DETERMINATION OF CURED MEAT PIGMENTS ON THREE CURED BEEF MUSCLES

Transcription

1 DETERMINATION OF CURED MEAT PIGMENTS ON THREE CURED BEEF MUSCLES (Pengukuran Pigmen Daging pada Tiga Jenis Daging Sapi) RENY DEBORA TAMBUNAN Balai Pengkajian Teknologi Pertanian Lampung, Jl. Hi. Z.A. Pagar Alam No. 1a, Rajabasa, Bandar Lampung ABSTRAK Pengukuran kadar pigmen daging pada 3 jenis otot sapi yang dicuring telah dilakukan di Laboratorium Fakultas Peternakan, University of the Philippine Los Banos, Filipina. Otot-otot sapi tersebut (adductor, longissimus dorsi dan semimembranosus) digunakan untuk analisa NaCl, NaNO2, dan untuk pengukuran pigmen daging curing. Sebelum digunakan untuk analisa, otot daging tersebut digiling menjadi partikel yang lebih kecil. Untuk setiap otot, setiap analisa diulang sebanyak 6 kali. Data yang diperoleh kemudian dianalisa secara deskriptif. Hasilnya menunjukkan bahwa otot longissimus dorsi memiliki kadar NaCl tertinggi (7,65%) sedangkan otot semimembranosus memiliki persentase terendah (7,38%). Otot semimembranosus memiliki sisa nitrit tertinggi (88,52 ppm) sedangkan otot longissimus dorsi memiliki sisa nitrit terendah (33,99 ppm). Otot adductor memiliki kadar nitroso pigmen tertinggi (144,28 ppm) sedangkan otot longissimus dorsi memiliki kadar terendah (114,41 ppm). Selain itu, otot adductor juga memiliki persentase konversi tertinggi (87,28%) sedangkan otot semimembranosus memiliki persentase terendah (36,26%). Secara umum, perbedaan tipe serabut otot dan kandungan myoglobin menyebabkan perbedaan hasil ini. Kata Kunci: Daging Curing, Daging Sapi, Pigmen Daging ABSTRACT The determination of cured meat pigments on three cured beef muscles were conducted in the Laboratory of Animal Science, University of the Philippine Los Banos, Philippines. The three cured beef muscles (adductor, longissimus dorsi and semimembranosus muscle) were used for sodium chloride analysis, sodium nitrite analysis, and for determination of cured meat pigments. Before used for analyses, these cured beef muscles were grounded into smaller particles. In each muscle, each analysis was repeated six times. Data collected then analyzed descriptively. Results showed that longissimus dorsi muscle had the highest sodium chloride content (7.65%) while semimembranosus muscle had the lowest content (7.38%). Semimembranosus muscle had the highest residual nitrite (88.52 ppm) while longissimus dorsi muscle had the lowest content (33.99 ppm). Adductor muscle had the highest nitroso pigments content ( ppm) while longissimus dorsi muscle had the lowest content ( ppm). Adductor muscle had the highest percent conversion (87.28%) while semimembranosus muscle had the lowest conversion (36.26%). Generally, differences in type of muscle fiber and myoglobin content caused the differences in the sodium chloride content, sodium nitrite content, total pigment, nitroso pigments and percent conversion between muscle/meat. Key Words: Cured Meat, Beef, Meat Pigments INTRODUCTION Long before packing establishments were developed, it had been found that cuts of meat could be preserved by treating them with a salt solution or by packing them in dry salt. Salt inhibited spoilage by reducing the amount of water available for microbial growth. However, it was found that high concentrations of salt could promote the formation of an unattractive gray color within the lean muscle. Consequently, the use of nitrate to "fix" the red color evolved. The use of nitrate most likely evolved by accident, because potassium nitrate (saltpeter) was most likely present as an impurity in the salt (BENJAMIN and COLLINS, 2003). From this, early meat processors learned that when nitrate is present, the meat developed a bright reddish color. It is from these meager 81

2 beginnings that the cured meat industry evolved. While the benefits of the curing process are well known, consumers and scientists have raised questions about the safety and necessity of these substances over the past 30 years, especially since some studies in the 1970s associated certain preservatives with cancer in laboratory animals, while other later studies suggested an association between cured meat consumption and illnesses in children. One of the substances of concern was the preserving agent known as sodium nitrite. Since a primary purpose of curing meat is to develop an attractive and stable color in processed products, it is necessary to know the concentration and stability of the cured meat pigments (total pigment and nitroso pigment). MATERIALS AND METHODS The determination of cured meat pigments on three cured beef muscles were conducted in the Laboratory of Animal Science, University of the Philippine Los Banos. Preparation of cured meat samples The three cured beef muscles (adductor, longissimus dorsi and semimembranosus muscle) were used for sodium chloride analysis, sodium nitrite analysis, and for determination of cured meat pigments. Before used for analyses, 100 gram of each cured beef muscles were grounded into smaller particles. In each muscle, each analysis was repeated six times. Data collected then analyzed descriptively. Sodium chloride analysis Percent of sodium chloride was measured using the Volhard Method. 0.3 grams of meat sample was placed in a 250-ml Erlenmeyer flask; added 10 ml of 0.1 N silver nitrated solution and swirled continuously. After adding with 5 ml of concentrated nitric acid, this sample was boiled for 10 minutes and cooled. After cooling, the sample then filtered. The volume was then adjusted to 75 ml with distilled water, and then added 5 ml of 10% ferric ammonium sulfate indicator with shaking continuously while adding. This final solution was titrated with 0.1 N KCNS to a permanent fresh orange end point. % NaCl = (ml KCNS blank - ml KCNS sample x N KCNS x NaCl x Sample weight NaCl = Sodium nitrite analysis In sodium nitrite analysis, 1.0 g ground cured meat sample was placed in 50-ml beaker then added 40 ml hot water (80 C) and mixed thoroughly with stirring rods taking care to break all lumps. After mixing, this sample than transferred to 125-ml Erlenmeyer flask and diluted with hot water to 75 ml. The flask with sample was allowed to stand on water bath (80 C) for 2 hours with occasional shaking to break lumps. After cooling in tom temperature, cooled sample was filtered into 100-ml volumetric flask, diluted to volume with distilled water and then shake. This suitable aliquot (20 ml) then transferred to 50- ml volumetric. After 5 minutes, into aliquot was added 2.5 ml sulfanilamide reagent and mixed. After another 5 minutes, was added into it 2.5 ml NED reagent and mixed. The volume of solution then adjusted with distilled water and mixed thoroughly. After 15 minutes of color development, the absorbance at 540 mµ was measured with a spectrophotometer. The sodium nitrite content of the solution was read from optical density concentration curve. Sodium nitrite in meat, ppm = A (50) (100) B (sample Wt.) Where: A = NaNO 2 content (micrograms) in the colored solution as read from the standard curve B = Volume in ml of aliquot used for color development 82

3 Determination of cured meat pigments In the determination of cured meat pigments, the total pigment, nitroso pigment, and % conversion were measured using Hornsey method (1956) with some modifications. Total pigment analysis In total pigment analysis, 10 grams sample was placed in 125-ml flask. To this flask then added 43 ml solvent (40 ml acetone and 3 ml concentrated HCl) and shake for 10 minutes. After twice filtration using Whatman No. 1 filter paper, % transmittance was measured at 640 mµ with a spectrophotometer. The absorbance and the amount of total pigment (ppm) were measured using calculations below. Optical density (absorbance) at 640 mµ = 2 log % transmittance Total pigment in ppm = Optical density x 680 Nitroso pigments analysis The procedures in nitroso pigment analysis were almost the same with the procedures in total pigment analysis, except for the solvent and the wavelength used in spectrophotometer. In this analysis, the solvent was 40 ml acetone and 3 ml distilled water and wavelength was 540 nm, while in total pigment analysis the solvent was 40 ml acetone and 3 ml concentrated HCl) and wavelength was 640 mµ. The absorbance and the amount of nitroso pigment (ppm) were measured using calculations below. Nitroso pigment in ppm = optical density x 290 % conversion = ppm nitroso pigment x 100 ppm total pigment RESULTS AND DISCUSSION Sodium chloride analysis Average percentages of Sodium Chloride (NaCl) content in different cured beef muscles were presented in Table 1 and Figure 1. Based on Table 1, longissimus dorsi muscle has the highest % NaCl (7.65%) while semimembranosus muscle has the lowest % NaCl (7.38%). It means that longissimus dorsi muscle absorbed more salt (NaCl) than other muscles (adductor and semimembranosus muscle). Differences in % NaCl of the muscles might be due to the differences in microscopic structure of the muscle. Longissimus dorsi muscle has small and very fine fibers than adductor and semimembranosus muscle. Besides that, the differences might be due to the differences in Water Holding Capacity (WHC) of the muscle. Based on the previous study, semimembranosus muscle has the lowest WHC (86.50%) than other muscles (adductor, 90.12% and longissimus dorsi muscle, 89.73%). It means semimembranosus muscle has more water (the structure was more watery because high drip loss) than other muscles. According to LAWRIE (1998), ground meat from muscles in which the structure was watery, had a poor absorption of salt. Moreover, apart from the salt concentrations of the brine (and the time of contact with the meat) and the microscopic structure of the musculature, various other factors affect the Table 1. Results on sodium chloride, sodium nitrite, total pigment, and nitroso pigment analyses in different cured beef muscles Muscle NaCl (%) NaNO2 (ppm) Total pigment (ppm) Nitroso pigments (ppm) % conversion Adductor Longissimus dorsi Semimembranosus

4 penetration of salt during curing. An increased temperature will increase the velocity of penetration. Sodium nitrite analysis The contents of sodium nitrite in the different cured beef muscles that still remain in the muscle were presented in Table 1 and Figure 1. These contents refer to the residual nitrite contents. Based on Table 1, semimembranosus muscle has the highest residual nitrite content (88.52 ppm) while longissimus dorsi muscle has the lowest content (33.99 ppm). These results were higher than result that reported by CASSENS (1997). According to him, modern-day cured meats at retail have a residual nitrite content of about 10 ppm because it decreases during product storage and distribution. The difference in residual nitrite content might be due to the length of time after curing process. In this study, the cured muscles were analyzed directly after curing process finished Figure 1. Graphics of % Sodium Chloride, Sodium Nitrite content, Total Pigment, Nitroso pigments and % conversion According to LEE et al. (1976); PRUSA and KREGEL (1985); and AHN and MAURER (1989), cured products prepared out of red muscle always contain more residual nitrite than those prepared out of white muscle from the same animal. This difference has been attributed to the higher ph found in red meat. LEE et al. (1976) reported that white muscle with a low ph produces a lower residual nitrite content than does red muscle with high ph from the same animal. Based on the previous study, it was indicated that semimembranosus muscle has the highest ph (6.0) while longissimus dorsi muscle has the lowest ph (5.5). Besides because of the type of muscle and ph, the difference might be due to the different function of the muscle, which then related to the myoglobin content, even though in this study the myoglobin content of muscles was not analyzed. According to MARQUEZ et al. (1995), it is likely that myoglobin play a more important role, in residual nitrite levels, when compared with ph. TOPEL et al. (1966) reported that semimembranosus muscle has higher myoglobin (4.05 mg/g of moisture and fat free lean) than has longissimus dorsi muscle (2.88 mg/g of moisture and fat free lean). Moreover, BRISKEY et al. (1960) reported that wide ranges exist in ultimate ph values, WHC and myoglobin concentrations between muscles because they apparently have different functions, sensitivities, workloads and chemical compositions. 84

5 Determination of cured meat pigments The procedure in cured meat pigments determination is based on the extraction of hematin from cured meat products in a wateracetone solvent. The moisture content of the meat sample is normally taken into account such that a calculated 80% acetone/water extraction results (KRAMLICH et al., 1973). Selective extraction as a nitric oxide-haemacetone complex is achieved by the use of an acetone/water solvent. Other meat pigments are not extracted under the conditions used. The acetone/water ratio is shown to be critical, maximum extraction being obtained with a ratio of 4 : 1, due allowance being made for the moisture present in the meat. With the inclusion of hydrochloric acid in the solvent, the method can be adapted to measure the total pigments present (HORNSEY, 1956). Total pigment analysis Replacement of 1 ml of water by 1 ml of concentrated hydrochloric acid in the solvent used, and keeping for 1 hour before filtering, gave a solution of acid haematin in the 80% acetone. This is composed of haematin derived from any uncombined pigments present, together with that resulting from the oxidation of the nitric oxide pigments. The optical density of this filtrate at 640 mµ is then measure of the total haem pigments present in the meat (HORNSEY, 1956). The overall concentration of pigments determines how red the meat appears. They can be measured by extracting them into solution, by acidified acetone (HORNSEY, 1956). This converts the pigments to acid haematin, which is measured at 640 nm. In general, higher myoglobin levels are found in the muscles of more active compared with sedentary animals, free-ranging compared with intensively-reared animals, and older compared with younger animals. A diet low in iron also leads to pale meat. The results in total pigment analysis of different cured beef muscles were presented in Table 1 and Figure 1. Semimembranosus muscle has the highest total pigment ( ppm) while longissimus dorsi muscle has the lowest total pigment ( ppm). It means semimembranosus muscle appear more red in color than adductor and longissimus dorsi muscle. In this study, all muscles have the levels above 140 ppm, where according to KRAMLICH et al. (1973) levels of about 100 ppm are considered a fair minimum for total pigments available for conversion and level above 140 ppm are very good. The difference between three muscles on total pigments may be due to the amount of myoglobin. Muscles to muscle differences in myoglobin content (and much of the variation among species) are due to the type of muscle fibers that are present. According to BOLES and PEGG (1999), fresh and cured meat color both depend on myoglobin, but are considerably different from each other in terms of how they are formed and their overall stability. Nitroso pigments analysis Nitroso pigments contents of different cured beef muscle were presented in Table 1 and Figure 1. Adductor muscle has the highest nitroso pigments content ( ppm) while longissimus dorsi muscle has the lowest content ( ppm). As in total pigment content, the difference in nitroso pigments content may be due to the difference in the type of muscle fibers that are present. The results in nitroso pigments content seem to disagree with the results on the total pigment determination. In this analysis, the tendencies of semimembranosus muscle to have higher nitroso pigments content because it has higher myoglobin content seem not occur. But there is a tendency of red muscles (adductor and semimembranosus muscle) to have higher nitroso pigments content than white muscles (in this study refer to longissimus dorsi muscle). % conversion Percent conversion is calculated on a theoretically possible 100% if all haematin can actually be converted to nitroso pigment (KRAMLICH, et al., 1973). Percent conversions of nitroso pigments to total pigment of different cured beef muscles are presented in Table 1. Adductor muscle has the higher percent conversion (87.28%) while 85

6 semimembranosus muscle has the lowest conversion (36.26%). The lowest percent conversion of semimembranosus muscle may be due to higher amount of total pigment content and low nitroso pigments content. In calculation of percent conversion, total pigment has a function as divisor factor. If the nitroso pigments content of the muscle relatively the same, the higher the total pigment content, the lower the percent conversion and the lower the total pigment content, the higher the percent conversion. CONCLUSIONS Longissimus dorsi muscle had the highest sodium chloride content (7.65%) while semimembranosus muscle had the lowest content (7.38%). Semimembranosus muscle had the highest residual nitrite (88.52 ppm) while longissimus dorsi muscle had the lowest content (33.99 ppm). Adductor muscle had the highest nitroso pigments content ( ppm) while longissimus dorsi muscle had the lowest content ( ppm). Adductor muscle had the highest percent conversion (87.28%) while semimembranosus muscle had the lowest conversion (36.26%). Generally, differences in type of muscle fiber and myoglobin content caused the differences in the sodium chloride content, sodium nitrite content, total pigment, nitroso pigments and percent conversion between muscle/meat. REFERENCES AHN, D.U. and A.J. MAURER Effects of added nitrite, Sodium Chloride, and Phosphate on Color, Nitrosoheme Pigment, Total Pigment and Residual Nitrite in Oven Roasted Turkey Breast. J. Poultry Sci. 68: BENJAMIN, N. and J. COLLINS Nitrite in Food Preservatives. 2 nd Edition. Edited by N.J. Russel and G.w. Gould. Kluwer Academic/ Plenum Publishers. New York. 380 p. BOLES, J.A. and R. PEGG Meat Color. Animal and Range Sciences, Montana State University, and Saskatchewan Food Product Innovation Program, University of Saskatchewan. BRISKEY, E.J., W.G. HOEKSTRA, R.W. BRAY and R.H. GRUMMER A comparison of certain physical and chemical characteristics of eight beef muscles. J. Anim. Sci. 19: HORNSEY, H.C The colour of cooked cured pork: I- Estimation of the nitric oxide-haem pigments. J. Food Agric. 7: KRAMLICH, W.E., A.M. PEARSON and F.W. TAUBER Processed Meats. The Avi Publishing Company, Inc. Westport, Connecticut. 348 p. LAWRIE, L.A Lawrie s Meat Science. Sixth Edition. Woodhead Publishing Limited. Cambridge England. 336 p. LEE, S.H., G. CASSENS and O.R. FENNEMA Effect of muscle type on residual nitrite in cured meat. J. Food Sci. 41: MÁRQUEZ, S.E, P. IZQUIERDO, L. RANGEL, A. ARCHILE and L.M. GARCÍA A Comparison Study of the Residual Nitrite in Cured Beef, Cured Beef and Cured Chicken Products. Rev. Fac. Agron. (LUZ) 12: PRUSA, K.J. and K.K. KREGEL Effect of muscle type and sodium tripolyphosphate on residual nitrite, ph, color, and instron measurement of turkey frankfurters. Poultry Science 64: TOPEL, D.G., R.A. MERKEL, D.L. MACKINTOSH and J.L. HALL Variation of some physical and biochemical properties within and among selected porcine muscles. J. Anim. Sci. 25: DISKUSI Pertanyaan : 1. Berapa banyak sampel yang digunakan untuk masing-masing bagian otot? 2. Berapa toleransi kadar NaNO2 yang dapat diterima untuk pengawetan daging? Apakah jenis ternak berbeda memerlukan toleransi kadar aman NaNO2? 86

7 Jawaban: 1. Untuk masing-masing bagian otot, sebanyak 100 g sampel otot daging dihaluskan. Setelah halus, untuk masing-masing analisa digunakan berat sampel yang berbeda, misalnya : untuk analisa Sodium Chloride (NaCl) digunakan 0,3 g sampel otot daging, analisa NaNO2 digunakan 1 gram sampel otot daging. Masing-masing analisa diulang sebanyak 6 kali untuk masing-masing sampel otot daging. 2. Menurut hasil penelitian beberapa ahli, batas maksimum penggunaan NaNO2 berbeda-beda tergantung metode curing yang digunakan (dry cured, immersion cured, massaged/pumped products) dan jenis produk yang dicuring (comminuted products (seperti sosis), bacon). Dosis maksimum penggunaan natrium nitrit yang diizinkan berdasarkan SNI pada sosis adalah 125 mg/kg daging, korned dalam kaleng 50 mg nitrit/kg daging, burger 125 mg/kg daging. Dalam Peraturan Menteri Kesehatan RI No.235/Men.Kes./VI/79 tentang Bahan Tambahan Makanan, ditetapkan bahwa konsentrasi nitrat (dalam bentuk garam natrium atau kalium) untuk mengawetkan daging dibatasi penggunaannya sampai 500 mg/kg bahan (daging), sedangkan untuk nitrit dibatasi sampai 200 mg/kg bahan. Konsumsi nitrit pada manusia dibatasi sampai 0,4 mg/kg berat badan per hari. Jenis ternak yang berbeda tidak memerlukan toleransi kadar aman NaNO2 yang berbeda, tetapi potongan karkas yang berbeda memerlukan toleransi kadar aman NaNO2 yang berbeda. Misalnya : untuk ham (paha), kadar NaNO2 tidak boleh lebih dari 156 ppm sedangkan untuk bellies (perut) sebesar 120 ppm karena bagian ini potensial terhadap pembentukan formasi nitrosamine yang bersifat karsinogenik. 87