Sample Essay On Sensory Evaluation Of Food

Introduction

There several sensations that are happening that could make the food good or very bad. This can include the aroma, the texture, how it feels in the mouth and most important the flavor which includes the smell and the taste. Things like texture i.e the roughness of a cracker, feeling in the mouth i.e. warm food or spicy flavor. Flavor is a combination of both smell (what we perceive in our nose) and taste what we perceive on our tongue.
Within this lab we are exploring the five areas of taste viz. bitter, sweet, salty, sour and umami. To explore taste the food has to be dissolved in liquid within the mouth in order to be perceived by the tastebuds on the tongue. The tongue itself has specific areas where tasted is more perceived specifically the tip of the tongue perceives sweet, flanking this this area salty is detected. Within the middle of the tongue the umami taste (which in Japanese means good flavor) is perceived. Also in the middle of the tongue but on each side the sour region is found. Lastly, bitter is near the back of the tongue near the throat. Sweet is caused from a glucose receptor, salty is from a salt causing a sodium channel opening, sour is from a hydrogen channel opening, umami is from binding of an amino acid and a salt (glutamate and inosinate ) which elicits a synergistic response and lasty bitter is from bittering agents (possibly evolved to prevent people from eating toxic plants in the past).
Not surprisingly, people do not all taste the same and there might be large differences in people that taste due factors like genetics, culture, gender or lifestyle. The taste bud is a cell where a protein (specifically G-protein couple receptor) senses the people with these genes expressing these proteins have a different genetic makeup e.g. Chinese vs. Caucasian they might not only have less of a particular protein in relation. They might also have a different number or are more sensitive to specific tastes. Being from a different culture might also change what people enjoy, specifically if a person grew up eating candy or salty foods they might be sensitized than someone that did not. People of different genders might also have different taste perceptions. Lastly, lifestyle plays a role as people that drink a lot of coffee or smoke cigarettes might have a different perception of bitter than someone that does not. All of these factors contribute to how and what makes up our taste.
This lab will explore the different tastes and determine whether particular people from different categories of age, gender, lifestyle, ethnic background or culture might perceive a variety of tastes differently than another person. It will also explore how people sense different tastes at different concentrations, different temperature and different sensory times. This lab could be considered a sensory evaluation and methods here could be used to compare different range of dishes to evaluate and improve a taste profile of a dish. The sensory evaluation can also be used for quality control. Additionally this test could help identify people with a good range of sensory perception. As it is very subjective it might depend on the for whom is receiving the dish but having people with good range might help to maintain a high level of quality.

Materials & Methods

Sucrose, sodium chloride, tartaric acid, quinine, monosodium glutamate (MSG), sodium benzoate (taste paper), phenylthiocarbamide (PTC) (taste paper) were calculated or used (in the case of taste paper) to the appropriate concentrations and were safe for human testing.

Threshold concentration of Primary tastes

Primary tastes (salty, sweet, bitter, sour and umami were calculated with increasing concentrations in water (concentrations are labeled in the table). Participants started with lowest concentrations rinsed mouth with water then went to the progressively higher concentrations.

Recorded amount was the concentration that was distinguible of the different tastes

Effect of temperature on taste
A sample of 10% sucrose solution was cooled or heated to different temperatures were used 4, 25, 49 deg C. Sample was placed on the tongue and a ranking of most sweet, moderately sweet and least sweet was recorded.

Perception of PhenylThioCarbamide (PTC) and Sodium Benzoate

Adaption of Receptors
Taste receptors were observed for their adaption. A 3% NaCl (salty solution) was placed in the mouth. A stopwatch recorded to judge when the salty taste subsided.

Results

Discussion
There is only a slightly different genetic makeup (table 1) within the class but perhaps these account for some of the differences in taste perception. One interesting thing is that although there might be a different genetic makeup there might be similar tastes based on culturally influences. For example if someone grew up in Japan they might have different ingredients in the home than someone that grew up in another place. Also with people that are older they might have different
Within the tastes the primary taste that was detected at the lowest level was bitter (table 2). Bitter is likely a receptor that was developed in order to warn of dangerous plants. So if it can be detected at the low levels then it could protect people better. However, people could taste sweet at the highest. Sweet was the highest taste recorded. People likely are accustomed to tasting sweet. There is some variation in the class. Older people (and people that drank coffee) and smokers could not taste bitter as well.
If a dish is hot or cold will make tasting it very different (table 3). People could perceive sweet at both the high and low ranges of temperature. Ice cream might need a certain range to be observed as good so more sugar might be better to be perceived however these results did not make sense because it was not linear. When at ambient temperature only medium amount of sugar could be detected. Too high might not be a good thing at 25 deg C. Warm temperatures like a warm cake are linear and an increased amount of sugar would could show the correct amount needed to be perceived (maybe lower amounts of sugar are needed.
It is possible that the 11% of the class that did not perceive PTC could have been smokers or people that drink coffee so this taste might not have been observed in them (table 4). As this was not recorded it could be observed as potential error in the design of the experiment as the variables are recorded within different table so it is difficult to compare them on a whole. The people that perceived PTC may also be more genetically susceptible to this. Possibly a similar group of people that tasted none in the table 2 under bitter were within this group (Table 4). Sodium benzoate like sauerkraut is really a strong taste and affects the receptors.
Chefs might add salt into the food rather than after if they know that it takes nearly 30 seconds for salt to subside (table 5). Also if a dish is saturated in salt it will be unedible.
Within this experiment they might be some error that needs to be evaluated. There might some error in the test itself. People might not have placed the droppers in the correct area of the tongue and people might not have washed their mouth. There could also be some influence from the participants as it is not a blind experiment. A larger range of people could also have been recorded to get some variance in the results. One thing people did not give was qualitative data. Nobody said they did not like a certain taste.
Why is this lab important? It gives a method for understanding sensory evaluation. In human nutrition taste and flavor is perceived in our everyday life. If the food has a bitter taste or is overly salty or not salty enough, or too sweet we may not be fulfilled and obtain psychological benefits from eating it. Good food is ultimately defined within our culture and a social affair and could differ with age, gender, lifestyle choices, culture or ethnicity. These variables could be things food tasters and chefs need to think about when preparing a dish.