Salt-reduced Foods Research Articles

A consumer evaluation of salt-reduced tomato soup and vegetable juice made with grape pomace.

Obesity and obesity-related illness have become an increasingly prevalent problem and there is a critical need to combat this by reducing sugar, salt, and fat consumption. Due to this concern, the food industry has been developing salt-reduced foods, however, these products need to maintain their sensory appeal and flavors, which has proven to be a challenge. Grape pomace (GP), the solids left after pressing grapes for winemaking and consisting of grape seeds and skins, has been proposed as an environmentally friendly solution that can enhance the acceptability of salt-reduced food products. However, GP is associated with a large number of flavor compounds. As such, the objective of this research is to investigate the acceptability of GP addition in salt-reduced foods. Two trials were conducted using hedonic scales and temporal check-all-that-apply (TCATA) to evaluate tomato soup (n=88) and vegetable juice (n=99). Each trial included a control and sample containing grape pomace. The addition of the GP decreased the consumers' overall liking and the liking of the flavor, as well as increasing consumers' perception of saltiness intensity. The samples made with GP were associated with bitterness, sourness, and wine flavor during the TCATA evaluations. The study identified that GP increased saltiness perception, however, it also adds other flavors to the food product, which decreased the acceptability of the food items. PRACTICAL APPLICATION: There is a consumer demand to create salt-reduced foods that do not have altered sensory properties. Furthermore, consumers are interested in sustainable and environmentally friendly ingredients. Grape pomace is a byproduct of the wine industry and has been proposed as an ingredient that can increase the saltiness perception of food products. Grape pomace was added to tomato soup and vegetable juice to evaluate its effect on consumer acceptability and saltiness perception. The grape pomace did increase saltiness perception, but also added bitterness, sourness, and wine flavor to the food products.

Umami and saltiness enhancements of vegetable soup by enzyme-produced glutamic acid and branched-chain amino acids.

One major challenge of reducing salt content in food is the risk of the overall taste becoming bland. Enhancing saltiness is an effective strategy for salt reduction, and the development of salt-reduced foods using these saltiness-enhancing flavorants as food additives is underway. However, an increasing number of consumers demand a reduction in additives in clean-label foods. Enzyme processing of food is an attractive strategy for developing clean-label foods because enzymes are not considered additives. We aimed to improve the saltiness and umami intensity of vegetable soups by enzyme treatment while meeting clean-label requirements. We first optimized the enzymatic reaction conditions of a protease and glutaminase blend and then investigated the synergistic effects of this enzyme blend on the taste of vegetable soup. Sensory evaluations indicated that the reaction products (e.g., protein hydrolysates or amino acids) could enhance the umami, kokumi, and saltiness intensity of vegetable soup supplemented with 0.5% NaCl. Notably, the saltiness intensity ratio of the enzyme-treated soup with 0.50, 0.45, and 0.40% NaCl were increased by 1.31-, 1.16-, and 0.99-fold, respectively, when this ratio for the control soup with 0.50% NaCl was set to 1.0. This indicates a 20% salt reduction rate can be achieved by enzyme treatment. Moreover, we found that these enhancements were synergically caused by enzyme-produced glutamic acid and branched-chain amino acids. Our findings suggest that using enzyme blends of bacterial and fungal proteases and glutaminase is an effective approach to enhancing the saltiness levels of vegetable soups while meeting clean-label requirements.

Exploration of optimal preparation strategy of Chenpi (pericarps of Citrus reticulata Blanco) flavouring essence with great application potential in sugar and salt-reduced foods

To obtain flavouring essence with application potential in sugar and salt-reduced foods, the optimal strategy for extraction and microencapsulation of essential oil (EO) from Chenpi was investigated. UPLC-QTOF-MS/MS and liquid–liquid-extraction-GC–MS confirmed the selectivity for volatiles ranked in hydrodistillation > supercritical fluid extraction > solvent extraction. The aroma characteristic of Chenpi EO was distinguished by 33 key volatiles (screened out via headspace-SPME-GC–MS) and quantitative descriptive analysis. EO extracted by supercritical fluid extraction was preferred for preserving the original aroma of Chenpi and displaying more fruity, honey and floral. Chenpi flavouring essence with superior encapsulation efficiency, particle size, water dispersibility, and thermostability was obtained through optimally microencapsulating EO with gum arabic and maltodextrin (1:1) by high-pressure homogenization coupled with spray drying. Chenpi flavouring essence was able to reduce the usage of sugar and salt by 20 % via enhancing flavour perception of sweetness and saltiness. This study first developed a flavouring essence promisingly effective in both sugar and salt-reduced foods.

Mechanism of salt effect on flavor formation in lightly-salted large yellow croaker by integrated multiple intelligent sensory and untargeted lipidomics analyses

Salt has a great influence on food flavor formation. In this study, electronic tongue and nose, gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and lipid oxidation levels were used to investigate the influence of different NaCl concentrations on the flavor formation of lightly salted large yellow croaker. The results showed that salt improves the sensory characteristics of the product. Hexanal, 2,5-octanedione, octanal, 1-octen-3-ol, nonanal, and heptanal were key flavor compounds. Phospholipids containing 18-carbon fatty acids are major flavor precursor substances. The TBARS values in samples increase with the increase of salt levels significantly (p < 0.05). Products marinated in 6% NaCl showed the highest lipase activity. Thus, NaCl promotes the hydrolysis and oxidation of phospholipids by increasing lipase activity to produce key flavor substances. This study provides valuable insights into the effects of NaCl on flavor formation, which may help to regulate the flavor of salt-reduced food.

Development and Optimization of a Highly Sensitive Sensor to Quinine-Based Saltiness Enhancement Effect

The saltiness enhancement effect can be produced by adding specific substances to dietary salt (sodium chloride). This effect has been used in salt-reduced food to help people forge healthy eating habits. Therefore, it is necessary to objectively evaluate the saltiness of food based on this effect. In a previous study, sensor electrodes based on lipid/polymer membrane with Na+ ionophore have been proposed to quantify the saltiness enhanced by branched-chain amino acids (BCAAs), citric acid, and tartaric acid. In this study, we developed a new saltiness sensor with the lipid/polymer membrane to quantify the saltiness enhancement effect of quinine by replacing a lipid that caused an unexpected initial drop in the previous study with another new lipid. As a result, the concentrations of lipid and ionophore were optimized to produce an expected response. Logarithmic responses have been found on both NaCl samples and quinine-added NaCl samples. The findings indicate the usage of lipid/polymer membranes on novel taste sensors to evaluate the saltiness enhancement effect accurately.

Effect of Piperine on Saltiness Perception.

Chemical irritants, like piperine, have the potential to increase human perception of tastes and odours, including saltiness. This cross-modal interaction could help the food industry develop new salt-reduced food products that maintain their salty taste. The objective of this study was: firstly, to determine the detection threshold of piperine (n = 72), secondly to evaluate piperine's influence on saltiness perception in model solutions (n = 78), and lastly to identify piperine's effect on sensory perception of low sodium soup using temporal check-all-that-apply (TCATA; n = 75). The group mean of the individual threshold was 0.55 ± 0.15 ppm. Piperine increased the saltiness perception of the model solutions, but it also increased the bitterness and decreased the sweetness of the solutions. The piperine significantly increased the saltiness intensity of the soups (evaluated using a generalized labelled magnitude), but during the TCATA task, the salty attribute was selected less for the soup with piperine than the control (based on the average proportion of selection). The TCATA indicated that the peppery attribute dominated the participants' perception of the soup with piperine. More studies are needed to assess piperine's cross-modal interactions.

Contribution of the retronasal odor of soy sauce to salt reduction.

The characteristic odor of soy sauce has been reported to enhance saltiness. However, soy sauce is used not only as a sauce that is added directly to food, but also as a seasoning. In addition, some of the aromatic compounds that contribute to the soy sauce odor change during cooking or heating. In the present study, the effects of the retronasal odor of uncooked and cooked soy sauce on the enhancement of saltiness and palatability of a low-salt solution were sensory evaluated. A probit analysis indicated that the saltiness-enhancing effect of the odor of 15% uncooked soy sauce was lost by heating. The odors of soy sauce boiled for 10min (cooked SS) and the residue of soy sauce heated at 200°C for 1min improved the palatability of the low-salt solution. Gas chromatography (GC) analyses, namely, GC-olfactometry and GC-mass spectrometry, showed that one active candidate aromatic component of soy sauce contributing to saltiness enhancement was 3-methyl-1-butanol (3-Me-BuOH). The saltiness-enhancing effects of cooked SS could be restored by adding 3-Me-BuOH, as assessed by the sensory evaluation. These data demonstrated that 3-Me-BuOH contributes to saltiness enhancement. PRACTICAL APPLICATION: We found that the odor of cooked soy sauce could improve the palatability of low-salt food. Although the saltiness-enhancing effect provided by the odor of uncooked soy sauce was lost, the saltiness-enhancing effect of the odor of cooked soy sauce can be partially restored by adding 3-methyl butanol. Thus, not only the odor of unheated soy sauce but also the odor of heated soy sauce following addition of 3-methyl butanol may be useful for developing palatable salt-reduced food.

The effect of the pungent sensation elicited by Sichuan pepper oleoresin on the sensory perception of saltiness throughout younger and older age groups

Excessive salt in the diet can pose significant health risks and, therefore, the reduction of salt derived from food is an important issue relating to human nutrition and health. Furthermore, the perception of saltiness will be different among people when considering their innate sensitivity, gender, age, psychological traits and dietary habits. In this study, 31 younger participants and 29 older participants were used as research subjects. A web-based questionnaire survey was used to collect information regarding of socio-demographics, consumption frequency and liking for salty and pungent food, as well as personality traits throughout the younger and the older participants. In addition, the 6-n-propylthiouracil (PROP) ratings were tested by the generalized Labeled Magnitude Scale (gLMS) in the laboratory conditions. The rated difference from control method was used to test the sensitivity differences in the saltiness of NaCl and the pungent sensation elicited by Sichuan pepper oleoresin between the younger and older groups. The results showed that the thresholds were significantly lower in the younger group than in the older group, except for the detection threshold of saltiness. Furthermore, the recognition threshold of saltiness decreased in the presence of the sub-threshold pungency solution, while, the salty intensity was enhanced in both the younger and older groups when exposed to the slightly pungent solution (0.106 g Sichuan pepper oleoresin/L water solutions) compared to the control (spring water). For the younger group, the enhancement percentage of the salty intensity was between 9.3% and 12.5%, while, at the concentration of 4.05 g/L, the salty-enhancement percentage increased by 6.4% in the older group. In addition, the reduction percentage of NaCl reached a level of up to 34.4% in the younger group and was 4.4% in the older group. The Partial Least Squares Regression (PLSR) results indicated that the percentage change in salty intensity increased when the detection threshold of saltiness, the sensation seeking ratings, and PROP ratings increased. On the contrary, the change decreased when the age, life satisfaction ratings, detection threshold of pungency, and consumption frequency of salty food increased. These findings not only provide new information for the flavor design of salt-reduced food and dishes, but also be valuable to public health as well as economic benefits.

Development of a Sensor with a Lipid/Polymer Membrane Comprising Na+ Ionophores to Evaluate the Saltiness Enhancement Effect.

The saltiness enhancement effect is the effect whereby saltiness is enhanced by adding specific substances to salt (sodium chloride). Since this effect can be used in the development of salt-reduced foods, a method to objectively evaluate the saltiness with this effect is required. A taste sensor with lipid/polymer membranes has been used to quantify the taste of food and beverages in recent years. The sensor electrodes of this taste sensor have the feature of selectively responding to each of the five basic tastes, which is realized by the lipid/polymer membranes. In this study, we developed a new saltiness sensor based on the lipid/polymer membrane with the aim of quantifying the saltiness enhancement effect. In addition to the conventional components of a lipid, plasticizer, and polymer supporting reagent, the membrane we developed comprises ionophores, which selectively capture sodium ions. As a result, the response of the sensor increased logarithmically with the activity of NaCl in measured samples, similarly to the taste response of humans. In addition, all of the sensor responses increased upon adding saltiness-enhancing substances, such as citric acid, tartaric acid and branched-chain amino acids (BCAAs), to NaCl samples. These findings suggest that it is possible to quantify the saltiness enhancement effect using a taste sensor with lipid/polymer membranes.

Determinants of intention to reduce salt intake and willingness to purchase salt-reduced food products: Evidence from a web survey

To study consumers’ intention to reduce their dietary salt intake and willingness to purchase salt-reduced food products, as well as the determinants of these, this research relies on data collected through a web survey of 1030 participants in Denmark. The majority of respondents (66.8%) express no intentions to change their dietary salt intake, but 12.6% indicate such intentions, and 20.6% claim to have already implemented a change. Willingness to purchase salt-reduced food products is high but varies across product categories, ranging from 52% for olives to 72% for meat spreads. Personal and social norms reveal the strongest influences on intention to change dietary habits, whereas personal norms, knowledge, and awareness of health consequences exert the strongest influences on willingness to purchase salt-reduced food products. These results suggest that most consumers are willing to purchase salt-reduced food products, even without having a salt reduction goal. These results are relevant for stakeholders and policy makers, as evidence of how consumers respond to salt-reduced food products and their intention to lower their dietary salt intake.

3 塩味・うま味増強香気成分による減塩食の嗜好性改善( うま味研究会公開シンポジウム「食べ物のおいしさにおけるうま味の役割-多感覚の相互作用」)

3 塩味・うま味増強香気成分による減塩食の嗜好性改善( うま味研究会公開シンポジウム「食べ物のおいしさにおけるうま味の役割-多感覚の相互作用」)

Effect of Salt Reduction on Consumer Acceptance and Sensory Quality of Food.

Reducing salt (NaCl) intake is an important public health target. The food industry and catering services are searching for means to reduce the salt content in their products. This review focuses on options for salt reduction in foods and the sensory evaluation of salt-reduced foods. Simple salt reduction, mineral salts and flavor enhancers/modifiers (e.g., umami compounds) are common options for salt reduction. In addition, the modification of food texture and odor-taste interactions may contribute to enhanced salty taste perception. Maintaining consumer acceptance of the products is a challenge, and recent examples of the consumer perception of salt-reduced foods are presented.

Consumer acceptance of reformulated food products: A systematic review and meta-analysis of salt-reduced foods

ABSTRACTFood product reformulation is promoted as an effective strategy to reduce population salt intake and address the associated burden of chronic disease. Salt has a number of functions in food processing, including impacting upon physical and sensory properties. Manufacturers must ensure that reformulation of foods to reduce salt does not compromise consumer acceptability.The aim of this systematic review is to determine to what extent foods can be reduced in salt without detrimental effect on consumer acceptability.Fifty studies reported on salt reduction, replacement or compensation in processed meats, breads, cheeses, soups, and miscellaneous products. For each product category, levels of salt reduction were collapsed into four groups: <40%, 40–59%, 60–79% and ≥80%. Random effects meta-analyses conducted on salt-reduced products showed that salt could be reduced by approximately 40% in breads [mean change in acceptability for reduction <40% (−0.27, 95% confidence interval (CI) −0.62, 0.08; p = 0.13)] and approximately 70% in processed meats [mean change in acceptability for reductions 60–69% (−0.18, 95% CI −0.44, 0.07; p = 0.15)] without significantly impacting consumer acceptability. Results varied for other products.These results will support manufacturers to make greater reductions in salt when reformulating food products, which in turn will contribute to a healthier food supply.

Salt reduction in sheeted dough: A successful technological approach

The challenge of reducing the salt content while maintaining shelf life, stability and acceptability of the products is major for the food industry. In the present study, we implemented processing adjustments to reduce salt content while maintaining the machinability and the saltiness perception of sheeted dough: the homogeneous distribution of a layer of encapsulated salt grains on the dough during the laminating process. During sheeting, for an imposed deformation of 0.67, the final strain remained unchanged around 0.50 for salt reduction below 50%, and then, increased significantly up to 0.53 for a dough without salt. This increase is, in fine, positive regarding the rolling process since the decrease of salt content induces less shrinkage of dough downstream, which is the main feature to be controlled in the process. Moreover, the final strain was negatively correlated to the resistance to extension measured with a texture analyzer, therefore providing a method to evaluate the machinability of the dough. From these results, a salt reduction of 25% was achieved by holding 50% of the salt in the dough recipe to maintain the dough properties and saving 25% as salt grains to create high-salted areas that would enhance the saltiness perception of the dough. The distributor mounted above the rollers of the mill proved to be able to distribute evenly salt grains at a calculated step of the rolling out process. An innovative method based on RX micro-tomography allowed to follow the salt dissolving and to demonstrate the capability of the coatings to delay the salt dissolving and consequently the diffusion of salt within the dough piece. Finally, a ranking test on the salted perception of different samples having either an even distribution of encapsulated salt grains, a single layer of salt grains or a homogeneous distribution of salt, demonstrated that increasing the saltiness perception in salt-reduced food product could be achieved by a technological approach.

Retronasal odor of dried bonito stock induces umami taste and improves the palatability of saltiness.

A traditional Japanese umami-rich stock, dried bonito stock, was reported to improve the palatability of a low-salt diet due to its characteristic aroma. Two pathways are available for the presentation of odors: the orthonasal and retronasal pathways. Aroma is perceived through the orthonasal pathway. In contrast, retronasal application of odors is thought to evoke different sensations from the orthonasal pathway, which is typically perceived as taste and modifies taste. Therefore, the effect of retronasal odor on salt-reduction might be different from that of aroma, that is, orthonasal odor. Thus, the effects of the retronasal odor of dried bonito stock on the enhancement and improvement of palatability upon salt reduction were examined using sensory evaluation. Moreover, the contributions to flavor expression and palatability of dried bonito stock were also investigated. Although the retronasal odor of dried bonito did not enhance saltiness, it improved the palatability of saltiness. In the presence of no tastants except 0.68% NaCl, a content 15% less than that of Japanese traditional soup, the retronasal odor of dried bonito generated umami, enhanced the suitability for dried bonito stock, and increased palatability. This indicates that the retronasal odor of dried bonito stock could improve the palatability of a salt-reduced diet. These findings can be applied to the development of new seasonings for improving the palatability of salt-reduced foods.

「減塩食品開発を目指して―天然物由来成分の塩味増強効果を定量的に評価するシステム開発」の経緯とその後

「減塩食品開発を目指して―天然物由来成分の塩味増強効果を定量的に評価するシステム開発」の経緯とその後

Improving the palatability of salt-reduced food using dried bonito stock.

The characteristic flavors, with the exception of umami, of dried bonito stock not only enhanced saltiness but also improved palatability, namely the acceptability, of salt-reduced foods. However, the respective effects of odorants and tastants of dried bonito stock on palatability have yet to be fully explained. Thus, the effect of dried bonito stock aroma on saltiness enhancement and palatability improvement in salt-reduced food was evaluated by sensory assessment. Probit analysis indicated that aromas of the stocks, arabushi and karebushi, did not affect the intensity of saltiness. However, the test sample with aromas of dried bonito stocks was significantly more palatable than the reference sample. The effects of the taste of dried bonito stock were also evaluated. Probit analysis indicated that enhanced saltiness was not observed in the MSG solution but was observed with the dried bonito stocks, when controlled for aroma. These results suggest that saltiness enhancement by dried bonito stock was caused by the characteristic taste (excluding umami) of dried bonito stock, while its characteristic aroma and umami were involved in preventing the loss of palatability of a low-salt diet. Moreover, it was found that using a combination of karebushi and dried kelp, as material for making stock, could contribute effectively to the preparation of palatable salt-reduced foods in Japan. Invention of new seasonings for improving the palatability of salt-reduced foods could exploit these findings.

Salt Reduction in Foods Using Naturally Brewed Soy Sauce

In recent years, health concerns related to salt/sodium chloride consumption have caused an increased demand for salt-reduced foods. Consequently, sodium chloride (NaCl) reduction in foods has become an important challenge. The more so, since a decrease in NaCl content is often reported to be associated with a decrease in consumer acceptance. The objective of the present study was to investigate whether or not it would be possible to reduce the NaCl content in standard Western European foods by replacing it with naturally brewed soy sauce. Three types of foods were investigated: salad dressing (n = 56), soup (n = 52), and stir-fried pork (n = 57). In the 1st step, an exchange rate (ER) by which NaCl can be replaced with soy sauce without a significant change in the overall taste intensity was established per product type, by means of alternative forced choice tests. In the 2nd step, the same consumers evaluated 5 samples per product type with varying NaCl and/or soy sauce content on pleasantness and several sensory attributes. The results showed that it was possible to achieve a NaCl reduction in the tested foods of, respectively, 50%, 17%, and 29% without leading to significant losses in either overall taste intensity or product pleasantness. These results suggest that it is possible to replace NaCl in foods with naturally brewed soy sauce without lowering the overall taste intensity and to reduce the total NaCl content in these foods without decreasing their consumer acceptance. Health concerns related to salt consumption cause an increased demand for salt-reduced foods. Consequently, the development of foods with reduced salt content without decreasing the consumer acceptance is an important challenge for the food industry. A new possible salt reduction approach is described in the present article: The replacement of salt with naturally brewed soy sauce.

Saltiness Enhancement by the Characteristic Flavor of Dried Bonito Stock

There is a pressing need for the development of ways of preparing palatable salt-reduced foods to reduce the salt intake of the Japanese population. The salt-reducing effect of the characteristic flavors other than umami of dried bonito stock, which is widely used in everyday Japanese food, was examined by sensory evaluation. In the 1st sensory evaluation, the effect was evaluated in a model solution. The saltiness of 0.80% NaCl solution was equivalent to that of 0.12% monosodium glutamate (MSG) solution containing 0.81% NaCl and dried bonito stock containing 0.68% NaCl. Saltiness enhancement could not be found when MSG solution was used, but was found with 6% dried bonito stock. The 2nd evaluation examined whether the effect was valid for 2 everyday Japanese foods--traditional Japanese clear soup (sumashi-jiru) and steamed egg custard (tamagodoufu). Although enhancement of saltiness by dried bonito stock could not be clearly demonstrated in the soup, a change in NaCl concentration within 15% did not affect the palatability of the soup. However, dried bonito stock not only enhanced the saltiness but also improved the palatability of steamed egg custard. These findings are expected to be useful for improving the palatability of salt-reduced food.