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Two important signalling pathways of NF-κB and ERK transmit merely 1 bit of information about the level of extracellular stimulation. It is thus unclear how such systems can coordinate complex cell responses to external cues. We analyse information transmission in the MAPK/ERK pathway that converts both constant and pulsatile EGF stimulation into pulses of ERK activity. Based on an experimentally verified computational model, we demonstrate that, when input consists of sequences of EGF pulses, transmitted information increases nearly linearly with time. Thus, pulse-interval transcoding allows more information to be relayed than the amplitude–amplitude transcoding considered previously for the ERK and NF-κB pathways. Moreover, the information channel capacity C, or simply bitrate, is not limited by the bandwidth B = 1/ τ , where τ ≈ 1 h is the relaxation time. Specifically, when the input is provided in the form of sequences of short binary EGF pulses separated by intervals that are multiples of τ / n (but not shorter than τ ), then for n = 2, C ≈ 1.39 bit h −1 ; and for n = 4, C ≈ 1.86 bit h −1 . The capability to respond to random sequences of EGF pulses enables cells to propagate spontaneous ERK activity waves across tissue.

The development of sugar-reduced food products is a strategy to reduce the high sugar intake, which is a leading cause of global health concerns. Replacement and/or reduction of sucrose often leads to reduced sweetness perception with the consequence of decreased consumer acceptance. The aim of this work is to implement sensory modulation principles in a model confectionery system with the goal of enhancing sweetness perception. By using 3D-printing, confectionary samples were meso-structured by inhomogenous distribution of sucrose concentrations and assessed with a trained panel regarding sweetness. All samples were made up of a high and low sucrose phase and compared to a homogeneous reference sample. The overall sugar content was kept constant at 22.8% in all samples and sweetness perception was compared. A significant increase of sweetness perception by over 30% was found for samples consisting of a sweet outer shell and an inner less sweet core with a high sucrose gradient between the two phases. Whilst textural effects on sweetness perception could not be fully excluded, results can be seen as a strong indication that sweetness modulation by inhomogenious distribution has a potential to be applied directly in solid food products., Food Quality and Preference, 88, ISSN:0950-3293, ISSN:1873-6343

Two sensory studies were carried out to compare the taste intensity, the perceived fluctuation of taste intensity and the consumer preference of food products with homogeneous and inhomogeneous distributions of tastants using 2-alternative forced choice tests. The first study evaluated pairs of gels, breads and sausages (1 homogeneous product and 1 inhomogeneous product). The second study evaluated 4 types of gel and 4 types of sausage (1 homogeneous product and 3 inhomogeneous products varying in the magnitude of tastant concentration differences). In the first study, all products with an inhomogeneous distribution of tastants were perceived sweeter or saltier than the respective homogeneous products. Tastant concentration differences were perceived as fluctuations of taste intensity in inhomogeneous gels and breads, but not in inhomogeneous sausages. Inhomogeneous gels and sausages were more preferred than the homogeneous products, whereas inhomogeneous and homogeneous breads were equally preferred. In the second study, inhomogeneous gels with large tastant concentration differences were perceived sweeter than the homogeneous gel. The taste intensity of homogeneous and inhomogeneous sausages did not differ. Tastant concentration differences induced perceivable taste intensity fluctuations in inhomogeneous gels, but not in inhomogeneous sausages. The inhomogeneous gel with the largest tastant concentration difference was more preferred than the homogeneous gel. Homogeneous and inhomogeneous sausages were equally preferred. Results suggest that the enhancement of taste that is caused by tastant concentration differences does not require the conscious perception of taste intensity fluctuations. We conclude that products in which tastants are heterogeneously distributed are equally or more preferred than products in which tastants are homogeneously distributed. Therefore, the modulation of the spatial distribution of tastants might be used as a strategy to reduce sugar and salt in food products without compromising consumer preference.

Aroma–taste interactions and heterogeneous spatial distribution of tastants were used as strategies for taste enhancement. This study investigated the combination of these two strategies through the effect of heterogeneous salt and aroma distribution on saltiness enhancement and consumer liking for hot snacks. Four-layered cream-based products were designed with the same total amount of sodium and ham aroma but varied in their spatial distribution. Unflavoured products containing the same amount of salt and 35% more salt were used as references. A consumer panel (n = 82) rated the intensity of salty, sweet, sour, bitter and umami tastes as well as ham and cheese aroma intensity for each product. The consumers also rated their liking for the products in a dedicated sensory session. The results showed that adding salt-associated aroma (ham) led to enhancement of salty taste perception regardless of the spatial distribution of salt and aroma. Moreover, products with a higher heterogeneity of salt distribution were perceived as saltier (p < 0.01), whereas heterogeneity of ham aroma distribution had only a marginal effect on both aroma and salty taste perception. Furthermore, heterogeneous products were well liked by consumers compared to the homogeneous products.

Variations of tastant concentration during the consumption of food products were shown to enhance taste intensity. The aim of this study was to investigate the relation between the frequency at which tastant concentration is varied during the consumption of products and the occurrence of taste enhancement. For this purpose, the sweetness intensity of sequences of 4 successive sweet stimuli represented by cubes of a semi-solid gel or spoons of a model custard dessert was assessed. The intensity and the order of the stimuli within the sequences were varied to obtain 4 types of sucrose concentration profile (decreasing, increasing, middle peak and boundary peak) at 2 magnitudes of concentration differences (small and large). Sequences of 4 stimuli containing a constant sucrose concentration were used as a reference. The sweetness intensity of the sequences of successive stimuli was assessed using line scale and time-intensity ratings. Line scale ratings showed that the type of sequence had an effect on sweetness intensity. A sweetness enhancement relative to the reference was observed in sequences that ended with high-intensity stimuli, whereas sweetness suppression was observed in sequences that ended with low-intensity stimuli. The observed sweetness enhancement and suppression were attributed to serial position effects (i.e. recency effects). Time-intensity ratings indicated that each stimulus in the sequences was evaluated individually by the assessors. Sequential effects seem to have occurred during the continuous evaluation of successive stimuli, since preceding stimuli in the sequences affected the evaluation of posterior stimuli. Furthermore, the overall sweetness intensity of the different sequences was not enhanced in relation to the reference. The lack of taste enhancement in sequences exhibiting variations of sucrose concentration was attributed mainly to the long period at which sucrose concentration was varied during the evaluation of the sequences. It was confirmed that the frequency of variation of tastant concentration affects the occurrence of taste enhancement.

Effects of subjects’ taste sensitivity (expressed as taste detection threshold), tastant quality and taste transduction mechanism on pulsation-induced taste enhancement were tested. Taste intensities of pulsatile MSG and NaCl stimuli at pulsation periods below, at and above individual taste fusion periods (TFP in seconds) were compared to taste intensities of a continuous reference of the same net tastant concentration and quality. In line with results previously reported for sucrose, pulsation-induced taste enhancement peaked around TFP for both MSG and NaCl and did not require perception of tastant pulsation. TFP and pulsation effects were independent of the taste transduction mechanism (G-protein-coupled receptor for MSG versus ion-channel for NaCl). The absence of a relation between TFP and taste sensitivity suggests that temporal gustatory resolution and taste sensitivity are not necessarily influenced by the same factors. The results support earlier findings that early stages of taste transduction are involved in pulsation-induced taste enhancement. Pulsation-induced taste enhancement is determined by the pulsation rate (i.e. TFP) which is longer for MSG than NaCl. This is probably due to the tastant-specific interaction with the receptor rather than the taste transduction mechanism (G-protein-coupled receptor versus ion-channel) involved.

Bread and cereals contribute 30% to the daily intake of sodium (Na) in the western human diet. Since the average Na intake is double the recommended intake, pressure has built up for the food industry to lower Na in their products. Especially replacing functionality of Na as a tastant remains very difficult. In this study we describe a strategy to enhance saltiness intensity in bread using an inhomogeneous spatial distribution of Na. Our results demonstrate that sensory contrast provides a promising strategy to significantly reduce the Na content in bread without loss of saltiness intensity and without the use of sodium substitutes, taste or aroma additives. © 2010 Elsevier Ltd.