Taste is the sense by which the chemical qualities of food in the mouth are distinguished by the brain, based on information provided by the taste buds. Human's ability to taste occurs when tiny molecules released by chewing, drinking, or digesting our food stimulates special sensory cells in the mouth and throat. These taste cells, or gustatory cells, are clustered within the taste buds of the tongue and roof of the mouth, and along the lining of the throat. Many of the small bumps on the tip of your tongue contain taste buds. At birth, we have about 10,000 taste buds, but after age 50, we may start to lose them.
When the taste cells are stimulated, they send messages through three specialized taste nerves to the brain, where specific tastes are identified. Each taste cell expresses a receptor, which responds to one of at least five basic taste qualities: sweet, sour, bitter, salty, and umami. Umami, or savory, is the taste we get from glutamate, which is found in chicken broth, meat extracts, and some cheeses. A common misconception is that taste cells that respond to different tastes are found in separate regions of the tongue. In humans, the different types of taste cells are scattered throughout the tongue.
Taste quality is just one aspect of how we experience a certain food. Another chemosensory mechanism, called the common chemical sense, involves thousands of nerve endings, especially on the moist surfaces of the eyes, nose, mouth, and throat. These nerve endings give rise to sensations such as the coolness of mint and the burning or irritation of chili peppers. Other specialized nerves give rise to the sensations of heat, cold, and texture. When we eat, the sensations from the five taste qualities, together with the sensations from the common chemical sense and the sensations of heat, cold, and texture, combine with a food's aroma to produce a perception of flavor. It is flavor that lets us know whether we are eating a pear or an apple.
Experiment Justification:
Human's ability to distinguish taste mainly depends on three aspects, which are the conscious perception of taste, emotional quality of taste and memories of taste. Perception and memories do dominate the most in distinguishing tastes, when different fruit juices are mixed together; the taste is mixed up, thus causing confusion in interpreting taste by human brain and fails to conclude out the taste. People may easily manage to recognize the flavor of fruit juices individually rather than mixing up them due to the conscious perception and memories of taste.
Experiment Variables:-
Manipulated variable: Mixture of fruit juices
Responding variable: The ability of subjects to identify each fruit juice
Constant variable: Ratio of mixing two fruit juices
Experiment Methodology:
Three types of juices, which are mango juice, orange juice and pink guava juice, were prepared.
The mango juice, orange juice and pink guava juice were labeled with alphabet A, B, and C respectively.
Two types of juices would be mixed together with the ratio 1:1.
A measuring cup was used to measure the juices.
The juices were mixed, which are A+B, B+C and A+C and labeled with number 1, 2, and 3 respectively.
Then, the mixed juices were ready to be tasted.
Experiment Result:
* IC - Identity card number, HP - handphone number, (M) - Male, (F) - Female
Table 1.1
Subjects
Juice 1
Juice 2
Juice 3
Name: Chong Lian (M)
IC: 590207-10-6623
HP: 016-2958828
Pink Guava + Orange
Pink Guava + Mango
Pink Guava + Mango
Name: Lee Chee Kong (M)
IC: 821127-10-5845
HP: 016-3466631
Mango + Lime
Pink Guava + Mango
Pink Guava + Orange
Name: Teh Chan Mun (M)
IC: 780505-14-5169
HP: 016-6065887
Grapes + Orange
Pink Guava + Lime
Mango + Carrot
Name: Wong Kah Xin (M)
IC: 910623-10-5339
HP: 010-2523512
Pink Guava + Orange
Pink Guava + Orange
Mango + Orange
Name: Teoh Chun Hooi (M)
IC: 910429-10-5319
HP: 017-3231088
Mango + Apple
Pink Guava + Carrot
Grapes + Pink Guava
Name: Chin Kah Mun (F)
IC: 880114-14-5506
HP: 016-2878136
Mango + Orange
Grapes + Pink Guava
Pink Guava + Mango
Name: Yong Suet Lai (F)
IC: 940619-14-5730
HP: 010-2193566
Mango + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Chong Li Fun (F)
IC: 820906-14-5120
HP: 016-3028989
Mango + Orange
Grapes + Pink Guava
Grapes + Mango
Name: Chong Kim Lan (F)
IC: 630112-06-5658
HP: 016-2958831
Mango + Orange
Pink Guava + Mango
Mango + Orange
Name: Chong Lee Thing (F)
IC: 910917-10-5764
HP: 016-2538982
Orange + Lime
Pink Guava + Orange
Grapes + Mango
Tested by: Chong Lee Kim
* IC - Identity card number, HP - handphone number, (M) - Male, (F) - Female
Table 1.2
Subjects
Juice 1
Juice 2
Juice 3
Name: Lye Wend Jin (M)
IC: 780212-08-6847
HP: 016-6825207
Mango + Orange
Pink Guava + Apple
Pink Guava + Orange
Name: Hong Han Kee (M)
IC: 891227-02-5619
HP: 010-2198076
Mango + Orange
Pink Guava + Apple
Mango + Apple
Name: Moo Phooi Loy (M)
IC: 640717-08-5415
HP: 016-5415722
Mango + Orange
Pink Guava + Carrot
Grapes + Blackcurrant
Name: Chong Kah Hoe (M)
IC: 930305-08-5019
HP: 016-5443520
Mango + Lime
Grapes + Pink Guava
Grapes + Mango
Name: Ngoi Zhan Nam (M)
IC: 910811-08-6307
HP: 016-5644709
Mango + Orange
Pink Guava + Carrot
Grapes + Mango
Name: Ng Li Keang (F)
IC: 790317-08-5536
HP: 016-6264557
Mango + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Chan Chooi Ling (F)
IC: 940109-02-6002
HP: 010-3885365
Mango + Orange
Pink Guava + Apple
Pink Guava + Lime
Name: Soon Mei Ling (F)
IC: 891025-01-5262
HP: 010-2259626
Mango + Orange
Pink Guava + Apple
Pink Guava + Carrot
Name: Fong Ai Lin (F)
IC: 790404-07-5340
HP: 016-4822611
Mango + Orange
Pink Guava + Apple
Grapes + Carrot
Name: Mok Chao Wen (F)
IC: 991027-14-6510
HP: 019-3325356
Mango + Orange
Pink Guava + Orange
Lime + Carrot
Tested by: Hong Wan Ying
* IC - Identity card number, HP - handphone number, (M) - Male, (F) - Female
Table 1.3
Subjects
Juice 1
Juice 2
Juice 3
Name: Lau Weng Kang (M)
IC: 910312-01-6771
HP: 014-3822713
Orange + Blackcurrant
Pink Guava + Orange
Pink Guava + Apple
Name: Hue Jiunn Jye (M)
IC: 911030-01-5011
HP: 012-7752669
Pink Guava + Orange
Pink Guava + Blackcurrant
Apple + Orange
Name: Khor Yu He (M)
IC: 911012-01-6345
HP: 016-7835143
Mango + Orange
Blackcurrant + Apple
Mango + Apple
Name: Chong Wey Kuen (M)
IC: 910213-08-3437
HP: 016-7365456
Mango + Apple
Mango + Orange
Blackcurrant + Apple
Name: Hannah Mok Han Rhu (F)
IC: 901213-01-5088
HP: 0197527440
Mango + Apple
Pink Guava + Apple
Apple + Orange
Name: Yap Swee Chee (F)
IC: 940421-02-3232
HP: 016-7302801
Mango + Orange
Mango + Apple
Pink Guava + Orange
Name: Lee Xiang Yi (F)
IC: 900523-01-3544
HP: 017-7105164
Pink Guava + Blackcurrant
Blackcurrant + Mango
Mango + Apple
Name: Koh Sok Fong (F)
IC: 930127-01-5184
HP: 0143123963
Pink Guava + Mango
Orange + Mango
Mango + Apple
Name: Thian Mee Lin (F)
IC: 701115-08-5182
HP: 012-7931909
Pink Guava + Apple
Apple + Orange
Pink Guava + Orange
Name: Chong Zhi Kuan (F)
IC: 940421-01-3232
HP: 013-7573171
Pink Guava + Mango
Orange + Mango
Apple + Orange
Tested by: Lau Sze Wei
* IC - Identity card number, HP - handphone number, (M) - Male, (F) - Female
Table 1.4
Subjects
Juice 1
Juice 2
Juice 3
Name: Lee Chin Chong (M)
IC: 561201-10-5475
HP: 012-5176628
Pink Guava + Orange
Lime + Orange
Pink Guava + Orange
Name: Ling Wen Kai (M)
IC: 940311-14-5945
HP: 016-3797543
Mango + Orange
Pink Guava + Carrot
Pink Guava + Mango
Name: Lee Bing Jian (M)
IC: 940713-14-5323
HP: 013-2646173
Orange
Mango + Orange
Mango + Lime
Name: Kong Chee Wai (M)
IC: 881113-56-6135
HP: 016-2373783
Orange + Apple
Pink Guava + Orange
Pink Guava + Mango
Name: Kong Chee Hung (M)
IC: 920307-14-5629
HP: 016-2702882
Orange + Lime
Grapes + Carrot
Pink Guava + Mango
Name: Lee Shu Wen (F)
IC: 900325-14-6248
HP: 012-3036001
Mango + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Tang Swee Kim (F)
IC: 651001-10-5752
HP: -
Orange + Apple
Mango
Pink Guava + Mango
Name: Lee Ying Ying (F)
IC: 880901-56-6684
HP: 012-1353268
Mango + Orange
Pink Guava + Carrot
Pink Guava + Mango
Name: Teoh Pei Yi (F)
IC: 940719-14-6378
HP: 017-9880318
Mango + Orange
Orange + Carrot
Mango + Orange
Name: Kong Wei Ling (F)
IC: 941027-14-6080
HP: 016-2334608
Orange + Apple
Pink Guava + Orange
Pink Guava + Mango
Tested by: Lee Shin Yi
* IC - Identity card number, HP - handphone number, (M) - Male, (F) - Female
Table 1.5
Subjects
Juice 1
Juice 2
Juice 3
Name: Simon Monjulim (M)
IC: 630523-12-5237
HP: 019-8505990
Lime + Orange
Pink Guava + Lime
Pink Guava + Orange
Name: Chong Guo Hao (M)
IC: 991116-12-5957
HP: 088-267718
Mango + Orange
Orange + Blackcurrant
Pink Guava + Mango
Name: Leong Hee Seng (M)
IC: 520826-71-5125
HP: 013-8517166
Grapes + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Kong Kai Lun (M)
IC: 920421-12-5699
HP: 012-8437862
Mango + Orange
Pink Guava + Orange
Lime + Orange
Name: Raymond Monjulim (M)
IC: 971109-12-5459
HP: 016-5841929
Mango + Orange
Grapes + Orange
Apple + Orange
Name: Liaw Seu Tee (F)
IC: 640922-12-5180
HP: 013-8655188
Mango + Orange
Pink Guava
Pink Guava + Blackcurrant
Name: Fong Kui Han (F)
IC: 601109-12-5362
HP: 012-8243318
Mango + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Ny Shy Tying (F)
IC: 930415-12-5376
HP: 016-8019603
Mango + Orange
Pink Guava + Orange
Lime + Orange
Name: Fong Kui Yin @ Fong Kui Tai (F)
IC: 560506-12-5106
HP: 088-221002
Mango + Orange
Pink Guava + Orange
Lime + Orange
Name: Gloria Monjulim (F)
IC: 931217-12-5230
HP: 016-5861231
Mango + Orange
Grapes + Orange
Mango + Lime
Tested by: Leong Boon Fung
* IC - Identity card number, HP - handphone number, (M) - Male, (F) - Female
Table 1.6
Subjects
Juice 1
Juice 2
Juice 3
Name: Lim Hock Leong (M)
IC: 910612-14-5669
HP: 012-3493396
Mango + Orange
Pink Guava
Carrot
Name: Chiew Chee Seng (M)
IC: 940419-08-5593
HP: 017-5075498
Mango + Orange
Orange + Carrot
Orange + Carrot
Name: Chang Wooi Keat (M)
IC: 940818-14-7325
HP: 016-2058256
Mango + Orange
Mango + Carrot
Mango + Carrot
Name: Wong Lap Tat (M)
IC: 530414-01-5201
HP: 012-7778332
Mango + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Yeo Jia Cai (M)
IC: 940114-01-5607
HP: 019-6969108
Mango + Orange
Orange + Apple
Mango + Apple
Name: Chua Ping Sian (F)
IC: 941205-04-5056
HP: 014-6269486
Mango + Orange
Orange + Carrot
Apple + Carrot
Name: Leng Chia Hui (F)
IC: 940730-01-6080
HP: 016-7346788
Mango + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Ng Ya Teng (F)
IC: 940515-10-5806
HP: 010-2109298
Mango + Orange
Pink Guava + Orange
Pink Guava + Mango
Name: Wau Hui Ying (F)
IC: 940824-05-5128
HP: 011-28205424
Mango + Orange
Apple + Orange
Mango +Apple
Name: Lau Soon Kia (F)
IC: 570422-01-5662
HP: 017-8434127
Mango + Orange
Pink Guava + Lime
Pink Guava + Orange
Tested by: Wong An An
Graph 1.7 shows the number of subjects who got correct and wrong in identifying 3 mixed juices. In juice 1, 37 subjects got correct while 23 subjects got wrong in identification of fruit juices; in both juice 2 and juice 3, 17 subjects got correct while 43 subjects got wrong in identification of fruit juices.
Table 1.8 shows the number of subjects according to age and the number of subjects who got correct identifying juice 1, juice 2 and juice 3. There are a total number of 60 subjects being tested, which are 41 subjects from age 10 to 29, 12 subjects from age 30 to 49, and 7 subjects from age 50 to 69.
Age range
Number of subjects
Number of subjects who got correct in
Juice 1
Juice 2
Juice 3
10 - 29
41
26
12
11
30 - 49
12
7
1
2
50 - 69
7
4
4
4
Chart 1.9 shows the percentage of subjects who got correct and wrong in identifying a total of 3 mixed juices despite of subject's gender and age. 39% of subjects got correct in identification of fruit juices while 61% of subjects got wrong in identification of fruit juices.
Result Discussion:
How taste works?
Taste signals go to the limbic system and to the cerebral cortex
http://faculty.washington.edu/chudler/gif/tastepat.gif
When the taste cells send electrical messages to the nerve cells, the messages are continuously passed to two major centers called limbic system and the cerebral cortex through relay neurons.
http://webspace.ship.edu/cgboer/limbicsystem.gif
The limbic system includes the hypothalamus, amygdala and hippocampus, which functions in emotional state and memory formation, makes us experience emotional changes and feel nostalgic when tasting. Meanwhile, the frontal cerebral cortex is responsible for conscious identification of flavor. The mixed up juices tend to become a very new taste ever in their life.
Thus, when the subjects consume the mixed fruit juices, they will feel odd and confused in the identification, feeling unacceptable to the "new" taste. The mixed up juices tend to become a very new taste ever in their life. Mixing of the fruit juices may sends conflicting information to the brain, thus causing confusion in identification. There may be some reason to explain. Firstly, they have no memory in tasting such "new" flavor. Secondly, due to the fruit juices are mixed, there is no conscious identification of flavor, meaning that they are not knowing the flavor of juices at all in advance.
Taste receptors response
Each receptor may respond best to only one type of taste, say sweet, but it can also weakly respond to sour taste. This is because the taste cells have more than one type of membrane receptor. The messages will be sent to brain, depending on what taste the subjects are testing. Also, complicated connections make neurons in the brain to detect a complex taste, such as sweet-sour taste.
Biases in flavor of real fruit juice and artificial fruit juice
In the experiment, the manipulated variable, which involves the fruit juices used are not extracted from real fruit but fruit juices with synthetic flavor, causing biases in flavor of real fruit and artificial fruit flavor. Difference in the flavor of real fruit and the artificial one may cause different interpretation and failure to interpret in human tongue.
Human's perception
Human often depends on perception; like their thinking may lead to the logical fruit color when they see the color of juices and the pulp in orange juice (visual). For example, (i) the subjects will have perceptual ability to guess whether it is orange or mango when they see yellow color in juices, consequently they will automatically eliminate the choice of blackcurrant. (ii) They may guess that it is orange juice when seeing orange pulps inside the juice.
And too, taste cells and olfactory cells often work together to identify flavor. Taste buds of the tongue identify taste; nerves in the nose identify smell. Both sensations are communicated to the brain so that the integration can be completed. When the subjects smell the juices, the volatile fruit juice odor penetrates into their nasal cavity. The perception of olfactory contributes to the identification of flavor.
Conclusion
Human's ability to distinguish taste is based on memory, perception and conscious flavor of taste.
