Beer Foam in New York and Beyond: A Summer of Research and Exploration

Jonathan Hunt, Centre CollegeThis enrichment project combined research experience and cultural exploration. Nine weeks were spent in Geneva, New York. Research was done at the Cornell University Agricultural Experiment Station in the lab of Dr. Karl J. Siebert. The focus of said research was evaluating and improving a system meant to model beer’s behavior in regards to foam production. Variables were manipulated and corrected to reconcile the model system with data compiled from several different types of beer. Additionally, several short trips were undertaken as a means of exploring nearby culture. These included excursions to: Niagara Falls, New York City, and Toronto. Exploration of culture in these locations involved samplings of local cuisine, art, and landmarks.

Abstract

ExplorationToronto

One weekend of my summer was spent in the city of Toronto, Ontario, Canada. I visited several art galleries, such as the Art Gallery of Ontario and the Royal Ontario Museum; I explored culture-rich areas of Toronto, such as the infamous West Queen Street; and I encountered world-famous landmarks, like the Canadian National Tower.

New York City

BackgroundPrevious efforts by Dr. Karl J. Siebert, professor of brewing science at Cornell University, to generate a beer foam model system for quality control reasons were promising, but certain flaws were present. The most notable flaw was the model’s reaction to changes in pH. while actual beer shows increased foam potential with increase in pH, Dr. Siebert’s model shows decreased foam potential with increase in pH.

Foam production is largely dependent on the concentrations of four beer components: ethanol, isoalpha acids (hop-bitter compounds), soluble gases (such as CO2), and “foam active” proteins, the existence of which was first suggested by Asano and Hashimoto (1980). These proteins were later found by Sorenson et al. (1993) to include the Z proteins and barley lipid transfer protein 1.

The net-charge of the “foam active” protein utilized by Siebert (ovalbumin) is representative of the net-charge of the Z proteins, but not at all representative of the net-charge of lipid transfer protein 1. Because beer foam production is a largely ionic process, this was suggested to be a potential source of error in the model system with regards to pH change.

This experiment set out to isolate lipid transfer protein 1 from barley and use it in place of ovalbumin as the beer foam model’s “foam-active” protein. Once this was accomplished, extensive foam testing was done to observe lipid transfer protein 1’s effect on the accuracy of the beer foam model.

ReferencesAsano, K. & Hashimoto, N. (1980, May). Isolation and Characterization of Foaming Proteins of Beer. The Research Laboratories of Kirin Brewery Co., Ltd., Miyahara-Cho, Takasaki, Gumma Pref., 370-12 Japan

Sorenson, S., Bech L., Muldbjerg, M., Beenfeldt, T., & Breddam, K. (1993). Barley Lipid Transfer Protein 1 is Involved in Beer Foam Formation. MBAA Technical Quarterly, Vol . 30, p p 136-J45, 1993

PurposeIsolate “foam active” barley lipid transfer protein 1 and observe changes that occur when it is substituted into beer foam model system.

Methods & ResultsProtein IsolationBarley (Lacey from the 2010 crop year) was ground to a flour. Approximately 4 liters of deionized water were added to the flour and the resulting mixture was refrigerated and stirred for two nights. The mixture was then centrifuged. The resulting clear extract was subjected to 40% ammonium sulfate fractionation and was then centrifuged. The resulting clear extract from this centrifugation was subjected to 75% ammonium sulfate fractionation and was once again centrifuged. The resulting clear extract underwent 6500 m.w. cutoff dialysis, and the dialyzed extract was then freeze-dried.

Dialysis cartridge with protein isolate

Once barley lipid transfer protein 1 had been effectively isolated, protein assays and SDS-PAGE were run on the isolate. Although the isolate proved to be somewhat impure, electrophoresis showed a large presence of an approximately 10,000 m.w. protein, assumed to be barley lipid transfer protein 1. Because the other compounds in the isolate would be present in beer regardless, and thus were unlikely to affect the integrity of our beer foam model, impurities were ignored.

Beer Foam Testing

The new beer foam model system, utilizing the lipid transfer protein 1 isolate, provided results different from the previous model system : with increase in pH, the new beer foam model system showed increase in beer foam potential.

New Beer Foam Model System

ConclusionsThe use of barley lipid transfer protein 1 as the “foam-active” protein in Dr. Siebert’s beer foam model provided results much closer to actual beer in respects to pH than when ovalbumin was used as the “foam-active” protein. Because ovalbumin is representative of the other known foam-active proteins (the Z proteins), these results provide circumstantial evidence that LTP1 is the major foam active protein. This knowledge can potentially help future quality control measures of beer foam production

As an intended biochemistry and molecular biology major with a strong career interest in the food science field, this was the perfect opportunity for me. Not only did this research teach me valuable skills (centrifugation, ammonium sulfate precipitation, pipetting) and gave me experience much needed for the future of my research and food science career (independence in the lab will be necessary when I am running my own lab), it also provided me with invaluable networking opportunities (Cornell University is considered the leading food science institute in the nation).

What This Experience Meant To Me

Another weekend was spent in New York City. As I stayed with a New York native, I was able to firmly grasp one of the many cultures within the city: I ate where native New Yorkers eat, I slept where native New Yorkers sleep, and I walked where native New Yorkers walk. I exposed myself to art at the Metropolitan Museum and explored a sub-culture at the New York City Pride Parade.

Niagara FallsI visited Niagara Falls with my family. While there is little culturally to partake in, Niagara Falls is likely one of the most important physical features of our nation. Viewing

the majesty of the falls is rewarding and enriching in and of itself.

ImportanceThis exploration was in continuance of the cultural exploration established by the 2011 Italy trip. It was important because Geneva, NY, the sight of my research, was a very small town where much exploration was not possible. These trips were valuable in the same way that the Italy trip was valuable: although not directly related to academic or career interests, exploration of a foreign area’s culture is always very enlightening.