Giants of the Past
Giants of the past: Cyril D. Evans (1909-1979)
Cyril (Cy) Evans was born and grew up in Anaconda Montana. He received his BS degree in chemistry from Montana State College in 1931. He did his graduate work at the University of Minnesota and was awarded MS and Ph.D. degrees (Biochemistry)in 1933 and 1938 respectively. After graduation, he took a position as a research chemist at the Armour Research Foundation. After several years a position became available at the newly opened Northern Regional Research Laboratory in Peoria Illinois and he was promoted to research chemist in 1942.
His early research interests centered on proteins. His first major accomplishment centered around extraction systems for zein proteins found in corn. This resulted in seven publications describing the isolation and utilization of the proteins.Following the completion of the basic research, he designed and constructed the equipment required to spin the zein proteins into fibers. This achievement was recognized by Superior Service Awards from the Department of Agriculture, Zein continues to be the subject of numerous patents and publications.Nearly 49,000 patents have been granted on uses for zein proteins. Evans basic work has been cited over 3,000 times in the patent literature despite the fact that it is over 70 years old. In addition to publications in the open literature, Evans received 7 patents relating to zein including one assigned to the A.E. Staley company in Decatur Illinois.
In about 1945 the Northern laboratory began research on the flavor stability of soybean oil which was critical to the advancement of the soybean industry. Thus Evans redirected his research from proteins to edible oils. He along with Herbert Dutton, Helen Moser, and John Cowan began by testing the theory advanced by German oil technologists that phosphatides were responsible and citric acid inactivated the flavor precursors. The results confirmed that indeed citric acid treatment did have a marked effect in improving the flavor and oxidative stability of the oil. However citric acid was shown to be a chelating agent for trace metal picked up during processing. In particular, vans showed that as little as 20ppb copper or 200 ppb iron were sufficient to impair flavor and oxidative stability and addition of citric acid improved the oil. The practical aspects of these discoveries lead to the replacement of brass valves in refineries and a switch from black iron deodorizers to those constructed .from stainless steel. The addition of citric acid was shown to be most effective when added on the cooling side of deodorization and destruction of hydroperoxides are necessary for maximum benefit. Citric acid is only sparingly soluble in edible oils but as little as 100 ppm is effective. Since metal inactivation is an important factor in flavor stability, other metal chelators were desirable, Cheap, effective and oil soluble alternatives were sought by the industry. His research group made an extensive effort to discover new metal chelating agents. About 25 publications and US patents resulted. Among those investigated were phytic acid, lecithin, phosphoric acid, chelidamic acid carboxymethyl succinic acid. The investigations showed the types of chemical structures need for metal inactivation in glyceride oils. Compounds with free hydroxyl groups are required. Perhaps the best alternative to citric acid would be phosphoric acid since it is cheap, effective and oil soluble. However, soybean oil so treated tends to develop undesirable “melony” flavors on storage and must be carefully controlled for dosage. Similarly, soybean lecithin meets the requirements for a metal scavenger but if added at too high a level the oil may darken excessively when heated. By the late 1950s emphasis shifted to the mechanism of autoxidation. Pure fatty acid hydroperoxides were prepared and characterized. The role of tocopherols in oxidative deterioration were investigated and the results showed that soybean oil contains more tocopherols than the need for optimum stability. These results were confirmed many years later by another research group. During this same time frame, the use of column chromatography to study lipids was introduced. A method to determine the extent of oxidation was developed by the separation of polymeric dimers by liquid-liquid chromatography on silicic acid. The study showed that the increase in dimers varied with the extent of oxidation prior to deodorization. Evans was the first to demonstrate that the extent of oxidation during processing of soybean oil has an adverse effect on initial flavor quality and after extended storage, Evans and co workers studied the effects of time and temperature in batch deodorizers and showed optimum conditions for producing oils with the best stability. The group developed a test to measure the stability of oils by exposing them to controlled fluorescent lighting. The industry responded by packaging retail bottled oils in amber glass bottles to prevent photoxidation. By 1960 soybean oil had surpassed cottonseed oil as an edible oil. Nontheless soybean oil was considered less stable than other oil. It was learned that the defense department did not purchase soybean oil for their needs and as a result, the Peoria lab under Cy Evans oil group undertook a long-term storage test of bottled oils under both ambient and accelerated storage conditions. The study revealed that soybean salad oils bottled under high purity nitrogen were stable and acceptable after 1 year at room temperature. Bottled oils with air or impure nitrogen deteriorated within a few months and conclusively proved the benefits of inert gas packaging.
This finding quickly lead to the adoption of inert gas blanketing by the industry. Storage tanks in refineries under nitrogen blanketing, sparging of oil during discharge from deodorizers and prior to bulk shipment was key to producing quality soybean oil.
At the time the Peoria lab began the research on soybean oil stability standard methods for assessing flavors were not available. Evans and co-workers developed standardized taste panel procedures to do so. These methods are still in use today throughout the industry and by research groups.
Trigylceride structure research was an important area in the 1960s. Aided by the discovery that pancreatic lipase is specific for the 1-3 positions on glycerol, and fatty acid analysis by gas chromatography, considerable progress was made leading to the 1-3 random -2 random theory of glyceride structure advanced by Coleman and Van DerWall. Under the theory saturated acids are found randomly in the 1-3 positions, oleic linoleic and linolenic acids are found randomly across all 3 positions but any excess linoleic acid is added to the 2 position of the triglyceride. However conclusive proof was lacking. Countercurrent distribution had been shown to be a powerful tool for the separation of trigylcerides and other lipids. Accordingly, a number of unsaturated trigylcerides from soybean, safflower and linseed oils were isolated by countercurrent distribution and subjected to lipase hydrolysis and their structures compared to those predicted by the 1-3 random 2-random theory. Excellent agreement was found and conclusively validated the theory. In reviewing the literature Evans showed that the structures of unsaturated trigylcerides can be determined from the fatty acid composition of the whole oil by applying 3 rules similar to the 1-3 random,2-random theory of glyceride structure. Saturated acids are placed exclusively on the 1-3 positions, oleic, linoleic and linolenate are placed equally in the 1,2 and 3, positions randomly, and any excess linoleic acid is added to the 2 position. The proportions of fatty acids from over 40 different oils were calculated and compared to lipase data from the literature and with few exceptions show excellent agreement.
During his career, he published well over 120 papers and was granted 26 US patents. His research was recognized with USDA awards one which was a distinguished service award given to the flavor stability team. As an AOCS member he served on numerous technical committees and lectured at AOCS short courses. Several of the scientists he supervised received awards from AOCS and IFT.
Evans was considered an international authority on edible soybean oil. During the period from 1963 until his retirement in 1974, hundreds of scientists from all over the world sought his advice and counsel. After his retirement, he was employed as a consultant to the American Soybean Association for which he made numerous trips to South and Central America advising processors on soybean processing and technical issues relating to soybean oil stability. Cy was an icon at AOCS meetings and many sought his wisdom and advice.
Cy Evans, Herb Dutton, and John Cowan played key roles in my career. Other giant articles have paid tribute to Dutton and Cowan and I would be remiss if the series was not complete. Dr. C.D. Evans was my supervisor from late 1963 until his retirement in 1974. He was always a source of encouragement as well as an excellent teacher. Early on he gave me a copy (2nd Ed) of Bailey's book and suggested I read it from cover to cover. I still have it in my library and refer to it often.and am reminded of the tremendous effect he had on my career and I will be forever greatful for the privilege of working with Cy Evans His research philosophy centered around having multiple projects going at one time since if one did not bear fruit others could be explored more fully. His phone was always ringing off the hook so he would hole up in the library to write and study. New employees were advised to never- never disturb him.
He wasn’t concerned about my lack of formal training in science and chemistry and gave me challenging assignments which allowed me to work independently. My first AOCS meeting was in 1967 in Chicago. I was quite nervous about giving my paper. Cy told me to thank the chairman, clear my throat, and he would be in the front row and finally pretend he was the only person in the room. Late in his career, he allowed me to write publications which I had contributed to. Shortly after my employment, he would always drop off his latest issue of JAOCS to read. This lead me to join AOCS as an associate member when dues were 5 dollars per year. This was one of the events that changed my career. Cy was a kind generous person but had a short fuse part of which resulted from a bout with colon in cancer in the mid-1960s. As mentioned earlier Cy and his wife Betty grew up in Montana and upon retirement moved to Bozeman expecting things to be as they were as young people. However, this was not the case since much change had occurred and they regretted the move. August was vacation for the Evans. Each year they would take their Airstream trailer west to escape from the ravages of hay fever which had plauged him all his life. One year he went to Alaska via the Alcan highway which at the time was largely unpaved. Cy was a master at setting up complex systems for his many research projects one of which consisted of manometers, vacumn pumps, stopcocks, valves and a maze of tubing. Even he would ocasionally turn the wrong stopcock and samples would be sucked into the vacumn pump. This was followed by a volley of damn, damn, damn!!! No one dared to laugh. An incident comes to mind. We received a drum of soybean oil that required filtration through an Alsop filter through a nitrogen pressure inlet. After adjusting the rate of filtration, the project was abandoned for a short time. On returning someone had increased the nitrogen pressure and the basement of the Northern lab was blessed with soybean oil all over the floor. Cy was not a happy camper.!!
He often remarked that only a coward would not tell his boss to go to hell if the occasion demanded it. That occurred only once in the 10 years we worked together but I regretted followed his advice.
Cy was not a self promotor nor did he seek credit for his research accomplishments. Nonetheless, he was highly respected by all who knew him. A prominent AOCS member related how he met Cy at an AOCS meeting in the early 1950s and made a young scientist feel welcome and showing him the ropes.
Cy was very interested in wildlife and had planned a trip to Yellowstone park. On the morning he was to leave, he passed away leaving wife Betty and two children.