Effect of Food Matrix on Saltiness Perception—Implications for Sodium Reduction

Enhancing sodium release from the food matrix, thus increasing saltiness perception, is a promising strategy to reduce the amount of salt needed in foods. However, the complex nature of the effect of the food matrix on saltiness perception makes it difficult to control saltiness perception when designing food products. The aim of this review is to provide an overview of the food matrix effects on saltiness perception of sodium chloride. The effects are discussed in the order of 3 stages in saltiness perception: release of sodium from food matrix into oral cavity (1st stage), delivery of sodium within oral cavity (2nd stage), and detection of sodium by the taste receptor cells (TRCs) (3rd stage). In the 1st stage, the food matrix affects the initial availability of sodium to be released, and also affects the spontaneous and facilitated migration of sodium from the matrix into the oral cavity. In the 2nd stage, the food matrix affects the availability of sodium and the mixing efficiency of sodium with saliva. The relationship between food matrix and oral processing of food that may affect the sodium release (1st stage) and the delivery (2nd stage) is also discussed. In the 3rd stage, the food matrix affects the physical availability of sodium for the TRCs, the physiological activity of TRCs, and the central activities involved in the perception process. Based on the understanding of complex nature of the matrix effects on saltiness perception discussed in this review, the properties of food matrix may be controlled effectively to enhance saltiness perception and achieve sodium reduction.     

Texture-taste interactions: Enhancement of taste intensity by structural modifications of the food matrix

The reduction of salt and sugar in food products remains a challenge due to the importance of those ingredients in providing a highly desired taste quality, enhancing flavor, determining the behavior of structuring ingredients, and ensuring microbiological safety. Several technologies have been used to reduce salt and sugar content in foods such as replacement of sugar by sweeteners, replacement of sodium salts by blends of other salts, taste enhancement by aromas and taste boosters or gradual reduction of sugar and salt in small steps over time. In this study we present two alternative approaches to enhance taste perception. First, the use of an inhomogeneous spatial distribution of sugar in food gels is introduced as a way to enhance sweetness perception [1]. The translation of the concept of taste contrast to bread applications is discussed which allows to reduce salt content in bread by 25% without loss of saltiness intensity and without addition of taste enhancers, aromas or salt replacers [2]. Secondly, it is demonstrated how the serum release under compression of mixed polysaccharide/protein gels can be engineered to enhance sweetness perception. An increase of serum release by 5x allowed to reduce sugar content of gels by 30% while maintaining sweet taste intensity [3]. The translation of this concept to low salt sausages is discussed. Sausages were engineered to exhibit enhanced juiciness which lead to a boost of saltiness allowing for up to 40% salt reduction [4]. These approaches can be used to further optimize the development of products with reduced salt and sugar content while maintaining taste intensity.     

The associations between genetics,salt taste perception and salt intake in young adults

Food liking is one of the main determinants of food intake. Salt taste perception and preference, that play a role in liking of salt, may be genetically determined, although research in humans is scarce. The aim of this study was to explore the associations between genetics, salt taste perception, preference, self-reported salt habit and intake. The participants were young (18–35 years) and healthy adults (32 males and 63 females). Salt taste thresholds were determined with British Standard ISO3972:2011 methodology and salt taste preference by ratings of saltiness and pleasantness of tomato soup with salt concentrations reflecting salt content in foods. Self-reported salt habit was determined by asking participants how salty they usually eat their food and salt intake with two 24-hour 5-step multiple pass recalls. Genotyping for variants in the SCNN1B rs239345 and TRPV1 rs8065080 was performed. Participants homozygous for the minor allele of the rs8065080 had lower ratings of saltiness (p = 0.008) and higher ratings of pleasantness of soup (p = 0.027) when compared to major allele carriers. Preference for salt in soup was associated with salt habit (p = 0.003) and participants with high salt preference had higher salt intake compared to those with low salt preference (2236 ± 261 vs. 1543 ± 107 mg/1000 kcal, p = 0.017). TRPV1 rs8065080 may play a role in salt taste perception and preference, which should be confirmed in a larger sample size study. Hedonic appeal of salty food should be considered when providing personalised advice to change this behaviour.     

胶体结构设计在减盐食品中的应用

食盐是常用的食用调味品,高盐(钠)饮食带来的高血压、心血管疾病等健康问题日趋严重,但直接减盐或使用盐替代品往往会使食品感官品质下降.饮食中的钠主要来源于加工食品,其中食品胶体是钠的重要来源.如何对现有的食品胶体体系进行结构设计,保留现有风味的同时减少钠的摄入,成为当前研究的热点.本文从食品基质角度出发简述了咸味感知机理...     

Fat and salt contents affect the in-mouth temporal sodium release and saltiness perception of chicken sausages

In cooked meats, sodium chloride is involved in taste, texture and flavour release. So a reduction in the salt content may have an impact on overall perception and acceptability. The aim of this study was to evaluate the influence of composition on sodium release and saltiness intensity in chicken sausages. The rheological properties of the sausages differed according to composition. Temporal sodium release and temporal saltiness intensity were evaluated by four selected subjects when eating sausages. At each time point, the effect of the salt level in sausages on sodium release was positive and highly significant. The effect of lipids on sodium release was negative. Concerning perception, the amount of salt used had a positive effect on saltiness intensity, and lipids seemed to exert a masking effect. Generally, clear relationships between salt levels, sodium release and saltiness intensity were found but the masking effect of lipids on saltiness intensity probably also involved texture or fat perception mechanisms.     

A salt substitute with low sodium content from plant aqueous extracts

The perception of the salty taste, obtained in humans by using sodium chloride (NaCl), is one of the most important attributes of the human sensory system. However, extra intake of sodium present in salt might lead to conditions such as hypertension. To develop a salt substitute with low sodium content, 13 plants were extracted with water, and their sensory perception was analyzed. After the sensory evaluation, 3 plant aqueous extracts (PAEs), representing salty and umami tastes, were selected using principal component analysis (PCA). They were powdered using a spray dryer, mixed, and subsequently referred to as plant salt substitute (PSS). The relative saltiness of PSS to NaCl was shown to be 0.65. When the degree of saltiness between PSS and NaCl is the same, PSS contains 43% less sodium than NaCl. Therefore, PSS can be used in food to reduce an individual's sodium intake while retaining the salty taste of NaCl.     

Reducing salt content in beef frankfurter by edible coating to achieve inhomogeneous salt distribution

High dietary salt (NaCl) intake is a global health concern which leads to various chronic diseases; hence, the reduction of salt content in foods has been a high demand in the food industry. Inhomogeneous salt distribution is a promising strategy for salt reduction. This study investigated the effect of inhomogeneous salt distribution using salt edible coating on the physiochemical and sensory attributes of beef frankfurter sausages. Results demonstrated that this method significantly reduced the salt content in frankfurter sausages by 60–81% without affecting the consumers’ perception of saltiness intensity. Among the coated samples, 7.5% and 10% salt coating samples showed the best performance on the product quality. However, the problems associated with high cooking loss and hard texture of the salt-coated sausages need to be further addressed. This research has potentially developed a new method for manufacture of salt-reduced food.     

Sensory design in food 3D printing – Structuring,texture modulation,taste localization,and thermal stabilization

Most 3D printing studies of foods deal with the feasibility and modulation of textures independent of flavor design aspects. As a cornerstone for the combined control over texturing and taste distribution, a 3D printing method for starch-based food textures was developed in a pioneering approach using dual extrusion coupled with focused on-board near infrared (NIR) heating for thermal stabilization. The developed method facilitated the design of hydrated starch-egg white powder-systems in reproducible printing configurations. To systematically study the influence of inhomogeneous taste distribution on sensory perception, it was applied in a saltiness sensory contrast study. For the first time, defined concentration gradients of sodium chloride were spatially printed in food textures. Comparable textural properties at the same infill levels were achieved for all printed structures with different sodium localizations. Furthermore, the inhomogeneous spatial distribution of sodium chloride caused saltiness enhancement. This 3D structuring, taste localization coupled with thermal stabilization (3D SLTS) methodology enables the elucidation of texture-taste release interactions.     

食品减盐方法研究进展

食盐作为日常生活中最常见的调味品之一,其主要成分氯化钠是人体中必不可少的物质。食盐具有改善食品风味和质构、延长食品货架期等作用。但摄入过量的食盐会增加患高血压、冠心病等心血管疾病的风险。本文综述了在不影响食品风味品质前提下,达到“减盐不减咸”目的的方法,如非钠盐替代、添加天然提取物或咸味肽、多感官协同作用增强咸味感知、食盐晶体结构优化、食品质构重组等,并对各种减盐方法的基本原理、特点以及研究进展做了详细阐述,以期为食品减盐方法和策略的深入研究提供科学依据和理论参考。     

(Not to be taken) with a grain of salt: Enhancing perceived saltiness by 3D-printed surface textures

Seeking to promote healthy food options through design, this study investigates whether food saltiness perception can be enhanced through the design of the surface texture of the container from which the product is sampled, using 3D-printing. An experimental study was conducted at a supermarket in which shoppers (N = 270) participated in a taste test. A full-factorial 3 (surface texture: smooth, rough, rough and irregular) × 3 (salt content: low, medium and high salt content) between-subject design was employed. Participants in each condition were asked to try the product and assess saltiness perception, taste intensity, taste liking and willingness to try. Results testify to the feasibility of enhancing saltiness impressions through both rough and irregular 3D-printed surface textures, but only for the medium-salt and high-salt variants. Findings on taste liking and willingness to try likewise testify to the importance of considering the interaction between surface texture and saltiness. These findings qualify previous research on cross-modal correspondences by showing that applications of surface textures may backfire when the gap between expectations triggered by tactile sensations and actual food contents becomes too large. Implications for initiatives aimed at promoting healthy food choices are discussed.     

Understanding of the influence of composition,structure and texture on salty perception in model dairy products

The aim of this study was to better understand salt release and perception in model dairy products, having different composition, structure and/or texture. Sensory and instrumental methods were used to quantify and relate texture to salt mobility and perception. A high dry matter content (protein and fat jamming) and a gel structure with a protein network formation induced a decrease of diffusion coefficient of salt in matrices. Moreover, salty perception was higher for non-renneted products than for gelled ones. For gels, saltiness was enhanced in fat products. These results were discussed in regards with textural and physico-chemical food properties: the structural parameter tan δ was the most correlated with salty perception highlighting the impact of product structure on saltiness. Results also demonstrated that physiology and complex events (mastication, dilution and mixing with saliva, dynamic of bolus formation) occurring during food consumption must be considered to go further in understanding.     

Correlation between saltiness perception and shear flow behaviour for viscous solutions

Salt plays a major role in the human diet and food as tastant, flavour enhancer, nutrient, preservative and structuring aid. While intake of salt is part of a healthy diet, the vast majority of people in the developed world consume salt at a level high enough to place them at risk of developing diet induced illnesses. Salt intake is predominantly from processed foods. In this study it has been investigated whether careful choice of the viscosity behaviour of food thickeners, as used in processed foods, is exploitable to enhance saltiness perception and therefore allows reducing the content of salt in processed foods without compromising flavour.     

Increasing saltiness perception through perceptual constancy created by expectation

Reducing salt levels in food products is an important motivation for research, as the general intake of salt by consumers is too high. Finding strategies for salt reduction, while maintaining salty taste of products remains a big challenge. In this paper we show the effect that a perceptual expectation of a taste can have on subsequent taste perception, in the same product. A perceptual expectation is based on previous experience, memory, or other information from the product. Our hypothesis is that, if a product looks the same, smells the same and has the same texture as the product one is used to eat, small variations in taste will go unnoticed. In a consumer study, we investigated if the expectation, or implicit assumption, that saltiness remains constant across mouthfuls, can indeed reduce the perception of variation in salt concentration. We were able to demonstrate the existence of such an effect. We found that perceptual expectation, based on the first bite, can influence saltiness perception.     

Cross-modal interactions between taste and smell: Odour-induced saltiness enhancement depends on salt level

In recent years, health concerns related to salt have led to extensive research on low-salt foods. One major remaining issue is to reduce sodium content while still providing the salty fix, to maintain food appreciation, acceptance and choice. Using well-selected odours has been proposed to compensate for sodium chloride reduction in food, due to the cross-modal interactions between odour and taste. However, interactions between taste and odour, with regards to saltiness, remain poorly investigated. Moreover, although a few studies have assessed the influences of odour and sweet supra-threshold intensity on cross-modal interactions, none focused directly on how they influence saltiness. Therefore, the aim of the present study is to determine if the level of saltiness, i.e., the concentration of sodium chloride in aqueous solutions, influences odour-induced saltiness enhancement (OISE). A panel of 64 untrained panellists evaluated the saltiness of water solutions including salt and a tasteless odorant. Following a full factorial design, three concentrations of salt were used in conjunction with three aroma conditions. The results confirmed that OISE depends on odour-taste congruency but also clearly indicated that OISE depends on salt concentration (salty intensity): the saltiness of a low- or medium-salt-content solution increased significantly when subjects perceived simultaneously the congruent sardine aroma, but OISE was no more significant with high-saltiness solutions. This effect has to be taken into account when using OISE as a compensation strategy in low-salt food.     

Saltiness perception related to salt release of surimi emulsified sausages: modulation in texture and microstructure by polysaccharides

The effect of κ-carrageenan (CG), high acyl gellan (HAG), xanthan gum (XG) and locust bean gum (LBG) on the salt release and saltiness perception of surimi emulsified sausages was investigated. CG, LBG and XG significantly reduced the fracture strain to 62.62%, 58.56% and 58.23%, causing the formation of disintegrating gels. Microstructure observation showed that sausages with CG or LBG had porous structure, but the former formed an interpenetrating network and promoted hydrophobic interactions and the formation of disulphide bonds, while the latter was physically filled in the protein network. The maximum salt release was observed in the sausage with CG due to rapid salt diffusion from porous and interpenetrating network structure. Sensory analysis further proved that the saltiness perception of sausages was enhanced by CG. The present work provided an approach for salt reduction in sausages by facilitating salt release achieved by modulating the texture attributes and microstructure using polysaccharides.     

Ham Particle Size Influences Saltiness Perception in Flans

One major issue of the food industry is reducing sodium content while maintaining food acceptability and liking. Despite extensive research in this field, little has been published on real complex food products. The aim of this study was to investigate whether the size of particles, a parameter easily adjusted in food processing, could influence the salty taste of low‐salt food product. We thus evaluated the effect of ham particle sizes (4 levels, including a zero level) on salt perception and the consumer liking of flans varying in their overall salt concentrations (low‐ and high‐salt content). Two consumer panels, composed of 107 and 77 subjects, rated, respectively, the saltiness of and liking for the developed flans (8 samples). The outcomes of this study indicated first, that the addition of ham to flans increased the salty taste perception and second, that a decrease in ham particle size (ground ham) increased the perceived saltiness. Moreover, low‐ and high‐salt flans were equally liked, demonstrating that food manufacturers could reduce the salt contents (here, by over 15%) while maintaining consumer acceptability through the manipulation of the size of the salt‐providing particles.     

Reducing salt: A challenge for the meat industry

Intake of dietary sodium has been linked to hypertension and consequently increased risk of cardiovascular disease (CVD). The estimated cost of CVD to both the EU and US economies is €169B and $403B, respectively. Currently the daily sodium adult intake is approximately three times the recommended daily allowance (Ireland and UK) and therefore public health and regulatory authorities are recommending reducing dietary intake of sodium to 2.4 g (6 g salt) per day. Processed meat products comprise one of the major sources of sodium in the form of sodium chloride (salt). Salt has an essential function in meat products in terms of flavour, texture and shelf-life. Apart from lowering the level of salt added to products there are a number of approaches to reduce the sodium content in processed foods including the use of salt substitutes, in particular, potassium chloride (KCl) in combination with masking agents, the use of flavour enhancers which enhance the saltiness of products when used with salt and finally optimising the physical form of salt so that it becomes more functional and taste bioavailable. The ultimate goal of ingredient suppliers and meat processors is to produce reduced sodium meat products that consumers can enjoy as part of an ongoing healthier diet and lifestyle. This article reviews some of the technological aspects of reduced salt meat products and how the meat and food ingredient industries are responding to this current health issue.     

基于固体食盐结构及成分设计的减盐策略及其研究进展

食盐是食品工业和居民日常生活中广泛使用的调味品,其主要成分氯化钠的过量摄入会增加高血压、胃癌、脑卒中等疾病的患病风险。如何在不影响食品口味的条件下减少含盐量是目前的研究热点。固体形式的氯化钠是日常膳食食盐摄入的重要部分,改善固体氯化钠结构及食盐成分是开发低盐食品的有效方法。本文在详细探讨咸味感知机理和机体内钠吸收代谢机制的基础上,对近年来国内外与氯化钠结构调控及成分设计有关的减盐策略进行综述,讨论减少食品含盐量而不影响咸味的各项技术,如调控氯化钠物理结构（形貌和粒径）、包埋氯化钠、添加氯化钠替代物（咸味矿物盐、风味增强剂和天然呈味物质）,并分析不同结构及成分食盐的减盐原理、缺点和适用场景,为未来设计新型食盐产品,开发减盐健康食品,减少居民膳食盐摄入量,提高居民健康水平提供理论依据和技术支撑。     

Odour–taste interactions: A way to enhance saltiness in low-salt content solutions

This study investigated odour–saltiness interactions in aqueous solutions. In a first experiment, 81 consumers indicated expected taste attributes for 86 labels of flavour related to common food items. Panellists were able to rate expected saltiness of food flavour evoked by food written items. Differences in expected saltiness were observed in relation to actual salt content of food. In experiment 2, we selected commercially available aromas corresponding to 14 of the salt-associated flavour labels found in experiment 1. Odour-induced saltiness enhancement was investigated for odours evoked by these aroma water solutions containing or not sodium chloride. Fifty-nine consumers rated odour and taste (bitterness, sourness, saltiness, and sweetness) intensity orthonasally and retronasally. Results showed that expected flavours could induce saltiness and enhance saltiness in solutions containing a low level of sodium chloride through odour-induced changes in taste perception. These results suggest that well selected odours could be used to compensate sodium chloride reduction in food.