- Email: [email protected]
Effects of dietary vitamin E supplementation and packaging on the colour stability of sliced pasteurized beef ham
Meat Science 58 (2001) 403–407 www.elsevier.com/locate/meatsci
Effects of dietary vitamin E supplementation and packaging on the colour stability of sliced pasteurized beef ham J.H. Houben *, A. van Dijk Department of the Science of Food of Animal Origin, Faculty of Veterinary Medicine, Utrecht University, PO Box 80175, 3508 TD Utrecht, The Netherlands Received 10 April 2000; received in revised form 14 July 2000; accepted 20 December 2000
Abstract The effect of supplementation of vitamin E (2025 IU animal 1 day 1) in the diet of beef bulls on the colour stability of pasteurized beef ham was studied. Control and enriched diets were provided for the last 136 days before slaughter. Pasteurized hams were manufactured from Mm. semitendinosus from eight animals per dietary group. Half of the samples of sliced ham from control (CON) and supplemented (SUP) bulls were packaged under vacuum (VAC) and half in low-oxygen modified atmosphere packs (FOG, gas mixture: CO2/N2=50/50). The packages were kept under constant illumination for 28 days at 8 C. During storage, the number of colony-forming units (CFU) reached a maximum of 5x107 g 1. The microflora was dominated by lactic acid bacteria. The supplementation with vitamin E showed no effect on microbial growth. Lipid oxidation was stable during storage. A significant difference between both dietary groups was detected for the decrease in the redness values during storage. Redness values of CON vacuum-packaged samples decreased (P < 0.01) with time, whereas those for the SUP products only tended to decrease. The redness values of FOG-packed ham were higher than those of VAC-packed ham at the end of the display period, irrespective of the dietary group. Overall, colour appeared to be more stable in the FOG-packed products than in the VAC-packed products. It can be concluded that dietary supplementation of bulls with vitamin E appears to offer only a minor improvement in colour stability over current feeding regimens when the Mm. semitendinosus are used to make cured, pasteurized ham-type products. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Pasteurized beef ham; Vitamin E; Colour stability; Vacuum packaging; Modified atmosphere packaging
1. Introduction There are many reports in the literature on the benefits of supplementing the diet of slaughter cattle with vitamin E (some recent articles include: Cabedo, Sofos, & Smith, 1998; Formanek, Kerry, Buckley, Morrissey, & Farkas, 1998; Garber, Roeder, Davidson, Pumfrey, & Schelling, 1996; Lavelle, Hunt, & Kropf, 1995; O’Grady, Monahan, Bailey, Allen, Buckley, & Keane, 1998; Sherbeck, Wulf, Morgan, Tatum, Smith, & Williams, 1995). Recent reviews were written by Faustman, Chan, Shaefer, and Havens (1998) and Liu, Lanari, and Schaefer (1995). The major benefits of vitamin E supplementation relate
* Corresponding author. E-mail address: [email protected] (J.H. Houben).
to an improved colour stability and diminished lipid peroxidation of the final meat product. However, no attention has been paid to the effects of dietary enrichment with vitamin E on the quality of cured beef products, or the effects of illumination in combination with low-oxygen packaging during retail display of sliced products. Pasteurized (sliced) cured meat products are known to discolour during illuminated display. Discolouration is due to a combination of light and residual oxygen, which is present in both vacuum and modified atmosphere packages (Rikert, Bressler, Ball, & Stier, 1957; Trout, 1991). The predominant pigment responsible for the pink colour of pasteurized cured meat products is nitrosomyochrome. When exposed to light, even at very low oxygen tensions, the pigment is gradually oxidized to metmyoglobin, which imparts a certain greyness to the product surface. Residual nitrite
0309-1740/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0309-1740(01)00042-0
404
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
and (iso)ascorbate are major factors which help stabilize the colour of cured meat during exposure to light (Skibsted, 1992). It is not known what the effect of an increased level of vitamin E, which is especially important in the inhibition of lipid oxidation (Kitts, 1997), is on this process. Since beef production systems in The Netherlands have not been studied in this way, a project to examine the effects of vitamin E supplementation on the properties of beef and cured beef products was undertaken. Other articles describe the effects of such supplementation on drip loss of selected muscles (Hertog denMeischke, Smulders, Houben, & Eikelenboom, 1997), colour stability of fresh and aged beef (Eikelenboom, Hoving-Bolink, Kluitman, Houben, & Klont, 2000), and colour stability and lipid oxidation in freshly minced, lean and fat beef (Houben, Van Dijk, Eikelenboom, & Hoving-Bolink, 2000) or in minced, previously frozen lean beef with or without addition of an ascorbic acid preparation (Houben, Van Dijk, & Eikelenboom, 2000). This paper focuses on the quality of pasteurized beef ham prepared from bulls fattened on diets supplemented with vitamin E. Hams were sliced and packaged under vacuum or in low-oxygen modified atmosphere packs and their shelf-life was determined during retail display.
2. Materials and methods 2.1. Feeding experiments Forty young bulls from a PiemonteseHolstein Friesian cross were fattened at the Institute for Animal Science and Health at Lelystad. At 12 months of age, the animals were assigned to treatment groups of twenty animals. During the last 136 days before slaughter, the cattle received different diets. The vitamin E-supplemented group (SUP) received 2025 mg vitamin E (DLa-tocopheryl acetate) head 1 day 1 in the form of a premix (Rovimix E-50 SD, Roche Nederland) added to the concentrate. The control group (CON) received a similar diet (corn silage and concentrate), except that no extra vitamin E was added to the concentrate. Further details of the feeding experiments and slaughter of the animals are given in Eikelenboom et al. (2000). 2.2. Manufacturing, packaging, and display of the pasteurized beef hams After approximately 48 h of chilling (initial chilling: 2 h at 0 C, followed by 46 h at 2–3 C), the carcases were cut and various muscles and meat pieces were collected from the same carcass sides, packaged, and stored at 23 C. Six days after slaughter, the membranes and superficial fatty tissue were removed from the Mm.
semitendinosus of eight randomly selected animals per dietary group, and the Mm. semitendinosus were processed into pasteurized hams (Szmanko, Duda, & Kosna 1989). Such hams are traditionally pork products. However, recently comparable products made from beef hindquarter muscles have appeared on the market in The Netherlands. To our knowledge, these hams and ‘‘Spiced Beef’’-type products are the only cured, pasteurized beef products made up of intact muscle. With a Retus Inject-O-mat type 15 multi-needle injector 15% (m/m) brine was evenly distributed over the individual muscles. The composition of the brine (in% m/m) was colorozo-salt 12.0 (= common salt containing 0.6% m/m NaNO2), injection brine phosphate (Instaphos) 3.3, glucose 3.3, mono-sodium glutamate 0.6, sodium ascorbate 0.3 and water 80.5. Injected muscles were coded, individually put in nets, massaged for 90 min in a meat tumbler (12 revolutions min 1), and vacuum packed. They were placed in a pear-shaped ham mould (5 l) equipped with a springloaded lid. The closed moulds were left overnight at 2 C to allow internal colour development. The next day the hams were pasteurized in a cooking cabinet (T-cook; T=25 C; maximum cabinet temperature 75 C, until a ham core temperature of 68 C was reached). Average P 70 10 was 34.1 min. After heating, the hams were cooled in running tap water to a core temperature of about 15 C and stored overnight at 2 C. The sixteen hams were sliced and packaged the next day in a commercial meat slicing plant. Ham slices (8 mm thick) were alternately packaged under vacuum (VAC) or in low-oxygen gas packs (referred to as FOG). The gas mixture contained about 50% CO2 and 50% N2. The volume ratio gas:product was approximately 1:2. The gas permeability of the vacuum-packaging material was < 7 cm3 O2 m 2 d 1 bar 1 measured at 23 C and a relative humidity of 75% and < 100 cm3 CO2 m 2 d 1 bar 1 measured at 23 C and a relative humidity 50% (the same material was used as the upper film of the FOG packs). Under the same test conditions, the gas permeability of the bottom film of the FOG-packs was < 5 and < 25 cm3 m 2 d 1 bar 1 for O2 and CO2, respectively. Duplicate samples of sliced ham for each product and packaging condition were placed on racks 44 cm away from sets of Philips TLD36W79 ‘‘meat’’lamps (colour temperature 3800 K) in a meat chilling room at 8 1 C. The illumination intensity on the surface of the meats was 578 lx (standard deviation 57 lx). Additional packs were displayed for bacteriological and chemical analyses. 2.3. Measurements during storage At intervals, the colour of meat on the light-side of the unopened packages was measured through the film in the chilling room.
405
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
Colour (CIELAB, L*, a* and b* values) was measured at three places per slice, using a Minolta Chromameter II (Minolta Inc., Osaka, Japan) equipped with a C-light source. The effective diameter of the measuring head was 53 mm. The instrument was calibrated against a vacuum-packaged white tile every 2 h of continuous measurements. At regular intervals three randomly selected packages per group were sampled on their illuminated side for microbiological analyses and measurement of 2-thiobarbituric acid (TBA) values. pH was measured at three sites per package with a Schott pH meter (type CG 818) equipped with an Ingold electrode. These packages were then discarded. The gas composition was measured in the modified atmosphere packages, which had to be opened for analytical purposes, with a Servomex 1420 Analyser (Servomex Ltd., Crowborough, UK). Illumination intensity was measured with a BBC Goertz Metrawatt MX4 instrument. 2.4. Methods of analysis
Table 1 Mesophilic aerobic counts (average log Ng 1 standard deviation; n=5) during display of packaged sliced hams at 8 Ca Period of storage (days)
CON VAC
SUP FOG
1.970.18
t=0
VAC 1.880.44
1.42 0.32 t=7
5.910.45
t=14
7.280.51
t=21
7.490.31
t=28
7.670.07
FOG 1.410.55
5.740.51 5.77 0.26
5.280.77 6.970.62
6.85 0.43
7.020.61 7.480.16
6.99b0.35
6.54a0.21 7.630.17
6.83 0.41
6.990.40
a Per horizontal line (possible diet effect) Student’s t-tests (two sided; P4 0.05) were performed. Different letters are presented when significant. CON, control, SUP, supplemented; VAC, vacuum; FOG, low-oxygen modified atmosphere packs.
Table 2 Numbers of lactic acid bacteria (average log Ng 1 standard deviation; n=5) during display of packaged sliced hams at 8 Ca
Moisture content was determined according to ISO/ 1442 guidelines (ISO, 1973), protein content according to Gru¨ndig (1994), fat content according to the Fosslet method (method 24.007/24.008; AOAC, 1980), ash content according to ISO/R936 guidelines (ISO, 1969), vitamin E content according to AFNOR (1997), and TBA values according to Raharjo, Sofos, and Schmidt (1992). Mesophilic aerobic bacteria were counted on Plate Count Agar (American Public Health Association) after the pour plates had been incubated for 3 days at 30 C. Lactic acid bacteria were counted on De Man Rogosa Sharpe agar after the pour plates had been incubated for 3 days at 25 C under anaerobic conditions.
Period of storage (days)
3. Results and discussion
Williams (1994) also observed that cooking dietary enriched beef muscles did not affect the vitamin E content. The CO2 content of the FOG packages was on average 46%; the O2 content was consistently below the level of detection (< 0.1%).
3.1. Composition of the ham and of the gas in the FOG packages The gross chemical composition of duplicate samples of hams from both groups of animals was very similar. The hams contained on average (in% m/m): moisture 74.1, protein 21.6, fat 1.8 and ash 2.8. The vitamin E content (mean and standard deviation; n=6) was 2.3 0.10 mg kg 1 and 4.6 0.27 mg kg 1 for CON and SUP samples, respectively. Pasteurization did not affect the vitamin E concentrations (levels assessed for various raw meats are presented by Eikelenboom et al. (2000) and Houben, Van Dijk, Eikelenboom, and Hoving-Bolink (2000); Houben, Van Dijk, and Eikelenboom (2000). Liu, Scheller, Schaefer, Arp, and
CON VAC
SUP FOG
2.311.07
t=0
VAC 1.410.62
1.13 b
1.71 0.80 5.840.25
t=7
5.230.55 5.90 0.15
t=14
6.870.38
t=21
7.090.37
t=28
7.140.32
5.560.78 6.500.57
6.89 0.43
6.490.52 6.840.33
7.20b0.34
b
6.75a0.21 7.170.32
7.02 0.38 a
FOG
7.030.51
See respective footnote to Table 1 Some counts below limit of detection.
3.2. Microbiological analyses and pH of products Mesophilic aerobic organisms (Table 1) and lactic acid bacteria (Table 2) had similar growth patterns in hams from the two dietary groups. This is in agreement with published data for vitamin E dietary-enriched, otherwise uncured (minced) beef (Cabedo et al., 1998; Chan, Hakkarainen, Faustman, Schaefer, Scheller, & Liu, 1995; Houben, Van Dijk, Eikelenboom, & HovingBolink, 2000; Houben, Van Dijk, & Eikelenboom, 2000).
406
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
After storage for 28 days there were on average 3107 CFU g 1 of mesophilic aerobic organisms. Lactic acid bacteria were the dominant microorganisms present. Although the colour of a product may be affected by the number of organisms present, no direct information on the effect of lactic acid bacteria anaerobically growing actively on the colour of cured meat products in intact packages was found in the literature. The redness of sliced, pasteurized pork ham, packaged in low-oxygen modified atmosphere was found not to be affected by the presence of aerobic microorganisms in numbers higher than 108 CFU g 1 (Møller, Jensen, Olsen, Skibsted, & Bertelsen, 2000). Since Møller et al. did not detect Brochothrix thermosphacta, lactic acid bacteria were probably the main species present (Davies et al., 1999; Holley, 1997; Silla, 1985). Hence, we may assume that the effect of actively growing lactic acid bacteria on the colour of anaerobically packaged cured meats will probably be small. The mean pH of the hams decreased from 5.95 in the fresh product to 5.76 after 28 days of display (P < 0.05). The mean pH was the same for hams from both dietary groups. The decrease in pH was probably caused by lactic acid released by the growing lactic acid bacteria. 3.3. Lipid oxidation Lipid peroxidation was stable throughout the storage period: there was less than 0.04 mg malonaldehyde kg 1 freshly sliced ham and this concentration remained below 0.07 during the 28 days of storage. In this low range, TBA measurements are unreliable. It should be remembered that these are low-fat, cured entire-muscle products, packaged after slicing in an oxygen-free atmosphere. Moreover, the additives nitrite and ascorbic acid usually contribute to the inhibition of lipid oxidation in meat products (Arendt, Skibsted, & Andersen, 1997; Freybler, Gray, Asghar, Booren, Pearson, & Buckley, 1993; Kanner, 1994; Kitts, 1997). Dietary enrichment with vitamin E apparently had no extra delay on lipid oxidation, probably because the overall oxidative stress in this system is already very low. 3.4. Meat colour Meat colour measurements (L, a* and b* values) are presented in Fig. 1. The statistical analysis (SPSS/PC+) did not reveal significant differences between hams from the two dietary groups. We did not measure residual nitrite levels for practical reasons and considering the adequate colour stability of the final product the used amount of nitrite was appropriate for colour reasons. Redness values decreased (P < 0.01) during storage of the CON-VAC products, but only tended to do so in the SUP-VAC products. The a* values were significantly different at the end of the storage period and this dif-
Fig. 1. Lightness, redness and yellowness during display of packaged sliced hams at 8 C. Letters C (P < 0.01) and s (P < 0.06) signify that differences were found between packaging treatments for CON and SUP products, respectively.
ference was related to the kind of packaging used. Redness was higher for FOG-packed hams than for VACpacked hams, irrespective of dietary group. The colour of the FOG-packed hams was very stable. A comparable stability of the redness component was observed by Møller et al (2000) for sliced pasteurized pork ham packaged in modified atmosphere at initial oxygen concentrations below 0.1%. We hypothesize that the residual oxygen concentration throughout the entire storage period was lower in the FOG packs than in the VAC packs, due to dilution of residual oxygen — initially remaining after the application of vacuum — by the supplied gas volume, and due to a decreased diffusion of oxygen through the otherwise identical foil as a consequence of a small pressure difference in/outside the packs during storage, which contributed to the better
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
colour stability. No data on comparably packaged cured beef products were found in the literature.
Acknowledgements The authors gratefully acknowledge the enthusiastic interest and skilled assistance of G. Keizer, J.L.M. Tjeerdsma-van Bokhoven, A.A.M. Spanjer and D. Keuzenkamp. This study was partly financed by the Dutch Product Boards for Livestock, Meat, Poultry and Eggs (grant No. 94.1.20) and was supported by Roche Nederland B.V. (Mijdrecht), Boers Vleeswaren (Sint Michielsgestel) and Philips Lighting B.V. (Roosendaal). References AFNOR (Assocation Francaise de Normalisation) (1997). Animal feedstuffs—determination of vitamin E content in feedstuffs, vitamin mineral compounds and concentrates. Paris: AFNOR. AOAC (Assocation of Official Analytical Chemists), 1980. Official methods of analysis. Meat and meat products. Method 24.007. Determination of fat content. W. Horwitz, Washington. Arendt, B., Skibsted, L. H., & Andersen, H. J. (1997). Antioxidative activity of nitrite in metmyoglobin induced lipid peroxidation. Z. Lebensm. Unters. Forsch, 204(1), 7–12. Cabedo, L., Sofos, J. N., & Smith, G. C. (1998). Bacterial growth in ground beef patties made with meat from animals fed diets without or with supplemental vitamin E. Journal of Food Protein, 61(1), 36–40. Chan, W. K. M., Hakkarainen, K., Faustman, C., Schaefer, D. M., Scheller, K. K., & Liu, Q. (1995). Color stability and microbial growth relationships in beef as affected by endogenous a-tocopherol. Journal of Food Science, 60(5), 966–971. Davies, E. A., Milne, C. F., Bevis, H. E., Potter, R. W., Harris, J. M., Williams, G. C., Thomas, L. V., & Delves-Broughton, J. (1999). Effective use of nisin to control lactic acid bacterial spoilage in vacuum-packed bologna-type sausage. Journal of Food Protection, 62(9), 1004–1010. Eikelenboom, G., Hoving-Bolink, A. H., Kluitman, I., Houben, J. H., & Klont, R. E. (2000). Effect of dietary vitamin E supplementation on beef colour stability. Meat Science, 54(1), 17–22. Faustman, C., Chan, W. K. M., Schaefer, D. M., & Havens, A. (1998). Beef colour update: the role for vitamin E. Journal of Animal Science, 76, 1019–1026. Formanek, Z., Kerry, J. P., Buckley, D. J., Morrissey, P. A., & Farkas, J. (1998). Effects of dietary vitamin E supplementation and packaging on the quality of minced beef. Meat Science, 50(2), 203–210. Freybler, L. A., Gray, J. I., Asghar, A., Booren, A. M., Pearson, A. M., & Buckley, D. J. (1993). Nitrite stabilization of lipids in cured pork. Meat Science, 33(1), 85–96. Garber, M. J., Roeder, R. A., Davidson, P. M., Pumfrey, W. M., & Schelling, G. T. (1996). Dose-response effect of vitamin E supplementation on growth performance and meat characteristics in beef and dairy steers. Canadian Journal of Animal Science, 76(1), 63–72. Gru¨ndig, A. (194). Vergleichende stickstoffbestimmungen in fleischerzeugnissen. Fleischwirtsch, 74(2), 173–175. Hertog den-Meischke, M. J. A., Smulders, F. J. M., Houben, J. H., & Eikelenboom, G. (1997). The effect of dietary vitamin E sup-
407
plementation on drip loss of bovine Longissimus Lumborum, Psoas Major and Semitendinosus muscles. Meat Science, 45(2), 153– 160. Holley, R. A. (1997). Asymmetric distribution and growth of bacteria in sliced vacuum-packaged ham and bologna. Journal of Food Protection, 60(5), 510–519. Houben, J.H., Van Dijk, A., Eikelenboom, G., & Hoving-Bolink, A.H., 2000a. Effect of dietary vitamin E supplementation, fat level and packaging on colour stability and lipid oxidation in minced beef. Meat Science 55, 331–336. Houben, J.H., Van Dijk, A., & Eikelenboom, G., 2000b. Effects of dietary vitamin E supplementation, an ascorbic acid preparation and packaging on the quality of displayed minced lean beef. Meat Science (submitted for publication). ISO/1442, 1973. Meat and meat products. The determination of moisture content. ISO/R936, 1969. Meat and meat products. The determination of ash content. Kanner, J. (1994). Oxidative processes in meat and meat products: quality implications. Meat Science, 36, 169–189. Kitts, D. D. (1997). An evaluation of the multiple effects of the antioxidant vitamins. Trends Food Science Technology, 8, 198–203. Lavelle, C. L., Hunt, M. C., & Kropf, D. H. (1995). Display life and internal cooked color of ground beef from vitamin E-supplemented steers. Journal of Food Science, 60(6), 1175–1178, 1196. Liu, Q., Lanari, M. C., & Schaefer, D. M. (1995). A review of dietary vitamin E supplementation for improvement of beef quality. Journal of Animal Science, 73, 3131–3140. Liu, Q., Scheller, K. K., Schaefer, D. M., Arp, S. C., & Williams, S. N. (1994). Dietary a-tocopheryl acetate contributes to lipid stability in cooked beef. Journal of Food Science, 59(2), 288–290. Møller, J. K. S., Jensen, J. S., Olsen, M. B., Skibsted, L. H., & Bertelsen, G. (2000). Effect of residual oxygen on colour stability during chill storage of sliced, pasteurised ham packaged in modified atmosphere. Meat Science, 54, 399–405. O’Grady, M. N., Monahan, F. J., Bailey, J., Allen, P., Buckley, D. J., & Keane, M. G. (1998). Colour-stabilising effect of muscle vitamin E in minced beef stored in high oxygen packs. Meat Science, 50(1), 73–80. Raharjo, S., Sofos, J. N., & Schmidt, G. R. (1992). Improved speed, specificity and limit of determination of an aqueous acid extraction thiobarbituric acid-C18 method for measuring lipid peroxidation in beef. Journal of Agricultural Food Chemistry, 40, 2182–2185. Rikert, J. A., Bressler, L., Ball, C. O., & Stier, E. F. (1957). Factors affecting qualilty of prepacked meat II. Color studies. Effects of air and oxygen under different pressures upon color of product. Food Technology, 11, 625–632. Sherbeck, J. A., Wulf, D. M., Morgan, J. B., Tatum, J. D., Smith, G. C., & Williams, S. N. (1995). Dietary supplementation of vitamin E to feedlot cattle affects beef retail display properties. Journal of Food Science, 60(2), 250–252. Silla, H. (1985). Shelf-life of cured, cooked and sliced meat products. II. Influence of Lactobacillus. Fleischwirts, 65(2), 205–207. Skibsted, L. H. (1992). Cured meat products and their oxidative stability. In D. E. Johnston, M. K. Knight, & D. A. Ledward, The chemistry of muscle-based foods (pp. 266–286). Cambridge: The Royal Society of Chemistry. Szmanko, T., Duda, Z., & Kosna, D. (1989). Influence of freezing and frozen storage of smoked beef ‘‘hams’’ on selected quality characteristics. Fleischwirts, 69(1), 99–103. Trout, G. R. (1991). Prevention of colour defects in meat and meat products. Food Australia, 43(2), 54–56.
Effects of dietary vitamin E supplementation and packaging on the colour stability of sliced pasteurized beef ham J.H. Houben *, A. van Dijk Department of the Science of Food of Animal Origin, Faculty of Veterinary Medicine, Utrecht University, PO Box 80175, 3508 TD Utrecht, The Netherlands Received 10 April 2000; received in revised form 14 July 2000; accepted 20 December 2000
Abstract The effect of supplementation of vitamin E (2025 IU animal 1 day 1) in the diet of beef bulls on the colour stability of pasteurized beef ham was studied. Control and enriched diets were provided for the last 136 days before slaughter. Pasteurized hams were manufactured from Mm. semitendinosus from eight animals per dietary group. Half of the samples of sliced ham from control (CON) and supplemented (SUP) bulls were packaged under vacuum (VAC) and half in low-oxygen modified atmosphere packs (FOG, gas mixture: CO2/N2=50/50). The packages were kept under constant illumination for 28 days at 8 C. During storage, the number of colony-forming units (CFU) reached a maximum of 5x107 g 1. The microflora was dominated by lactic acid bacteria. The supplementation with vitamin E showed no effect on microbial growth. Lipid oxidation was stable during storage. A significant difference between both dietary groups was detected for the decrease in the redness values during storage. Redness values of CON vacuum-packaged samples decreased (P < 0.01) with time, whereas those for the SUP products only tended to decrease. The redness values of FOG-packed ham were higher than those of VAC-packed ham at the end of the display period, irrespective of the dietary group. Overall, colour appeared to be more stable in the FOG-packed products than in the VAC-packed products. It can be concluded that dietary supplementation of bulls with vitamin E appears to offer only a minor improvement in colour stability over current feeding regimens when the Mm. semitendinosus are used to make cured, pasteurized ham-type products. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Pasteurized beef ham; Vitamin E; Colour stability; Vacuum packaging; Modified atmosphere packaging
1. Introduction There are many reports in the literature on the benefits of supplementing the diet of slaughter cattle with vitamin E (some recent articles include: Cabedo, Sofos, & Smith, 1998; Formanek, Kerry, Buckley, Morrissey, & Farkas, 1998; Garber, Roeder, Davidson, Pumfrey, & Schelling, 1996; Lavelle, Hunt, & Kropf, 1995; O’Grady, Monahan, Bailey, Allen, Buckley, & Keane, 1998; Sherbeck, Wulf, Morgan, Tatum, Smith, & Williams, 1995). Recent reviews were written by Faustman, Chan, Shaefer, and Havens (1998) and Liu, Lanari, and Schaefer (1995). The major benefits of vitamin E supplementation relate
* Corresponding author. E-mail address: [email protected] (J.H. Houben).
to an improved colour stability and diminished lipid peroxidation of the final meat product. However, no attention has been paid to the effects of dietary enrichment with vitamin E on the quality of cured beef products, or the effects of illumination in combination with low-oxygen packaging during retail display of sliced products. Pasteurized (sliced) cured meat products are known to discolour during illuminated display. Discolouration is due to a combination of light and residual oxygen, which is present in both vacuum and modified atmosphere packages (Rikert, Bressler, Ball, & Stier, 1957; Trout, 1991). The predominant pigment responsible for the pink colour of pasteurized cured meat products is nitrosomyochrome. When exposed to light, even at very low oxygen tensions, the pigment is gradually oxidized to metmyoglobin, which imparts a certain greyness to the product surface. Residual nitrite
0309-1740/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0309-1740(01)00042-0
404
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
and (iso)ascorbate are major factors which help stabilize the colour of cured meat during exposure to light (Skibsted, 1992). It is not known what the effect of an increased level of vitamin E, which is especially important in the inhibition of lipid oxidation (Kitts, 1997), is on this process. Since beef production systems in The Netherlands have not been studied in this way, a project to examine the effects of vitamin E supplementation on the properties of beef and cured beef products was undertaken. Other articles describe the effects of such supplementation on drip loss of selected muscles (Hertog denMeischke, Smulders, Houben, & Eikelenboom, 1997), colour stability of fresh and aged beef (Eikelenboom, Hoving-Bolink, Kluitman, Houben, & Klont, 2000), and colour stability and lipid oxidation in freshly minced, lean and fat beef (Houben, Van Dijk, Eikelenboom, & Hoving-Bolink, 2000) or in minced, previously frozen lean beef with or without addition of an ascorbic acid preparation (Houben, Van Dijk, & Eikelenboom, 2000). This paper focuses on the quality of pasteurized beef ham prepared from bulls fattened on diets supplemented with vitamin E. Hams were sliced and packaged under vacuum or in low-oxygen modified atmosphere packs and their shelf-life was determined during retail display.
2. Materials and methods 2.1. Feeding experiments Forty young bulls from a PiemonteseHolstein Friesian cross were fattened at the Institute for Animal Science and Health at Lelystad. At 12 months of age, the animals were assigned to treatment groups of twenty animals. During the last 136 days before slaughter, the cattle received different diets. The vitamin E-supplemented group (SUP) received 2025 mg vitamin E (DLa-tocopheryl acetate) head 1 day 1 in the form of a premix (Rovimix E-50 SD, Roche Nederland) added to the concentrate. The control group (CON) received a similar diet (corn silage and concentrate), except that no extra vitamin E was added to the concentrate. Further details of the feeding experiments and slaughter of the animals are given in Eikelenboom et al. (2000). 2.2. Manufacturing, packaging, and display of the pasteurized beef hams After approximately 48 h of chilling (initial chilling: 2 h at 0 C, followed by 46 h at 2–3 C), the carcases were cut and various muscles and meat pieces were collected from the same carcass sides, packaged, and stored at 23 C. Six days after slaughter, the membranes and superficial fatty tissue were removed from the Mm.
semitendinosus of eight randomly selected animals per dietary group, and the Mm. semitendinosus were processed into pasteurized hams (Szmanko, Duda, & Kosna 1989). Such hams are traditionally pork products. However, recently comparable products made from beef hindquarter muscles have appeared on the market in The Netherlands. To our knowledge, these hams and ‘‘Spiced Beef’’-type products are the only cured, pasteurized beef products made up of intact muscle. With a Retus Inject-O-mat type 15 multi-needle injector 15% (m/m) brine was evenly distributed over the individual muscles. The composition of the brine (in% m/m) was colorozo-salt 12.0 (= common salt containing 0.6% m/m NaNO2), injection brine phosphate (Instaphos) 3.3, glucose 3.3, mono-sodium glutamate 0.6, sodium ascorbate 0.3 and water 80.5. Injected muscles were coded, individually put in nets, massaged for 90 min in a meat tumbler (12 revolutions min 1), and vacuum packed. They were placed in a pear-shaped ham mould (5 l) equipped with a springloaded lid. The closed moulds were left overnight at 2 C to allow internal colour development. The next day the hams were pasteurized in a cooking cabinet (T-cook; T=25 C; maximum cabinet temperature 75 C, until a ham core temperature of 68 C was reached). Average P 70 10 was 34.1 min. After heating, the hams were cooled in running tap water to a core temperature of about 15 C and stored overnight at 2 C. The sixteen hams were sliced and packaged the next day in a commercial meat slicing plant. Ham slices (8 mm thick) were alternately packaged under vacuum (VAC) or in low-oxygen gas packs (referred to as FOG). The gas mixture contained about 50% CO2 and 50% N2. The volume ratio gas:product was approximately 1:2. The gas permeability of the vacuum-packaging material was < 7 cm3 O2 m 2 d 1 bar 1 measured at 23 C and a relative humidity of 75% and < 100 cm3 CO2 m 2 d 1 bar 1 measured at 23 C and a relative humidity 50% (the same material was used as the upper film of the FOG packs). Under the same test conditions, the gas permeability of the bottom film of the FOG-packs was < 5 and < 25 cm3 m 2 d 1 bar 1 for O2 and CO2, respectively. Duplicate samples of sliced ham for each product and packaging condition were placed on racks 44 cm away from sets of Philips TLD36W79 ‘‘meat’’lamps (colour temperature 3800 K) in a meat chilling room at 8 1 C. The illumination intensity on the surface of the meats was 578 lx (standard deviation 57 lx). Additional packs were displayed for bacteriological and chemical analyses. 2.3. Measurements during storage At intervals, the colour of meat on the light-side of the unopened packages was measured through the film in the chilling room.
405
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
Colour (CIELAB, L*, a* and b* values) was measured at three places per slice, using a Minolta Chromameter II (Minolta Inc., Osaka, Japan) equipped with a C-light source. The effective diameter of the measuring head was 53 mm. The instrument was calibrated against a vacuum-packaged white tile every 2 h of continuous measurements. At regular intervals three randomly selected packages per group were sampled on their illuminated side for microbiological analyses and measurement of 2-thiobarbituric acid (TBA) values. pH was measured at three sites per package with a Schott pH meter (type CG 818) equipped with an Ingold electrode. These packages were then discarded. The gas composition was measured in the modified atmosphere packages, which had to be opened for analytical purposes, with a Servomex 1420 Analyser (Servomex Ltd., Crowborough, UK). Illumination intensity was measured with a BBC Goertz Metrawatt MX4 instrument. 2.4. Methods of analysis
Table 1 Mesophilic aerobic counts (average log Ng 1 standard deviation; n=5) during display of packaged sliced hams at 8 Ca Period of storage (days)
CON VAC
SUP FOG
1.970.18
t=0
VAC 1.880.44
1.42 0.32 t=7
5.910.45
t=14
7.280.51
t=21
7.490.31
t=28
7.670.07
FOG 1.410.55
5.740.51 5.77 0.26
5.280.77 6.970.62
6.85 0.43
7.020.61 7.480.16
6.99b0.35
6.54a0.21 7.630.17
6.83 0.41
6.990.40
a Per horizontal line (possible diet effect) Student’s t-tests (two sided; P4 0.05) were performed. Different letters are presented when significant. CON, control, SUP, supplemented; VAC, vacuum; FOG, low-oxygen modified atmosphere packs.
Table 2 Numbers of lactic acid bacteria (average log Ng 1 standard deviation; n=5) during display of packaged sliced hams at 8 Ca
Moisture content was determined according to ISO/ 1442 guidelines (ISO, 1973), protein content according to Gru¨ndig (1994), fat content according to the Fosslet method (method 24.007/24.008; AOAC, 1980), ash content according to ISO/R936 guidelines (ISO, 1969), vitamin E content according to AFNOR (1997), and TBA values according to Raharjo, Sofos, and Schmidt (1992). Mesophilic aerobic bacteria were counted on Plate Count Agar (American Public Health Association) after the pour plates had been incubated for 3 days at 30 C. Lactic acid bacteria were counted on De Man Rogosa Sharpe agar after the pour plates had been incubated for 3 days at 25 C under anaerobic conditions.
Period of storage (days)
3. Results and discussion
Williams (1994) also observed that cooking dietary enriched beef muscles did not affect the vitamin E content. The CO2 content of the FOG packages was on average 46%; the O2 content was consistently below the level of detection (< 0.1%).
3.1. Composition of the ham and of the gas in the FOG packages The gross chemical composition of duplicate samples of hams from both groups of animals was very similar. The hams contained on average (in% m/m): moisture 74.1, protein 21.6, fat 1.8 and ash 2.8. The vitamin E content (mean and standard deviation; n=6) was 2.3 0.10 mg kg 1 and 4.6 0.27 mg kg 1 for CON and SUP samples, respectively. Pasteurization did not affect the vitamin E concentrations (levels assessed for various raw meats are presented by Eikelenboom et al. (2000) and Houben, Van Dijk, Eikelenboom, and Hoving-Bolink (2000); Houben, Van Dijk, and Eikelenboom (2000). Liu, Scheller, Schaefer, Arp, and
CON VAC
SUP FOG
2.311.07
t=0
VAC 1.410.62
1.13 b
1.71 0.80 5.840.25
t=7
5.230.55 5.90 0.15
t=14
6.870.38
t=21
7.090.37
t=28
7.140.32
5.560.78 6.500.57
6.89 0.43
6.490.52 6.840.33
7.20b0.34
b
6.75a0.21 7.170.32
7.02 0.38 a
FOG
7.030.51
See respective footnote to Table 1 Some counts below limit of detection.
3.2. Microbiological analyses and pH of products Mesophilic aerobic organisms (Table 1) and lactic acid bacteria (Table 2) had similar growth patterns in hams from the two dietary groups. This is in agreement with published data for vitamin E dietary-enriched, otherwise uncured (minced) beef (Cabedo et al., 1998; Chan, Hakkarainen, Faustman, Schaefer, Scheller, & Liu, 1995; Houben, Van Dijk, Eikelenboom, & HovingBolink, 2000; Houben, Van Dijk, & Eikelenboom, 2000).
406
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
After storage for 28 days there were on average 3107 CFU g 1 of mesophilic aerobic organisms. Lactic acid bacteria were the dominant microorganisms present. Although the colour of a product may be affected by the number of organisms present, no direct information on the effect of lactic acid bacteria anaerobically growing actively on the colour of cured meat products in intact packages was found in the literature. The redness of sliced, pasteurized pork ham, packaged in low-oxygen modified atmosphere was found not to be affected by the presence of aerobic microorganisms in numbers higher than 108 CFU g 1 (Møller, Jensen, Olsen, Skibsted, & Bertelsen, 2000). Since Møller et al. did not detect Brochothrix thermosphacta, lactic acid bacteria were probably the main species present (Davies et al., 1999; Holley, 1997; Silla, 1985). Hence, we may assume that the effect of actively growing lactic acid bacteria on the colour of anaerobically packaged cured meats will probably be small. The mean pH of the hams decreased from 5.95 in the fresh product to 5.76 after 28 days of display (P < 0.05). The mean pH was the same for hams from both dietary groups. The decrease in pH was probably caused by lactic acid released by the growing lactic acid bacteria. 3.3. Lipid oxidation Lipid peroxidation was stable throughout the storage period: there was less than 0.04 mg malonaldehyde kg 1 freshly sliced ham and this concentration remained below 0.07 during the 28 days of storage. In this low range, TBA measurements are unreliable. It should be remembered that these are low-fat, cured entire-muscle products, packaged after slicing in an oxygen-free atmosphere. Moreover, the additives nitrite and ascorbic acid usually contribute to the inhibition of lipid oxidation in meat products (Arendt, Skibsted, & Andersen, 1997; Freybler, Gray, Asghar, Booren, Pearson, & Buckley, 1993; Kanner, 1994; Kitts, 1997). Dietary enrichment with vitamin E apparently had no extra delay on lipid oxidation, probably because the overall oxidative stress in this system is already very low. 3.4. Meat colour Meat colour measurements (L, a* and b* values) are presented in Fig. 1. The statistical analysis (SPSS/PC+) did not reveal significant differences between hams from the two dietary groups. We did not measure residual nitrite levels for practical reasons and considering the adequate colour stability of the final product the used amount of nitrite was appropriate for colour reasons. Redness values decreased (P < 0.01) during storage of the CON-VAC products, but only tended to do so in the SUP-VAC products. The a* values were significantly different at the end of the storage period and this dif-
Fig. 1. Lightness, redness and yellowness during display of packaged sliced hams at 8 C. Letters C (P < 0.01) and s (P < 0.06) signify that differences were found between packaging treatments for CON and SUP products, respectively.
ference was related to the kind of packaging used. Redness was higher for FOG-packed hams than for VACpacked hams, irrespective of dietary group. The colour of the FOG-packed hams was very stable. A comparable stability of the redness component was observed by Møller et al (2000) for sliced pasteurized pork ham packaged in modified atmosphere at initial oxygen concentrations below 0.1%. We hypothesize that the residual oxygen concentration throughout the entire storage period was lower in the FOG packs than in the VAC packs, due to dilution of residual oxygen — initially remaining after the application of vacuum — by the supplied gas volume, and due to a decreased diffusion of oxygen through the otherwise identical foil as a consequence of a small pressure difference in/outside the packs during storage, which contributed to the better
J.H. Houben, A. van Dijk / Meat Science 58 (2001) 403–407
colour stability. No data on comparably packaged cured beef products were found in the literature.
Acknowledgements The authors gratefully acknowledge the enthusiastic interest and skilled assistance of G. Keizer, J.L.M. Tjeerdsma-van Bokhoven, A.A.M. Spanjer and D. Keuzenkamp. This study was partly financed by the Dutch Product Boards for Livestock, Meat, Poultry and Eggs (grant No. 94.1.20) and was supported by Roche Nederland B.V. (Mijdrecht), Boers Vleeswaren (Sint Michielsgestel) and Philips Lighting B.V. (Roosendaal). References AFNOR (Assocation Francaise de Normalisation) (1997). Animal feedstuffs—determination of vitamin E content in feedstuffs, vitamin mineral compounds and concentrates. Paris: AFNOR. AOAC (Assocation of Official Analytical Chemists), 1980. Official methods of analysis. Meat and meat products. Method 24.007. Determination of fat content. W. Horwitz, Washington. Arendt, B., Skibsted, L. H., & Andersen, H. J. (1997). Antioxidative activity of nitrite in metmyoglobin induced lipid peroxidation. Z. Lebensm. Unters. Forsch, 204(1), 7–12. Cabedo, L., Sofos, J. N., & Smith, G. C. (1998). Bacterial growth in ground beef patties made with meat from animals fed diets without or with supplemental vitamin E. Journal of Food Protein, 61(1), 36–40. Chan, W. K. M., Hakkarainen, K., Faustman, C., Schaefer, D. M., Scheller, K. K., & Liu, Q. (1995). Color stability and microbial growth relationships in beef as affected by endogenous a-tocopherol. Journal of Food Science, 60(5), 966–971. Davies, E. A., Milne, C. F., Bevis, H. E., Potter, R. W., Harris, J. M., Williams, G. C., Thomas, L. V., & Delves-Broughton, J. (1999). Effective use of nisin to control lactic acid bacterial spoilage in vacuum-packed bologna-type sausage. Journal of Food Protection, 62(9), 1004–1010. Eikelenboom, G., Hoving-Bolink, A. H., Kluitman, I., Houben, J. H., & Klont, R. E. (2000). Effect of dietary vitamin E supplementation on beef colour stability. Meat Science, 54(1), 17–22. Faustman, C., Chan, W. K. M., Schaefer, D. M., & Havens, A. (1998). Beef colour update: the role for vitamin E. Journal of Animal Science, 76, 1019–1026. Formanek, Z., Kerry, J. P., Buckley, D. J., Morrissey, P. A., & Farkas, J. (1998). Effects of dietary vitamin E supplementation and packaging on the quality of minced beef. Meat Science, 50(2), 203–210. Freybler, L. A., Gray, J. I., Asghar, A., Booren, A. M., Pearson, A. M., & Buckley, D. J. (1993). Nitrite stabilization of lipids in cured pork. Meat Science, 33(1), 85–96. Garber, M. J., Roeder, R. A., Davidson, P. M., Pumfrey, W. M., & Schelling, G. T. (1996). Dose-response effect of vitamin E supplementation on growth performance and meat characteristics in beef and dairy steers. Canadian Journal of Animal Science, 76(1), 63–72. Gru¨ndig, A. (194). Vergleichende stickstoffbestimmungen in fleischerzeugnissen. Fleischwirtsch, 74(2), 173–175. Hertog den-Meischke, M. J. A., Smulders, F. J. M., Houben, J. H., & Eikelenboom, G. (1997). The effect of dietary vitamin E sup-
407
plementation on drip loss of bovine Longissimus Lumborum, Psoas Major and Semitendinosus muscles. Meat Science, 45(2), 153– 160. Holley, R. A. (1997). Asymmetric distribution and growth of bacteria in sliced vacuum-packaged ham and bologna. Journal of Food Protection, 60(5), 510–519. Houben, J.H., Van Dijk, A., Eikelenboom, G., & Hoving-Bolink, A.H., 2000a. Effect of dietary vitamin E supplementation, fat level and packaging on colour stability and lipid oxidation in minced beef. Meat Science 55, 331–336. Houben, J.H., Van Dijk, A., & Eikelenboom, G., 2000b. Effects of dietary vitamin E supplementation, an ascorbic acid preparation and packaging on the quality of displayed minced lean beef. Meat Science (submitted for publication). ISO/1442, 1973. Meat and meat products. The determination of moisture content. ISO/R936, 1969. Meat and meat products. The determination of ash content. Kanner, J. (1994). Oxidative processes in meat and meat products: quality implications. Meat Science, 36, 169–189. Kitts, D. D. (1997). An evaluation of the multiple effects of the antioxidant vitamins. Trends Food Science Technology, 8, 198–203. Lavelle, C. L., Hunt, M. C., & Kropf, D. H. (1995). Display life and internal cooked color of ground beef from vitamin E-supplemented steers. Journal of Food Science, 60(6), 1175–1178, 1196. Liu, Q., Lanari, M. C., & Schaefer, D. M. (1995). A review of dietary vitamin E supplementation for improvement of beef quality. Journal of Animal Science, 73, 3131–3140. Liu, Q., Scheller, K. K., Schaefer, D. M., Arp, S. C., & Williams, S. N. (1994). Dietary a-tocopheryl acetate contributes to lipid stability in cooked beef. Journal of Food Science, 59(2), 288–290. Møller, J. K. S., Jensen, J. S., Olsen, M. B., Skibsted, L. H., & Bertelsen, G. (2000). Effect of residual oxygen on colour stability during chill storage of sliced, pasteurised ham packaged in modified atmosphere. Meat Science, 54, 399–405. O’Grady, M. N., Monahan, F. J., Bailey, J., Allen, P., Buckley, D. J., & Keane, M. G. (1998). Colour-stabilising effect of muscle vitamin E in minced beef stored in high oxygen packs. Meat Science, 50(1), 73–80. Raharjo, S., Sofos, J. N., & Schmidt, G. R. (1992). Improved speed, specificity and limit of determination of an aqueous acid extraction thiobarbituric acid-C18 method for measuring lipid peroxidation in beef. Journal of Agricultural Food Chemistry, 40, 2182–2185. Rikert, J. A., Bressler, L., Ball, C. O., & Stier, E. F. (1957). Factors affecting qualilty of prepacked meat II. Color studies. Effects of air and oxygen under different pressures upon color of product. Food Technology, 11, 625–632. Sherbeck, J. A., Wulf, D. M., Morgan, J. B., Tatum, J. D., Smith, G. C., & Williams, S. N. (1995). Dietary supplementation of vitamin E to feedlot cattle affects beef retail display properties. Journal of Food Science, 60(2), 250–252. Silla, H. (1985). Shelf-life of cured, cooked and sliced meat products. II. Influence of Lactobacillus. Fleischwirts, 65(2), 205–207. Skibsted, L. H. (1992). Cured meat products and their oxidative stability. In D. E. Johnston, M. K. Knight, & D. A. Ledward, The chemistry of muscle-based foods (pp. 266–286). Cambridge: The Royal Society of Chemistry. Szmanko, T., Duda, Z., & Kosna, D. (1989). Influence of freezing and frozen storage of smoked beef ‘‘hams’’ on selected quality characteristics. Fleischwirts, 69(1), 99–103. Trout, G. R. (1991). Prevention of colour defects in meat and meat products. Food Australia, 43(2), 54–56.