In recent years, dietary changes appear to be shifting universally towards a diet with high intakes of caloric sweeteners, foods from animal origin and edible oils. There is an enormous societal pressure in both middle and high income countries in the world to reduce salt, sugar and fat levels in foods. However, attempts to reduce these levels face the challenge of keeping sensory perceptions of tastes at optimal levels. From this perspective it is important to have insight in the relationships between the physical, chemical or nutrient composition of commonly consumed foods and the sensory perception of taste. In addition, the taste characteristics in current diet-within and across cultures- are highly relevant for nutritional research. Nevertheless, this demands for accurately described food-taste databases, which are supported with data on the reliability and performance of the sensory panel that determined the taste values.
The present thesis has two main objectives. First, to quantify taste of commonly consumed foods by means of a trained sensory panel that acquired a common frame of references throughout training. Followed by to describe and compare the dietary patterns of two target populations, i.e. Dutch and Malaysian in terms of the quantified taste food database.
In order to quantify the taste profiles of commonly consumed foods, we set-up and trained a Dutch and Malaysian taste panel, based on taste modalities of sweetness, sourness, bitterness, umami, saltiness and fat sensation, with the aid of inspired SpectrumTM scales (Chapter 2). Performance of both panels was described by discrimination, repeatability (RMSE), and agreement. Our descriptive training procedure yielded two panels from different cultures that were similar in panel performance. More importantly, they obtained similar taste profiles for 19 different foods. This implies that food-taste databases obtained with valid and standardized training procedures may be used to quantify the sensory profiles of dietary patterns of populations.
In Chapter 3, we first compiled and translated the obtained taste profiles of a total of 892 commonly consumed foods (i.e. representing 83% and 88% of daily Dutch and Malaysian individual’s average daily energy intake) into Dutch and Malaysian taste databases. We then further combined with compositional data to investigate whether taste could function as a nutrient sensor in the context of the current diet, within and across populations. Results showed that sweetness was associated with mono- and disaccharides, umami was associated protein content, saltiness was associated with sodium content, and fat sensation was associated with fat content, in both commonly consumed Dutch and Malaysian foods. This suggests that sweetness, umami, saltiness and fat sensation can signal the presence of nutrients, and that associations of taste intensity and nutrient content are not culture-specific.
Combined with food consumption data, the taste databases can be used to describe the taste exposures in the whole diet, i.e. dietary taste patterns. In Chapter 4, we first described the dietary taste patterns in Malaysia, and compared to these to the dietary taste patterns in The Netherlands, a country with Western eating patterns. Next to this, we further compared dietary taste patterns of specific demographic subgroups in Dutch and Malaysians, that is men and women, younger and older individuals, and overweight and normal-weight individuals. Our findings indicated that the overall dietary taste patterns were different between two populations, in which Malaysians consumed a larger percentage of energy from ‘savory fatty’ tasting foods but a smaller percentage of energy from ‘neutral’ tasting foods than Dutch. Despite these differences, men consume more savory fatty foods than women in both populations. No consistent differences were seen according to age and weight status.
In Chapter 5, we described and compared the taste dietary patterns in the Netherlands and Malaysia, based on different eating occasions at both the level of energy contribution as well as the frequency of consumption. In total eating occasions, Malaysian individuals heightened energy intakes from ‘savory fatty’ tasting foods than ‘sweet fatty’ tasting foods compared to their Dutch counterparts. We also observed that the dietary taste patterns of main meals and snacking behaviors in the Dutch population were more varied and distinct over a day, compared to the Malaysian population. This suggests that cultural context plays an important role in determining food choice and intake patterns, even when the available foods have similar taste profiles.
Summarizing, the research described in this thesis provides new insights by putting sensory science (i.e. perception of taste) into nutrition and public health domain. The findings showed the standardized training procedure yields similar panel performance of two cross-cultural trained taste panels, and whereby this serves as the ground work to obtain food taste profiles that can be further translated into populations’ taste databases. The information richness of the quantified food taste databases allows it to cross-correlate with compositional and consumption data, within and across cultures. The results demonstrate that taste can signal the presence of nutrients, and that associations of taste intensity and nutrient content are not culture-specific. Whilst, the overall dietary taste patterns are different across cultures, in which Malaysians heightened energy intakes from ‘savory fatty’ tasting foods than ‘sweet fatty’ tasting foods compared to Dutch. Interestingly, men consume more ‘savory fatty’ foods than women in both populations. Across eating occasions, dietary taste intake patterns of the Dutch population are more varied and distinct over a day, compared to the Malaysian population.
In conclusion, assessing the role of taste in diet faces numerous challenges that extend beyond the rigorous measures to quantify taste and appropriateness to describe the dietary behavior as a whole diet. This thesis highlights the use of objective panel, taste databases and dietary patterns to describe and compare the taste characteristics of a diet within and across cultures. By focusing on the role of taste in diet, we learned that cultural context plays an important role in determining food choice and intake, even when the available foods have similar taste characteristics. Much more needs to be done not only in expanding and updating food taste databases; there is also a need to further assess the dietary taste patterns in other population groups, i.e. children, elderly, patients and ethnic-specific groups. Future prospective studies should be carried-out to relate the dietary taste patterns with chronic diseases. Studying dietary patterns from a taste perspective - and not only a nutritional perspective – can provide us with a deeper understanding of the role of taste in dietary intake.