SEPPO LAHTINEN ABSTRACT

Transcription

1 PHYSICAL EFFECTS OF SALT MIXTURES IN MAYONNAISE SEPPO LAHTINEN Department of Food Chemistry and Technology University of Helsinki SF Helsinki 71, Finland Accepted for Publication January 8, 1985 ABSTRACT The physical effects of the substitution of Morton Lite Salt@ or mineral salt (65% NaC1,25% KCl and 10% MgS0,*7H2O by weight) for NaCl in mayonnaise were studied taking the different degrees of saltiness into consideration. The relative saltiness was determined to be 0.81 * 0.07 for Morton salt and 0.71? 0.07 for mineral salt as against 1.O% wiw of NaC1. Salt addition, but neither salt concentration nor salt type, affected the flow parameters of mayonnaise. Salt type had little effect in an industrial type of condiment. Morton salt, with no other additives in the emulsion, impaired the stability of mayonnaise. Saltiness had little or no influence on the rheological properties through the concentration. However, it was significant for stability. INTRODUCTION The most natural way to study the effects of salt mixtures in emulsions is to add the same salt concentration by weight to an emulsion. More intricate ways of investigating the effects of the ions are necessary for texture and stability modifying purposes ('Iblstoguzov et al. 1971; Whiting and Richards 1978; Sharma 1981; Lahtinen 1984). However, the taste and the saltiness of salt mixtures could indirectly affect the physical properties as much as do the salt concentration and the type of the ions. The total amount of salt needed to produce similar sensory properties is likely to be different in emulsions containing only NaCl and in emulsions containing a salt mixture. The effect of partial substitution of potassium and magnesium ions for sodium has been reviewed with regard to processed meats (Marsh 1983; Terrell1983), bakery products (Salovaara 1982; Marsh 19831, cheese, beverages, vegetables and fruits (Marsh 1983). Efforts have been made to ensure that neither the sensory, nor the physical properties of foods have changed very much during salt substitution. Consumers are often ac- Journal of Food Quality 9 (1986) All R' hts Reserved 0 Copyright 1986 by Food & Nutrition Press, ym., Westport, Connecticut 1

2 2 S. LAHTINEN customed to a certain viscosity range in commercial emulsions. The aim of the present study was to clarify the effects of NaCl and two salt mixtures on the physical properties of emulsions. These effects were compared after measuring the saltiness and stability and the flow characteristics of a mayonnaise containing the salts. MATERIALS AND METHODS Preparation of Emulsions Two emulsions were prepared as prescribed in the Finnish legislation on food additives (!Bible 1). The starch (acetylated distarch adipate) used was Instant Clearjel manufactured by Laing National Ltd. The Frimulsion 10, containing 50% locust bean gum and 50% guar gum, was a product of Cesalpinia spa, Bergamo, Italy. For the preparation of samples, the basic emulsions described in!bible 1 were divided into portions. The salts (Merck p.a.) were mixed into these portions to obtain samples differing from each other only in salt concentration and the type of salt mixture. NaCl and Morton Lite Salt@ (50% NaCl and 50% KCl w/w) or mineral salt (65% NaC1,25% KCl and 10% MgSO4-7H,O w/w) were used in the study. Mineral salt is a commonly used salt mixture in Scandinavia. The basic emulsion of mayonnaise was prepared with a blender according to the directions; the composition was as given in the literature (Bennett et al. 1968). Basic emulsion I1 was prepared adapting the above directions. The ph of the basic emulsions was Measurement of Flow Curves Six samples, each containing 0.85% or 1.45% w/w of one salt, were prepared from mayonnaise, and three samples, 1.0% w/w of salt in each, from basic emulsion 11. One sample of each emulsion was left without salt for comparison. In each case the samples of one emulsion were kept in a refrigerator for an equal period (two or three days). Two or three parallel measurements were conducted on the samples, all taken from fresh material. The measurements were done at a constant temperature of 20.0"C with the roughened MV I P coaxial cylinder assembly (mayonnaise) or the MV I assembly (emulsion 11) of the Haake Rotovisco RV3 viscometer. The rate of change in the continuously increasing shear rate was s-~ and the shear rate region was 0-70 s-l, assessed from reports on the

3 SALT MIXTURES IN MAYONNAISE 3 Table 1. Compositions of the basic emulsions used in the study Ingredients Amount in emulsion (% w/w) Emulsion I Emulsion I1 (mayonnaise) Soybean oil Egg yolk Milk powder (fat-free) Vinegar (3.25 %) (10 X ) Water (distilled) Sugar Mustard White pepper Starch Frimulsion OO stimuli associated with the oral evaluation of viscosity of fluid foods (Shama and Sherman 1973a, 1973b). The curves were recorded on a Honeywell 550 XY recorder. Twelve paired shear stress (7) and shear rate (D) values were calculated from the recorded curves, and the extrapolated yield values T,,( = bz) were calculated from the intercepts of the linear regressions of the Casson model fitted to the data

4 4 S. LAHTINEN The coefficients of consistency k and the flow behavior indices n of the Herschel-Bulkley equation T - To = kdn were then calculated from the linear regressions of In (T - TJ against In D. The significance of the differences between the means of the parallel measurements was tested statistically by one-way analysis of variance and Tukey's test. Sensory Evaluations The saltiness of Morton salt or mineral salt in mayonnaise was compared with that of NaCl in mayonnaise by the forced-choice paired comparison test two days after preparation. The five paired samples given in 'Pable 2, each pair containing 0.5% or 1.0% w/w NaCl and one of the two salt mixtures at some concentration, were randomized and served simultaneously for purposes of evaluation. The more salty sample was selected. The mixture concentration corresponding to 50% selections of both kinds was determined from the linear regression line from the percentage of NaCl that was more salty against the concentration of the salt mixture. The errors in the relative saltiness were calculated from the standard error of estimate divided by the regression coefficient (Doebelin 1976). The sensory evaluation was conducted by two panels, each with 20 members. All the panelists had previously participated in similar experiments but not on mayonnaise. Their ages ranged from 20 to 24. The day Table 2. Salt concentrations of the mayonnaise in paired comparison tests Concentration of NaCl Concentrations of Morton salt or mineral salt (% w/w) (% w/w) oo 0.25, 0.45, 0.65, 0.85, , 0.90, 1.10, 1.30, 1.50

5 SALT MIXTURES IN MAYONNAISE 5 preceding the actual evaluation was spent in training the panelists. Only female panelists evaluated the saltiness of Morton salt, whereas four males were included on the panel evaluating that of mineral salt. The sample was evaluated at a temperature of C. The panelists rinsed their mouths with warm, active carbon-filtrated water between each pair of samples. Stability Measurements Duplicate samples containing one of the three salts were prepared at each concentration (O.OO%, 0.85% and 1.45% w/w). Before dividing the portions, 0.1% sodium benzoate, 60 ppm actinedione, 120 ppb neomysine, 30 ppb chloramphenicol and 0.02% butylated hydroxyanisole (BHA) were added to the basic emulsion to provide protection against microbial and oxidative deterioration. The emulsion rating (ER) values were determined according to the procedure recommended by McDermott et al. (1981) five times during the period the samples were stored (four months at +35"C). To prevent moisture loss, the samples were kept in hermetically sealed glass containers, and the air in the storage space was kept saturated with pots of water. At each determination three parallel values were measured on each of the samples. Linear, exponential and power law regression were calculated from the data. The error in the mean value b of the regression coefficients b, and b, was calculated from where sh and % are the standard errors of b, and b, respectively. RESULTS AND DISCUSSION Rheological methods can be utilized in predicting the behavior of materials in food processing and in the mouth. This study was mainly concerned with sensory responses, and so the range of the shear rate was narrower than that often used in the industry. In mayonnaise, no difference was observed in the extrapolated yield values T~ (Rible 3). When 0.85% or 1.45% of any salt was added to the basic emulsion, the coefficient of consistency k was significantly (~~0.05) greater in all but one case than in the samples with no salt. However, no statistical differences in

6 Table 3. Mean values of the flow parameters of the Herschel-Bulkley model Emulsion I Emulsion 11 (mayonnai s e) Salt No salt NaCl Morton salt Mineral salt NaCl Morton salt Mineral salt NaCl Morton salt Mineral salt Variance ratio F n.s. 6.69* n.s. 29.9** n.s. n. s. The honestly significant difference ~ p LO. 01 (0.82) 14.0 'J 11 ~ ~ ~~ n.s.-not significant,*(p=s0.05), * *(pso.o1) 1) between NaCl and the other systems

7 SALT MIXTURES IN MAYONNAISE 7 coefficients k were observed between the samples containing the salts. In contrast, with 1.0% NaCl there was a significantly or highly significant (~~0.01) smaller yield value than with the other salts or when there was no salt in emulsion I1 (lbble 3). The coefficients of consistency k did not differ from each other in the statistical tests for this emulsion type. The Herschel-Bulkley model successfully described the flow characteristics of the emulsions. The coefficient of determination r2 in calculating regressions In (T-T~) against In D ranged from to with mayonnaise (except in one instance when it was 0.990) and from to with emulsion 11. Morton salt was observed to have a distinctly adverse effect on the stability of may onnaise. The linearized (logaritmic) form of the exponential model ER = ERo exp( - bt) clearly had the best fit to the data. According to this model, decay rates b two or three times higher were evident in mayonnaise containing Morton salt than in the other systems (?\able 4). On the basis of the errors calculated, differences in the values of b between NaCl and mineral salt were not significant and did not markedly differ from the values of samples with no salt in the mayonnaise. lhble 4. Mean values of the decay rates b of mayonnaise. The individual values calculated as regression coefficients of In ER = In ER, - bt were in all highly significant (~~0.001). The coefficients of determination r2 are given for the parallel samples Salt 6 concentration 4 (S w/w) (d x 10 ) 2 r No salt 1.45 NaCl Morton salt Mineral salt 0. a5 NaCl Morton salt Mineral salt a a a a

8 8 S. LAHTINEN Saltiness and sweetness are functions of concentration in the aqueous phase, and play an important part in the sensory properties of emulsions. The more oil dispersed in the emulsion, the stiffer the emulsion will be. A tight and stiff emulsion results in a mild flavor, but a weak emulsion can emphasize sweetness, tartness and saltiness, thereby making a poorly balanced flavor especially apparent (Weiss 1970). Ib ensure good flavor, the emulsion must therefore be tight, which means much oil but only a little water. If this is not possible the texture should be achieved with additives. Sensory evaluations indicated proportional calculated saltinesses of 0.72 k 0.11 and 0.81? 0.07, or 0.80 k 0.06 and of Morton salt or mineral salt in relation to 0.5% and 1.0% of NaC1, respectively (Fig. 1). This means that about 20-40% more Morton salt or mineral salt should be used to achieve the same saltiness in mayonnaise as achieved with NaCl. However, the results indicate that neither salt concentration nor salt type are important factors in the formation of rheological properties-as long as there is (a minimum concentration of, a salt in the emulsion ( Igble 3). So probably, no major immediate change in the rheological properties can be expected on substituting other cations for part of the sodium in the basic type of mayonnaise. The stability, and hence the rheological properties, may be restricting factors in the substitution if Morton salt is used instead of NaCl in mayonnaise. The higher the concentration, the greater was the adversing effect of Morton salt (able 4). Therefore, if equal saltiness is the object of the substitution, it should be remembered that the difference in the saltiness has a considerable impact on stability through the concentration. The results do not exclude the possibility of greater changes in the physical properties of emulsions of some other composition. In commercial products the gelation of texture modifying agents by ions could possibly be utilized. However, before any utilization is worth considering, the bitter taste noted at the higher concentrations of the mixtures should be diminished. Even if there are technological advantages, but if the possible competitive status of dietetic emulsion is lost because of the different taste or saltiness, it is questionable whether the substitution is reasonable in mayonnaise and salad dressing emulsions. Nutritional motives are not relevant because of the negligible role of these foods in the diet. CONCLUSIONS Morton Lite Salt@ or mineral salt can apparently be successfully substituted for NaCl without adversely affecting the physical quality of may-

9 100 v) al m U 3.- rc 0 al 50 m ID 4- c Q) U L al n o 1.5 Concentration of Morton salt, O/O o 1.5 Concentration of Mineral salt, O/O FIG. 1. PERCENTAGES OF PANELISTS WHO CONSIDERED 0.5% (0) OR 1.0% (0) NaCl MORE SALTY THAN THE CONCENTRATION OF MORTON SALT OR MINERAL SALT USED Relative saltinesses of 0.72?0.11 or 0.81a0.07 (Morton salt) and 0.80?0.06 or 0.71? 0.07 (mineral salt) were calculated. cn m

10 10 S. LAHTINEN onnaise and some other emulsions, if certain precautions are taken. A somewhat lower or higher viscosity can, if necessary, be achieved with a small amount of additive; the same probably applies to stability. As to equal saltiness, a 38% decrease in added sodium can be achieved if Morton salt is substituted for 1.0% w/w of NaCl; a 9% decrease is achieved with mineral salt. In order to diminish the bitter taste, however, the saltiness should be lower than in the traditional product. Otherwise the taste should be masked, perhaps with an additive. REFERENCES BENNETT, H., BISHOP, J. L. Jr., and WULFINGHOFF, M. L Practical Emulsions. Vol 11. pp. 87, 88. Chemical Publishing Company, Inc., New York. DOEBELIN, E Measurement Systems. p. 57. McGraw-Hill International Book Co., Tokyo. LAHTINEN, S Effects of dietary salts on the rheological properties of food emulsions. Lebensm.-Wiss. Technol. 17, 299. MARSH, A. C Processes and formulations that affect the sodium content of foods. Food Technol. 37(7), 45. McDERMOTT, R. L., HARPER, W. J. and WHITLEY, R A centrifugal method for characterization of salad dressing emulsions. Food Technol. 35(5), 81. SALOVAARA, H Sodium chloride and its partial replacement with potassium chloride and some other salts in baking. D.Sc. Dissertation, University of Helsinki, EKT series 627. SHAMA, F. and SHERMAN, P. 1973a. Identification of stimuli controlling the sensory evaluation of viscosity. 11. Oral methods. J. Texture Studies, 4, 111. SHAMA, F., and SHERMAN, P Variation in stimuli associated with oral evaluation of the viscosities of glucose solutions. J. Texture Studies 4, 254. SHARMA, S.C Gums and hydrocolloids in oil-water emulsions. Food Technol. 35(1), 59. TERRELL, R.N Reducing the sodium content of processed meats. Food Technol. 37(7), 66. TOLSTOGUZOV, V.B., BRAUDO, E.E. and MIKHEEVA, N.V [Method for obtaining food emulsionsl. U.S.S.R. Patent 303,819, WEISS, T.J Food Oils and Their Uses. p AVI Publishing Co. Westport, Conn. WHITING, R. C. and RICHARDS, J. F Influence of divalent cations on poultry meat emulsions and sausages. J. Food. Sci. 43, 312.