Giants of the Past
John C. Cowan (1911-1991)
John C. Cowan (AOCS President 1968) was born October 26 1911 in Danville Illinois. He began his undergraduate work at the University of Illinois in 1930 and received an undergraduate in 1934. His graduate work was continued at Illinois under Carl (speed) Marvel and received his PhD in organic chemistry in 1938. Marvel’s interest in polymer chemistry and ornithology had a significant effect on Cowan’s career as well as a lifelong interest in bird watching. During graduate school Cowan held a position as an assistant. In 1938 he married Lucille Chenowith shortly after completing his doctorate. The University of Illinois under the leadership of Roger Adams, Carl Marvel, Raymond Fuson and William Shriner produced a number of top chemists. Most of them went into academia or industry but a few entered government service. However Cowan, Howard Teeter, and Allene Jeanes all joined the staff of the Northern Regional Laboratory in Peoria, Illinois. Howard Teeter directed much productive research in the area of industrial uses of fats and oils. Allene Jeanes became an outstanding carbohydrate chemist. Her discovery of xanthan gum and dextran proved to be of immense importance. Xanthan gum found its way into numerous foods and industrial applications. Dextran was shown to be a blood plasma substitute and saved many lives during the Korean war. Dr Jeanes was inducted into the Agricultural Research Hall of Fame in 1996.
Cowan first took a position at DePauw University as an instructor as well as a DuPont researcher. In the 1939-1940 time frame, however, academia and industry were not appealing to him. The US was locked in the Great Depression. World war two was on the horizon, and huge surplus of agricultural commodities existed. Congress responded with the Agricultural Adjustment Act of 1938. A key provision was funding to build and staff 4 regional laboratories whose mission was to conduct utilization of farm products including fats and oils, wheat, corn, dairy products, fruits and vegetables. Each of the four regions (North, South, East and West) were assigned crops grown in their location. The Northern region (Peoria lab) included soybeans, corn and wheat as major commodities. The Southern region (New Orleans) had responsibility for cottonseed and its oil. The Eastern region (Philadelphia) had responsibility for dairy products and animal fats. The Western region (Albany, California) was assigned fruits, vegetable and wool as major commodities. Construction of the 4 labs was quickly begun at a cost of 800,000 dollars each and they were operational by late 1940/early 1941. Cowan began his career in Peoria in the summer of 1940 in laboratory space donated by Bradley University while the Northern lab was being built. It opened in December 1940. By then it became apparent that war was eminent and top priorities would be given to the war effort. As head of all oil and protein research Cowan’s first research was directed toward production of synthetic rubber via polymerization reactions and tires produced by this technology performed well. Other accomplishments included plastics dimer and cyclic acids from vegetable oils. The publications resulting from the war effort research were delayed but laid the foundation for commercialization of both dimer and cyclic acids later on.
After the war ended research was focused on edible uses of soybean oil. By 1945 although the soybean industry was well established, the oil was considered a poor drying oil and lacked the flavor and oxidative stability of cottonseed oil which at the time was the predominant edible oil. It became obvious that the flavor problem needed to be solved if the industry was to expand and grow. In the 1940s top scientists from academia, industry and government met yearly to review progress on the flavor stability problem. There was little consensus on the cause. Polymers, unsaponifables, lecithin and linolenic acid were suggested.
The problem was examined by the Northern lab. In 1946 Dr. Herbert Dutton, who was at the Western lab, transferred to Peoria to lead the research on edible soybean oil. A clue on where to begin came from a Peoria engineer Warren Goss who toured Germany in the latter stages of WW Two( disguised as an army major) to learn German oil processing practices. The consensus of the German technologists was that residual lecithin was the cause of the flavor problem and could be corrected by the addition of citric acid. Dutton’s first publication documented that citric acid did indeed improve the flavor of soybean oil. However, later work showed that citric acid did not inactivate lecithin as the Germans claimed but acted as chelator of trace metals (iron and copper) picked up during processing. The final piece of the puzzle came from a study in which soybean, cottonseed, and cottonseed oil interesterified with 8% linolenic acid were aged under controlled conditions and then subjected to sensory evaluation . The taste panel identified cottonseed oil and soybean oil correctly but the interesterified oil as soybean oil. Thus linolenic acid was shown to be the cause of poor flavor stability.
Several Peoria scientists made important contributions to the flavor problem. Ms. Helen Moser (an original staff member) developed the taste panel methods so vital to the work. These methods are still in use throughout the world for assessing edible oil quality. Dr. C. D. Evans investigated the occurrence and effects of numerous trace metals on the flavor and oxidative stability. As little as 20 ppb copper or 300 ppb iron cause the quality of soybean oil to be impaired but the addition of citric acid during the cooling side of deodorization markedly improves the oil.
Since the inactivation of metals is vital the industry replaced brass valves in refineries to reduce copper contamination and black iron deodorizers were replaced with stainless steel.
Cowan conducted studies aimed at clarifying the role of citric acid as a metal inactivator. It was known that acidic compounds including citric, phosphoric and caboxy methylmercaptosuccinic acids could act as stabilizers for edible oils. Sorbitol was also recognized as having metal- inactivating properties, Cowan investigated the addition of sorbitol, citric acid and combinations of them together with added amounts of prooxidant iron. The results provided strong evidence that citric acid acts as a metal inactivating agent rather than a synergistic effect from the added sorbitol.
As late as the 1960s the defense department did not purchase liquid soybean oil for their needs.At the request of the US Army Quartermaster the Peoria lab under Cowan’s leadership began a long term storage study of packaged salad oils packaged under air and nitrogen. Oils packaged with air in the headspace deteriorated within a period of 3 months. However the oils packaged under inert gas remained stable for a year at ambient temperatures. Today the benefical effects of nitrogen packaging are well recognized and are standard practices in refineries.
Since removal of linolenic acid was the key to improved stability, several options were available. Fractionation was a possibility and tank car lots of furfural fractionated oil produced by the Pittsburgh Plate Glass company in the 1950s. Both an improved edible and a drying fraction resulted. Plant breeding was also an option but results up to about 1980 were only partially successful. C.D. Evans reported that, while linolenic acid reduction from 10 to 5% resulted in some improvement, a further reduction to 3% would be needed. Dr Earl Hammond at Iowa State University teamed up with Walter Fehr to conduct soybean plant breeding studies. By the late 1980s they succeeded in reaching the 3% level. Later a 1% or less linolenic acid oil was achieved.
By the early 1990s the low (3%) linolenic acid oil was commercialized but was not very successful because of the increased costs of grower premiums and identity preservation compared to commodity oils. In retrospect, trait modified oils were introduced too early. Trans-fat labeling beginning in 2003-2006 has revived interest in trait modified soy, canola and sunflower oils as trans-fat replacements. Today about 20% of domestic edible oil needs are met with trait modified oils and, as supplies increase, this figure is certain to rise.
A third option was catalytic hydrogenation and was explored by academia, industry and Cowan’s group in Peoria. This was simple in theory but difficult in practice because traditional nickel catalysts were nor selective enough to completely remove linolenic acid at reasonable IV levels where high yields liquid oil are realized. The IV must be reduced from 130 to 90 for complete removal and yields of liquid may be only 50-60% .A reduction of about 20 IV units results in 3% linolenic acid with a yield of about 90% liquid oil.
Cowan’s group began to search for catalysts that would give complete removal of linolenic acid at high IV levels. The search bore fruit with the discovery that copper chromite catalysts are very selective. Plants were built in the US, France and Holland to produce hydrogenated winterized soybean salad oil. However, unexpected variations in catalyst activity were noted in the US plant. Some batches were active and worked well while others were too slow for maintaining production schedules and were abandoned.
Cowan’s edible oil group was headed by CD Evans who began his career in Peoria as a protein chemist. He, along with Brad Croston, did the basic research on zein proteins and built equipment for spinning fibers from zein. After transferring to the edible oil group, Evans discovered many new metal chelating agents and held 26 US patents as well as authoring well over 100 technical publications. Evans was an early researcher in volatile components from oxidized oils. He was among the first to show that aliphatic hydrocarbons are among the first products of hydroperoxide decomposition and his group developed gas -solid chromatography methods for their separation . Applications of the methods to study the flavor and oxidative stability of soybean and cottonseed oils showed that high correlations between pentane and flavor profiles exist. Cowan’s interests included triglyceride structure. By the early 1960s, Coleman and Van Der Wall advanced the 1, 3 random 2-random theory of glyceride structure in which saturated acids are distributed randomly on the 1, 3 positions of glycerol, oleic and linolenic are distributed randomly across 1, 2 and 3 positions while linoleic acid shows a preference for the 2 position and the excess over 33.3 % is added to the 2 position. Highly unsaturated trigylcerides from linseed (8 double bonds) soybean (5 or 6 double bonds) and safflower (7 double bonds) were isolated by countercurrent distribution and subjected to lipase hydrolysis and recovery of the 2-monoglycerides. The results verified the validity of the 1, 3 random 2 random theory since the experimental results agreed quite well the theoretical values.
Cowan’s group include an oil coating and plastic research unit headed by Dr. Lyle Gast. Major accomplishments include development of emulsion based paints and the use of linseed oil to seal concrete.
Dr. Everett Pryde headed up the exploratory reactions research group. The group made numerous discoveries on the ozonolysis of fats and oils. They include aldehyde oils. A process to produce eruamide from crambie oil is used as monomer for nylon 13 production.
For many years Dr. A. K. Smith lead the research on soy proteins. After his retirement in the early 1960s, Dr Walter Wolf assumed leadership. Major accomplishments are characterization of the soy proteins, improvements in soy protein functionality, nutrition, utilization of soy flours, concentrates and isolates in foods. Flavor problems of soy proteins, removal of flatus precursors, methods to determine soy proteins in meat products, isolation and characterization of soy isoflavones, Identification and removal of toxic materials in animal feeds.
Dr. Cowan was one of my supervisors from 1963-1973. He had an impact on my career. He taught me how to use the library. Often he would send me to the library to locate something he needed. He always had a pet project that needed help and I was the go to person. A technician had never given a presentation at a national scientific meeting. He sent me to Chicago in1967 to give a paper. He gave me a book chapter to write. Every time I needed a promotion he would oblige. At his retirement we put on a spit/roast. I had the pleasure of playing Dr. Cowan. The audience roared and he even smiled and laughed.
Dr Cowan retired in 1973. Upon retirement he took a position as an adjunct professor at Bradley University in Peoria. He was employed as a consultant by the American Soybean Association. In 1981 he authored a report entitled “Soy Oil Bibliography, Processing, Composition, Reactions and Edible and Related Uses” an ASA Publication (with nearly 2,400 references and 172 pages).
Dr Cowan was active in AOCS for many years. He served as Assoc. Editor for JAOCS, on many committees, the Governing Board, Secretary, Vice President, and President in 1968. He received numerous Awards from USDA. He was an early recipient of The A.E. Bailey Medal (1961) and The Chevreul Medal (French Oil Chemists) 1975. During his career he authored about 260 publications and held about 60 US Patents. Dr Cowan had an intense interest in birds and was an accomplished lapidary. On retirement he moved to New Mexico. In 1988 AOCS was held in Phoenix, Arizona where he and many of his old research group met for lunch.
Times have changed. Today USDA scientists travel all over the world to attend conferences and meetings etc., at government expense. I can recall only one such trip for Dr. Cowan and that was funded by the agency that extended the invitation. If my memory serves me correctly it was a Regional Oil Conference in 1964 in Tehran, Iran.
Updated: February 18, 2016