Math Contest at CU

Eighty-two students from Middle Tennessee area high schools participated in the 63rd annual American Mathematics Contest hosted by the Cumberland University Mathematics Department and the Abelian Group (Student Chapter of the Mathematical Association of America).  The contest was held on Wednesday, February 22, 2012.  The students competed for Cumberland University Scholarships as well as other national awards.  The purpose of the contest, which covers high school mathematics, is to spur interest in mathematics and develop talent through the excitement of friendly competition at problem solving in a timed format. The contest was divided into two categories:  the AMC 10 for students under 17.5 years of age who are not entering 11^th or 12^th grades and the AMC 12 open to any high school student under the age of 19.5 years.

The AMC 10 and the AMC 12 are part of a series of contests sponsored each year by the Mathematical Association of America, through their program, the American Mathematics Competitions.  The AMC offers the only math competition series in the country leading to the United States of America Mathematical Olympiad (USAMO) and the Mathematical Olympiad Summer Program (MOSP). From this group of students, the AMC sends the highly competitive USA Team to the prestigious annual International Mathematical Olympiad.

Students from seven Middle Tennessee high schools participated in the contest hosted at Cumberland University for 2012, including Mt. Juliet High School, McGavock Comprehensive High School, Ravenwood High School, Davidson Academy, Watertown High School, Lebanon High School and Brentwood High School. The top three scorers on the AMC 10 at Cumberland were awarded $500 scholarships.  Third place went to Steven Sheffey from Lebanon High School, with Joyce Kang from Brentwood High School taking second place, and first prize going to Gene Xijie Li from Ravenwood High School.  Cumberland also awarded $1000 scholarships to the top four scorers on the AMC 12 for 2012. Sean- Michael Tibbs and Chase Buscherfeld from Mt. Juliet High School tied for third prize, Austin Cook had the second highest score, while Ryan Downs earned the highest score on the AMC 12 this year. Both Austin and Ryan are from Mt. Juliet High School as well.

In addition to the testing and presentation of awards, students were treated to a campus tour as well as a lecture and demonstration on mathematical knot theory presented by Dr. Kevin Gammon of the Cumberland University Mathematics Department assisted by group of Cumberland students majoring in Mathematics and volunteers from the audience.  Each participant in the contest received a goody bag as well as a Certificate of Participation.  Door prizes were also given out.

Details concerning the 2012 AMC 10/12 contests, as well as the rest of the AMC programs are available on the AMC website: http://amc.maa.org./  For further information, contact the AMC directly by phone (800-527-3690) or via email (amcinfo@maa.org).  For information regarding the host site (Cumberland University), please call (615-547-1278) or email (Ldishman@cumberland.edu) Dr. Laurie P. Dishman, Dean of Liberal Arts & Sciences and Associate Professor of Mathematics.

 

Pre-Professional Society and BBB Biological Honor Society Service Project

This post was written by Paige Moorhead, president of the Pre-Professional Society.

 

The student organizations at Cumberland University are gearing up to start a green revolution on our campus.  The Pre-Professional Society and the BBB Biological Honor Society have teamed up in this mission to make our student body and our community more environmentally conscious.  With this ideal in mind, the two organizations wanted to make a donation to a foundation called the Looking Out Foundation which serves to support environmental organizations whom uphold the goal of taking care of the Earth.  The foundation has supported such groups as the Captain Planet Foundation, Honor the Earth, Reverb, and Yele.  In order to make our donation, we are gaining the support of local businesses.  In return for a donation, we will be displaying the business name and/or logo on a banner on our campus.  The banner will be titled: “Your Community Cares About Being Green”.  In this manner we want to influence our students that it does matter and it is cool to “go green” by showing them that the community businesses care.

 

Journal Club: Bio-oil as a Fuel Source and the Products that Come With It

This post was written by Nathan Gibson. His article was “Formation of Aromatic Structures during the Pyrolysis of Bio-oil”. 

During the age of fossil fuels, finding means for using anything to make efficient energy has become a priority.  Biomass has become a key material that scientists have been working with to create energy.  Biomass has come to be known as organic material used as fuel.  Biomass can be converted into bio-oil through a process known as Pyrolysis.  Through this process, bio-oil becomes a “complex mixture of chemical compounds that can be used in many ways.”  The bio-oil can be upgraded into a liquid or used as a feedstock for boilers or gasifiers.  When used in this manner, the bio-oil is burned with coal.

 

Many problems can arise with not knowing the chemicals released from the burning of bio-oil.  The research by Yi Wang, Xiang Li, Daniel Mourant, Richard Gunawan, Shu Zhang, and Chun-Zhu Li shows that the burning of bio-oil yields the formation of various aromatic structures.  These structures can lead to the development of tar.  The studies done by these scientists help to show the appropriate temperature at which burning bio-oil will yield less tar and be efficient in creating energy.

 

The paper written by Yi Wang, Xiang Li, Daniel Mourant, Richard Gunawan, Shu Zhang, and Chun-Zhu Li was published in the September 14, 2011 edition of the Energy and Fuels Journal for the American Chemical Society.  It is titled:  Formation of Aromatic Structures during the Pyrolysis of Bio-oil.  The scientists used gas chromatography-mass spectrometry and ultraviolent fluorescence spectroscopy in order to trace the development of aromatic ring structures during pyrolysis.  With the results, they were able to determine the efficient temperature for pyrolysis of bio-oil as well as the source that yielded the highest aromatic structures concentrations.

 

Here is a summary of their work.

Introduction:

Bio-oil when further heated is drastically reactive and undergoes many changes.  The formation of large complex aromatic ring systems develops.  Understanding the formation of these structures becomes important.  With the formation of aromatic structures problems arise such as the creation of tar and coke.  Tar becomes a prominent problem when bio-oil is used within gasifiers and boilers.  Tar gums up the equipment and causes buildup.  Coke is a substance created by the burning of coal and other materials to form a solid material that is not soluble or able to be broken down.

 

Bio-oil can be broken down into different cellular components when woody biomass is used:  lignin, cellulose, and hemicellulose.  By testing each component for the production of aromatic structures, bio-oil can further be understood as a whole.

 

This study sought out to investigate the creation of aromatic structures through the pyrolysis of bio-oil between the temperatures of 350 and 850 ◦C.

 

 

Methods:    

The bio-oil used within this study was made from the pyrolysis of mallee eucalypt wood at fast heating rates in a fluidized-bed reactor at 500 ◦C.  To test the cellular components within the bio-oil, the bio-oil was separated into water-soluble and water insoluble fractions.  The water-insoluble was further separated by producing Methylene Chloride soluble and insoluble fractions.  The lignin-derived oligomers within the bio-oil are primarily the water-insoluble/Methylene Chloride-soluble fraction.  The cellulose powder was a component with the water-soluble components.  The reasoning behind separating bio-oil was to determine which cellular component created the highest concentration of aromatic structures during pyrolysis.

 

To determine the presence of aromatic structures during the increase in temperature of pyrolysis, the process was carried out in a novel two-stage fluidized-bed/fixed-bed quartz reactor.  Sand was placed in the bottom stage and fluidized with argon.  The bio-oil was fed into the reactor through an injection probe at a constant rate.  The stages on the reactor were able to be the same temperature of 500 ◦C, or with the bottom being 500 ◦C and top ranging to 850 ◦C.  Three tar traps were placed at the end of the reactor to catch any tar that was produced via aromatic structure formations.  Tar was also present within the sand of the bottom stage.  The tar was totaled and studied further based on formation per temperature.  An image of the reactor can be viewed on figure 1 of the article.

 

The tar of each sample was tested using UV fluorescence spectroscopy to show the relative size and concentration of aromatic rings.  To determine larger aromatic structures, the spectroscopy was used, however for smaller aromatic structures, gas chromatography was used.  The gas chromatography determines the mass of compounds that flow through a capillary column.  A full description of the process of UV florescence spectroscopy and gas chromatography can be seen within the text.

 

These methods were used to determine the size and concentrations of aromatic structures created when pyrolysis of bio-oil was done.  Based on the different temperatures of the second stage of the reactor resulted in higher levels of aromatic structures resulting in production of tar.

 

Results:

To begin, the authors created a figure (figure 2) showing a UV florescence spectroscopy of bio-oil and the soluble/insoluble components.  The figure illustrated that the lignin-derived materials contained larger aromatic structures than cellulose after pyrolysis.  Figure 3 demonstrates raw bio-oil as well as the water-insoluble/methylene chloride soluble fraction that went through the process of gas chromatography.  The graph shows that in raw oil, there are multiple aromatic structures present but at low concentrations.  Similar aromatic structures were present in the water-insoluble/methylene chloride soluble fraction, but these compounds were at much greater concentrations.

 

Next, Cellulose was experimented on and explained within figures.  Figure 4, represented the amount of tar yield from the pyrolysis of cellulose between the temperature ranges of 500-850 ◦C.  At 500 ◦C, the greatest amount of tar was created.  As the temperature increased, the tar yield decreased to nearly nothing.  Figure 5 shows the tar from cellulose pyrolysis undergo a UV florescence spectroscopy.  The results of the graph show the creation of aromatic structures being greatest at the higher temperatures of 800 and 850 ◦C.  Figure 6, represents the tar from cellulose pyrolysis at 700, 800, and 850 ◦C using gas chromatography.  The results show that at higher temperatures, more complex aromatic structures were made.

 

Next, lignin-derived oligomers in the bio-oil were tested to show the levels and complexity of aromatic structures when pyrolysis occurs.  Figure 7 represents the tar yield from the pyrolysis of lignin.  The total tar yield and trapped tar yield were recorded.  At 350 ◦C, the trapped tar was low, but the overall tar yield was at the highest concentration.  It was not until 500 ◦C that the total tar yield began to decrease.  In figure 8, the tar from the lignin-derived oligomers from temperatures of 350-800 ◦C were put into a UV fluorescence spectroscopy and tested for the presence of aromatic structures.  Within the lignin tar, larger aromatic structures were created as the temperatures increased.

 

Lastly, bio-oil as a whole underwent pyrolysis to determine to total tar yield and presence of aromatic structures.  Figure 9, represents the total tar yield from pyrolysis of bio-oil from temperatures            350-850 ◦C.  Again, the tar concentration was higher at a low temperature and shows a decrease at higher temperatures.  When the tar from bio-oil was tested for aromatic structures using UV florescence spectroscopy, the levels showed that new aromatic structures were created through the pyrolysis of bio-oil.  These results can be seen within figure 10.

Discussion:

Cellulose and lignin are components within bio-oil.  By testing these two components separately, scientists can understand where the larger and more complex aromatic structures are created.  By separating the components and testing them separately, at constant energies, the controls for the experiment were made.  By understanding the complexity of aromatic structures that are made during cellulose and lignin pyrolysis, bio-oil as a whole can be assessed.  Both cellulose and lignin created little tar as the temperature of pyrolysis became greater than 500 ◦C.  When pyrolysis of lignin was done, at higher temperatures aromatic structures resulted in the most complex and large aromatic structures.  This can be seen within figure 8.  However, at higher temperatures with more complex aromatic structures, few of the compounds could actually be made.  With lower tar production at higher temperatures, there is little available material for the aromatic structures to be made in.

 

Based on the results of testing bio-oil for aromatic structures, some conclusions could be made.   No matter how high the temperature for pyrolysis of bio-oil is, aromatic structures are going to be created.  But, at higher temperatures, available energy is the greatest with little yield to aromatic structures.  With the studies done on cellulose and lignin individually, one can understand this concept.  The same concept of pyrolysis at higher temperatures resulted in less tar and aromatic structures and more available energy, when the scientists tested bio-oil.

 

Using the methods of UV fluorescence spectroscopy and gas mass chromatography was an effective way to determine the complexity and concentrations of aromatic compounds.  The UV fluorescence spectroscopy was far more effective in showing the larger aromatic compounds that were present in lignin, while the gas mass chromatography was effective in displaying the smaller compounds found within cellulose pyrolysis.

 

Bio-oil as a fuel is an effective means to produce energy.  Understanding the effects of burning bio-oil has led to the use of this fuel in a wide-scale way.  Using this fuel within boilers and gasifiers allow for industrial companies to replace pricy heating oils.  Understanding bio-oil as a fuel source has opened the door for many ways in which to access energy.

Thoughts:

I found this article to be interesting.  When using fuel to operate any type of machinery, I never thought that someone had to determine what the byproducts of burning the fuel were, nor what the best temperature to burn the fuel efficiently was.  By learning how scientists must confront the effects of burning fuels, I have come to question what could be done to other fuel sources to gain a better use of fossil fuels.  New developments with recycled materials for fuels are a much more effective way to create energy than discarding the organic material to rot.  The understanding of bio-oil is just a stepping stone into the discovery of other means of energy around us.

 

Journal Club: Biodiesel Reactive Distillation

This post was written by Cody Ferrell.  His journal article was entitled, “Biodiesel Production from Integration Between Reaction and Separation System: Reactive Distillation Process.” 

 

Introduction

Vegetable oil and animal fat are renewable feedstock that is being made into a clean-burning fuel called biodiesel.  Biodiesel is better for the environment that it produces less carbon monoxide, sulfur dioxide, and unburned hydrocarbons than petroleum-based fuel.  It is safer to handle because it is biodegradable, non-flammable, and is non toxic.  In this experiment they used reactive distillation, also called Intensified Process, to produce biodiesel from soybean oil and bioethanol.  There are many variables that can affect the production of biodiesel.  Some of these variables are the catalyst concentration, reaction temperature, level of agitation, ethanol/soybean oil molar ratio, reaction time and the raw material type.  In this experiment different ratios were used to determine the best production amounts along with the appropriate temperature and catalyst amounts.  It is important for us to take hold of biodiesel production because it has such few harming effects on the environment compared to diesel and gas burning vehicles.  The only drawback of biodiesel is that it is not readily available for much of the population.

Materials and Results

The materials used for the experiment was refined soybean oil which was received by a supermarket in Brazil, and sodium hydroxide the catalyst for this experiment also obtained in Brazil.  The experiment used many tanks, glass rings, water condenser, temperature controller, and reflux controller.  These were used to reflux, boil, transfer, and condense the ethanol and soybean oil.  The entire reaction was taken after 6 minutes though it took longer to reflux and condense the solutions.  Each of the variables was changed to have different solutions to get the best percent outcome.  In the first run catalyst would be (0.5) which is one percent less than the constant used and the molar ratio would be (3) one percent less as well.  In the second run the catalyst would be (1.5) one percent high and the molar ration would be (3) one percent low.  In the third run the catalyst would be (0.5) one percent low and the molar ration would be (6) one percent high.  The fourth run had the catalyst as (1.5) one percent high as would be the molar ratio (6).  In the fifth, sixth, and seventh the catalyst and the molar ratio were the same on the middle mark.  These were the control, with the catalyst at 1 and the molar ratio at 4.5.  The results show the highest yield in the fourth run at 94.54%.  This one had greater amounts of both the catalyst and the molar ratio.  The first run had the lowest percent weight at 62.36%.  This run had both the catalyst and the molar ratio at one percent less than the constant.  Shown in this experiment the most important change or variable in the process was the amount of catalyst used.  This held the reaction at the right rate for the right amount of time to produce the best amount of product for this experiment.

In the second experiment the control, which was used in the ninth through the eleventh runs, for the catalyst was at 1 and the molar ratio was at 6.  In this experiment they had even more mixtures ran than the first experiment did.  In run one the catalyst was one percent less and the molar ratio was one percent less as well.  In run two the catalyst was one percent higher and the molar ratio remained one percent low.  The third run had the catalyst one percent low and the molar ratio at one percent high.  In the fourth run the catalyst was one percent high and the molar ratio was one percent high as well. In runs five and six the molar ratio was at the constant and the catalyst was at the one percent lower and higher from the first experiment, respectively. In the seventh and eighth runs the catalyst remained constant and the molar ratio was one percent lower and higher from the first experiment, respectively.  The results showed in the percent weight obtained from each run the third was the highest at 98.18% and the fourth was second highest at 97.19%. These both had the most molar ratio in them at one percent higher than the constant.  The catalyst amounts differed though.  In run three the catalyst was one percent less than the constant and had the greater percent weight in the run opposed to the fourth which had one percent more than the constant with just less than one percent less weight.  This shows that the concentration of each is a major factor in producing an adequate and worthwhile amount of product.  The seventh run obtained the lowest percent weight at 69.91%.  The amount of catalyst had much to do with the reaction time of how the experiment began its process of distilling.  On figure four in the article p. 253 their comparison of predicted values and observed values matched up pretty straight forward.  It was not an exponential growth but a linear growth pattern in the amount of product obtained.

 

Response

            This experiment with the tests that were ran and the data that was received could be easily used to predict the ester concentration of the soybean oil with the catalyst concentration within the limits that the experiment ran.  The tables and the results that were obtained were clearly stated and logged well.  Each experiment was carried out precisely and had usable data that added up to their hypothesis.  The experiment was made easier for them because the boiling point of ethanol and the product mixture of ethyl esters and glycerol were so large the separation was made much easier from the alcohol.  With the high percentages obtained from the experiments in this process it makes logical sense to use biodiesel more often.  This process seems to be easier than the process of making regular diesel and this has fewer side-effects when used in engines.

 

Journal Club: Aspartame

This post was written by Jesse Reynolds. His article was entitled “Determination of Aspartame and its Breakdown Products in Soft Drinks by Reverse-Phase Chromatography with UV Detection.”

Introduction:
Aspartame is a non-calorie alternative to sugar that is thought to have an advantage over other sugar substitutes because its flavor is so similar to sucrose. In fact, Aspartame does have calories but is close to 200 times sweeter than sucrose, and such a minimal amount is not required to be labeled by the FDA. We can find it in everything from breakfast cereal to the soft drinks consumed in many parts of the world. The question of concern deals with Aspartame’s degradation under factors of heat moisture and pH. The experiment set out to run soft drinks through an HPLC at varying shelf life periods to test the sustainability of aspartame flavored soft drinks. The effects of storage were tested with the product being kept in storage for periods of 1 and 6 months at 22 ±1ºC. This was relevant due to the increasing intake of aspartame by diabetics and those that are dieting or just prefer the taste.
Methods:
Readings were verified on aspartame, citric acid, saccharin, DKP, caffeine, sodium benzoate, and phenylalanine separately on HPLC before the soft drinks were tested as a whole. Soft drinks from Canada were used due to their consistency of having only aspartame sweetened when compared to America made soft drinks, which have a mixture of aspartame and saccharin. The choice to use saccharin free products eliminated a large peak which would be made by saccharin that may have skewed the results. Also, Canadian made soft drinks are required to label how much aspartame is in each can, which ensured an accurate initial quantity. Two brands of lemon-lime and two brands of cola were tested.
Results:
The first test was the one month period where the lemon-lime had an average of 88.5%, and the colas averaged 89.25% of the initial amount of aspartame present. The 6 month test resulted in 46.9% for the lemon-lime and 33.2% for the colas. While the 36 month test averaged aspartame levels of 10.06% for the lemon-lime and 3.84% for the colas from the original quantity. In correlation with the decreasing percentages DKP, aspartylphenylalanine, and phenylalanine all rose in the sum of quantities equivalent to the loss of aspartame.
Conclusions:
Aspartame, being 200 times sweeter than sucrose, is used in small dosages. Though its degradation formed some unsettling compounds, these soft drinks contain such trace amounts that there won’t be any effects with moderate consumption. Although, those suffering from PKU should not be consuming these products, but due to this circumstance all products with aspartame clearly state “PHENYLKETONURICS: CONTAINS PHENYLALANINE.”

 

Journal Club: The Possible Impacts of BRS-3 Agonists

This post was written by K.C. McGinley.

We are all aware of the rising rates of obesity in our world today. Just in the United States, the rate of obesity has doubled in adults and tripled in children within the past 30 years and is currently affecting one-third of adults as well as sixteen percent of children. This serious health risk is the cause of several medical conditions including type 2 diabetes, hypertension, cardiovascular disease, cancer, and arthritis. Obviously, one solution to this issue is a change in lifestyle such as an increase in physical activity as well as a decrease in calorie intake. However, for many people, it is simply not enough. Consequently, this epidemic has lead the pharmaceutical industry on a search for possible drugs that could help people reduce their weight by reducing the amount of food intake as well as speeding up their metabolism. The drawback is that many of these drugs have major health risks. Recently, the drug Sibutramine was withdrawn from the market because it increased the likeliness of strokes and/or heart attacks leaving Orlistat as the only drug on the market approved to treat obesity in the United States. However, the scientists at Merck Research Laboratories have made some major strides in pursuing new drugs to fight the obesity problem.

Introduction:

The scientists at Merck Research Laboratories have made an enormous advancement in the fight to fight obesity. These scientists along with many others have identified that BRS-3 (Bombesin Receptor Subtype 3) receptors could possibly serve as a potential treatment for obesity. They are a primary role in regulating energy homeostasis. This has been proved in experiments using mice. Furthermore, mice lacking functional BRS-3 tend develop obesity. Thus, these scientists have set out on a mission to find which BRS-3 agonists could yield the most effective results. What makes the experiments and data of Merck Research Laboratories significant, however, is the discovery of a novel family of BRS-3 agonists which exhibited unusual chirality.

Experiment:

In their experiments, the scientists began with a high-throughput screening lead to determine if the diazepine ring was the best option to use in the BRS-3 agonist. In each case that included moving the pyridine or breaking the diazepine ring, the effectiveness of the drug was completely lost. Hence, they focused their studies around varying the substituents of the aromatic rings while keeping the diazepine core. After the synthesis of diazepine sulfonamide, silica gel chromatography and reverse-phase high performance liquid chromatography were used in attempt to separate the undesired regioisomer. However, these processes were not enough to separate the mixture. Therefore, the scientists used a ChiralCel OD column to separate the two. They expected to get two different peaks which would represent the two regioisomers but instead got three peaks. While one of these peaks represented the undesired regioisomer they were originally trying to separate, the other two appeared to be possible enantiomers. They contained the exact same molecular structure just opposite rotation. One of them was rotated -157˚; the other was rotating in the positive direction 155˚. The odd thing about this particular molecule is it does not have a chiral center. There are several factors that could explain the observed atropisomerism. These include the restricted rotation about the N-S single bond, hindered inversion of the sulfonamide nitrogen, and the restriction of the diazepine ring. Even further baffling, they conducted an X-ray analysis of the two enantiomers and found that the sulfonamide N has typical single-bond lengths connecting to the surrounding atoms, but the geometry is almost planar. The scientists then attempted a variety of substituent groups on the phenol rings to compare potencies of the HBRS-3 agonists using IC₅₀ and EC₅₀ values. They looked into 17 different compounds starting with the one found using the high-throughput screening lead with the two methyl substituents on one of the phenol ring as a control.

Next, the scientists also decided to experiment with a number of different substitutes on the aryl sulfonyl group as well. There nine different substituents used to compare and contrast the potencies and pharmacokinetic properties of each.

Results and Discussion:

It was clear that for the BRS-3 agonist to be most potent, the compound needed to contain the diazepine ring. This is because the ring was conformationally constrained and caused severe steric hinderance when the phenol ring attached to it. When the phenol ring was flipped one way, the substituents were very close to the sulfonyl group creating major steric hindrance. Consequently, the compounds could be separated and exhibited atropisomerism.

In comparing the two original atropisomers, the 8a) (S)-isomer was very potent with an hBRS-3 IC₅₀ rate of 1.4 nM. However, the 8b) (R)-isomer was not very potent at all with an hBRS-3 IC₅₀ rate of 169 nM.

Compared to the initial lead, potency also increased from the initial lead when CF₃ occupied the 2 position. The 2 position could tolerate several substituents. However, the 3 position preferred none. For the left phenol ring, potency was slightly improved with the deletion of 8-methyl. It did decrease potency when both the 7-methyl and 8-methyl were both deleted. Comparable potency occurred when 7-methyl was replaced by chloro, fluoro, or hydroxyl substituents. When a phenol substituent was added, the potency was very high with an hBRS-3 IC₅₀ of 0.7 nM. In fact, it was among the most potent of the compounds used in the experiment.

I think after looking at the results the larger the steric hindrance, the more potent a compound was. There was also definite relationship between the compound 8a) which was the (S)-isomer and BRS-3 receptors. In the mice, the compound caused a significant amount of weight loss in the wild type and established diet-induced obese mice. However, it did not have any affect at all on the mice that the BRS-3 receptor had been inactivated in.

Conclusion:

In conclusion, I think there is definitely a correlation between the BRS-3 receptors and weight loss. I also think a number of compounds can be synthesized and experimented with to find those that will exhibit the greatest effectiveness as medication. The chirality of the compounds found by the scientists at Merck Research Laboratories also plays an important role in the potency levels.

I think the experiment done was valid. They began with one compound as a control and then added different substituents to different places to test the amount of potency in each. I do find it interesting they stuck with the diazepine ring for all compounds because benzodiazepine is a drug used in the pharmaceutical world to treat anxiety, insomnia, muscle spasms, seizure disorders, and alcohol withdrawals. So I think moving forward, it might prove interesting to see if other types of drugs could utilize the diazepine ring which seems to work  phenomenally for our bodies. Another thing I think could be done with this experiment is testing more of the compounds on the mice to see if they affect weight. The only one they actually tested on the mice was compound 8a) which was successful in the mice that had the BRS-3 receptors. One final problem I had with the article was some of the abbreviations and figures were rather confusing and not necessarily labeled very well. I think it would have been beneficial to the readers the authors had been a little more informative about the different terms being used throughout the paper. Overall, I found the experiment to be highly interesting

References:

 

Liu, Ping (2011). Discovery of Benzodiazepine Sulfonamide-Based Bombesin Receptor Subtype 3 Agonists and Their Unusual Chirality. ACS Medicinal Chemistry Letters.

 

Journal Club: Investigation into Benzene, Trihalomethanes and Formaldehyde in Chinese Lager Beers

This blog post was written by Will Judson. 

 

This journal article investigates the presence of potentially harmful benzene, trihalomethanes, and formaldehydes in the up and coming brewing industry in China.  The production of beer has become a very prominent industry in China over the past decade, and it now has become one of the largest beer producing countries in the world⁸.  However, with most upstart industries in developing countries it is seen that the quantity of the product being produced far outweighs the quality.  The research presented within this journal article peers into the idea that Chinese beers contain harmful carcinogens that are added to the beer in the production process.  Along with determining what these carcinogens are, the researchers also determine the amount of the particular carcinogens that are present and compare these results to the amount found in the water sources of the area.  These particular results will also be compared to the allowance levels of the particular carcinogens released by the World Health Organization (WHO) and other prominent organizations.  Benzene in beer is harmful and is listed by International Agency for Research in Cancer (IARC) as a harmful carcinogen⁷.  Although benzene is listed as harmful when consumed by humans, many industries introduce benzene to their product during the packaging and preservation steps.  Along with benzene there is a group of chemical contaminants that affect brewing liquor known as trihalomethanes.  Trihalomethanes is a group of chemical contaminants that are formed during chlorination when the chlorine reacts with organic acids within untreated water; these include chlorinated hydrocarbons, chlorophenols, chloroform, bromodichloromethane, bromoform, and several pesticides^1,4.  The most shocking addition to Chinese beer is formaldehyde which is added during the mashing process and is believed to improve the overall clarity and stability of the wort (the liquid extracted during the mashing process that will undergo fermentation)⁸.

As the scientists strived to determine what contaminants resided in Chinese beers they used several methods and experiments to perform the task of analyzing the beer samples.  While testing for harmful benzene within the beer the researchers obtained 84 different beer samples, in which 77 were brewed in China.  In order to detect the benzene levels of different beers they used a gas chromatograph and a headspace autosampler.  A gas chromatograph is used as an analytical tool to find out how many components are in a mixture. It can also be used to separate small amounts of material³.  None of the seven beer brands brewed outside of China contained detectable benzene (the gas chromatographer would not detect benzene levels lower than 1.0 µg/L).  However, 7 of the 77 beer brands brewed in china contained benzene, the highest level of benzene detected was 7.1 µg/L while the lowest detected level was 1.9 µg/L with an average level of 4.0 µg/L.  As for the detection of trihalomethanes in beer the scientists used a method that was proposed by Anheuser-Bush⁸.  This method once again called for the use of a gas chromatograph and a headspace autosampler which would measure the total amount of trihalomethanes within a beer.  The total amount of trihalomethanes is reported as the sum of chloroform, bromodichloromethane, and bromoform⁸; these numbers were obtained from 107 different beer samples.  The maximum level of trihalomethanes found was 5.2 µg/L, with an average of 1.2 µg/L.  An interesting aspect of this study is that the scientists also took total trihalomethane levels in the water found in 27 different sites on which several beer brands are brewed.  The water obtained from these sites has levels of trihalomethanes ranging from 2.7 µg/L to 46.9 µg/L, with an average of 19.1 µg/L.  One water sample even contained 79.3 µg/L of total trihalomethanes.  The detection of formaldehyde in beer was done using Solid-phase microextraction (SPME) techniques⁸.  Of the 29 beer samples analyzed, all contained formaldehyde with levels ranging from 0.082 mg/L to 0.356 mg/L.  All of the experiments and analysis techniques performed throughout this study were done using the most advanced technology available in determining what contaminants reside within Chinese beer.  This study accurately portrays not only what harmful compounds are in Chinese beer, but also the levels that these harmful compounds reach.

In the study of benzene contaminants in beer it was shown that a majority of the samples analyzed did not contain detectable amounts of benzene.  All 6 samples of beer that did contain benzene had levels below 10.0 µg/L, which is the limit for benzene in drinking water recommended by the World Health Organization⁶.  After detecting the benzene in the 6 samples of beer, the scientists then set out to determine the cause of harmful benzene within the product.  The inclusion of benzene into the final product was thought to occur in the dilution process, however the breweries all showed strict guidelines when it came to the water used in the dilution process⁸.  The traces of benzene were then linked to the carbonation of the beer under the discovery that many Chinese beers have relatively low original gravities (lower alcohol content).  These low original gravity levels mean that less carbon dioxide was produced during the fermentation process⁸.  Breweries rely on carbon dioxide to keep their product fresh on the shelves, and the less carbon dioxide produced within the fermentation process means the more carbon dioxide they have to introduce to the product from outside sources.  All six breweries that contained detectable benzene had relatively low annual outputs (small and less established breweries) and relatively low original gravities which required them to obtain their carbon dioxide for packaging from outside sources.  This carbon dioxide was obtained from less than renowned sources that lacked adequate quality control systems⁸.  It was stated that several brands obtained their carbon dioxide from fertilizer plants⁸.  The fact that breweries obtain their ingredients from fertilizer plants should be alarming to consumers in the Chinese market.  But the amount of benzene in beer from these breweries should not deter Chinese consumers from buying beer produced in china simply because the water levels in China most likely contain more benzene.  The article also brings up a good point about soft drinks and the amount of carbon dioxide that goes into the production of soft drinks.  Soft drinks obtain all of their carbonation from outside sources, and if these sources are the same sources that smaller Chinese breweries obtain their carbon dioxide from, it could pose a major health threat to the consumers.

As far as the results for the analysis of trihalomethanes in beer goes, it was shown that all of the beer samples contained trihalomethanes even if they occurred in very minute amounts.  Figure 1 in the journal article shows a very intriguing pattern as it lists the total number of trihalomethanes in a beer sample and plotted it with the beers original gravity.  With all of the data plotted on a single graph it is easily seen that beers with the most trihalomethanes typically have a lower original gravity.  This lower original gravity was also the culprit in the presence of benzene contaminants in beer.  However, trihalomethanes would generally not be found in carbon dioxide sources added to a beer, so there must be a different source that adds these organic contaminants to the final product.  It is stated in the article that trihalomethanes are typically boiled off or lost during the boiling process of making the beer⁸, so the trihalomethanes are coming from a different source.  It was also concluded in the paper that the source of these trihalomethanes was the blending liquor added to the product after the fermentation and boiling processes⁸.  The scientists did not present an adequate argument as to why they concluded that the source of the trihalomethanes was the blending liquor added to the product; therefore I have drawn my own conclusion linking the trihalomethanes found in beer to the breweries water supply.  A control study performed by the scientists tested the trihalomethane levels in the water sources of 20 different breweries.  These locations had levels ranging from 2.7 µg/L to 79.3 µg/L.  Figure 2 lists all 20 locations on a graph and shows the contaminants in the water as well as their levels, this is interesting because it gives the reader an idea of what actually was found at these locations.  It is stated in the article that it is the brewmaster’s job to ensure that the quality of water received from the local water source meets brewery standards⁵.  However, if these are the same breweries that purchase carbon dioxide for their products from fertilizer plants, I have a hard time believing that these water quality standards are being met.  Granted, most of the trihalomethanes found in the water supplies will be boiled off and lost in the production process, but some will always remain in the final product.

As the scientists set out to determine the amount of formaldehyde in beer, they discovered that all 29 samples contained the contaminant to some degree.  The scientists were using a very advanced technique to analyze the samples, which made it possible to detect formaldehyde even at the smallest amounts.  This raised the question, were breweries in China the only ones who added formaldehyde to their final product? Or was this a trend seen around the world?  In the article it was mentioned that a similar study of formaldehyde in beers was done by Donhauser and co-workers² as they examined beers from Europe using a less advanced method.  It was found that 65% of the European beers contained detectable formaldehyde, but the detection level of the method they were using was 0.2 mg/L².  With this detection level many of the Chinese beers tested would have shown no traces of formaldehyde.  So the 65% reported by the study of European beers was a flawed number.  As shocking as it is, the addition of formaldehyde to beer is a common practice seen around the world.  Recently formaldehyde has been listed as a carcinogen⁸, and studies have shown it to be hazardous to human health when consumed.  In saying this, no matter how popular formaldehyde had become as an additive to beer it can no longer be used in the production process.  Many breweries now choose a product known as PVPP (polyvinylpyrrolidone) in order to improve the clarity of the wort of beer⁸.  In the article the formaldehyde levels were measured in milligrams per liter instead of micrograms per liter like trihalomethane levels and benzene levels.  Seeing this, formaldehyde levels could be the consumer’s greatest concern when purchasing beer.

This article did raise concern about beers being brewed in China’s up and coming industrial society.  With harmful contaminants floating around such as benzene, formaldehyde, and the various types of trihalomethanes one can only wonder that the beer that purchase can cause more adverse effects than just a bad hangover the next morning.  All of the samples tested throughout this experiment did not exceed WHO drinking water levels, so how harmful are these contaminants in the beer that individuals consume? All of the contaminants found and analyzed were found in very minute levels, in some cases as low as 1 microgram per liter.  I believe in order for these contaminants to have adverse effects on one’s body, the person would have to consume large amounts of the breweries product at a time.  The mean value for trihalomethane levels in the beers analyzed in this study was 1.2 µg/L, where as the mean value for trihalomethane levels in the water sources sampled was 19.1 µg/L.  The water sources have roughly 16 times the amount of trihalomethane levels than the beers being sampled in this experiment.  In order for one to be exposed to the same levels of contaminants that are found in local water supplies in China they would have to consume very unhealthy amounts of beer.  An individual drinking this amount of beer would see far more health issues related to the consumption of a mass amount of alcohol, rather than the carcinogens found in these beers.  I believe this article was very helpful when it came to exposing what contaminants are actually being introduced into the Chinese breweries.  The study and experiments were well thought out as they successfully found out what they originally wanted to investigate.  However, I do believe that the scientists performing these studies were expecting to find higher numbers of these carcinogens as they analyzed the various beer samples, and so was I.    Overall this article portrayed accurate information about the upstart brewing industry in China, and it successfully relayed trustworthy information to the public dealing with the quality of beer being produced.

References

1.            Baxter, E.D., The influence of brewing liquor on beer safety and quality. Ferment, 1999, 12(4), 13-18.

2.            Donhauser, S., Glas, K., and Walla, G., Detection of formaldehyde in beer. Monatsschrift fűr Brauwissenschaft, 1986, 39(10), 364-368.

3.            “Gas Chromatography.” CU Boulder Organic Chemistry Undergraduate Courses. Web. 10 Nov. 2011.

4.            Grant, A.P., Liquor quality. Ferment, 1995, 8(4), 252-255.

5.            McGarrity, M.J., McRoberts, C., and Fitzpatrick, M., Identification, cause, and prevention of musty off-flavors in beer. Tech. Q. Master brew. Assoc. Am., 2003, 40(1), 44-47.

6.            World Health Organization 2001. Guidelines for Drinking Water Quality. World Health Organization, Geneva.

7.            World Health Organization International Agency for Research on Cancer: IARC monographs on the evaluation of carcinogenic risks to humans. Supplement 7, 1987, IARC Press: Lyons, pp.120.

8.            Wu, Qian-Jun, Hong Lin, Wei Fan, Jian-Jun Dong, and Hua-Lei Chen. “Investigation into Benzene, Trihalomethanes and Formaldehyde in Chinese Lager Beers.” The Institute of Brewing and Distilling 112.4 (2006): 291-94. Print.

 

Journal Club: Repeated cycles of chronic intermittent ethanol exposure in mice increases voluntary ethanol drinking and ethanol concentrations in the nucleus accumbens

This post was written by Nicki Herald. 

 

Introduction

Alcoholism is a disease that millions of people suffer from, worldwide.  It is a “roller coaster” sort of lifestyle, with periods of abstinence followed by relapses.  Each time an affected individual drinks, they must drink more than they did the last time to get the “reward” they are looking for.  As it turns out, other animals exhibit this pattern when exposed to ethanol, as well.  Mice, for example, possessed a type of dependence when they were chronically exposed to ethanol, in this study.  The control and experimental groups were placed in an identical environment, with the same opportunity to consume ethanol.  As expected, and explained in greater detail below, the experimental mice consumed much more ethanol.

Methods

This study involved three experiments, but some of the variables were the same in all three.  All of the control mice (CTL) were given saline and pyrazole injections, whereas all of the experimental mice (EtOH) were given 1.6 g/kg ethanol and pyrazole injections.  All mice were placed into a chronic ethanol exposure chamber, basically a gas chamber, for sixteen hours a day, four days at a time.  The gas was turned off for three days, and the mice had no access to ethanol.  After this period of abstinence, no gas was turned on for five days, but the mice had a choice to drink either tap water or ethanol.  This cycle was repeated multiple times during the study.

In experiment one, the goal was to find out how much ethanol the mice were voluntarily consuming.  The sucrose fading procedure was employed to establish a 15% baseline ethanol.  Four separate tests were conducted.

In experiment two, the goal was to compare voluntary ethanol consumption and the ethanol concentrations in the brain.  In vivo microdialysis was used to measure the ethanol concentration in the brain.  Probes were implanted into the brains of seventeen EtOH mice and ten CTL mice, the day before the dialysis was needed (Figure 6 illustrates the placement of the probes).  When dialysis was ready to be collected, .22 micrometers of artificial cerebral spinal fluid was diffused through the probes.  The dialysate was collected into tubes containing six microliters of .75 M perchloric acid.  After each twenty minute collection interval, two microliters of dialysate was removed to be tested for ethanol.  This was done using gas chromatography with flame detection.

In experiment three, ethanol concentrations in the blood and brain were tested immediately after being taken out of the gas chamber.  These results were compared with those found after the mice had drunk voluntarily for four cycles.  A baseline ethanol of 15% was set, again, using the sucrose fading test.  Four test cycles were done under drinking-only sessions.  After the fourth cycle, thirteen of the mice had blood drawn from behind their eyes to test the ethanol concentration.  Fourteen of the mice went through one more cycle in the gas chamber, and had blood and cortex tissue removed immediately after the cycle was finished.  This was used to test ethanol concentration solely from the ethanol gas.

Results

As expected, in experiment one, voluntary drinking increased with time spent in an environment filled with ethanol.  The control mice stayed constant at the baseline of 2.1 g/kg, but the experimental mice reached 4.1 g/kg by the end of the experiment.  Again, just like humans, the mice that went into the chambers with ethanol already in their bloodstream were much more likely to keep drinking more and more.  An individual struggling with alcoholism would have a much harder time not drinking when it was freely available, than someone who did not have a drinking problem.  Once the affected individual started drinking, it would be harder for him/her to stop until he/she reached the euphoria he/she was looking for.  Figures 1a and b make it easy to see that the EtOH mice were much more vulnerable to the ethanol.  As time went on, they increased their voluntary consumption.  This is supported by post-hoc tests.  Though it may seem like common sense that with increased exposure to alcohol, the EtOH mice would voluntarily drink, but this is a valid experiment.  This had to be shown and proven in order for experiments two and three to make sense.

In experiment two, the same trend was seen.  As test cycles went on, voluntary consumption increased in the EtOH mice, as shown in figure 5a.  This part of the experiment, in my opinion, was not necessary to include in the article again.  It is essentially a repeat of experiment one.  The second half of the experiment, however, is valid.  The microdialysis procedure proved that the EtOH mice had significantly higher concentrations of ethanol in their nucleus accumbens than the CTL mice.  Four samples were tested, and in each one the concentration increased (figure 5c).

In experiment three, the first part was, once again, testing ethanol concentration in the blood and brain after a drinking session.  Obviously, EtOH mice had much higher levels.  Again, I feel like this part of the article was redundant.  The second half of the experiment was valid, and yielded surprising results.  The EtOH mice that were tested immediately after coming out of the gas chamber had blood and brain concentrations with no significant difference than those tested in the first part of this experiment (table 2).  This goes to show that, during drinking sessions, they were trying to obtain as much ethanol as they were receiving in the gas chambers.

Discussion

I think that this was a very valid experiment, overall.  Alcoholism is a real disease, and humans share many of the relapsing and dependent characteristics with the mice.  Since humans are not ethically able to be researched on, experiments such as this one may lead to a remedy for alcoholism.

 

Journal Club: Pyrazole Still Has More to Offer in Antibiotics

This post was written by Nathan Schneider.  His article was entitled ” Synthesis and Antibacterial Activity of Some New Derivatives of Pyrazole.”

 

Introduction:

The synthesis of bioactive compounds is an area of study of great interest to the medical field, especially compounds with antimicrobial effects. Through synthesizing new compounds and studying their properties and bioactivity, scientists can discover new and possibly more effective antibiotics.  Derivatives of the molecule pyrazole have been used for their effects as an anti-inflammatory, antipyretic, anticonvulsant, anti-arrhythmic, and antibacterial agent.  In recent years, some new derivatives of Pyrazole have been synthesized and evaluated for their antimicrobial activity.  In the study Synthesis and antibacterial activity of some new derivatives of pyrazole conducted by Mohammad Rahimizadeh, Mehdi Pordel, Mehdi Bakavoli, Shima Rexaeian, and Ali Sadeghian, some new derivatives of pyrazole were assessed for their antibacterial effects with gram-positive bacteria.  In this study, certain derivatives of pyrazole were analyzed and observed to “show moderate to strong antimicrobial activities against gram positive bacteria”. ¹

 

Methods:

In this experiment, 10 different derivatives of pyrazole were obtained by synthesizing different acid chlorides with the compound “5-amino-1-(2,4-dinitrophenyl)-H-4-pyrazolecarbonitrile” (1).  The 5-amino-1-(2,4-dinitrophenyl)-H-4-pyrazolecarbonitrile was obtained from the reaction of 1-(2,4-dinitrophenyl)hydrazine with 2-(ethoxymethylene) malononitrile in ethanol under reflux condition.  The acid chlorides that were used in the reaction with the 5-amino-1-(2,4-dinitrophenyl)-H-4-pyrazolecarbonitrile were either purchased, or obtained through the reaction of thionyl chloride and a carboxylic acid.  The final step in obtaining the pyrazole derivatives was the synthesis of the acid chlorides with the 5-amino-1-(2,4-dinitrophenyl)-H-4-pyrazolecarbonitrile in dry pyridine for a four-hour reflux.

 

Results:

The resulting pyrazole derivatives were analyzed for melting point, absorption of the IR spectra, elemental percentage, and percent yield.  They were further tested for antibacterial activity against Escherichia coli, Staphylococcus areus, methicillin susceptible S. aureus, Pseudomonas aeruginosa, and Bacillus subitilis. Against all of the gram-negative bacteria, the pyrazole derivatives were uninhibitory, but against Staphylococcus areus and methicillin susceptible S. aureus, different derivatives showed “moderate to strong antimicrobial activity.” ¹ The study did comparative measurements against Erythromycin, Cloxacillin, and Cephalexin and two of the derivatives had lower minimum inhibitory concentrations than that of Erythromycin, Cloxacillin, and Cephalexin against either Staphylococcus areus, or methicillin susceptible S. aureus (these derivatives had substituted R groups of para-nitrobenzene and para-cyanobenzene).  Minimum inhibitory concentrations were obtained through use of dilution test tub method, and then confirmed by culturing samples of bacteria on Petri dishes and determining the minimum inhibitory concentration of the test organism by detecting a lack of visual turbidity.

 

Conclusions and Discussion:

The results of this experiment demonstrate how certain new derivatives of pyrazole have a strong antibacterial capability against certain forms of gram-positive bacteria.  This capability was demonstrated to be stronger than some antibiotics being used at the time of the study.  The procedures of the experiment appear to be sound in aspects of both chemistry and biology.  The chemical procedures, equipment, and sources of materials are all documented, and the antibacterial capabilities of the pyrazole derivatives were tested with both test tube dilution method, and in Petri dishes for the elimination of visual turbidity. Moreover, they were tested against Erythromycin, Cloxacillin, and Cephalexin, all current antibiotics on the market during the time of study.  Overall, the study appears to be well put together, conducted, and documented.

After this study it would be unlikely that someone would argue against the antibacterial capabilities of the assessed pyrazole derivatives, and from this study, further experiments can be conducted using these derivatives to assess their safety and effectiveness for consumption.  While we currently do not know if these derivatives will ever be used for drug design or antimicrobial therapeutics, this study can now be used as a foundation for the further experimentation and examination of these pyrazole derivatives because it was conducted accurately and effectively.

 

 

 

Journal Club: Changes in Water-Soluble Vitamins and Antioxidant Capacity of Fruit Juice-Milk Beverages As Affected by High-Intensity Pulsed Electric Fields (HIPEF) or Heat during Chilled Storage

Every year students in our Organic Chemistry class review a journal article and write a blog post about it.  This blog post was written by Adam Wiss. 

 

My assignment was to pick a journal article to review and discuss in class. The article had to pertain to some area of organic chemistry. I picked this journal article that deals with fruit juice-milk beverages, because I enjoy learning about nutrition. The experiment was completed by a group in Spain led by Laura Salvia-Trujillo. The article, “Changes in Water-Soluble Vitamins and Antioxidant Capacity of Fruit Juice-Milk Beverages As Affected by High-Intensity Pulsed Electric Fields (HIPEF) or Heat during Chilled Storage,” looks at the components of these beverages after different types of processing and after being stored.

Introduction:

With a rise in obesity and cardiovascular disease, companies have been exploiting the opportunity and promote “the most healthful items on the market.” Therefore, nutritious items are becoming increasingly more accepted. Fruit juices and milk are in this category because of their antioxidant properties. In order to market these products and make them easily accessible, companies must determine how to retain the properties of the natural product. High-intensity pulse electric fields is a suggested method to accomplish this. This study uses HIPEF processing, thermal treatment, and untreated fruit juice-milk beverages to evaluate initial and final values of vitamin C, B vitamins, antioxidant capacity, enzyme activity, and color. HIPEF has been seen to make a substance preserve antioxidant powers. Also, two enzymes, peroxidase (POD) and lipoxygenase (LOX), can be harmful to healthful items that are processed. Optimistically, the goal for HIPEF was to inactivate these detrimental enzymes.

Materials and Methods:

The samples used in this experiment were an orange, mango, kiwi, and pineapple fruits that were purchased at a supermarket in Lleida, Spain. These fruits were cleaned, juiced, then mixed with commercial pasteurized whole (FJ-WM) or skim milk (FJ-SM). As mentioned previously, HIPEF and thermal treatment were used to process the samples. HIPEF is a non-thermal method of stabilizing food products that uses pulses of electricity to inactivate microbes while keeping its nutritional integrity. For the thermally treated method, microorganisms were eradicated by pumping the samples through a stainless steel heat exchanger coil system. Experiments were carried out twice in order to attain a mean value that would be used for ANOVA and significance differences.

Results:

Vitamin C content was retained 99.5 and 97.0% after applying HIPEF. These results have also been observed in other experiments. Furthermore, Vitamin C degradation was slower in the thermally treated samples than HIPEF and untreated. This could be due to lower POD inactivation in HIPEF treated beverages compared to thermal processing. HIPEF processed samples retained 50% Vitamin C content after 21 days; however, thermally processed samples retained it for 28 days. For B vitamins, each method withheld the suggested values reported by the USDA after processing and storage. It was interesting that HIPEF treated and untreated beverages were observed to have significantly higher levels of riboflavin after processing and storage compared to thermally treated beverages. This was not similar to results from other studies. As a result, one can conclude that water-soluble vitamins are more susceptible to heat than HIPEF. The B vitamins remained stable during storage. No significance was found in amount of antioxidants of treated or untreated beverages following processing. However, antioxidant capacity values were significantly correlated with vitamin C content. Furthermore, FJ-WM demonstrated higher antioxidant capacity than skim milk, regardless of treatment. This shows a contribution from lipophilic antioxidants to scavenge radicals in the products. For enzyme activity, while POD activity significantly decreased after HIPEF, it had a minimal effect on LOX activity in either beverage. In the HIPEF processed samples, the type of milk used was relative to the amount of POD inactivated with skim milk being lower. Thermal treatments also significantly decreased POD activity, but they also significantly lowered LOX activity in both milk types. The tests showed that POD activity was irreversible after HIPEF and thermally treated samples. Since levels of LOX significantly increased from the third week of storage in all samples, despite type of milk or treatment, then it’s proven that HIPEF nor heat cause irreversible changes in LOX activity in fruit juice-milk beverages. With respect to color, HIPEF and thermally treated FJ-WM and FJ-SM samples had lighter values after processing and during storage compared to the beverages that were untreated. Hue angle values showed significant decrease no matter what treatment was applied.

Final note:

Overall I thought this experiment was completed well. However, some questions did arise during my research. First, the article did not explain why the fruits (orange, mango, kiwi, and pineapple) were used. I would assume the types of fruit used could make a significant difference in results, especially if the pH is not kept consistent. Furthermore, I’m curious as to how the HIPEF and thermal settings would affect the results, and why they chose these. Another thing that caught my attention was how often the journal article referenced other experimental results. It seemed odd, even though the results were usually similar to what others had discovered, to put all of that information into the article with their results. This made it difficult to distinguish which results belonged to the experiment at hand. Also, I would like to know if beverages with greater concentrations of vitamin C and B vitamins would have a better retention rate after processing and storage.