SOUTHWEST RETORT
SEVENTY-FOURTH YEAR
December 2021
Published for the advancement of Chemists, Chemical Engineers and Chemistry in this area published by The Dallas-Fort Worth Section, with the cooperation of five other local sections of the American Chemical Society in the Southwest Region.
Vol. 74(4) December 2021 Editorial and Business Offices: Contact the Editor for subscription and advertisement information. Editor: Connie Hendrickson: retort@acsdfw.org Copy and Layout Editor: Lance Hughes: hugla64@gmail.com Business Manager: Martha Gilchrist: Martha.Gilchrist@tccd.edu The Southwest Retort is published monthly, September through May, by the Dallas-Ft. Worth Section of the American Chemical Society, Inc., for the ACS Sections of the Southwest Region.
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TABLE OF CONTENTS Fifty Years Ago………………………….......5 ARTICLES and COLUMNS Letter from the Editor…..…..……..............14 NEWS SHORTS Why Cannabis Smells Skunky……………..6 Vehicles are an Under-recognized Source of Urban Ammonia Pollution…………...…….8 A Wild Strwberry Aroma for Foods-from a fungus growing on Fruit Waste………..…..10
Recent Advances in Edible Food Packaging (Review and References).………………...12 INDEX OF ADVERTISERS Huffman Laboratories……………..…........3 TMJ Data Entry and Editing.………......…3 ANA-LAB…………………………...….…..4 Positions Available……………………....….5
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DOCUMENT TITLE
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FIFTY YEARS AGO IN THE SOUTHWEST RETORT Compiled by E. Thomas Strom
Science Laboratory Manager For a descrip-
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tion of primary job duties, required qualifications, and details on how to apply, please see: https://mcm.peopleadmin.com/postings/3750 McMurry University is committed to an educational and working environment that provides equal opportunity to all members of the university community and prohibits unlawful discrimination on the basis of race, color, gender, national origin, age, genetic information, disability or veteran status, in employment or the provision of services, in accordance with applicable federal, state and local laws. Discrimination on the basis of sexual orientation is also prohibited pursuant to University policy.
POSITIONS AVAILABLE Texas Christian University (Fort Worth, TX) is looking to hire several adjuncts to supervise General Chemistry Labs in Spring 2022. Ph.D. preferred, M.S. or Ph.D. in progress will be considered. Post-docs looking for teaching experience or retired teachers are encouraged to apply.
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From the ACS Press Room
Why Cannabis Smells Skunky that contribute to their unique aromas. However, although terpenoids are the most abundant aroma compounds in cannabis, there is little evidence that they provide the underlying skunk-like smell of many cultivars. ACS Omega Skunks use several VSCs in their smelly defense sprays, so Iain Oswald and colleagues As cannabis is legalized in more areas, it has suspected that there could be similar molebecome increasingly popular as a medicinal cules in cannabis. The team decided to use and recreational drug. This plant produces a sensitive analytical techniques to find out. pungent, skunk-like odor that is pleasing to The researchers analyzed flowers from 13 some but repulsive to others. Now, researchcannabis cultivars using a custom-built 2D ers reporting in ACS Omega have discovered gas chromatography system with three differa new family of prenylated volatile sulfur ent types of detectors. Then, a four-person compounds (VSCs) that give cannabis its panel ranked the pungency of the cultivars on characteristic skunky aroma. The findings a scale from 0 to 10. The most pungent one, open up opportunities to investigate the mole- called Bacio Gelato, had the highest concencules for medicinal benefits, the researchers tration of VSCs. The team identified seven say. VSCs in this cultivar, some of which were also present in other cultivars. Five of the VSCs contained the prenyl functional group and had skunk-like or sulfuric aromas. One compound in particular, 3-methyl-2-butene-1 -thiol, referred to as VSC3, was the most abundant VSC in the cultivars that the panel reported to be most pungent. This compound has previously been implicated in the flavor and aroma of “skunked beer” — beer that goes bad after being exposed to UV light. “Identification of a New Family of Prenylated Volatile Sulfur Compounds in Cannabis Revealed by Comprehensive Two-Dimensional Gas Chromatography”
Cannabis sativa L. produces more than 200 known aroma compounds. Prior studies have focused mainly on terpenoids — molecules that range in odor from fuel-like to woody, citrusy or floral. Different cannabis cultivars have diverse mixtures of these compounds
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To confirm that VSC3 was the main source of the skunk-like aroma, the team added it to a mixture of 10 other major aroma compounds from cannabis, producing a combined odor very similar to the characteristic scent of cannabis. They also detected VSC3 in cannabis concentrates, such as those used for
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vaping. Finally, in greenhouse experiments, the researchers determined that the prenylated VSCs increased significantly toward the end of the flowering stage of cannabis growth, reached a maximum during curing and then dropped substantially after 10 days of storage. Because the molecular structures of the VSCs resemble compounds from garlic that have anticancer and cardioprotective effects, the new family of prenylated odor molecules should be investigated for medicinal properties, the researchers say. The authors do not acknowledge any external funding sources for this study. Three of the authors have filed a patent related to the findings.
2021 DFW Section Officers Chair: Trey Putnam Chair-elect: Mihaela C. Stefan Past Chair: Mihaela C. Stefan
Treasurer: Martha Gilchrist Secretary: Heidi Conrad Councilors: Mary Anderson, Linda Schultz, E. Thomas Strom, and Jason McAfee Alternate Councilors: Michael Bigwood, John McIlroy, Daniela Hutanu, and Danny Tran
Happy Holidays
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From the ACS Press Room
Vehicles are an Under-recognized Source of Urban Ammonia Pollution “COVID-19 Lockdowns Afford the First Satellite-Based Confirmation That Vehicles Are an Under-Recognized Source of Urban NH3 Pollution in Los Angeles”
that agriculture is the greater culprit, despite some labor-intensive measurement studies that suggested otherwise in a few cities. Daven K. Henze and colleagues wanted to see if Environmental Science & Technology Let- satellite data could be used to answer this question for the first time from space, since ters such an approach, in principle, could be apBy disrupting normal societal activities, such plied more broadly to urban areas throughout as driving, COVID-19 lockdowns afforded a the world. unique opportunity to study their impacts on the environment. Researchers now report in The researchers focused on western Los AnACS’ Environmental Science & Technology geles, where previous on-the-ground measLetters that satellite data from before and urements found that vehicle emissions of during the spring 2020 lockdown in Los An- NH3 were being underestimated. The team geles shows that vehicles, rather than agricul- anature, are the main source of urban airborne lyzed ammonia (NH3), which forms small particles satelthat contribute to air pollution and harm hu- lite readman health. ings When emitted into the atmosphere, NH3 is of converted into tiny particles of inorganic NH3, compounds, including ammonium sulfate and as ammonium nitrate. On a national or global well as NO2. Because the main source of scale, most NH3 pollution comes from agri- NO2 in the region is on-road transportation, cultural sources, such as livestock manure. the compound can serve as a proxy for But vehicles also contribute to the problem changes in traffic volume and an indicator of because their catalytic converters or selective vehicular as opposed to agricultural ammonia catalytic reduction systems — which are de- emissions. The team correlated concentrasigned to reduce emissions of nitrogen oxide tions of the two pollutants, and also took me(NOx) pollutants including NO2 — have the teorological effects into account, to calculate undesirable side-effect of producing ammo- the amount of ammonia emissions that can be nia emissions. In cities, it’s been hard to tell traced to vehicles. They found that vehicles whether agriculture or traffic emits more NH3, and the default assumption has been Continued on Page 11 December 2021
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From the ACS Press Room
A Wild Strawberry Aroma for Foods — From a Fungus Growing on Fruit Waste “Wild Strawberry-like Flavor Produced by the Fungus Wolfiporia cocos -Identification of Character Impact Compounds by Aroma Dilution Analysis after Dynamic Headspace Extraction”
Journal of Agricultural and Food Chemistry The wild strawberry is even more highly prized than its store-bought cousin because of its intense aroma and uniquely sweet taste. However, they’re hard to find in the wild, so some companies make synthetic versions of this flavor. Now, researchers reporting in ACS’ Journal of Agricultural and Food Chemistry have come up with a naturally derived wild strawberry aroma by having an edible fungus make it from waste from black currant juice production. Often found in forests, wild strawberries are smaller than cultivated varieties, but they’re bursting with flavor. And between their rarity and size, it’s expensive to get a natural wild strawberry flavor — the combination of their distinct aroma and taste — into foods. Interestingly, some species of fungi are adept at converting plant material into pleasant odor compounds, including vanillin, raspberry ketone and benzaldehyde, an almond-like odor. One particular edible brown-rot fungus, Wolfiporia cocos, can break down a variety of foods, even tea and carrot peels, and release fruity and floral aromas in the process. An abundant and nutrient-rich substrate for the fungus could come from the black currant juice industry, which produces a lot December 2021
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From the ACS Press Room of pulp, seed and skins — waste known as pomace — that is usually thrown away. So, Holger Zorn and colleagues wanted to grow W. cocos on pomace from black currants and tweak the conditions to naturally produce the unique aroma associated with wild strawberries, which is highly desired by the food industry. The researchers initially grew W. cocos with black currant pomace as the fungus’ sole source of nutrition, which resulted in fruity and floral aromas. When then the team added ammonium nitrate, sodium L-aspartate monohydrate, monopotassium phosphate and a few other substances to the medium, the culture released an aroma similar to wild strawberries. To pinpoint the exact compounds that contributed to the scent, the researchers used gas chromatography-mass spectrometryolfactometry (GC-MS-O) and 10 trained panelists. The most intense odors that the sensory panel perceived were (R)-linalool, methyl anthranilate, geraniol and 2aminobenzaldehyde. The researchers then combined artificial versions of these four compounds into a model wild strawberry smell and found that the sensory experts rated it as being very similar to the wild strawberry-like odor from the cultivated fungus. So, by growing W. cocos on food waste, the researchers say they’ve developed a sustainable and cost-effective way to produce an aroma that could be used industrially in a natural flavoring agent.
“Urban Ammonia Pollution” Continued from page 8
accounted for 60% to 84% of total NH3 emissions at this urban location, consistent with estimates provided by modeling, but substantially higher than the 13% to 22% share estimated by government agencies. The researchers say their findings suggest the health impact of vehicle-related ammonia may rival that of NOx, yet it has been largely under-recognized and uncontrolled. The authors acknowledge funding from NASA.
The authors acknowledge funding from the Hessian initiative for scientific and economical excellence (LOEWE) within the Hessian Ministry of Higher Education, Research and the Arts.
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From the ACS Press Room
Recent Advances in Edible Food Packaging (Review and References) Packaging helps keep food safe from spoilage, and currently, many food items are wrapped in plastic. But growing concerns about the effects of plastic when it ends up in the environment have prompted researchers to explore alternative packaging materials, including those that can be eaten right along with the foods they are protecting. Below are some recent papers published in ACS journals that report on progress toward edible food packaging materials.
“Laccase-Catalyzed Grafting of Lauryl Gallate on Chitosan To Improve Its Antioxidant and Hydrophobic Properties”
“Bioactive Peptides: A Promising Alternative to Chemical Preservatives for Food Preservation” Journal of Agricultural and Food Chemistry Oct. 14, 2021 In this review of bioactive peptides, researchers describe the benefits of using these compounds to preserve food. They also discuss the latest research to incorporate them into edible films and coatings, which can transport these additives to the foods they protect. December 2021
Biomacromolecules Oct. 3, 2021 Chitosan, a chemically modified form of chitin, which is commonly obtained from the ex-
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From the ACS Press Room oskeletons of sea creatures such as crabs and shrimp, is being pursued by many researchers as a basis for plastic alternatives. Here, researchers added a phenolic compound called lauryl gallate to chitosan with a process called grafting, and showed that the resulting material has the potential to be used as an edible coating. “Plasticization Efficiency and Characteristics of Monosaccharides, Disaccharides, and Low-Molecular-Weight Polysaccharides for Starch-Based Materials”
ACS Sustainable Chemistry & Engineering Aug. 26, 2021
As a step toward a new packaging material, these researchers evaluated various sugar molecules as plasticizers, or molecules that could make starch-based films more flexible. Starch is biodegradable and edible, and therefore is a good candidate for packaging that people can consume.
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From the Editor Oh, I love fungi (although I like to say fun-gee, like Italian waters asking if you want mushrooms with that). Holger Zorn and colleagues grew Wolfiporia cocos on pomace from black currents (pulp, seed and skin waste is called pomace that is usually thrown away). W. cocos, an edible brown-rot fungus, can break down a variety of foods, even tea and carrot peels, and release fruity and floral aromas in the process. By growing the fungus solely on black current pomace, the unique aroma associated with wild strawberries, highly desired by the food industry, was produced. Chromatographymass spectrometry-olfactometry (GC-MS-O) and 10 trained olfactory panelists were used to identify the odor. (Brown-rot fungus? Really?) It’s a short Retort issue, but things will pick up in January. Have a safe and happy holiday season.
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