Hue Linh Huynh, Robert Danhi, and See Wan Yan
Historically, fish sauce has been a standard condiment and ingredient in various Southeast Asian cuisines. Moreover, fish sauce imparts umami taste, which may enhance perceived saltiness in food. This quality suggests that fish sauce may be used as a partial substitute for sodium chloride (NaCl) in food preparation, which may present a valuable option for health-conscious and salt-restricted consumers. However, the degree to which NaCl can be decreased in food products without compromising taste and consumer acceptance has not been determined. We hypothesized that NaCl content in food may be reduced by partial replacement with fish sauce without diminishing palatability and consumer acceptance. Preparations of 3 types of food were assessed to test this hypothesis: chicken broth (n = 72); tomato sauce (n = 73); and coconut curry (n = 70). In the first session, the percentage of NaCl that could be replaced with fish sauce without a significant change in overall taste intensity was determined for each type of food using the 2-Alternative Forced Choice method. In the second session, subjects rated 5 samples for each food with varying NaCl and/or fish sauce content on 3 sensory attributes: deliciousness; taste intensity; and saltiness. Our results demonstrate that NaCl reduction was possible in chicken broth, tomato sauce, and coconut curry at 25%, 16%, and 10%, respectively, without a significant loss (P < 0.05) in deliciousness and overall taste intensity. These results suggest that it is possible to replace NaCl in foods with fish sauce without reducing overall taste intensity and consumer acceptance.
Keywords: consumer acceptance, culinary, fish sauce, sensory evaluation, sodium reduction
This study demonstrates that fish sauce may be used as a partial substitute ingredient for salt as a means to reduce sodium content in food without diminishing palatability. These results may aid chefs and food manufacturers in creating foods lower in sodium content to better meet the needs and expectations of consumers, healthcare providers, governmental organizations, and consumer advocacy groups without compromising taste. Consequently, using fish sauce as a partial replacement for salt in food preparations may be a delicious and creative alternative for many low sodium diets. Introduction Sodium chloride (NaCl) is a chemical compound that evokes the perception of saltiness (D¨otsch and others 2009). In food, this perceived level of saltiness significantly influences consumer food preferences (IOM 2010). Consequently, NaCl is a crucial component in diversifying the organoleptic profile of food because it reduces bitterness while enhancing saltiness, sweetness, and other desirable flavor effects (Keast and Breslin 2003). According to Ruusunen and Puolanne (2005), the functions of NaCl extend beyond the augmentation of flavor and texture, as it also has the practical ability to control the growth of microorganisms. Although the perception of saltiness and its effect on consumer’s dietary selections and preferences has been described, the understanding of the mechanism underlying sodium perception is still incomplete (Beauchamp and Stein 2008). While an appropriate level of sodium consumption is essential to the normal functions of the human body, the average current sodium intake far exceeds MS 20142012 Submitted 12/9/2014, Accepted 10/27/2015. Authors Huynh and Danhi are with the School of Hospitality and Tourism, Taylor’s Univ. Lakeside Campus, No.1, Jalan Taylor’s 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia. Author Yan is with the School of Biosciences, Taylor’s Univ. Lakeside Campus, No.1, Jalan Taylor’s 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia. Direct inquires to author Yan (E-mail: firstname.lastname@example.org). the recommendations for good health (Brown and others 2009). Sodium has been identified to be the primary cause of high blood pressure, which increases the risk of cardiovascular diseases. Previous research reveals 49% of patients who suffered from stroke, and 62% of patients who had coronary heart disease, also suffered from high blood pressure (He and MacGregor 2010). Additionally, excessive consumption of sodium also diminishes bone density (Tsugane and others 2004); increases the possible risk of gastric cancer (Liem and others 2011); and contributes to obesity (He and MacGregor 2008). However, high sodium content indicated on food products was found to be insignificant in influencing consumer food preference (Kim and others 2012), even though consumers were aware of the increased risk of developing sodiumrelated diseases as a consequence of a high sodium diet (Kim and Lee 2014). Consequently, a consumer’s preference for foods with the perception of saltiness may be more related to habituation than to informed choice. Although the harmful effects of excessive sodium consumption have been identified, the percentage of high sodium food remains relatively constant in many consumer diets (Cordain and others 2005). Various attempts have been made to minimize sodium content in food by reducing the quantity of salt or replacing salt with substitutes. Reducing NaCl could be achieved by 2 main methods. First, NaCl could be replaced by other types of salts C 2015 Institute of Food Technologists R S150 Journal of Food Science Vol. 81, Nr. 1, 2016 doi: 10.1111/1750-3841.13171 Further reproduction without permission is prohibited S: Sensory & Food Quality Salt substitution using fish sauce . . . such as calcium chloride (CaCl2) and potassium chloride (KCl); this has been proven to reduce sodium by 50% in cheese and meat products (Katsiari and others 1997; Kremer and others 2009). However, the application of such attempts in food preparation was found to be as insignificant as only 0.3% in processed food from 1983 to 2004 (Jacobson 2005). The second approach has been to utilize the interactions of primary tastes (sweetness, sourness, saltiness, bitterness, and umami) to enhance perceived saltiness (Mojet and others 2004). Umami, specifically, as a category of taste in foods, has a potential for affecting perceived saltiness and tastiness when increased by adding it to foods (Yamaguchi and Ninomiya 2000; Yeomans and others 2004). However, these 2 sodium reduction techniques have not achieved significant success due to their undesirable effect on overall texture and flavor (Keast and others 2004). Taste enhancing synergy between 2 umami compounds—lglutamate and 5-ribonulceotides—creates a unique tastiness in food, which is naturally found in vegetables, fruit, meat, cheese, soya sauce, and fish sauce (Yamaguchi and Ninomiya 2000). Previous studies have demonstrated that the umami quality of soya sauce (Lioe and others 2006; Lioe and others 2010) and fish sauce (Park and others 2002; Jiang and others 2007) influences consumer preference and overall liking. The practical application of soya sauce to reduce NaCl in cream of tomato soup, stir fried pork, and salad dressing has been described (Kremer and others 2009). However, there is insufficient evidence to demonstrate the specific effectiveness of fish sauce in reducing NaCl when used as a substitute for sodium in foods. This study explores the partial substitution of fish sauce for NaCl as a method to reduce sodium in chicken broth, tomato sauce, and coconut curry while maintaining palatability. Materials and Methods Subjects For each food item—chicken broth, tomato soup, and coconut curry—75 subjects, aged between 18 and 59 y, were recruited for all 3 taste tests. All subjects are students or staff at Taylor’s University Lakeside Campus, Subang Jaya, Kuala Lumpur, Malaysia. All subjects are Malaysian of various ethnicities (Malay, Chinese, Indian, and others) and have good command of the English language. Written informed consent was obtained from all the subjects prior to the food tasting sessions. The actual number of subjects for each recipe was 72 for chicken broth (29 male), 73 for tomato soup (26 male), and 70 for coconut curry (31 male). For each food item, the same subjects participated in 2 tasting sessions of approximately 90 min each. Participation was voluntary. Samples For the preparation of the 3 recipes, first grade fish sauce, nuoc mam nhi, from Phu Quoc Island, Vietnam was selected and obtained from the manufacturer Red Boat Fish Sauce (DBA Viet Phu Inc., Milpitas, Calif., U.S.A.). To achieve product consistency, all samples were prepared from the same batch of 40°N grade fish sauce made from the black anchovies of the Stolephorus species Baccaneeri, Miarcha, and Purpureus and sea salt. The sodium content of the sample fish sauce was measured using atomic absorption spectroscopy (AAS) (PerkinElmer, Waltham, Mass., U.S.A.) according to a method described by Tee and others (1996). The result of the tests revealed 7.90% NaCl in the sample fish sauce. To eliminate variance in both weight and volume in the preparation of the recipes, a saline solution was created with the same sodium content as the fish sauce so that the recipes would have the same amount of liquid. Table salt (NaCl) of 20.13% was dissolved into 79.87% of water, resulting in a solution with 7.90% sodium content, thus matching the sodium content of fish sauce. Recipe development Equipment, time, and temperature controls were monitored. To maintain consistency from batch to batch, recipe yield was measured and water was added back to achieve accurate final yield. After preparation, sodium content of the 3 prepared samples was determined by AAS. Then sodium calculation for samples was conducted on each batch (with salt solution and fish sauce) and all samples were prepared from the same batch of each recipe, in which the range of concentration was finalized based on a pilot test amongst colleagues (n = 15). Chicken broth A basic chicken broth was prepared to produce an overall flavor suitable to be utilized in both Asian and non-Asian cuisines. The broth was prepared according to the following recipe: 1699.18 g chicken thighs/legs (bone in, skin off) and 2199.11g water were combined, heated to 100 °C/212 °F (Thermapen, ThermaWorks, England), and then skimmed. 31.52 g peeled and sliced ginger; 337.93 g peeled and quartered onions; 28.59 g smashed garlic cloves; and 3.67 g cracked white peppercorns were stirred in. The heat source was reduced to simmer the broth at 88 °C/190.4 °F until there was a 84.1% yield. The broth was strained through fine-wire mesh strainer, cooled in an ice bath, and stored in a food grade refrigerator at 4.45 °C/40 °F. This broth was tested on its own and also used as an ingredient in the tomato sauce and coconut curry recipes. Tomato sauce A tomato sauce was prepared, typical of those used in American, Italian, French, and other non-Asian cuisines. The sauce was prepared according to the following recipe: 175.07 g pure olive oil was heated over low heat (121 °C/250 °F); 267.72 g small dice yellow onions were added and stirred constantly for 5 min; then 70.03 g minced garlic was added and cooked for 1 min. 2578.38 g chopped sodium-free prepared tomatoes (Monte Verde (M) Sdn. Bhd, Malaysia); 0.35 g dried oregano; 8.40 g ground black pepper; 19.54 g chopped fresh basil; and 1346.58 g the chicken broth were stirred in. The mixture was heated to 100 °C/212 °F, and then the heat source was reduced to simmer the sauce at 88 °C/190.4 °F until there was a 62.3% yield. Then the sauce was cooled in an ice bath and stored in a food grade refrigerator at 4.45 °C/40 °F. Coconut curry A variety of coconut curries are common dishes in Southeast Asian cuisines. The curry for this study was prepared according to the following recipe: 125.93 g vegetable oil; 276.63 g shallots; 57.95 g garlic; 103.73 g lemongrass; 65.15 g galangal; and 28.01 g curry powder (Adabi Consumer Industry Sdn. Bhd, Malaysia) were pureed in a blender for 1 min until a smooth paste was achieved. The paste was then cooked for 5 min over low heat (121 °C/250 °F) and stirred constantly. 712.31 g of the chicken broth was added. The mixture was brought to 100 °C/212 °F, reduced to 88 °C/190.4 °F, and held for 15 min. 414.94 g coconut milk (Kara Marketing (M) Sdn. Bhd, Malaysia) and 1528.35 g water were stirred in and the curry was simmered at 88 °C/190.4 °F until there is a 53.43% yield. The curry was strained through a perforated (2.25-mm hole size) metal conical Vol. 81, Nr. 1, 2016 Journal of Food Science S151 S: Sensory & Food Quality Salt substitution using fish sauce . . . Table 1–Recipes for samples (chicken broth, tomato sauce and chicken curry) 1 to 4. Salt Sample Sample Sample Sample Standard #1 #2 #3 #4 Chicken broth Total NaCl (% w/w) 1.58 1.58 1.38 1.18 0.98 NaCl reduction (%) 0 0 13 25 38 Fish sauce (Red Boat 40N) (%) 0 75 75 75 75 Salt solution (%) 100 25 25 25 25 Tomato sauce Total NaCl (% w/w) 1.28 1.28 1.08 0.88 0.68 NaCl reduction (%) 0 0 16 31 47 Fish sauce (Red Boat 40N) (%) 0 75 75 75 75 Salt solution (%) 100 25 25 25 25 Coconut curry Total NaCl (% w/w) 1 1 0.90 0.85 0.80 NaCl reduction (%) 0 0 10 15 20 Fish sauce (Red Boat 40N) (%) 0 75 75 75 75 Salt solution (%) 100 25 25 25 25 strainer. The mixture was cooled in an ice bath and stored in a food grade refrigerator at 4.45 °C/40 °F. Determination of the range of sodium concentration The range of sodium concentration to be used for the consumer acceptance test for each recipe was based on a pilot testing session with 15 students and staff at Taylor’s University. The first goal of this pilot test was to determine a base NaCl level that would be accepted as a “well-seasoned/palatable” sample to be used as the Salt Standard. This pilot test also aimed to identify the palatable sodium range that could fulfill 3 possible results: no significant difference in overall taste intensity between Salt Standard with fish sauce samples; Salt Standard have stronger overall taste intensity compared to fish sauce samples; and fish sauce samples have stronger overall taste intensity compared to Salt Standard. The first stage of the process to determine sodium range was to create a Salt Standard (100% NaCl), which was determined to be “well-seasoned” in a pilot test. The second stage was to create Sample #1 with 75% fish sauce and 25% salt solution to equal the sodium content of the Salt Standard. Diluting the fish sauce variation with water was necessary in order to reduce the strong taste of fish sauce which could introduce bias in rating. Samples 2, 3, and 4 were created similarly, with the same ratio of 75% fish sauce and 25% salt solution. The total reduced sodium content is listed in Table 1. Procedure The tasting sessions were conducted at Culinary Bar Theatre, Taylor’s University Lakeside Campus,Malaysia for 3 d (1 food item per day). Tasting sessions were conducted from 10 am to 11:30 am. Room temperature was controlled to be 23.9 °C/75 °F. Prior instructions on specific terminology and the method to cleanse the palate using both water and plain bread were clearly explained to all subjects. For all tasting sessions, 5 samples (1 Salt Standard and 4 samples) with varying table salt/fish sauce ratio (Table 1) were prepared 24 h before serving. All samples were placed in 2000 mL/70.4 fl oz airtight containers and stored in a food grade refrigerator at 4.45 °C/40 °F. Fifteen minutes before serving, each sample was mixed and reheated to 73.9 °C/165 °F, then portioned into 15 mL/.53 fl oz. samples in 25 mL/.89 fl oz. plastic cups, and allowed to cool to 30 °C/86 °F. There were 2 tasting sessions (2-AFC test and Rating on Attributes) for each food item. In the first session, subjects responded to 4 2-Alternative Forced Choice (2-AFC) tests to determine the level by which NaCl could be replaced with fish sauce without a significant change in the overall taste intensity. Subjects compared the 4 samples of different fish sauce concentrations with that of a standard at 100% NaCl concentration. They then indicated which of the 2 samples had the stronger taste intensity. The subjects answered the same question for all 4 sample sets during this session. After the first session, the optimal percentage by which NaCl can be replaced with fish sauce without respondents noticing the significant change in the overall taste intensity was determined. In the second session, 5 samples (comprised of Salt Standard and 4 samples with different table salt and/or fish sauce concentrations) were evaluated using 100 mm line scales (anchored from “Not at all” to “Extremely”) for degree of liking (measured by scale of “deliciousness”) (Luscombe-Marsh and others 2008), overall taste intensity, and perceived saltiness. Following this procedure, each subject rated a total of 3 attributes, 5 times each during this session. All samples were coded with random 3 digit identifiers and were counterbalanced so that each sample appeared in a particular tasting order an equal number of times. Between samples, subjects were given a 5 min break during which they cleansed their palates with water and plain bread. These 2 tasting process were repeated 3 times for 3 food items (chicken broth, tomato sauce, and coconut curry). Statistical analysis All data were analyzed using Statistical Package for the Social Sciences Version 17 (SPSS Inc., Chicago, Ill., U.S.A.). In the first session, 1 sample t-test was performed to observe the significant difference between Salt Standard with 4 other samples. The t-value indicated a significant difference in mean value, which indicates whether or not consumers are able to detect the difference between the 100% sodium standard recipe and the sodium reduction samples. Significant difference was defined as P < 0.05. In the second session, one-way repeated measures ANOVA was conducted to test for overall differences in ratings of deliciousness, taste intensity and perceived saltiness. Significant level was set at probability P < 0.05. Results and Discussion 2-AFC test results A summary of the results of 2-AFC test is displayed in Figure 1. Comparison of the data for each recipe follows below. S152 Journal of Food Science Vol. 81, Nr. 1, 2016 S: Sensory & Food Quality Salt substitution using fish sauce . . . For the chicken broth recipe, subjects rated a stronger taste intensity in Sample 1 than in the Salt Standard in Pair 1 (equal in sodium content). Subjects also rated a stronger taste intensity in the Salt Standard than in Sample 4 in Pair 4 (38% salt reduction). There was no significant difference reported in Pair 2 (13% salt reduction) and Pair 3 (25% salt reduction). Thus, it can be concluded that chicken broth with 1.58% NaCl tasted equally as intense as chicken broth prepared with 75% fish sauce and 25% NaCl with a maximum 25% salt reduction (Table 1). In Pair 1 of the tomato sauce recipe, Sample 1 was identified to be significantly more intense compared to the Salt Standard. Rating for Pair 2 indicated no significant difference in taste intensity, whereas for Pair 3 and Pair 4, the Salt Standard was reported to be more intense. Thus, it can be concluded that tomato sauce prepared with 1.28% NaCl tasted equally as intense as tomato sauce prepared with 75% fish sauce and 25% NaCl with a 16% salt reduction (Table 1). For the coconut curry, the NaCl reduction gap was relatively small (5% to 10% reduction from each sample), and no significant difference in taste intensity was rated across the samples. Thus, it can be concluded that coconut curry prepared with 1% NaCl tasted equally intense as coconut curry prepared with 75% fish sauce and 25% NaCl. Consequently, using fish sauce as a NaCl substitute in coconut curry could be performed in any concentration without affecting consumer acceptance, noting an optimal sodium reduction up to 20% (Table 1). Rating on attributes (deliciousness, taste intensity, and perceived saltiness) Figure 2 displays subjects rating on deliciousness, taste intensity, and perceived saltiness of the Salt Standard and samples for chicken broth, tomato sauce, and coconut curry. First, a significant overall difference (P < 0.05) was observed for deliciousness [F(2.962, 210.314) = 10.705; P < 0.05], taste intensity [F(3.255, 231.078) = 2.946; P < 0.05], and perceived saltiness [F(3.734, 265.149) = 42.591; P < 0.05] for salt standard and all the 4 samples of the chicken broth. Subjects perceived Sample 4 to be the most delicious, Sample 1 to have the strongest taste intensity, and Salt Standard to be the saltiest. 0 10 20 30 40 50 60 Pair 1 Pair 2 Pair 3 Pair 4 Subjects (n=72) Salt Standard- 1.58% Sample 1- 1.58% Sample 2- 1.38% Sample 3- 1.18% Sample 4- 0.98% * * 0 10 20 30 40 50 60 Pair 1 Pair 2 Pair 3 Pair 4 Subjects (n=73) Salt Standard- 1.28% Sample 1- 1.28% Sample 2- 1.08% Sample 3- 0.88% Sample 4- 0.68% * * * 0 10 20 30 40 50 60 Pair 1 Pair 2 Pair 3 Pair 4 Subjects (n=70) A B C Salt Standard- 1.00% Sample 1- 1.00% Sample 2- 0.90% Sample 3- 0.85% Sample 4- 0.80% Figure 1–2-AFC test for overall taste intensity of chicken broth (A), tomato sauce (B), and coconut curry (C). ∗Asterisk indicates a significant difference between samples and salt standard at P < 0.05. Vol. 81, Nr. 1, 2016 Journal of Food Science S153 S: Sensory & Food Quality Salt substitution using fish sauce . . . Second, for the tomato sauce recipe, deliciousness [F(3.840, 276.471) = 5.899; P < 0.05), taste intensity (F(3.909, 281.429) = 3.354, P < 0.05), and perceived saltiness (F(3.912, 281.688) = 9.150; P < 0.05) were observed to have significant difference amongst all the samples. Sample 1 was identified to be the most delicious, to have the strongest taste intensity, and to be the saltiest. Third, a significant difference (P < 0.05) was also identified for deliciousness [F(4.000, 276.000) = 3.810, P < 0.05] and taste intensity (F(3.502, 241.668) = 3.067, P < 0.05] amongst samples of coconut curry. No significant difference (P > 0.05) was observed for saltiness [F(3.474, 239.708) = 2.027, P > 0.05]. Subjects rated Sample 1 to be the most delicious and to have the strongest taste intensity. Overall, Sample 1 was identified to be the saltiest and the strongest in overall taste intensity for all 3 food items. It can be concluded that for the 3 recipes of chicken broth, tomato sauce, and coconut curry, the use of fish sauce as a sodium reduction technique not only amplified the level of saltiness but also strengthened the overall palatability and taste intensity as well. These results demonstrate that using fish sauce can result in an expected 10% to 25% reduction in sodium without any significant negative impact on deliciousness and overall taste intensity for the foods tested in this study. It is to be noted, however, that the similar and successful use of fish sauce as a sodium reduction technique in other recipes would depend vastly on the flavor profile of each food. Using fish sauce as a salt reduction technique in foods This study has demonstrated the possibility of using fish sauce to reduce sodium in 3 types of food items without significantly impacting consumer acceptance and food palatability. This conclusion can be further explained by examining the chemical compounds naturally found in fish sauce. Preliminarily, fish sauce contains an abundance of amino acids originating from fish proteins, which gives it a remarkable and complex umami taste. Park and others (2002) research on taste active compounds in fish 0 1 2 3 4 5 6 7 8 Salt Standard Sample 1 Sample 2 Sample 3 Sample 4 Intensity Deliciousness Taste Intensity Saltiness 0 1 2 3 4 5 6 7 8 Salt Standard Sample 1 Sample 2 Sample 3 Sample 4 Intensity Deliciousness Taste Intensity Saltiness 0 1 2 3 4 5 6 7 8 Salt Standard Sample 1 Sample 2 Sample 3 Sample 4 Intensity Deliciousness Taste Intensity Saltiness C B A Figure 2–Rating on attributes (deliciousness, taste intensity, and saltiness) for chicken broth (A), tomato sauce (B), and coconut curry (C). Straight line = significance difference, dotted line = no significance difference between samples and salt standard at P < 0.05. S154 Journal of Food Science Vol. 81, Nr. 1, 2016 S: Sensory & Food Quality Salt substitution using fish sauce . . . sauce concluded that the free amino acids (including threonine, cystine, proline, methionine, tyrosine, alanine, glutamic acid, and valine) affected the receptivity of saltiness, sweetness, bitterness, and sourness on the human tongue. Despite the slight ammonia scent, the taste of fish sauce has been described as the merging of cheesy and meaty flavors due to the volatile fatty acid and dominant free amino acid glutamate that are present in fish sauce (Yamaguchi and Ninomiya 2000; Curtis 2009). The findings of the current study also support previous research on the taste effect of acid oligopeptide fraction in fish protein hydrolysate (Fujimaki and others 1973), where the researchers reported that fish sauce added a remarkable brothy flavor and pleasant aftertaste in foods. It was also confirmed by subsequent research that fish sauce contains a high molecular weight fraction which likely transforms the perception of primary taste intensity and flavor profile of foods (Ueda and others 1997). Although not totally comprehensive in scope, the current study demonstrates that sodium reduction by substituting fish sauce in the recipes of chicken broth, tomato sauce, and coconut curry was successful without significantly compromising consumer acceptance. The scientific mechanism of using fish sauce as a sodium reduction technique is still in need of further in depth understanding to explore the chemical interaction at the molecular level of each food component during cooking. The NaCl compensation level of fish sauce would need to vary according to individual recipes, the concept of which is reflected through the current findings where optimal sodium reduction in chicken broth is 25%; tomato sauce is 16%; and coconut curry is 10%. The reason for the variance may because the high level of free glutamate in both tomatoes and coconut milk suppressed the sodium reduction ability of the fish sauce (Kremer and others 2009). Other factors may influence perceived flavor and saltiness such as serving temperature and tasting quantity (Paulus and Reisch 1980). Consequently, all samples from the 3 recipes in the current study were presented in a premeasured quantity at room temperature (23.9 °C/75 °F). Examining this study’s Rating on Attributes, fish sauce is shown to be a potential substitute of NaCl without diminishing degree of liking/deliciousness. Thus, a gradual reduction method is applicable in order to accomplish sodium reduction in a range of other food items. To apply this method more broadly, however, consideration must be given to each recipe regarding how fish sauce will affect expected color and aroma. Amongst the 3 recipes tested, chicken broth was an obvious example of subtle changes in color intensity as the « brown » color across samples was easily distinguished by the subjects. The change in color may influence the consumer primary perception of the taste of foods. Throughout the current study, none of the subjects reported any detection of “fishy” or “ammonia” odor. Even though the aroma was almost identical across samples in all 3 recipes, it would be advisable to monitor consumer acceptance over a longitudinal study to ensure that long term acceptance of subtle aroma and a color change is possible. Conclusion This study demonstrates that using fish sauce as a substitute ingredient to reduce sodium in 3 types of food items (25% in chicken broth; 16% in tomato sauce; and 10% in coconut curry) can be accomplished without significantly impacting consumer acceptance or food palatability. However, it is noted that the level of NaCl reduction needs to be varied across recipes based on the complexity of the ingredients and preparation method. Thus, future research involving different recipes is recommended. Acknowledgments The authors gratefully acknowledge the assistance of Nancy Vathsala Rajan during the data collection phases of this project. Special appreciation is dedicated to Michael Chang for his assistance in reviewing the manuscript. Thanks to Red Boat Fish Sauce, Milpitas, CA DBA Viet Phu Inc. for providing fish sauce samples to be used in all recipes. The authors also wish to confirm that there are no known conflicts of interest associated with this publication that could have influenced its outcome. Author Contributions Robert Danhi and Hue Linh Huynh designed the study. Robert Danhi, Hue Linh Huynh, and See Wan Yan collected the data. Hue Linh Huynh, See Wan Yan, and Robert Danhi drafted the manuscript. References Beauchamp GK, Stein LJ. 2008. Salt taste. 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