Consistently yummy: examining the consistency of mashed potatoes

Consistently yummy: examining the consistency of mashed potatoes

Mini-experiment

Background:  It’s all about the starch.  As a soccer player, starch is an important food to be consistently eating throughout the season.  I thought it would be interesting to investigate one of my personal favorite starch-specific recipes, mashed potatoes.   Potatoes are comprised of 16-22% starch, which makes the texture and taste majorly influenced by the starch content of the potato (text, 237).  Starch molecules are very easily manipulated and different creams, stirring techniques, and temperature exposure can change cause molecules to burst changing the texture and taste potential for this dish.  I specifically was interested in the consistency of the potatoes because I have had mashed potatoes that were fluffy and creamy, but I have also had mashed potatoes that were gluey and runny.  I was interested to investigate the causes of each consistency, so I decided to look at the addition of half and half cream compared to sour cream. 

Hypothesis:  Sour cream will make the mashed potatoes thicker and more cohesive to a plate than mashed potatoes made with half and half. 

Null hypothesis: There will be no difference between the cohesiveness to a plate of mashed potatoes made with half and half and sour cream. 

Independent variable: Sour cream or half and half

Dependent variable: time to fall off of plate

I will standardize:

-          Amount of mashed potatoes

o   2 lbs each batch

-          Mashing method

o   Ricer

-          Sour cream/ half and half added

o   1 cup

Results

	Half and half	Sour cream
Time (s)	8.53	11.53
	26.91	44.26
	35.28	58.19
Average	23.57333333	37.99333
Stdev	13.68358993	23.95292
SEM	7.900224329	13.82922

     

The average time for a scoop of mashed potatoes to fall off of a plate when turned upside down was greater for sour cream (M=37.99333) than for half and half (M=23.57333).  

Mashed potatoes with half and half

Mashed potatoes with sour cream

Upside down plate to measure potato consistency

Discussion

Although the sour cream had a higher mean time to fall during the experiment, it was not a significant result.  Without a significant result, the null hypothesis must be accepted.  The standard error of the mean was very high because there was a high variance among data collected.  The mashed potatoes made with sour cream were expected to be thicker, and therefore stay on the plate longer.  This hypothesis was made due to the simple fact that sour cream has a thicker texture than half and half cream.  When the data was being collected, the same scoop of potatoes was used 3 times in a row which might have influenced the cohesiveness because it is clear that the potatoes took longer to fall after each trial.  The experiment was kept mostly consistent in terms of standardizing variables, but the one limitation in standardization came from the plate drop.  When the same scoop was put back onto the drop plate, it still had potato remnants on it which may have influenced the cohesiveness.  For future experimentation, it would be valuable to investigate further methods for data collection in potato consistency, the influence of stirring would also have interesting implications for consistency as starch granules often are crushed in intense stirring which leads to gluey runny results.   


Sources:

Text book

Crosby, G. (2012). The science of good cooking: master 50 simple concepts to enjoy a lifetime of success in the kitchen. Brookline, Massachusetts: America's Test Kitchen.

Not so much of an angel food cake

Mini-experiment: Coagulation of egg whites in angel food cake

Background:

Cream of tartar is thought of as a stabilizing agent to help egg whites coagulate.  Although it says cream, it is actually a powder found in the spices section of the grocery store.  The coagulation process is due to the acidity introduced by this ingredient when mixed for angel food cake (Christensen, 2008).  The spice is used because it is odorless and tasteless.  I wanted to see how something acidic as lemon juice could substitute for this process.  Although I am expecting an obvious taste difference, I am looking to see how the substitution affects any of the other aspects of the cooking result.  As lemon juice is only a substitution, it made sense that the juice might not produce as consistent of a result and will not stabilize the egg whites as well as the cream of tartar.   

Hypothesis:  The angel food cake with lemon juice substitute will have more cracks in it than the cake with cream of tartar. 

Null hypothesis: There will be no difference in the amount of cracks between the cakes.

 

Independent variable: Cream of tartar/ lemon juice

Dependent variable: Number of cracks in cake

I will standardize:

-          Oven

o   Cooked at same time

-          Whipping method

o   Whisk – recipe calls for electric mixer

-          Pan

o   Disposable loaf pan with parchment paper lining bottom

-          Ratio of lemon juice to cream of tartar

o   1:1

Results

	Cream of tartar	Lemon juice
Cracks	6	1

  

The cake with lemon juice in it took had less cracks than the cream of tartar.

 

Ingredients

Parchment paper lining

Unable to make peaks while mixing

Ready to cook!

Left: lemon juice  Right: cream of tartar

Discussion

I did not accept the null hypothesis or support my hypothesis in this experiment.  The opposite of what was expected happened.  There were a significant amount of cracks in the cake with cream of tartar compared to the cake with lemon juice.  With lemon juice as a known substitute for cream of tartar it made sense that the lemon juice would not stabilize the egg as well as the cream of tartar because as a substitute it traditionally has been inconsistent in the past (Palmer, 2007).  Past research and experiences cooking this recipe express that the recipe needs to be followed strictly or else the cakes might collapse (Christensen, 2008).  There were a few mistakes that happened during the preparation that could explain this outcome and that will lead to limitations.  First of all, I accidentally mixed all of the sugar into the flour mixture when I was supposed to reserve half of it for the whipping of the egg whites.  To correct this mistake I added ¼ cup of sugar to the egg whites when whipping.  Also, when I was adding the lemon juice I accidentally squirted a little extra juice in the mixing bowl, missing the teaspoon.  Another limitation might be that I did not have an electric mixer and I was unable to get the egg whites to form peaks after whisking manually.  Although they were bad mistakes, some of them were caused by a little confusion by some of the wording of the recipe and I learned what everything meant by the time I was finished.  This angel food cake preparation turned out to be a tough process. 

Good news is, I learned a lot; it was all what not to do, but that is an important part of the learning process I think.

Thanks for reading!

Red and green and everything in between

Mini-experiment 3: Oxidation with red and green apples

Background:  Whether an apple is cut or bitten into, there is an oxidation process that occurs which makes the fruit begin to turn brown and deteriorate.  Polyphenol oxidase is the enzyme within cells that is triggered to oxidize compounds in the presence of oxygen.  There were several questions that arose among researchers:

Do red apples brown faster than green ones?

Does a smaller piece of apple brown quicker than a larger comparison? 

And lastly, would the enzymes in human saliva catalyze the oxidation deterioration in apple?

The saliva is actually comprised of about 97-99.5% water, but the rest is made up of enzymes.  The three enzymes found in the human saliva are salivary amylase, lingual lipase, and an antibacterial compound called lysozymes (Niedziocha, 2011).  There are many types of apples, and researchers examined if there would be a difference between two types: red delicious and granny smith.  Research was aimed to observe not only the difference between apples, but the effect of enzyme variation. 

There were two hypotheses:  

-          Human saliva would increase the deterioration of the apple from oxidation

-          Red delicious apples will oxidize faster than granny smith apples

Null hypotheses:

-          Human saliva will have no effect on the deterioration of the apple from oxidation

-          There will not be a significant difference between the oxidation of red and green apples

Independent variables:

-          Presence of human saliva/not

-          Type of apple

Dependent variables

-          Oxidation level of apples

I will standardize:

-          Browning time

o   30 minutes

-          Depth of apple slice

o    

-          Exposure to alpha-amylase

o   10 seconds in my mouth

Results

Granny smith (L) Red delicious (R)

Oxidation after 5 minutes

Oxidation after 30 minutes

Regular red delicious apple (L) Saliva apple (R)

Regular granny smith apple (L) Silva apple (R)

The slice of apple in contact with 10 seconds of human saliva was found to oxidize slower than the apple which was not in contact with the human saliva.  The granny smith apple was found to oxidize more significantly over 30 minutes compared to the red delicious.  A limitation involved in this experiment were the age/ripeness of the apple.  

Discussion

Both of the hypotheses were disproved in this experiment.  It cannot be said that the null hypotheses can be accepted because there was a clear change in the opposition of what was predicted.   After 5 minutes the apples still looked similar in oxidation level, but after 30 minutes it was clear that the granny smith apples were browning faster and the saliva exposed apples were not oxidizing.  Although it seemed to make sense that the addition of another enzyme which breaks down food would aid in the deterioration process, it clearly denatured some aspect of the processes.  According to World’s Healthiest foods, “Flavonoids like quercetin found in apples can inhibit enzymes like alpha-amylase” (whfoods.com, 2014).  As alpha-amylase is found in the human saliva it then makes sense that those apples would not oxidize similar to the other samples.  Also, it was hypothesized that the sourness of the granny smith and thus seemingly more acidic pH would decrease oxidation over the course of a 30 minute time span.  The pH of these two particular apples was determined to be around 6.2 for each one, so that would nullify that particular hypothesis.


Sources

http://www.scientificamerican.com/article.cfm?id=experts-why-cut-apples-turn-brown

http://www.livestrong.com/article/423200-what-are-the-digestive-enzymes-in-the-stomach-mouth-called/

http://www.whfoods.com/genpage.php?tname=foodspice&dbid=15

 

Avocado's Number

Trying to find Avocado’s number

Mini-experiment 2:  Polyphenol oxidase activity in avocado

Background:  Guacamole has always been a top party favorite for picnics, family gatherings, or summer time get togethers.  Although it usually goes pretty quick, if guacamole is left out it begins to change.  An enzyme referred to as polyphenol oxidase begins a process called melanoidin.  This is triggered by contact with the atmosphere; it begins to turn brown.  Interestingly, it is only outside layer in contact with the air that begins melanoidin.  This is similar to the process with apples when they begin to brown.  There is an age old tradition that leaving the pit of the avocado in the guacamole will slow this process.  According to the Huffington Post, avocados are actually a berry and are one of the few high-protein fruits.  With its rich content of monounsaturated fat, it can actually substitute for butter in baking as well.  Although they are rich fruits, they are known to deteriorate quickly.  This was the inspiration for my mini-experiment, as our big project aims to investigate the properties of avocado to determine what will help naturally preserve the fruit a little longer.  Hopefully it will help our guacamole recipe!

Hypothesis: The seed will slow the melanoidin process in avocado compared to avocado without seed

Null hypothesis: There will not be a difference in melanoidin between avocados with the pit compared to without the pit

Independent variable: Avocado with seed in it/avocado without seed

Dependent variable: Melanoidin level

I will standardize:

-          Browning time

-          Amount of avocado (1 – two halves compared)

-          State of avocado

o   In halves (3 hours)

o   Mashed

Results

Avocado after three hours

Avocado before picture

Avocado this morning -- 18 hours from initial, 15 hours since mashed

Avocado 8 hours from initial, 5 hours after being mashed (seed on left)

The possible limitations included ripeness of the fruit, the physical state of the fruit, and the halves might not have been exactly cut into equal weighing pieces.  The limitation of the physical state of the fruit was that after three hours avocados were mashed to hopefully speed up the process.  Also it seemed to make more sense if the avocado was tested in the state that it would be in guacamole.

Discussion

The null hypothesis was accepted in this experiment as neither half of the avocado browned faster than the other.  The avocados did not deteriorate very much at all actually; as you can see by the photos, even after 8 hours the avocados still had not changed significantly as was anticipated.  The avocado was bought right before the beginning of testing and colleagues questioned the ripeness of them.  After three hours, the avocado had not deteriorated very much so it was mashed up as if to be preparing guacamole to test whether the physical state of the fruit would catalyze polyphenol oxidase.  After 5 more hours, the avocado still had not browned very significantly.  This morning, it was clear that the melanoidin level had advanced 18 hours after the initial split and 15 hours after being mashed.    

This mini-experiment relates to the final project because we aim to investigate the properties of avocados in order to try and determine a quality natural preservative to include in guacamole recipes.  My partners Tim, Tom, and Alejandro all examined different mediums of possible preservatives including concealing the fruit, adding lemon juice, and sprinkling salt and pepper over the avocado.  Although we did not receive great results from the experiment, we hope to utilize what we learned and continue to research moving forward.  

References

http://desigrub.com/tag/avoid-browning-avocado/

http://www.huffingtonpost.com/2013/08/22/avocado-health-facts-didnt-dont-know_n_3786419.html

Happy Friday

Quackulate -- changning from liquid to solid

Patrick Langan

Science of food and cooking

10 January 2014

Pasteurization

                Pasteurization has become a commonly practiced technique to remove bacteria in milk.  By simply heating milk to 145° F for half an hour, all bacteria is killed and is safe to drink.  Some raw milk enthusiasts argue that there is a great amount of nutritional value in unpasteurized milk that should be utilized.  There have been cases of raw milk coming in handy with problems such as asthma, and allergy difficulties.  Although there seems to be a chance of benefit, health authorities question the ethics of the sale of the product if it is not consistently safe.  I disagree.  If an individual would like to take a chance at trying the product for potential benefit, they should have the freedom to do so, especially when there are potential benefits for sick individuals seeking wellness.  Although pasteurization is a guarantee of “clean milk”, I do not think it would be ethical to outlaw this product. 

                As an American, there are many freedoms we are blessed with.  Living in the capitalistic society we live in today, it is important to realize that there are products we have the freedom to buy that might not necessarily be the healthiest for our bodies.  Cigarettes and alcohol are sold in stores and they are proven to be one of the worst things you can ingest into your body.  The country we live in is founded on freedom, and to have the freedom to buy milk revoked because it might make you sick does not seem ethical when there are products on the shelves that not only have no health benefits, but also will guarantee health problems later in life with continued use.  They might not directly lead to acute diseases after one use, but they are not used for their potential health benefits either.  The fact is that there are good bacteria in milk as well as bad bacteria.  While pasteurization kills the bad bacteria in the milk, it also kills the good bacteria that is has potential to help fight health ailments. 

                Living in an urban type area growing up, I actually never even heard of anyone drinking raw milk.  My impression of this product is that it is not consumed on a regular basis by the majority of the population for obvious reasons.  The risks are very apparent that when drinking unpasteurized milk there is potential for dangerous health issues following consumption.  That being said, I would assume that more often the individuals searching for raw milk products would be looking for a potential health benefit that has been observed in the past.  If the individual looking for the product is sincerely looking to better themselves by drinking raw milk, they must be pretty desperate because in modern medicine there are many alternatives that could be safer.  As long as the product has labels on the packaging that reiterates the warnings to the buyer of the potential bacterial problems, I think that it should be legal to sell.

                Food safety news reported that raw milk has very serious potential dangers and the ethics of the sales are coming into question by health authorities.  The weaker immune systems are most often affected by these problems including children and the elderly; in recent proximity to the publication of the article, 9 children were suffering from health problems that were attributed to the consumption of the raw milk.  Five of the nine children were hospitalized, three of which actually developed hemolytic uremic syndrome, which is a serious kidney problem.  The Tennessee Department of Health State Epidemiologist Tim Jones remarked, “Milk from the healthiest-appearing cows in the cleanest dairy operations can still contain deadly microorganisms”.  This process is just too inconsistent to gamble with peoples’ lives.  Food safety experts also argued that the health benefits discussed from raw milk were not actually based on science, but rather anecdotal claims.  Although there are clear dangers of using this product, the ban from legal sale is unethical because people are free to be able to buy products if they believe they will receive help from the product.  Even if they do not believe they will receive health benefit (cigarettes), they are still legally able to buy dangerous products.  Capitalism is motivated by the drive to sell unique products with unique uses.  Also, although the product can be dangerous in certain cases, it can also be tested before sold.  With the questionable ethics of the sale of this product, one would think that there would be some method to test whether the batch of milk is contaminated or not.  People should be able to pursue their own remedies within certain boundaries, and the sale of raw milk seems completely ethical in my opinion. 

                The question of ethics in this situation is clear.  Although there are health risks, the majority of the population will not be pursuing this beverage and if there are potential health benefits it should remain legal.  If a technique to test batches of milk prior to sale, it would resolve this problem as well.  If I was suffering from allergies and had tried all other options, I would like to give raw milk a try to see if it aided my problem.  

Investigation of heat, specifically with water and salt

Mini-experiment 1: Investigation of heat, specifically with water and salt

Background: 

I remember my mother always telling me that salt makes water boil quicker, but I always wondered why that was.  In class we have briefly investigated the specific heat of water and how the addition of salt changes the specific heat.  When salt is spread over snow and ice, it melts faster or it lowers the specific heat.  Although I am pretty certain that the water will boil quicker when salt is present, I want to investigate the variance. This will be tested by comparing the boiling time of each separate scenario. 

Hypothesis: There will be a decrease in boiling time between water with salt added and without salt added. 

Null hypothesis: there will not be a significant difference in boiling time between water with salt added and without salt added. 

Independent variable: whether the water has salt added or not.

Dependent variable: time to boil. 

I will standardize:

·         -the salt added (1 Tbs)

·         -the amount of water (6 cups)

·         -the heat (high)

·         -pot (same)

·         -the initial temperature of the water (13° C)

Results

	Trial 1	Trial 2	Trial 2
Time to boil w/salt	789	808	795
Time to boil w/out salt	810	814	809

	With salt	Without salt
Average	797.3 seconds	811 seconds
Standard Deviation	9.712535	2.645751
SEM	5.607535	1.527525

With a p-value of .08, the data supports the null hypothesis that salt does not have a cause a significant decrease in time to boil.  The limitations from this experiment would arise from possible human error in terms of measuring when the pot was “boiling”.  It is tough to stop the time as soon as the water seems to be boiling.  Also, I did not stir the salt into the water so it did not dissolve in the solvent before I heated the pot. 

 

Discussion

The null hypothesis was supported that the salt would not cause a significant decrease in the boiling time of water.  Although salt is accepted to lower the specific heat of water and has been shown through salting streets and prior research, in this particular setting it did not show a significant change.  This experiment would be more accurately observed and analyzed if there were two identical pots being heated simultaneously.  This way, the level of boiling would be able to be recognized more accurately.  It was hard to tell the level of boiling for each trial, but if there were multiple being heated simultaneously it would be easier to compare between them as they heat.  This experiment would be interesting to run with different salt concentrations at different water volumes; that way an optimal salt to water ratio could be examined. 

Pictures

Ready to boil!

Water with salt

Materials