplicate for chemical composition and the values given in Table 3. The data were analysed by least-square means method using the GLM procedure (SAS Institute Inc., 1989). 3. Results and discussion Grau (1958), discussing the role of phosphates and water binding in meat products, indicated that the addition of phosphates does not increase the water absorption of meat, but rather causes meat products to bind water more completely and, in so doing, preventing losses during processing. This probably explains the results from various researchers (Wasserman, 1957) that cured meat products with added phosphate, including sausage products, bind more water, are plumper when encased in sausage casings and lose less water during smoking and heat processing. The results in Table 1 supported this, indicating that the ostrich ham-like products made with the 0.3% phosphate (on ®nal yield) still had a signi®cantly (P<0.10) lower cooking loss (0.78%) when compared to the 0.15% phosphate ham-like products (1.59%). Ostrich meat, which has an ultimate pH of ca. 6.0 (Sales, 1994), should, by implication, have a high water-holding capacity (Lawrie, 1991) and thus be able to retain high levels of moisture. The addition of phosphates to value added ostrich products will not have such a marked eect on moisture retention as with, for example, pale, soft and exudative (PSE) pork (Fisher, 1998), but will still reduce cooking losses. Although not evaluated in this investigation, the ham-like products made with the higher level of phosphate addition tended to be more rubbery in texture, which could be considered as a less desirable sensory trait. In addition, the inhibitory eect of phosphates on the relative activity of Table 1 Cooking/processing losses and colour of chopped ostrich ham-like products (means std error)a Product
Ham (0.30% phosphate)
Ham (0.15% phosphate)
Cooking loss (%) L* a* b*
0.788a0.264 33.180.276 11.710.155 4.02a0.059
1.59b0.264 33.170.276 11.490.155 4.19b0.059
a
Values in the same row with dierent letters dier (P<0.10).
P. Fisher et al. / Meat Science 55 (2000) 251±254
253
Table 2 Cooking/processing losses and colour of ostrich viennas and commercial viennas (meansstd. error)a,b Characteristic
Ostrich vienna (32% fat)
Ostrich vienna (27% fat)
Smoked vienna
Low fat vienna
Cooking loss (%) L* a* b*
8.500.559 47.84a,c0.249 12.5c0.126 8.06c0.127
9.670.559 46.60b,c0.249 12.77c0.126 8.31c0.127
± 52.28d0.295 8.33d0.149 15.92d0.151
± 47.47a,c0.295 9.88e0.149 18.32e0.151
a b
a±b-Values in the same row with dierent letters dier (P<0.10). c±d-Values in the same row with dierent letters dier (P<0.001).
certain endogenous proteases (calcium dependent proteases) could also aect tenderness negatively (Van Jaarsveld, Naude & Oelofsen, 1997). Dierences between the two treatments were non signi®cant (P > 0:10) for the L and a values, with the 0.15% added phosphate ham-like products having signi®cantly (P < 0:10) higher b values (4.19) compared to the 0.30% added phosphate ham-like products (4.02), suggesting a lighter, or yellowish chromacity. However, attention should be drawn to the low L values of both types of ham, indicating that the product is dark in appearance, a typical feature of fresh ostrich meat. Cooking losses did not dier signi®cantly (P > 0:10) between the two types of ostrich viennas, but there was a tendency towards increased cooking loss for the viennas with the lower (27%) fat addition (Table 2). This was probably due to the higher lean content, and thus higher moisture content, of the emulsion used. Comparison of tristimulus colour values indicated notable dierences between the dierent types of viennas. The higher level of fat (32% added fat vs. 27% added fat) included in the ostrich viennas resulted in a signi®cant higher (P < 0:10) L value (luminance). This value is similar to the commercial low fat viennas. The increased L values for the ostrich viennas (compared to the fresh ham-like products Ð Table 1) was probably due to the pork fat used, which had a white appearance and thus an increased luminance. The commercial smoked viennas had the highest (P < 0:001) L value (52.28) compared to the two types of ostrich viennas (47.84 and 46.60) and the commercial low fat vienna (47.47). The ostrich viennas also had signi®cantly higher (P <.001) a and signi®cantly (P < 0:001) lower b values, suggesting a redder colour compared to the other two types of commercial viennas. This was as expected since ostrich meat does appear redder compared to other species such as pork and poultry, which were the primary constituents of the viennas. Proximate analyses values of both the fresh ostrich meat and the processed products (Table 3) indicate large variations in dry matter (DM), ash, protein and fat content. Comparison of the DM content of the fresh ostrich meat and the two types of chopped ham did not indicate large dierences, suggesting that the high water binding capacity (due to a high ultimate pH) of ostrich
Table 3 Values for chemical composition of processed products Type
DM (%)
Ash (%)
Protein (%)
Fat (%)
Fresh ostrich meat Ham (0.30% phosphate) Ham (0.15% phosphate) Ost.vienna (32% fat) Ost.vienna (27% fat) Smoked vienna Low fat vienna
23.07 21.72 22.51 43.85 39.50 33.68 32.92
0.33 3.28 2.97 2.69 2.29 3.89 3.59
17.48 15.14 17.73 11.72 12.29 15.08 11.45
3.57 3.17 1.56 24.83 22.99 16.95 13.16
meat was retained, even when the meat was subjected to severe processing procedures such as grinding and cooking. Values for protein content did not indicate large variations for both fresh meat or chopped hams, with fat content being the highest for the fresh meat (3.57%) and lowest for the 0.15% added phosphate ham (1.56%). Since no fat was added during the manufacturing process it must then be assumed that the differences in fat content was due to either sampling or a reduced fat content for the speci®c batch. The higher ash content in the hams, compared to the fresh meat, suggested that the increase was due to the addition of the salt and spices. The composition of the four types of viennas (2 types of ostrich viennas and a smoked and a low-fat pork/poultry vienna) varied considerably, especially the fat content. The high fat and low protein content of the two types of ostrich viennas (compared to the pork/poultry viennas) was mainly due to high levels of fat included in the emulsion. However, the replacement, or partial replacement, of pork fat with a modi®ed starch/oil emulsion would reduce the fat content of the ostrich viennas, without aecting their quality negatively and also extend the higher cost meat fraction of the ®nal product (Bater, Descamps & Maurer, 1993). 4. Conclusion The results from this study do indicate that the manufacturing of value-added products from ostrich meat is a viable option for an industry that has largely relied on the fresh meat sector of the market to sell its product. The ham-like products, although having a dark appearance,
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P. Fisher et al. / Meat Science 55 (2000) 251±254
still resulted in an acceptable product with regard to its chemical composition. Although not evaluated, it is advisable to reduce added phosphate in order to avoid a possible rubbery texture in the ®nished product. The use of fat as an extender in the emulsion products resulted in products with comparable, if higher, fat content than the commercial products. With the judicious use of alternative extenders the fat content can be reduced to a more acceptable level. This will help to ensure that, if produced in sucient quantities, ostrich meat can compete successfully with other `healthy' meat products. References Association of Ocial Analytical Chemists. (1979). Ocial method of analysis (16th ed). Arlington, VA: Association of Ocial Analytical Chemists. Bater, B., Descamps, O., & Maurer, A. J. (1993). Quality characteristics of cured turkey thigh meat with added hydrocolloids. Poultry Science, 72, 349.
BoÈhme, H. M., Mellett, F. D., Dicks, L. M. T., & Basson, D. S. (1996). The use of ostrich meat in Italian type salami production. Meat Science, 44, 173. Fisher, P. (1998). Proportional yields and processing properties of pork derived from dierent halothane hyperthermia pig genotypes. Ph. D. Agric. Dissertation, University of Stellenbosch. Grau, R. (1958). Kondensierte Phosphate in Lebensmitteln, Symposium, Mainz, Berlin: Springer-Verlag, 89. Lawrie, R. A. (1991). Meat Science (5th ed). Oxford, UK: Pergamon Press. Mellett, F. D. (1992). Die volstruis as slagdier: Aspekte van groei. Ph. D. Agric. Dissertation, University of Stellenbosch. Sales, J. (1994). Identi®cation and improvement of quality characteristics of ostrich meat. Ph. D. thesis, University of Stellenbosch, South Africa. Sales, J. (1998). Fatty acid composition and cholesterol content of dierent ostrich muscles. Meat Science, 49, 489. SAS Institute Inc. (1989). SAS/STAT user's guide, version 6, 4th ed. Cary, NC: SAS Institute. Van Jaarsveld, F. P., Naude, R. J., & Oelofsen, W. (1997). Optimisation of calcium-dependent Protease and cathepsin D assays in ostrich muscle and the eect of chemical and physical dry-curing parameters. Meat Science, 47, 287. Wasserman, M. (1957). U.S. Patent No. 2, 812, 261.
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Technical note
Processing and nutritional characteristics of value added ostrich products P. Fisher*, L.C. Homan, F.D. Mellett Department of Animal Sciences, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa Received 13 May 1999; received in revised form 4 October 1999; accepted 10 October 1999
Abstract Two types of processed products, chopped hams (0.15% and 0.30% phosphate on ®nal yield) and viennas (27 and 32% fat extension) were manufactured from ostrich fan ®llets (M. ilio®bularis) to determine the suitability of ostrich meat for processing purposes. Cooking losses diered signi®cantly (P<0.10) between the two types of ham-like products (0.15% phosphate=1.59 and 0.30% phosphate=0.78%), indicating that an increase in phosphate addition reduced cooking loss. Cooking losses did not dier (P>0.10) between the two types of ostrich viennas. Colour evaluation (L ; a ; b ) of the fresh ostrich meat and processed ostrich products (chopped hams and viennas) indicated signi®cant dierences between the dierent types of viennas. Chemical composition (moisture, ash, protein and fat content) of the ostrich meat, processed ostrich products and similar types of commercially available products suggested that processed ostrich products can be formulated to compete successfully with similar types of products derived from other meat species. # 2000 Elsevier Science Ltd. All rights reserved.
1. Introduction Ostrich meat is perceived and marketed as a healthy alternative to other red meats due to a favourable fatty acid pro®le (intramuscular ostrich fat contains 16.50% polyunsaturated o-3 fatty acids) and a low intramuscular fat content (Mellett, 1992; Sales, 1998). However, published data on value added ostrich products are limited. BoÈhme, Mellett, Dicks and Basson (1996) proved that ostrich meat can be used successfully in Italian style fermented sausage with the use of speci®c starter cultures. The relatively high ultimate pH value of ostrich meat (Sales, 1994) makes it an ideal processing meat, since the natural water binding capacity is high, which in turn can reduce the use of moisture retaining agents, such as phosphates when processed. The aim of this investigation was to determine the processing and nutritional characteristics of certain ostrich meat products, and to compare them with other commercially available products. 2. Materials and methods Ostrich meat was obtained from 12 to 14 months old birds (n 12) that were slaughtered at a local European * Corresponding author. Tel.: +21-808-4916; fax: +21-808-4750. E-mail address: [email protected] (P. Fisher).
Union approved abattoir using industrial slaughtering techniques. This included electrical stunning and cutting of the neck for exsanguination, where after the feathers and skin were removed. The intestines were then removed and, together with the carcass, inspected by a government health ocial. The carcasses were then chilled at 2 C for 24 h till the following day. The fan ®llets (M. ilio®bularis) were removed from the carcass 24 h after slaughter, shrink wrapped, boxed and frozen at ÿ40 C prior to processing. After thawing, the ®llets were chopped by hand into smaller pieces, mixed (to avoid possible inter animal eects), minced using a 32 mm diameter mincing plate and chilled to 0 C. The minced meat was then subdivided into four batches for the manufacturing of a chopped ham-like product and thin diameter emulsi®ed and smoked products (viennas). The chopped ham-like products were manufactured with two dierent levels of phosphate inclusion (0.30 and 0.15% on ®nal yield) to determine level of water binding in the product. Brine ingredients, expressed as a percentage in the brine, consisted of 10% salt, 0.25% sodium ascorbate, 1% NaNO2, sodium tripolyphosphate (1.5 and 0.75% respectively) and water (87.25 and 88% respectively). The brine mixture (addition: 20% [by weight] of meat) for each treatment was then added to the meat and the latter tumbled for 20 min. After tumbling, the ham mixtures were stued into
0309-1740/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0309-1740(99)00139-4
252
P. Fisher et al. / Meat Science 55 (2000) 251±254
plastic casings (500 g, 10 casings per treatment). Each stued casing within each treatment was weighed and cooked to a core temperature of 68 C. After cooking, the products were immersed in cold water for approximately 15 min, and then chilled (2 C) for 24 h. After chilling, the products were removed from the casings, touch dried with absorbent paper, and casing weights recorded, separate from product weights. Cooking loss was expressed as follows: cooking loss (%)=[(raw weight-cooked weight)/raw weight]100. Note that the raw weight refered only to the raw mixture, since the weights of the casings were subtracted from both fresh and cooked values. Two dierent types of viennas (32 and 27% fat extension) were also manufactured to determine the eect of the level of fat inclusion on water binding and chemical composition. Ingredients (expressed as kg/kg lean ostrich meat) were: (for the 32% fat extended viennas) 0.81 kg pork fat, 0.63 kg ice water, 0.05 kg salt, 0.005 kg NaNO2, 0.0015 kg ascorbic acid, 0.0012 kg seasoning and (for the 27% fat extended viennas) 0.607 kg pork fat, 0.55 kg ice water, 0.044 kg salt, 0.0044 kg NaNO2, 0.0013 kg ascorbic acid, 0.0011 kg seasoning. The pork fat and lean meat for each treatment were minced separately through a 13 mm plate and chilled to 0 C. The lean meat, spices and two-thirds of the water were placed in a bowl cutter and cut at high speed, where after the fat and remaining water were added and cut till the mixture resembled a ®ne paste. The emulsion temperature was constantly monitored and maintained below 6 C. The emulsion was then placed into a Handmann sausage ®ller (model FA 30) calibrated to ®ll links into 65 g portions. Collagen casings (Devro Teepak1) were used to minimize the risk of case rupturing during the manufacturing process. After completion, the sausages were divided into bundles of 10 sausages/bundle. The bundles were weighed individually (raw weight) and hung on a smoke rack. The viennas were dry smoked (using Meranti wood chips) for 60 min at 60 C. After smoking the viennas were cooked to a core temperature of 68 C, and allowed to dry before chilling (2 C) for 24 h. The bundles were weighed (cooked weight) and percentage cooking loss determined. Two commercially available types of viennas (smoked viennas and low-fat viennas) were purchased to compare with the ostrich viennas for colour and chemical composition. The declared contents of the smoked viennas and the low-fat viennas were: meat (pork and poultry for the smoked viennas, beef and poultry for the low-fat viennas), water, starch, soya protein, spices, dextrose, salt, potassium chloride, phosphates, ¯avour enhancers, stabilisers, antioxidants and sodium nitrite as preservative. Re¯ectance and hue were evaluated using a Colorgard System 2000 colorimeter (Paci®c Scienti®c, Silver Spring, MD, USA) to determine CIELAB values (L ; a and b values) on the processed ostrich products (chopped
ham-like products and viennas) and both the smoked and low-fat pork/poultry viennas. The following chemical constituents were determined (Association of Ocial Analytical Chemists, AOAC, 1997) on the minced samples of the lean meat and processed ostrich products: moisture content, by drying 2.5 g sample at 100 C to constant weight, ashing at 500 C for 5 h, protein content by the block digestion method and ether-extractable fat content by solvent extraction. All samples were analyzed in triplicate for chemical composition and the values given in Table 3. The data were analysed by least-square means method using the GLM procedure (SAS Institute Inc., 1989). 3. Results and discussion Grau (1958), discussing the role of phosphates and water binding in meat products, indicated that the addition of phosphates does not increase the water absorption of meat, but rather causes meat products to bind water more completely and, in so doing, preventing losses during processing. This probably explains the results from various researchers (Wasserman, 1957) that cured meat products with added phosphate, including sausage products, bind more water, are plumper when encased in sausage casings and lose less water during smoking and heat processing. The results in Table 1 supported this, indicating that the ostrich ham-like products made with the 0.3% phosphate (on ®nal yield) still had a signi®cantly (P<0.10) lower cooking loss (0.78%) when compared to the 0.15% phosphate ham-like products (1.59%). Ostrich meat, which has an ultimate pH of ca. 6.0 (Sales, 1994), should, by implication, have a high water-holding capacity (Lawrie, 1991) and thus be able to retain high levels of moisture. The addition of phosphates to value added ostrich products will not have such a marked eect on moisture retention as with, for example, pale, soft and exudative (PSE) pork (Fisher, 1998), but will still reduce cooking losses. Although not evaluated in this investigation, the ham-like products made with the higher level of phosphate addition tended to be more rubbery in texture, which could be considered as a less desirable sensory trait. In addition, the inhibitory eect of phosphates on the relative activity of Table 1 Cooking/processing losses and colour of chopped ostrich ham-like products (means std error)a Product
Ham (0.30% phosphate)
Ham (0.15% phosphate)
Cooking loss (%) L* a* b*
0.788a0.264 33.180.276 11.710.155 4.02a0.059
1.59b0.264 33.170.276 11.490.155 4.19b0.059
a
Values in the same row with dierent letters dier (P<0.10).
P. Fisher et al. / Meat Science 55 (2000) 251±254
253
Table 2 Cooking/processing losses and colour of ostrich viennas and commercial viennas (meansstd. error)a,b Characteristic
Ostrich vienna (32% fat)
Ostrich vienna (27% fat)
Smoked vienna
Low fat vienna
Cooking loss (%) L* a* b*
8.500.559 47.84a,c0.249 12.5c0.126 8.06c0.127
9.670.559 46.60b,c0.249 12.77c0.126 8.31c0.127
± 52.28d0.295 8.33d0.149 15.92d0.151
± 47.47a,c0.295 9.88e0.149 18.32e0.151
a b
a±b-Values in the same row with dierent letters dier (P<0.10). c±d-Values in the same row with dierent letters dier (P<0.001).
certain endogenous proteases (calcium dependent proteases) could also aect tenderness negatively (Van Jaarsveld, Naude & Oelofsen, 1997). Dierences between the two treatments were non signi®cant (P > 0:10) for the L and a values, with the 0.15% added phosphate ham-like products having signi®cantly (P < 0:10) higher b values (4.19) compared to the 0.30% added phosphate ham-like products (4.02), suggesting a lighter, or yellowish chromacity. However, attention should be drawn to the low L values of both types of ham, indicating that the product is dark in appearance, a typical feature of fresh ostrich meat. Cooking losses did not dier signi®cantly (P > 0:10) between the two types of ostrich viennas, but there was a tendency towards increased cooking loss for the viennas with the lower (27%) fat addition (Table 2). This was probably due to the higher lean content, and thus higher moisture content, of the emulsion used. Comparison of tristimulus colour values indicated notable dierences between the dierent types of viennas. The higher level of fat (32% added fat vs. 27% added fat) included in the ostrich viennas resulted in a signi®cant higher (P < 0:10) L value (luminance). This value is similar to the commercial low fat viennas. The increased L values for the ostrich viennas (compared to the fresh ham-like products Ð Table 1) was probably due to the pork fat used, which had a white appearance and thus an increased luminance. The commercial smoked viennas had the highest (P < 0:001) L value (52.28) compared to the two types of ostrich viennas (47.84 and 46.60) and the commercial low fat vienna (47.47). The ostrich viennas also had signi®cantly higher (P <.001) a and signi®cantly (P < 0:001) lower b values, suggesting a redder colour compared to the other two types of commercial viennas. This was as expected since ostrich meat does appear redder compared to other species such as pork and poultry, which were the primary constituents of the viennas. Proximate analyses values of both the fresh ostrich meat and the processed products (Table 3) indicate large variations in dry matter (DM), ash, protein and fat content. Comparison of the DM content of the fresh ostrich meat and the two types of chopped ham did not indicate large dierences, suggesting that the high water binding capacity (due to a high ultimate pH) of ostrich
Table 3 Values for chemical composition of processed products Type
DM (%)
Ash (%)
Protein (%)
Fat (%)
Fresh ostrich meat Ham (0.30% phosphate) Ham (0.15% phosphate) Ost.vienna (32% fat) Ost.vienna (27% fat) Smoked vienna Low fat vienna
23.07 21.72 22.51 43.85 39.50 33.68 32.92
0.33 3.28 2.97 2.69 2.29 3.89 3.59
17.48 15.14 17.73 11.72 12.29 15.08 11.45
3.57 3.17 1.56 24.83 22.99 16.95 13.16
meat was retained, even when the meat was subjected to severe processing procedures such as grinding and cooking. Values for protein content did not indicate large variations for both fresh meat or chopped hams, with fat content being the highest for the fresh meat (3.57%) and lowest for the 0.15% added phosphate ham (1.56%). Since no fat was added during the manufacturing process it must then be assumed that the differences in fat content was due to either sampling or a reduced fat content for the speci®c batch. The higher ash content in the hams, compared to the fresh meat, suggested that the increase was due to the addition of the salt and spices. The composition of the four types of viennas (2 types of ostrich viennas and a smoked and a low-fat pork/poultry vienna) varied considerably, especially the fat content. The high fat and low protein content of the two types of ostrich viennas (compared to the pork/poultry viennas) was mainly due to high levels of fat included in the emulsion. However, the replacement, or partial replacement, of pork fat with a modi®ed starch/oil emulsion would reduce the fat content of the ostrich viennas, without aecting their quality negatively and also extend the higher cost meat fraction of the ®nal product (Bater, Descamps & Maurer, 1993). 4. Conclusion The results from this study do indicate that the manufacturing of value-added products from ostrich meat is a viable option for an industry that has largely relied on the fresh meat sector of the market to sell its product. The ham-like products, although having a dark appearance,
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still resulted in an acceptable product with regard to its chemical composition. Although not evaluated, it is advisable to reduce added phosphate in order to avoid a possible rubbery texture in the ®nished product. The use of fat as an extender in the emulsion products resulted in products with comparable, if higher, fat content than the commercial products. With the judicious use of alternative extenders the fat content can be reduced to a more acceptable level. This will help to ensure that, if produced in sucient quantities, ostrich meat can compete successfully with other `healthy' meat products. References Association of Ocial Analytical Chemists. (1979). Ocial method of analysis (16th ed). Arlington, VA: Association of Ocial Analytical Chemists. Bater, B., Descamps, O., & Maurer, A. J. (1993). Quality characteristics of cured turkey thigh meat with added hydrocolloids. Poultry Science, 72, 349.
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