Food coloring influences taste and flavor perception Moa Strandberg ProCivitas Privata Gymnasium, VT 2014 Abstract Research about our senses is essential when understanding our body and our brain. One might think that when I drink a glass of milk, the taste buds tell the truth, which is not the case. It has long been known that a flavor is not only the signal our taste buds send. This pilot study used a simple lemonade test with three cups, using ordinary strawberry lemonade and using food coloring in two of the cups, ending up with red, light red and purple colored drinks. The participants (n=36) were then asked to taste the three drinks and answer five questions. The main question is: Which one has the most flavor intensity? and the other question of interest is: Which one tastes most delicious?. The other questions were used to hide the purpose of the study. The hypothesis is that we can be fooled to think the darker the drink is, the more flavor intensity and the greater it tastes even though they taste exactly the same. The results showed that 73% (26 people) said they thought the red drink and the purple drink had more flavor intensity and 64% (24 participants) said that the red drink and the purple drink tasted more delicious. The findings in this pilot study suggest that red food coloring and red + blue food coloring poured into an already red drink do influence taste and flavor perception. Key words: Flavor, food coloring, perception, taste, human senses Background Many people are not aware of how unreliable our brain can be and how easy it can be fooled. Understanding human senses is crucial when understanding how the human body works, and especially how the brain interprets information. Research about how the senses operate and how they can be affected by earlier experiences is therefore a subject worth investigating. Does food coloring influence taste and flavor perception in humans? This question has been investigated by several researchers and yet an unequivocal answer has not been reached, at least when investigating whether food coloring influences human perception of a particular flavor (e.g., banana, strawberry, orange, etc.) or taste attribute (e.g., sweetness, saltiness, etc.). The results from these studies are rather ambiguous. Some results suggest that food coloring does influence taste and flavor perception in humans (Auvray and Spence, 2008; Stevenson, 2009 see Spence et al., 2010) but on the other hand, there are studies that have not been able to show that effect (Alley and Alley, 1998; Frank et al., 1989 see Spence et al., 2010) The International Standards Organization (ISO 5492, 1992) defines a flavor as a
complex combination of the olfactory, gustatory and trigeminal sensations perceived during tasting. The flavor may be influenced by tactile, thermal, painful and/or kinaesthetic effects. This implicates that it is not only our taste buds that affect the taste we perceive. A study made by North (2012) showed that even music can affect our flavor perception. Before the test was implemented he came up with four alternatives that could both describe wine and music. Two examples used in the test are Powerful & Heavy and Mellow & Soft. The four songs were experimentally chosen with a pilot study. The participants were served a glass of wine, either red or white, and were then exposed to one out of four songs. Afterwards they were asked to choose one out of four alternatives that fitted best with what the wine tasted like. Note that all the participants got either a white wine or a red wine, but none of the two wines fitted any of the songs in particular. The results showed that the alternative they chose for the wine they tasted, described the song they were exposed to. As an example, if the participant had listened to Slow Breakdown by Michael Brook, which fits with the description Mellow & Soft, the participant reported that the wine tasted Mellow & Soft. Priming is one way to affect us without us being conscious about it. Priming refers to unconscious influences for example being exposed to word or objects which facilitate identifying them later on, without being conscious about this connection (NE, 2013-10-10; Collins and Quillian, 1969). An example is if you see the word EAT and are then asked to fill in a missing letter in the word, SO_P. You are probably more likely to write U creating the word SOUP, than writing A, creating the word SOAP, since SOUP has associations to the word eat. The aim of this study is to investigate whether or not food coloring influences the taste that is perceived, using lemonade with the same flavor intensity, but with different colors. The A priori hypothesis is that priming will affect the participants, creating an illusion of that the cup with the highest color intensity has the strongest flavor intensity, since usually the darker the drink is, the more it tastes. The second hypothesis is that the participants will say that the cup with the highest color intensity tastes most delicious, since food with more color usually contains more flavor and in most cases therefore taste better. Materials and Methods Lemonade with strawberry taste was diluted according to the directions on the bottle and poured into 3 plastic bottles. In one of the bottles red food coloring was added and in another one red and blue food coloring was added, ending up in 3 bottles with the exactly same taste, but different colors, red(r), purple(p) and light red(lr). A blind test was made to ensure that they tasted alike. Participants were 36 volunteers (21 males, age 16-18). They were asked to participate while passing by a table in the corridor, tasting a cup of each one in the order R, LR, P and then asked to answer the following questions; Which one tastes most delicious?, Which one do you think is the most expensive?, Which one tastes most synthetic?, Can you taste any additional flavor in any of them?, Which one has the most flavor intensity?. The first four questions were used to confuse the participants and make the purpose less obvious since the last question is of the most interest in this study. Results Differences were found in all questions, meaning that not all the participants answered the same option. Eight participants did not report any flavor differences. There were only small differences between the three options from the questions Which one tastes most synthetic? and Which one do you think is
the most expensive?, see full results in attachment 1. The participants reported some additional flavors, in the R: strawberry, lingonberry, raspberry, in the LR: strawberry, diluted lemonade, raspberry and in the P: blackberry, black currant, wild berries, raspberry. Eight participants did not distinguish any certain additional flavors, and a couple participants said that they just tasted very sweet. The results to the other two questions are being presented in diagrams below. ALL THE SAME 22% Which one has the most flavor intensity? PURPLE 42% 31% LIGHT 5% Figure 1. A circle diagram showing the results in percent of what the participants answered to the question Which one has the most flavor intensity? NO ANSWE R 6% Figure 2. A circle diagram showing the results in percent of what the participants answered to the question Which one tastes most delicious? Discussion Which one tastes most delicious? ALL THE SAME 22% PURPLE 33% 31% LIGHT 8% The results suggest that the darker color, the greater and more it tastes, which corresponds to the a priori hypothesis in this study. Even though the darkest cup, P, did not get that many more votes than R, see figure 1. The R cup was also dark, and it looked as if the P and the R were two different kinds of lemonade, meaning that they still could have the same flavor intensity. However it is notable that LR only got 5% of the votes, representing two participants, in comparison to P+R, 73%, representing 26 participants. This implies that red food coloring and red and blue food coloring combined truly influence taste intensity when poured into an already red drink. Furthermore, the results do correspond to the second hypothesis too, for the same reason, see figure 2. R looked like strawberry lemonade and P looked liked black currant lemonade, both with much flavor, therefore it is not obvious that P should get the most votes. P+R compared to LR, 64% (24) against 8% (3) still suggests that the darker color, the
greater it tastes, when talking about red lemonade. One explanation to why the participants answered this way on the questions in figure 1 and 2, is that through our life we learn that lemonade with darker color usually taste more and therefore better. We are being primed with this, and the brain uses earlier experiences to interpret information, for example, what a drink tastes like. However, eight of the participants (22%) reported that the lemonade tasted all the same, which may be an indication of that all people are not equally primed. Another possible explanation to the difference in taste reports could be that some of the participants had understood the purpose of the task. They could have done similar tests before because the participants were not asked if they had participated in similar experiments. It would then be possible that some of the participants figured out that it has to be an experiment investigating something and not just a test asking for opinions about lemonade. That could have made them more critical and analyzing, and therefore the effect was left out. Furthermore, this is a small pilot study with 36 participants in total. It is hard to come to a conclusion. This study does not contain any significant differences showed with statistics due to the small sample size. However, the experiment still suggests that the darker color, the bigger flavor intensity and greater taste in the participants included in this test. In percentage, P+R are much bigger than LR, which indicates that we can be fooled. Conclusively, it looks like food coloring does influence taste intensity and the taste that is perceived. Even though there are no significant differences in this study, it is still worth noting that they reported that one of the colored beverages tasted better than the other ones, since they were exactly the same. It is also very fascinating that the color of the drink brought out certain additional flavors, which was not the main purpose of this study, but still interesting to look at. For instance lingonberry in R and blackberry in P, this is probably explained due to priming. Purple drinks usually taste like blackberry, wild berries, blackcurrant, or grapes, and red drinks usually taste strawberry, lingonberry or raspberry, and as a result these flavors were distinguished. No one reported that P tasted strawberry even though the lemonade chosen had strawberry flavor, which speaks for that humans create strong connections between colors and certain flavors, especially fruit flavors. If this study would be followed up with more participants and implemented outside of school, in the city, it is likely that less people would report that they tasted all the same since they would be asked what they think is the purpose of the study and therefore participants who are aware about the secret motive could not participate. A larger sample would be crucial to support the results in this study and make them more reliable. In the future it would be interesting to do tests with more participants investigating how the color of food and drinks affects the perceived taste and maybe an unequivocal answer could be reached. It would be interesting to use other food coloring, for example three green drinks and see if the same results would apply. If similar results are acquired in these experiments, there would be stronger indications that food coloring influences taste perception. It would be fun to repeat the test in this study on small children, age 4-5, to investigate if the same results are acquired. Small children do presumably not have strong connection between colors and fruit flavors, and have not been primed as long as the participants in this study. If the results differ from the results in this study, it strengthens the hypothesis that
priming is one of the causes to why the brain is fooled. Acknowledgements I would like to thank my teacher, Ann Linderoth for all the guidance and my supervisor from Karolinska Institutet, Alva Appelgren for all the input and guidance throughout the study. References Collins, A., & Quillian, M.(1969) Retrieval time from semantic memory. Journal Of Verbal Learning And Verbal Behavior,8, pp. 240 247. ISO.(1992). Standard 5492: Terms relating to sensory analysis. International Organization for Standardization. Nationalencyklopedins nätupplaga, www.ne.se, Sökord: Priming, 2013-10-10 North, A.C., (2012), The effect of background music on the taste of wine, British Journal of Psychology, 103, pp. 293-301 Spence, C., Levitan, C.A., Shankar, M.U., Zampini, M., (2010) Does Food Color Influence Taste and Flavor Perception in Humans?, Chemosensory Perception, 3, pp.68-84 Collins, A., & Quillian, M.(1969) Retrieval time from semantic memory. Journal Of Verbal Learning And Verbal Behavior,8, pp. 240 247.
Attachment 1 Question LIGHT PURPLE NO ANSWER Which one 11 3 12 2 tastes most delicious? Which one 10 7 9 2 tastes most synthetic? Which one 4 10 14 do you think is the most expensive? Can you taste any additional flavors? 8 Strawberry: 4 Raspberry: 1 Lingonberry:2 Sugar: 2 Diluted lemonade: 1 Wild strawberries: 1 Stevia: 1 Strawberry: 1 Raspberry: 1 Diluted lemonade:3 Wild strawberries: 1 Sugar : 1 Wild berries: 1 Raspberry:2 Diluted lemonade: 1 Black currant: 2 Blackberry: 1 Sugar:1 Stevia: 1 Which one has the most flavor intensity? How many did not report any taste differences? 11 2 15 8