Cross-modal interactions in complex food matrices

In the light of increasing rates of nutrition related diseases, such as obesity, diabetes, high blood pressure and stroke it is necessary to reduce sugar, salt and fat contents of industrial produced food. Reduction of those components generally leads to changes of the sensory properties of the products and rejection by the consumer. Traditional compensation strategies like the use of taste enhancers, artificial sweeteners or fat replacers often lead to off-flavours and consequently to consumer rejection. This thesis describes cross-modal interactions as an alternative strategy to reduce sugar, salt and fat. In the past cross-modal interactions have been describe to influence taste and texture perception, however up to now research focused on simple model systems lacking in perceptual, as well as chemical complexity. This thesis aimed on the application of cross modal interactions involving aroma modification to complex food systems, such as apple juice and cheese. It was investigated whether aromas are able to modify taste perception in complex food matrices and what the driving factors are to which extend aromas can enhance taste perception. Furthermore different cross modal approaches were combined in order to investigate possible additive or synergistic effects on taste enhancement. At first, the question whether individual aroma components can be identified that have the capacity to enhance taste perception in a complex beverage was addressed [chapter 2]. Apple juice was choosen to represent a complex matrix where interactions between taste and aroma are a natural product characteristic. Ethylhexanoate was identified to significantly enhance sweetness in apple juice, while three other esters selected on the same basis did not show sweetness enhancement. Ethylhexanoate induced sweetness enhancement appeared to be concentration dependent. Concentrations of 5 ppm were found to be most effective to enhance sweetness in this specific system. However, next to sweetness undesired attributes such as flowery and synthetic were also increased significantly. As a conclusion it has to be noticed that flavour balance in complex food is fragile and has to be carefully altered in order to use odour induced taste enhancement as a tool in sugar, salt and fat reduction. Chapter 3 describes the masking of off-flavours induced by ethylhexanoate as described in chapter 2. It was hypothesised that ethylhexanoate induced off-flavours can be masked by restoring flavour balance by equally adding combinations of all four esters. A combination of ethylhexanoate, ethylbutanoate and ethyl-2-methylbutanoate was found to be most effective to restore flavour quality while maintaining ethylhexanoate induced sweetness enhancement. It was concluded that all components that are naturally part of an aroma are needed to achieve a balanced product. Optimisation of odour presentation time in order to achieve maximum taste enhancement was subject to the study described in chapter 4. Swallowing is the key to aroma release during food consumption. It was demonstrated that aroma is most presented most effectively either 1.7 – 2.5 seconds before or 2.6 – 3.6 seconds after the moment of swallow. Aroma presented directly at the moment of swallow was found to be least effective to enhance taste. It is assumed that olfactory receptor neurons (ORN) do not transmit the activation signal to the brain at the exact moment of swallow in order to spare energy and function most effective, as during normal food consumption the aroma is released shortly after swallowing. This hypothesis was further tested in an fMRI study. Preliminary results support this theory, however at the moment of completion of this thesis data evaluation was still in progress. In chapter 5 further optimisation of odour/taste interactions was studied, by investigating the influence of temperature on odour induced taste enhancement. Consumption temperatures differ strongly among products. As aroma release strongly depends on the temperature of the food, it was hypothesised that the magnitude of aroma effects on taste perception changes over consumption temperature. Subjects consumed a sweet and a savoury system at four different temperatures (7, 25, 37 and 50°C). Stimuli temperature and odour presentation were fully controlled by temperature optimised gustometry and olfactometry. Both aroma/taste systems were known to have induced taste enhancement in the past (sweet: apple flavoured tea/ethylhexanoate; savoury: broth/sotolon). No significant effect of temperature was found for either of the stimulus pairs. Results indicate that the complexity of the experiment led to confusion by the panelists under fully randomised stimuli delivery conditions. It was therefore concluded, that temperature effects on the magnitude of odour induced taste enhancement need to be studied in a reduced experimental design. Temporal contrast as a strategy to enhance salty taste was studied in the experiments described in chapter 6. Salty solutions of different NaCl concentrations were presented in alternating sequence by a gustometer, creating a sensory contrast of low-in salt and high-in salt pulses. It was demonstrated that the sensory contrast induced by the pulsed delivery led to significant taste enhancement. It was shown that high concentrations of NaCl delivered in short pulses were most effective to enhance salty taste. It was concluded that pulsed stimulus delivery can be an additional tool to reduce salt and sugar concentrations in industrial produced food. Chapter 7 combines both cross-modal strategies to enhance taste in this thesis so far, odour induced taste enhancement and temporal contrast of stimulus delivery. Subjects were presented with taste and aroma pulses timed via a gustometer. The aroma was either presented in-phase or out-of-phase with the taste stimulus. A cumulative effect of aroma/taste interactions and temporal contrast of tastant delivery was found, resulting in higher taste enhancement than each of the strategies alone. Overall highest sweetness enhancement was observed when aroma and taste pulses were presented out-of-phase. Texture modification is a third cross-modal strategy to enhance taste perception. Combinatory effects of texture modification and odour induced taste enhancement are subject to the study reported in chapter 8. Apple juice containing gels were engineered differing in textural properties, aroma and sugar concentration. In contrast to the results presented in chapter 7, only an additive but no synergistic effect was found for those strategies. Texture modification was found to be more effective than aroma modification. Chapter 9 studies effects of aroma on the taste and the texture of cheese and dairy model gels. In the first study subjects consumed different types of cheese with and without a nose-clip. This way the contribution of the aroma phase on the flavour and texture perception of cheese was studied. Saltiness was influenced significantly by the aroma. It was concluded that the aroma of cheese strongly contributes to a cheeses salty taste. Furthermore it was observed that a decrease in cheese firmness strongly correlated with an increase in buttery aroma notes. This was further studied in fully controlled dairy model gels. For gels tasting of cream cheese a significant decrease in firmness was found upon increasing aroma concentration. No effect of butter aroma on firmness was found for yoghurt-like gels. This once more demonstrates the importance of congruency between stimuli. Only congruent sensory impressions can influence each other. In addition, an increase in creaminess was observed with increasing aroma concentration. The results described in chapter 9 clearly show that aromas cannot only modify taste perception, but also are a valid tool for texture modification. This thesis demonstrates for the first time, that flavour and texture modification and subsequently the reduction of sugar, salt and (possibly also) fat can be achieved by using cross modal interactions in complex food matrices. New methods have been developed and existing methods have been combined to study aroma/taste interactions in fully controlled settings. Its multidisciplinary approach combines chemical, physical and psychological knowledge in order to discuss and explain results. It furthermore shows that combinations of different strategies are most effective in order to achieve healthier products reduced in sugar, salt and fat. </p

Destabilization of dark states and optical spectroscopy in Zeeman-degenerate atomic systems

We present a general discussion of the techniques of destabilizing dark states in laser-driven atoms with either a magnetic field or modulated laser polarization. We show that the photon scattering rate is maximized at a particular evolution rate of the dark state. We also find that the atomic resonance curve is significantly broadened when the evolution rate is far from this optimum value. These results are illustrated with detailed examples of destabilizing dark states in some commonly-trapped ions and supported by insights derived from numerical calculations and simple theoretical models.Comment: 14 pages, 10 figure

Assessing fatigue in childhood cancer survivors:Psychometric properties of the Checklist Individual Strength and the Short Fatigue Questionnaire––a DCCSS LATER study

BACKGROUND: Fatigue is often reported by patients with childhood cancer both during and after cancer treatment. Several instruments to measure fatigue exist, although none are specifically validated for use in childhood cancer survivors (CCS). The aim of the current study was to present norm values and psychometric properties of the Checklist Individual Strength (CIS) and Short Fatigue Questionnaire (SFQ) in a nationwide cohort of CCS. METHODS: In total, 2073 participants were included from the Dutch Childhood Cancer Survivor Study (DCCSS) LATER cohort. Normative data, construct validity, structural validity, and internal consistency were calculated for the CIS and SFQ. In addition, reliability and a cutoff score to indicate severe fatigue were determined for the SFQ. RESULTS: Correlations between CIS/SFQ and vitality measures asking about fatigue were high (>0.8). Correlations between CIS/SFQ and measures of different constructs (sleep, depressive emotions, and role functioning emotional) were moderate (0.4–0.6). Confirmatory factor analysis resulted in a four‐factor solution for the CIS and a one‐factor solution for the SFQ with Cronbach's alpha for each (sub)scale showing good to excellent values (>0.8). Test–retest reliability of the SFQ was adequate (Pearson's correlation = 0.88; ICC = 0.946; weighted Cohen's kappa item scores ranged 0.31–0.50) and a cut‐off score of 18 showed good sensitivity and specificity scores (92.6% and 91.3%, respectively). CONCLUSION: The current study shows that the SFQ is a good instrument to screen for severe fatigue in CCS. The CIS can be used as a tool to assess the multiple fatigue dimensions in CCS

Prevalence and risk factors of cancer-related fatigue in childhood cancer survivors:A DCCSS LATER study

BACKGROUND: Cancer-related fatigue is a debilitating late effect after treatment for childhood cancer. The prevalence of fatigue in childhood cancer survivors (CCSs) and associated factors for fatigue has varied widely in previous studies. Two important aspects of cancer-related fatigue, its severity and chronicity, are often not assessed. This study investigated the prevalence of, and risk factors for, severe chronic fatigue (CF) in a national cohort of Dutch CCSs. METHODS: In this study, 2810 CCSs (5-year survivors of all childhood malignancies diagnosed between 1963 and 2001 with a current age of 12-65 years) and 1040 sibling controls were included. CF was assessed with the Short Fatigue Questionnaire and was defined as a score ≥ 18 and persistence of fatigue for ≥6 months. Cancer- and treatment-related characteristics, current health problems, and demographic and lifestyle variables were assessed as potential risk factors for CF via multivariable logistic regression analyses. RESULTS: In adult CCSs and sibling controls (≥18 years old), the prevalence of CF was 26.1% and 14.1%, respectively (P 2, 2.20; 95% CI, 1.50-3.21), and a central nervous system diagnosis (OR, 1.74; 95% CI, 1.17-2.60) were significantly associated with CF in adult CCSs. CONCLUSIONS: This study shows that CCSs, regardless of their cancer diagnosis, report CF more often than sibling controls. This study provides new evidence for the prevalence of fatigue in CCSs

The Impact of Cancer-Related Fatigue on HRQOL in Survivors of Childhood Cancer:A DCCSS LATER Study

Simple Summary Survivors of childhood cancer have an increased risk to experience symptoms of severe and persistent fatigue. We studied how fatigue might affect the health-related quality of life of these survivors. Questionnaire items asking about a broad range of daily life aspects were compared between fatigued survivors, survivors without fatigue and the general Dutch population. A total of eleven aspects were studied which were all negatively affected by fatigue, with the largest impact seen for Vitality (how much energy does a person have), General Health (perception of current and future health) and Role Limitations (work-related activities). Results show the negative impact fatigue can have on the daily lives of survivors and why it is important to treat fatigue adequately. Background: Early detection and management of late effects of treatment and their impact on health-related quality of life (HRQOL) has become a key goal of childhood cancer survivorship care. One of the most prevalent late effects is chronic fatigue (CF). The current study aimed to investigate the association between CF and HRQOL in a nationwide cohort of CCS. Methods: Participants were included from the Dutch Childhood Cancer Survivor Study (DCCSS) LATER cohort, a nationwide cohort of CCS. Participants completed the Checklist Individual Strength (CIS) to indicate CF (CIS fatigue severity subscale >= 35 and duration of symptoms >= 6 months) and the Short Form-36 (SF-36) and TNO (Netherlands Organization for Applied Scientific Research) and AZL (Leiden University Medical Centre) Adult's Health-Related Quality of Life questionnaire (TAAQOL) as measures for HRQOL. Differences in mean HRQOL domain scores between CF and non-CF participants were investigated using independent samples t-tests and ANCOVA to adjust for age and sex. The association between CF and impaired HRQOL (scoring >= 2 SD below the population norm) was investigated using logistic regression analyses, adjusting for confounders. Results: A total of 1695 participants were included in the study. Mean HRQOL domain scores were significantly lower in participants with CF. In addition, CF was associated with impaired HRQOL on all of the domains (except physical functioning) with adjusted odds ratios ranging from 2.1 (95% CI 1.3-3.4; sexuality domain) to 30.4 (95% CI 16.4-56.2; vitality domain). Conclusions: CF is associated with impaired HRQOL, urging for the screening and regular monitoring of fatigue, and developing possible preventative programs and interventions

Chronic fatigue in childhood cancer survivors is associated with lifestyle and psychosocial factors; a DCCSS LATER study

Background: The purpose of this study was to determine factors associated with chronic fatigue (CF) in childhood cancer survivors (CCS). Patients and methods: Participants were included from the Dutch Childhood Cancer Survivor Study (DCCSS) LATER cohort, a nationwide cohort of CCS (≥5 years after diagnosis) and siblings as controls. Fatigue severity was assessed with the ‘fatigue severity subscale’ of the Checklist Individual Strength (‘CIS-fatigue’). CF was defined as scoring ≥35 on the ‘CIS-fatigue’ and having fatigue symptoms for ≥6 months. Twenty-four parameters were assessed, categorized into assumed fatigue triggering, maintaining and moderating factors. Multivariable logistic regression analyses were carried out to investigate the association of these factors with CF. Results: A total of 1927 CCS participated in the study (40.7% of invited cohort), of whom 23.6% reported CF (compared with 15.6% in sibling controls, P &lt; 0.001). The following factors were associated with CF: obesity [versus healthy weight, odds ratio (OR) 1.93; 95% confidence interval (CI) 1.30-2.87], moderate physical inactivity (versus physical active, OR 2.36; 95% CI 1.67-3.34), poor sleep (yes versus no, OR 2.03; 95% CI 1.54-2.68), (sub)clinical anxiety (yes versus no, OR 1.55; 95% CI 1.10-2.19), (sub)clinical depression (yes versus no, OR 2.07; 95% CI 1.20-3.59), pain (continuous, OR 1.49; 95% CI 1.33-1.66), self-esteem (continuous, OR 0.95; 95% CI 0.92-0.98), helplessness (continuous, OR 1.13; 95% CI 1.08-1.19), social functioning (continuous, OR 0.98; 95% CI 0.97-0.99) and female sex (versus male sex, OR 1.79; 95% CI 1.36-2.37). Conclusion: CF is a prevalent symptom in CCS that is associated with several assumed maintaining factors, with lifestyle and psychosocial factors being the most prominent. These are modifiable factors and may therefore be beneficial to prevent or reduce CF in CCS.</p

Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry

Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase

Combinatory Effects of Texture and Aroma Modification on Taste Perception of Model Gels

In this study, the effects of texture modification and aroma-induced sweetness enhancement were systematically investigated in apple-flavored semi-solid Na-caseinate gels. Gels containing apple juice as a basic flavor were developed differing in stiffness, brittleness and serum release (texture modification), aroma, and sugar concentration (flavor modification). In a full factorial design (2 x 2 x 2), eight samples were evaluated by a sensory panel on ten attributes (five texture, five flavor). Sweetness was enhanced significantly by modification of texture, aroma, and sugar concentration. Texture modification was found to be by far the greatest contributor to overall sweetness. In comparison to texture modifications, aroma modification and changes of sugar concentration resulted only in small sweetness enhancement. When texture and aroma modifications are combined, a small additive effect of aroma modification on sweetness enhancement was found in addition to the sweetness enhancement caused by texture modification. This suggests that the relationship between texture (modification) and flavor (modification) and sweetness is additive in a nonlinear manner. It can be concluded that texture modification is a valid tool to enhance taste intensity. Hence, texture modification can compensate for a loss of sweet taste intensity induced by sugar reduction, while aroma-induced sweetness enhancement can contribute to further taste enhancement in order to develop healthier products