Did you know artificial flavorings are industrial chemicals that are derived from oil or gas? Fresh banana, a waft of flowers, blueberry: the scents in Shota Atsumi's laboratory in the Sacramento and Davis area's UC Davis Department of Chemistry are a little sweeter than in most university chemistry laboratories.
The idea kind of makes you think of having a piece of green tea cake instead of a cake colored green with artificial food colorings. If so, check out the recipe, "Green Tea Layer Cake Recipe." Or see the website for the green tea (matcha) pound cake recipe with red azuki beans. But aside from recipes, a chemistry lab sometimes smells like fruit instead of reeking of paint or fuel being prepared there. Here's why.
That's because Atsumi and his team are engineering bacteria to make esters — molecules widely used as scents and flavorings, and also as basic feedstock for chemical processes from paints to fuels, according to the March 10, 2014 UC Davis news release, "Sweet smell of sustainability." Their latest work, "Expanding ester biosynthesis in Escherichia coli," is published March 9, 2014 online in the journal Nature Chemical Biology. Nearly all industrial chemicals, from artificial flavorings to paint, are derived from oil or gas, Atsumi said, according to the news release.
The source material for the bacteria is based on sugars, which can come from renewable biomass
"Our motivation is to make chemicals from renewable sources instead," Atsumi said, according to the news release. Scents and flavorings make up a $20 billion industry worldwide, he explained. Esters are molecules in which two chains of carbon atoms are linked through an oxygen atom. They are made chemically by reacting an alcohol with an organic acid. But the thermodynamics of this reaction mean that it tends to run the other way — it's easier to break up an ester than to make it.
Living cells can also make esters. For example, yeasts produce small amounts of esters that give flavors to wine and beer, without requiring high temperatures or special conditions
"The reaction is chemically difficult but biologically easy," Atsumi said in the news release. "Nature gives you a great system to work with." Nature uses a class of enzymes called alcohol O-acetyltransferases to make esters from acyl-Coenzyme A (acyl-CoA) molecules. Changing the acyl- part of acyl-CoA that goes into the reaction changes the type of ester that is produced. Atsumi, graduate student Gabriel Rodriquez and postdoctoral researcher Yohei Tashiro took genes for biochemical pathways from yeast and introduced them into E. coli bacteria, a reliable test system for genetic engineering.
By tweaking the acyl-CoA pathway, they could manipulate one half of the ester: by adjusting the pathway that produces alcohols in the cell, and by shutting down other potential pathways, they could adjust the other half. Therefore, they were able to pick the final ester made by the bacteria. The technique, which has been patented, opens up possibilities for producing many different esters in biological systems, Atsumi said, according to the news release.
Ultimately, Atsumi hopes to engineer these chemical pathways into cyanobacteria (blue-green algae), single-celled organisms that can draw energy directly from sunlight and carbon from the atmosphere. The work was partly supported by a Hellman Fellowship awarded to Atsumi.
Tasting Chinese food and culture at UC Davis is open to the public, and many of the lectures are free
Also, if you're in the Sacramento and Davis area, check out, "Eclectic programs offer taste of Chinese culture." Paper-cutting workshops, tai chi classes and lectures on Chinese customs will be among the savory offerings of the Confucius Institute at UC Davis this spring. Established in 2012, the institute is the first of hundreds of Confucius Institutes around the world to focus on promoting understanding of Chinese food and beverage culture. All of the following events are open to the public, and most are free.
Wisdom of Balance in Diet and Cuisine
Thursday, March 27 — The first of the Yin and Yang Lecture Series will focus on this Chinese concept of balance between complementary forces and its relationship to a modern healthy diet. Presenting the lecture will be Jianqiao Dong, deputy director of the institute and professor with the School of Foreign Studies at Jiangnan University. Other lectures in the series will be added later. Registration is requested. 4 p.m. to 5 p.m., Sensory Theater, Robert Mondavi Institute.
Tea and Conversation
Wednesdays, April 2 to June 11 — This lecture series will feature salon-style discussions of Chinese folk customs, the Chinese family and Chinese community. Topics include how Chinese names are given and their meanings, the customs and taboos of eating, Chinese games, and wedding and marriage customs. Institute instructors will facilitate the discussions. Registration is required. 12:05 p.m. to 12:55 p.m., 3013 Wickson Hall.
Tuesdays and Thursdays, April 8 to June 10 — The reported benefits of this series of choreographed, slow, fluid and continuous movements include physical strength and vitality, balance and coordination, reduced pain and stiffness, reduced stress and enhanced sleep. Leading classes will be Janny Wu, who was trained in China and has taught in the Sacramento area since 2007. Registration is required, and the cost is $150 for the series. 6 p.m. to 7:30 p.m., outdoors on the Davis campus.
Chinese Paper Cutting
April 11 and more — Hands-on workshops will bring to life the history, culture and folk tradition of paper cutting in China. Introductory sessions will be offered in April, May and June, but specific dates have not yet been set. Chinese characters, a more advanced workshop, will be offered on April 11 and a May date yet to be determined. Registration is requested. 1:30 p.m. to 2:45 p.m., 1017 Wickson Hall. Two workshops on zodiac animals will be scheduled in May and June.
Tea and Beverage Workshops
April 14, May 5, June 9 — Through this series of tea tastings and lectures, participants will tour the areas where China’s best tea leaves are produced, visit four kinds of tea houses and trace the voyage of tea around the world. Dan (Danna) Cao, an institute instructor, will lead the workshops. Registration is requested. Noon to 1 p.m., Sensory Theater, Robert Mondavi Institute.
For more information
More information about institute events and registration is available at the Confucius Institute at UC Davis. http://confucius.ucdavis.edu/.
Some of the institute events will take place during the Fix 50 construction project in Sacramento. Learn how regional traffic may be affected at the Fix 50 website.
About the Confucius Institute at UC Davis
The institute combines signature strengths of UC Davis and China’s Jiangnan University as world leaders in food and beverage science and technology to promote understanding of Chinese food and beverage culture. Since 2004, Hanban/Confucius Institute Headquarters, affiliated with China’s Ministry of Education, has partnered with universities and other organizations to establish hundreds of institutes to promote Chinese language and cultural teaching resources and services worldwide.
Sodabriety: Cutting teenage sugar intake
A new study, "Sodabriety” Challenge Successful at Cutting Teen Sugar Intake," recently published in the Journal of School Health shows that teenagers can be persuaded to cut back on sugary soft drinks -- especially with a little help from their friends. The study finds a secret to cutting sugary drink use by teens, says a new study. A student-run ‘Sodabriety’ effort also boosted water consumption. You also may wish to see, "A “Sodabriety” Challenge: Strategies to Reduce Sweetened Beverage Consumption By Teens in Rural Ohio."
This study shows that teenagers can be persuaded to cut back on sugary soft drinks – especially with a little help from their friends. “With the right guidance and support, [teenagers] are powerful influencers. We might as well use peer pressure to our advantage.” Another publication of interest to those who want to learn more about dried fruits as healthy foods and/or their effects is the journal Dried Fruits: Phytochemicals and Health Effects.
A 30-day challenge encouraging teens to reduce sugar-sweetened drink use lowered their overall consumption substantially and increased by two-thirds the percentage of high-school students who shunned sugary drinks altogether
The “Sodabriety” challenge, piloted by Ohio State University researchers, was an effort to confront the largest source of added sugar in the U.S. diet: sugar-sweetened soft drinks, sports and energy drinks, and flavored milk and coffee. Also see, "What proportion of preschool-aged children consume sweetened beverages?"
Students were tapped to establish teen advisory councils, whose members led the interventions at two rural Appalachian high schools. They designed marketing campaigns, planned school assemblies and shared a fact per day about sugar-sweetened drinks over the morning announcements.
The primary message to their peers: Try to cut back on sugar-sweetened beverages for 30 days. Students opted not to promote eliminating these drinks entirely during the challenge
Overall, participating teens did lower their intake of sugary drinks, and the percentage of youths who abstained from drinking sugar-sweetened beverages increased from 7.2 percent to 11.8 percent of the participants. That percentage was sustained for 30 days after the intervention ended. In an unexpected result, water consumption among participants increased significantly by 60 days after the start of the program, even without any promotion of water as a substitute for sugar-sweetened drinks.
“The students’ water consumption before the intervention was lousy. I don’t know how else to say it. But we saw a big improvement in that,” said Laureen Smith, according to the March 26, 2014 news release, "Study finds secret to cutting sugary drink use by teens." Smith is an associate professor of nursing at Ohio State and lead author of the study. “And there was a huge reduction in sugar-sweetened beverage consumption. The kids were consuming them fewer days per week and when they were consuming these drinks, they had fewer servings.”
Smith originally set out to conduct a community-based study concerning the prevalence of Type 2 diabetes in Appalachian Ohio
Through a series of meetings, surveys and focus groups, parents in these communities tended to express concern about kids’ diets. “Sugar-sweetened beverages kept coming up,” Smith said in the news release. According to the Centers for Disease Control and Prevention, about 80 percent of youths – especially those age 12 to 19 years – consume sugar-sweetened beverages daily, and these drinks contribute between 13 and 28 percent of their daily calorie intake. Children and adolescents in Appalachia have higher rates of sugary beverage consumption compared with others of the same age.
In all, 186 students at two high schools participated in the challenge – almost half of each school’s headcount, and almost 70 percent of eligible students when teens attending vocational training were excluded. Smith surveyed the students about vending machine access and beverage options, sugar-sweetened beverage drinking habits and water consumption. Once the intervention began, students were instructed to keep a log, recording how many servings of sugary drinks and other beverages they consumed each day.
For this study, sugar-sweetened beverages included regular soft drinks, sweet tea, fruit drinks, sports drinks, energy drinks, flavored or sweetened milk, coffee with sugar, other coffee drinks and an “other” category
Regular soft drinks were the preferred beverage for 92 percent of sugary drink users before and after the study. At baseline, nearly half – 41 percent – of the students reported buying sugary drinks from school-based sources: vending machines, the cafeteria or school stores. In addition, 63 percent of students reported consuming sugary drinks at least three days a week, with more than a third reporting daily intake of these beverages – a figure that dropped to 7.2 percent of students immediately after the challenge ended.
One month after the intervention ended, almost 60 percent of students reported consuming sugary drinks fewer than three days each week. Over the course of the study, from the start of the challenge until a month after it ended, respondents achieved a nearly 30 percent reduction in days per week that they consumed sugary drinks.
A similar pattern was seen in servings: The intervention reduced average daily servings of sugar-sweetened beverages from 2.3 to 1.3 – about one serving, or 8 ounces, per day
Water consumption increased from baseline to immediately after the challenge ended, and continued to increase over the next 30 days to an average of 5 ½ servings of water per day, reaching a 30 percent increase from baseline measures. Smith heard from students that they had lost weight, felt better and had recruited parents to join them in the challenge. Based on this anecdotal data, she plans to follow up with a similar school-based challenge that includes measures of health outcomes and involvement of students’ families.
In the long run, Smith hopes a drop in the use of sugary drinks could help curb Type 2 diabetes in rural communities. Through this study and previous work, she also has found that teens can be effective at changing peer behavior.
“We’re teaching kids to help themselves, and it’s a really cost-effective way of promoting health and delivering a message,” she said in the news release. “We tend to think first of risky behaviors when we study adolescents, but they do positive things, too. With the right guidance and support, they are powerful influencers. We might as well use peer pressure to our advantage.”
This work was supported by a grant from the National Center for Advancing Translational Sciences to Ohio State’s Center for Clinical and Translational Science. Additional project personnel included Carol Smathers and Cynthia Oliveri of Ohio State University Extension.