Stabilization of meat lipids with nitrite-free curing mixtures

Meat Science 22 (1988) 73-80

Stabilization of Meat Lipids with Nitrite-Free Curing Mixtures

Fereidoon Shahidi Department of Biochemistry, Memorial University of Newfoundland, St John's, Newfoundland, Canada A1B 3X9

Leon J. Rubin Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A4

&

Darrell F. Wood Stange Canada, Inc., 3340 Orlando Drive, Mississauga, Ontario, Canada L4V 1C7 (Received 20 November 1987; accepted 18 January 1988)

ABSTRACT Several nitrite-free meat-curing mixtures have been formulated. The mixtures included salt, sugar, ascorbates, an antioxidant and/or a chelator, an antimicrobial agent and dinitrosyi ferrochemochrome (DNFH). They imparted to meat a similar oxidative stability as that of sodium nitrite. Butylated hydroxyanisole and t-butylhydroquinone were the best antioxidants and polyphosphates, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid were the superior chelators. The antimicrobial agents used were potassium sorbate, propryl paraben, fumarate esters and sodium hypophosphite. In the above mixtures, the added effect of ( D N F H ) on 73 Meat Science 0309-1740/88/$03"50 © 1988 Elsevier Applied Science Publishers Ltd, England. Printed in Great Britain

74

Fereidoon Shahidi, Leon J. Rubin, Darrell F. Wood oxidative stability of the cooked meats was similar to the added effect of 150ppm sodiun nitrite.

INTRODUCTION Current meat-curing practice involves the addition to meat of nitrite, and sometimes nitrate, as well as salt, ascorbate or erythorbate, with or without carbohydrate materials, phosphates, and possibly seasonings. Nitrite in meat is responsible for the development of the typical cured-meat colour and flavour and functions as an antioxidant (Shahidi et al., 1984). Also, nitrite is an effective preservative in general, and particularly against the growth and toxin formation of Clostridium botulinum in meats (Pierson & Smoot, 1982). Unfortunately, nitrite also has some serious disadvantages. It forms carcinogenic N-nitrosamines in meat, particularly bacon, in the parts per billion range. On ingestion it may cause formation of N-nitrosamines in the stomach (Wishnok, 1977). It has recently been reported that nitrite enhances the carcinogenic action of N-nitroso-N-methylbenzylamine in the production of esophageal tumors (Schweinsberg & Burkle, 1985). Therefore, it is desirable to find a suitable substitute for nitrite in the preparation of curedmeat products. Our approach has been to develop a multi-component system in which individual constituents are used to reproduce the colour and flavour imparted by nitrite, and to reproduce its antioxidant and antimicrobial effects. To reproduce the typical cured-meat colour, dinitrosyl ferrohemochrome, the so-called 'cooked cured-meat pigment', was prepared from hemin extracted from beef red blood cells (Shahidi et al., 1985). The cured-meat flavour and antioxidant effect of nitrite were reproduced by the addition of antioxidants and/or chelators. These included polyphosphates, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, butylated hydroxyanisole, t-butylhydroquinone, ascorbates or their fat-soluble derivatives such as ascorbyl palmitate and ascorbyl acetal (Shahidi et al., 1986, 1988a). Several combinations of these chemicals were found that gave meat products a flavour which, in preliminary experiments, had a similar acceptability to that produced by sodium nitrite (Shahidi et al., 1987c; Yun et al., 1987). Microbiological safety of the products was best ensured by addition of sodium hypophosphite or potassium sorbate (Wood et al., 1986). In this paper we report on the antioxidant activity of several nitrite-free meat-curing mixtures consisting of DNFH, an antioxidant and/or chelator, and an antimicrobial agent, as well as salt and ascorbate. The antioxidant activity of some of the individual components of these mixtures has already been reported (Shahidi et al., 1987a, b).

Stabilization of meat iipids with nitrite-free curing mixtures

75

MATERIALS A N D METHODS Materials and methods used in this study were essentially similar to those reported previously (Shahidi et al., 1987a, b). The meat, pork loin, was deboned and trimmed to remove most of the surface fat. It was then ground twice using an Oster meat grinder, model 990-68 (0-48 cm plate). Chemicals were added directly to the meat followed by the addition of 20% by weight of distilled water. The mixture was then thoroughly homogenized in a blender. The samples were cooked in a beaker, placed in a thermostated water bath for about 40 min, to an internal temperature of 75 + I°C. They were then mixed well and stored in plastic bags at 4°C until use. Their fat and moisture contents were determined as previously described (Shahidi et al., 1987a). TABLE 1 Effect of Pickle Ingredients on the TBA Numbers of Cooked Meat a

Experiment number

Additives

Storage time at 4°C (days) 1

1 2 3 4 5 6 7 8 9 l0 11 12 13 14 15 16 17 18 19 20 21 22 23 24

No additive NaCI (2%) Sucrose (1"5%) Ascorbic acid (500ppm) Erythorbic acid (500ppm) SA(550ppm) Ascorbylpalmitate(1000ppm) Ascorbylacetal(1000ppm) STPP(3000ppm) SPP(3000ppm) SHMP(3000ppm) Na2EDTA(500ppm ) DTPA(500ppm) BHA(30ppm) BHT(30ppm) PG(30ppm) TBHQ(30ppm) NaNO2(150ppm) DNFH(12ppm) SHP(3000ppm) K Sorbate (2600ppm) Propyl paraben(3000ppm) Monoethyl fumarate (1250ppm) Dimethylfumarate(1250ppm)

4.39 7.04 5'61 1.63 1.53 1-98 0.34 0-47 0.31 0"35 1-41 0-31 0"29 0-25 2.31 1.07 0-32 0.50 0-39 5.54 7"21 4.12 4.02 4.79

7

14

21

28

35

11'41 11"00 13-28 13"76 15"46 11'36 11"06 12"40 14"60 15"75 10'36 11.05 - - 12"83 - 5 . 4 5 5'39 5'81 7.01 - 5 . 8 9 5.67 5.65 7.80 - 5 . 7 3 7.32 7.40 7.12 8.23 0.85 0.48 0.63 0.72 1-06 0.90 0"68 0-55 0.63 1.27 0 - 5 8 0.90 1.05 1.39 2.07 0"32 0-39 0.48 0.69 1.13 3.46 4.70 6.00 7.88 8.78 0.64 0.71 0-86 0.90 0.96 0.38 0"33 0-34 0-33 0"36 0"43 if50 0"46 0"59 0-44 4 . 4 1 4.17 4.30 4.13 4.31 2.66 2.79 2.68 2.66 3.03 0.58 0"30 0-38 0-40 0"35 0.55 0"58 0.58 0.60 0-63 8.10 7.32 9"64 9.08 9.89 9.54 9.92 11.47 12.43 12-08 9"79 10"61 9-04 9"49 10-07 10-48 10.44 11.48 13-12 13.89 8.10 8"18 8.41 9.73 10.10 6.98 6.99 7.18 8.14 10.41

a Cooked meat samples contained 10"67 + 0"13% fat and 70"05 + 0-20% moisture.

76

Fereidoon Shahidi, Leon J. Rubin, Darrell F. Wood TABLE 2

Effect of Several Meat-Curing Mixtures on the TBA Numbers of Cooked Meat ° Experiment number

Additives

Storage time at 4°C(days) 1

3 4 5 6 7 8 9 10 I1 12 13 14 15 16 18 19 20

No additive (15%) NaC1 (2%) + Sucrose (1'5%) + SA (550ppm) (2)+STPP(3000ppm) (2)+DNFH (12ppm) (3)+DNFH(12ppm) (3)+NaNOe(150ppm) (5)+SHP(3000ppm) (7) but 1 500ppm STPP and SHP (5)+K Sorbate (2600ppm) (7), but SHMP (3000ppm) for STPP (7), but SPP (3000ppm) for STPP (7), but Na2EDTA (500 ppm) for STPP (7), but DTPA (500ppm) for STPP (7), but Ascorbyl Palmitate (1000ppm) forSA (7), but Ascorbyl Acetal (1000ppm) for SA (7)+BHA(30ppm) (7)+PG (30ppm) (7)+TBHQ(30ppm) (7)+BHT(30ppm)

7

14

21

28

35

4.95 8.96 lff50 11.67 12.12 13.73 1.35 0.58 0'59 0.24 0.38 0.27 0"30 0.64 0"38 0"33 0.40 0.51

7.74 0.53 6.81 0.35 0.40 0.34 0.35 0.53 0-27 0-30 0"76 0.31

8.46 0.51 8.66 0.34 0"35 0.36 0.37 0.74 0'33 0'29 0'36 --

8.64 0-66 -0.37 0"36 0.33 0.39 0.46 0'49 0'35 0'78 0'53

- - 15.93 0-86 1.32 0.37 0.45 0-50 0"50 - - 0"30 -0.51 -0-47 0"35 0"31 0"29 0"30 0"57 - 0.43 - -

0.15 0.22

0"23 0.27 0.38 0.22

0"27 0"28 0"22 0"22 0"22

0"22 0"24 0"21 0"20 0"19

0"26 0'27 0.16 0"20 0'20

0"25 0"27 0"37 0"22 0"31

0'26 0'38 0'23 0"21 0'28

0"27 0'28 0"39 0'21 0"56

a Cooked meat samples contained 10.60 + 0.11% fat and 69"93 + 0"10% moisture.

T h e additives used in this s t u d y were s o d i u m chloride, sucrose, ascorbic a n d e r y t h o r b i c acids, s o d i u m a s c o r b a t e (SA), a s c o r b y l palmitate, ascorbyl acetal, s o d i u m t r i p o l y p h o s p h a t e (STPP), s o d i u m p y r o p h o s p h a t e (SPP), s o d i u m h e x a m e t a p h o s p h a t e ( S H M P ) , d i s o d i u m salt o f e t h y l e n e d i a m i n e tetraacetic acid ( N a 2 E D T A ) , d i e t h y l e n e t r i a m i n e p e n t a a c e t i c acid ( D P T A ) , b u t y l a t e d h y d r o x y a n i s o l e (BHA), b u t y l a t e d h y d r o x y t o l u e n e (BHT), p r o p y l gallate (PG), t - b u t y l h y d r o q u i n o n e ( T B H Q ) , dinitrosyl f e r r o h e m o c h r o m e ( D N F H ) , s o d i u m h y p o p h o s p h i t e (SHP), p o t a s s i u m s o r b a t e ( K sorbate), p r o p y l p a r a b e n a n d m o n o e t h y l a n d d i m e t h y l fumarates. T h e i r a d d i t i o n levels are given in T a b l e s 1 a n d 2. T h e e x t e n t o f lipid o x i d a t i o n in the m e a t samples, after c o o k i n g (day 1) a n d after 7, 14, 21, 28 a n d 35 d a y s was e x a m i n e d b y the 2 - t h i o b a r b i t u r i c acid (TBA) p r o c e d u r e o f T a r l a d g i s e t al. (1960), as modified b y Shahidi e t al. (1987a).

Stabilization of meat lipids with nitrite-free curing mixtures

77

RESULTS AND DISCUSSION The TBA numbers (milligrams malonaldehyde equivalent per kg sample) of meat treated with the individual pickle ingredients used in this study are summarized in Table 1, using a factor of 8"1 for conversion of absorbance units to TBA numbers (Shahidi et al., 1987a). Results for the TBA numbers of meat samples treated with several nitrite-free meat-curing mixtures are given in Table 2. The values reported are averages of two or three determinations. The deviation from averages was less than 0.05 for TBA numbers of <0"96 and was not greater than 0.12 for the others. In general, the TBA numbers increased as the length of the storage period increased. However, for samples with an initial TBA number of less than 0.5 the increase was only marginal. Among the individual pickle ingredients reported in Table 1, only sodium chloride showed a marginal pro-oxidant activity at the level of 2%, particularly after cooking (day 1). Presence of metal-ion impurities in the NaC1, as well as direct oxidative action based on the reactivity of the chloride ion (Ellis et al., 1968) may account for this weak prooxidant effect. The effect of sucrose on the TBA numbers was small and the values were slightly lower than the control with no additives. This is consistent with the chemical nature of this compound. On the other hand, ascorbic acid, erythorbic acid, and sodium ascorbate reduced the TBA number of meat to less than half of that of the untreated meat after 3 to 4 weeks of storage (Shahidi et al., 1986). Ascorbyl palmitate and the acetal of ascorbic acid, which are fat soluble, have been shown to act as antinitrosamine agents for bacon (Sen et al., 1976; Bharucha et al., 1980). In this current study strong and comparable antioxidant activity was observed and the TBA numbers of meats cooked in the presence of these compounds was less than 1.5 after 5 weeks of storage at 4°C (Table 1). Sodium nitrite alone showed an acceptable antioxidant effect (i.e. TBA numbers of less than 1; Tarladgis et aL, 1960) only when added at a level of 150ppm (Table 1). The weak antioxidant activity of dinitrosyl ferrohemochrome has already been reported elsewhere (Shahidi et al., 1987a). Antimicrobial agents--sodium hypophosphite (SHP), potassium sorbate, propyl paraben, monoethyl and dimethyl fumarates--caused a slight decrease in the TBA numbers of meat (Table 1). While the antimicrobial properties of these reagents are well documented, no studies are available in the literature as to their effect on lipid oxidation. The effect of sodium tripolyphosphate (STPP), sodium pyrophosphate (SPP), sodium hexametaphosphate (SHMP), disodium salt of ethylenediaminetetraacetic acid (Na2EDTA) on the TBA numbers has already been reported (Shahidi et al., 1986), and their activity has been related to

78

Fereidoon Shahidi, Leon J. Rubin, Darrell F. Wood

their ability to sequester metal ions, as well as perhaps to other more specific interactions. Although sodium ascorbate showed antioxidant properties (Table 1), in the presence of sodium chloride and sucrose, this effect was observed only during the first 3 weeks of storage, and then the prooxidant effect of sodium chloride perhaps appeared to overcome the antioxidant effect of sodium ascorbate (Table 2). Addition of dinitrosyl ferrohemochrome (DNFH) to this mixture resulted in further reduction of TBA numbers as expected from the antioxidant effect produced by this pigment. Replacement of sodium ascorbate with its fat-soluble analogues, ascorbyl palmitate and ascorbyl acetal, greatly reduced the TBA numbers during the 5-week storage period (Table 2). Addition of STPP to meats containing sodium chloride, sucrose, and ascorbate also appreciably reduced the TBA numbers, showing strong synergism with sodium ascorbate (Table 2). Addition of DNFH to meats containing sodium chloride, sucrose, sodium ascorbate, and STPP had a significant effect on the TBA numbers, and reduced them by a factor of 3 after a 5-week storage period. Addition of SHP or potassium sorbate to the above nitrite-free compositions did not alter the TBA numbers to any appreciable extent. A decrease in the addition level of both STPP and SHP from 3000 to 1500 ppm resulted in a marginal increase in TBA numbers to 0-51 after 5 weeks of storage. While SHMP alone played a minimal antioxidant role in meat (Table 1), it significantly reduced the TBA numbers in the meat system containing sodium chloride, sucrose, sodium ascorbate, and DNFH (Table 2). This indicates a strong synergism of SHMP and sodium ascorbate in the above mixture (Shahidi et al., 1987b). Replacement of STPP with Na2EDTA or DTPA was equally successful; however, this is mainly due to the overwhelming effect of these chelators themselves in controlling lipid oxidation(Table 1). Although the addition of BHA, TBHQ, or sodium nitrite (25 and 50 ppm) to systems containing sodium chloride, sucrose, sodium ascorbate, STPP, and DNFH had a minimal further effect on the TBA numbers (Table 2), there is an indication that they may improve the flavour acceptability of cooked 'cured' meats (Yun et al., 1987). The appearance of all of the nitrite-free meat-curing mixtures containing sodium chloride, sucrose, sodium ascorbate or one of its related compounds, an antioxidant and/or a chelator, an antimicrobial agent, and DNFH was identical to that of nitrite-cured meats, i.e. bright pink in colour. A recent study has shown that their microbial stability was also similar to that of their nitrite-cured counterparts (Wood et al., 1986), especially for sodium hypophosphite.

Stabilization of meat lipids with nitrite-free curing mixtures

79

CONCLUSION Several nitrite-free meat-curing mixtures have been shown to give meat similar quality characteristics as those of nitrite-cured meat. The mixtures studied included sodium chloride, sucrose, ascorbates, an antioxidant and/or a chelator, an antimicrobial agent, and DNFH. The ascorbates may be sodium ascorbate, ascorbyl palmitate, or ascorbyl acetal. The best antioxidants were BHA or TBHQ, and the best sequestrants were polyphosphates, Na2EDTA, or DTPA. The antimicrobial agents tested were sodium hypophosphite, potassium sorbate, propyl paraben, or fumarate esters. The quality characteristic which was specifically checked for in this paper was oxidative stability. In the above mixtures the additive effect of D N F H on oxidative stability of the meat systems was similar to the additive effect from 150ppm of NaNO2. Thus, the systems examined here have the colour, oxidative stability, and presumably flavour acceptability, and microbial stability which are imparted by nitrite to cured-meat products.

ACKNOWLEDGEMENTS This work was supported, in part, by Agriculture Canada through contract number 0151-1-1429. Technical assistance of N. Kassam and J. Brooker is highly appreciated.

REFERENCES Bharucha, K. R., Cross, C. K. & Rubin, L. J. (1980). J. Agric. FoodChem., 28, 1274. Ellis, R., Currie, G. T., Thronton, F. E., Bollinger, N. C. & Gaddis, A. M. (1968). J. Food Sci., 33, 555. Pierson, M. D. & Smoot, L. A. (1982). CRC Critical Reviews in Food Science as Nutrition, CRC Press, 10, 141. Sen, N. P., Donaldson, B., Seaman, S., Iyengar, J. R. & Miles, W. F. (1976). J. Agric. Food Chem., 24, 397. Shahidi, F., Rubin, L. J., Diosady, L. L., Chew, V. & Wood, D. F. (1984). Can. Inst. Food Sci. Technol. J., 17, 33. Shahidi, F., Rubin, L. J., Diosady, L. L. & Wood, D. F. (1985). J. Food Sci., 511,272. Shahidi, F., Rubin, L. J., Diosady, L. L., Kassam, N., Li Sui Fong, J. C. & Wood, D. F. (1986). Food Chem., 21, 145. Shahidi, F., Rubin, L. J. & Wood, D. F. (1987a). J. Food. Sci., 52, 564. Shahidi, F., Rubin, L. J. & Wood, D. F. (1987b). Food Chem., 23, 151. Shahidi, F., Yun, J., Rubin, L. J. & Wood, D. F. (1987c). Can. Inst. FoodSci. Technol., J., 20, 104.

80

Fereidoon Shahidi, Leon J. Rubin, Darrell F. Wood

Schweinsberg, F. & Biirkl¢, V. (1985). J. Cancer Res. Clin. Oncol., 109, 200. Tarladgis, B. C., Watts, B. M., Younathan, H. T. & Dugan, Jr, L. R. (1960). J. Am. Oil Chemists' Soc., 37, 44. Wishnok, J. S. (1977). J. Chem. Educ., 54, 440. Wood, D. S., Collins-Thompson, D. L., Usborne, W. R. & Picard, B. (1986). J. Food Protec., 49, 691. Yun, J., Shahidi, F., Rubin, L. J. & Diosady, L. L. (1987). Can. Inst. FoodSci. Technol. J., 20, 246.