RESEARCH
American Chemical Society Award in the Chemistry of Milk sponsored by The Borden Company Foundation, Inc.
CHARLES A. ZITTLE
storage. GDA is miscible with water and m o s t organic solvents. AYThen the compound reacts with water, alcohols, carboxylic acids, phenols, and other reagents having active Hydrogens, t h e epoxide ring opens to form beta-substituted lactaldehydes. Primary amines form epoxy aldimines by interaction with t h e carbonyl group. Similarly, says Payne, active methylone c o m p n n n d s like ethv! cvanoacetate and nialonic ester give glycidyiidene derivatives when condensed with GDA. If a ketone group activates the methylene ( acetylacetone or acetoacetic ester are t-wo examples ) cyclization occurs to give furfuryl alcohols.
Tattle-Tale Gray C a r b o n a c e o u s matter isn't the r e a l culprit in d i n g y laundered fabrics, says W h i r l p o o l researcher "Outstanding research o n the chemistry of milk proteins/* That's how one colleague of Charles A. Zittle. this year's winner of the American Chemical Society Award in the Chemistry of Milk, sponsored by T h e Borden Company Foundation, Inc., sums u p the extensive contributions t h a t Zittle has made to milk chemistry in particular, and to biochemistry in general. Specifically, Zittle is one of t h e pioneers to study the physical stability of milk proteins in the presence of milk salts, under the influence of heat. His study o n the effect of heat on casein solutions containing calcium led to discoveries w h i c h explain changes occurring in stored evaporated milk. An unharried scientist, Zittle tries to leave no stones unturned in his effort to get more fundamental information on milk and its constituents. H e h a s detailed and purified several enzyme systems present in milk, and lias pinpointed the contributions of t h e s e enzymes to the changes in flavor a n d physical stability of milk. His studies on milk were interrupted during the Korean emergency when the Army Chemical Coips took advantage of Zittle's recognized ability in purifying enzymes. (Zittle b a s several reviews in Advances in Eiizymology and a chapter in " T h e E n z y m e s / ' ) Result of this stint: a purified cholinesterase, an enzvme found in h u m a n red blood cells. 50
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Zittle has shown an uncanny ability to relate his research findings to the every-day job of milk processing, a fact appreciated by the milk-producing industry. His findings have been especially important toward understanding and controlling the chemical a n d physical changes which occur w h e n milk is processed a n d stored. A native of Pennsylvania, Zittle was educated in public schools a n d received his B.S. in biology and chemistry from Franklin & Marshall College in 1925. After spending five years in industry as a chemist, the academic b u g led him to the University of California, where he was a w a r d e d his Ph.D. in 1934. Zittle then turned his training toward teaching chemistry and mathematics, and in 1938 he joined the University of Pennsylvania medical school, w h e r e his research in streptococcus infections proved invaluable in immunity studies against the virulent o n a n i s m . As head of Parke, Davis' immunochemistry division, h e m a d e several contributions toward understanding the vagaries of the bacterial pyrogens—the fever-producing substances. His work at the Biochemical Research F o u n d a tion in Newark, Del., led to a high-yield procedure for isolating a n d purifying the blood grouping substances. Zittle began his studies of the milk proteins at t h e U . S. D e p a r t m e n t of Agriculture's Eastern Regional Research Laboratory in Philadelphia in 1948.
ACS NATIONAL MEETING Cellulose Chemistry T h e o r y has it t h a t fabrics remain dull and dingy after laundering because of the buildup of carbonaceous material. This theory gets an abrupt jolt thanks to t h e findings of William C. Powe of Whirlpool Corp. The real cause of tattle-tale gray, says Powe, is clay. Yellowing of fabrics may stem from the color of the clay itself or of the organic or inorganic impurity, Powe told the Division of Cellulose Chemistry. This new knowledge on fabric discoloration should help scientists develop better ways t o test the effectiveness of detergents. r* Pïcsîes e r Reds. Clavs loom as likely culprits in fabric discoloration because they are the main component of dirt. Electron micrographs of dingy fibers suggest that the soil consists of plate- or rod-like particles of clay. These particles are mainly hydrated aluminum silicate, containing small amounts of combined iron or magnesium. After adsorbing colored organic material, clays may develop a yellow, gray, or black appearance—a small amount of organic contaminant m a y go a long way. The pigmenting agent may also be an inorganic material such as iron oxide, Powe explains.
RESEARCH Because clays are finely divided and have large surface areas in relation to their mass, they are ideal particles to adhere firmly to textile fibers. Whether the forces involved in the adsorption of clay particles are coulombic\ Van der YVaals, or hydrogen bonds is a matter of speculation. All three types of adsorptive bonding probably are involved, Powe believes.
What's in That Morning Coffee Aroma? \jrc?niidià u n c i I U V J ^ I ^ V J
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Acids link to Cellulose ACS NATIONAL MEETING Cellulose Chemistry Substituted succinamic acids have turned out to be surprisingly reactive with cellulose in the presence of acetic anhydride. The almost quantitative reaction of substituted succinamic acids with cellulose appears to be unique, according to George P. Touey, John E. Kiefer, and John R. Caldwell of Ten nessee Eastman. Yarns produced from cellulose esters containing 2V-substituted suceinamoyl groups can be readily dyed with acid wool dyes. On the other hand, ordi nary cellulose acetate yarn is only slightly tinted by these dyes. The easy dyeability of the new materials stems from the fact that, like wool, they contain combined nitrogen. As with cellulose acetate, tensile strengths of the new fibers are 1.2 to 1.3 grams per denier; their elongations range from 28 to 3 5 ' r , Kiefer told the Divi sion of Cellulose Chemistry. For the time being, at least, these findings are solely of academic interest. All research on the new fibers at Ten nessee Eastman has been on a labora tory scale, and no commercial appli cations are foreseen, Kiefer says. T o prepare the new materials, cel lulose is first activated with water, which is then replaced with dioxane. In one procedure, 0.3 mole of the Λ7substituted succinamic acid is heated to 70° to 100° C. with 1 mole of ac tivated pulp, 4 moles of acetic anhy dride, and a catalytic amount ( 0 . 0 9 mole) of sulfuric acid. After the catalyst is neutralized with aqueous magnesium acetate, the vis cous material is precipitated in water in the form of white flakes. The prod uct is a mixed ester containing both acetyl and suceinamoyl groups.
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Agricultural and Food Chemistry What makes roasted coffee smell so good? A combination of over 3 0 vola tile components, Albert Zlatkis of Uni versity o f Houston told the Division of Agricultural and Food Chemistry. He isolated and identified these by gasliquid chromatography and mass spec trometry. Included in the aroma, says Zlatkis, is a pentadiene, which is prob ably isoprene, and a complex mixture of C4-('T olefins and paraffins. Even tual goal of the work: a synthetic coffee aroma to be used in instant coffee or in a synthetic coffee beverage. But the analysis of the aroma is still incomplete; still to be analyzed is a
high molecular weight fraction which probably contains more components than the essence fraction which was analyzed. Being much less volatile than the essence fraction, it has been difficult to analyze quantitatively bymass spectrometry, but Zlatkis feels that current developments in gas chromatog raphy, which use ionization detectors and capillary columns, will help to furι η ci
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The analyses to dace should be a big step toward making the synthetic coffee aroma essence, however. Michael Sivetz, now with Café Soluble de Nicaragua in San Francisco and with J- A. Folger and Co. at the time of the study, prepared a mixture of the components identified in the aroma essence fraction and found that it gave an aroma similar to the original natural essence. • QMC, Too. l \ S. Army Quartermaster Research and Engineering Center ( O R E O . Natick, Mass., has also analyzed coffe aroma using an analytical mass spectrometer with gas chromatography and high vacuum techniques. James H. Sullivan, Q R E C , told the division that QREC's work thus far has identified 2 3 compounds and has tentatively identified six more.
These Compounds Put the Smell in Coffee A R O M A ESSENCE
WEIGHT PER CENT
Acetaklehye Acetone Diacctyl n-Valer a l d e h y d e 2-MethyIbuiyraldehyde 3-MethylbutyraIdehyde Methyl fur a n Propionaldehyde Methyl formate Carbon d i o x i d e Fur an Is obntyr a l d e h y d e Pentacliene Methyl ethyl k e t o n e C 4 -C- paraffins a n d olefins Methyl acetate D i m e t h y l sulfide n-Btityraldehyde Ethyl f o r m a t e Carbon disulfide Methyl a l c o h o l Methyl m e r c a p t a n Thioplxene
19.9 18.7 7.5 7.3 6.8 5.0 4.7 4.5 4.0 3.8 3.2 3.0 3.0 2.3 2.0 1.7 1.0 0.7 0.3 0.2 0.2 0.1 0.1
DRY AROMA
VACUUM VOLATILES
Methyl formate Ethyl formate Methyl acetate Formic acid Acetic acid Propionic acid Water Acetone Methyl ethyl ketone Co k e t o n e s Ethyl alcohol n-Butyr a l d e h y d e Is obutyr a l d e h y d e C(; a l d e h y d e s Furfural Furfural d e r i v a t i v e s C 5 esters
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