American cnioropnyii riant at Lake worm, ria.
MELVIN A. JUDAH, Assistant Editor
Staff-Industry Collaborative Report
in collaboration with
K',
AND
ROBERT G. CARROLL
n, Strong, Cobb and Co., Inc., Lake Worth, F h
0
NE of nature's most importaut organic compounds, chloro-
phyll, has become an object of intensive development in the past decade. Reaching a peak market in 1952, when products containing the green material attracted over $50,000,000from American consumers (4), this young chemical specialty now appears to be getting its second wind. Stable oon8umer items, among them toothprtstes,chewing gums, and candies,plus potential medical rtud pharmaceutical us= seem to offer a promising future. Although earlier scientists had studied the green plant pigment, i t was only in 1913 that the first significant research on its structure, separation, and properties wis reported (7). This work, which won the 1915 Nobel priae for the German chemist Willststter, serves as the baais for today's commercial production of chlorophyll. With modifications developed by the United States Department of Agriculture (1), those solvent extraction techniques are now the foundation of the chlorophyll industry in the United States. However, some chlorophyll and carotene have been produced commercially by chromatographic absorption from alfalfa leaf meal as described in a previous report ( 8 ) . ~ r e ~ e 8ddr-a. nt chemical conruitant, 225 Ind. .. nncn
s t . , weatLafayette
Basically, the production methods developed by the Deparb ment of Agriculture involve extraction of carotene from dried leaf meal with petroleum ether and recovery of carotene by coucentration of the extract. Chlorophyll and xanthophyll are then extracted from the meal with acetone. The acetone extract is dissolved in petroleum ether and the major portion of the acetone removed by washing with water. Xanthophyll is separated from this second extract by eriraction with 85% methanol. Careful washing with water removes the alcohol from the petroleum ether solution, thus permitting the chlorophyll t o be separated by precipitation. Chlorophyll is p d e d by repredpitation from acetonepetroleum ether solution. Carotene and xanthophyll are purified by recrystallization. As the most popular chlorophyll product, a t present, is the water-soluble chlorophyllinform, American Chlorophyll and other producers use the basic USDA process modified with a saponification step ( 6 ) . Thorough saponification of chlorophyll extract with B methanol-potassium hydroxide solution facilitates separ ration of the water-soluble chlorophyllin from the eolvent, usually a hexane-acetone blend, for further purification and finishing. The water-soluble materials are, strictly speaking, not entirely
NDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 46,No. 11
PLANT PROCESSES-Chlorophyll soluble in water; all show the T p d a l l phenomenon. A beam of light becomes visible when passed through these turbid solutions Extract may be finished, instead, as oil-soluble chlorophyll by removal of plant waxes and oils. Solvent washings and evaporation complete the finishing of the oil-soluble products. Three major producers now employ solvent extraction processing with individual variations which are jealously guarded in the keenly competitive industry. From pilot scale production beginning in 1933, American Chlorophyll Division of Strong, Cobb and Co. a t Lake Worth, Fla., has developed with the industry and now recovers not only chlorophyll and carotene, but xanthophyll, phytol, and research quantities of a number of derivatives. Keystone Chemurgic Corp. of Bethlehem, Pa., also extracts chlorophylls from alfalfa. The Glidden Co. extracts alfalfa a t Buena Park, Calif., and ships the extract to Collett-Week a t Ossining, N. Y., for finishing into chlorophyllins. Organized in Washington, D. C., American Chlorophyll Co. conducted research activities and limited production in nearby Alexandria, Va., until 1947. All company operations were then shifted to the 17-acre site on the Palm Beach Canal in Lake Worth. More active processing research and design efforts brought this plant into large scale production in 1950, just in time to progress with chlorophyll's best market year to date, 1952. In that year the company merged with Strong, Cobb and Co., a pharmaceutical manufacturing firm of Cleveland, Ohio. When operating on a 24-hour-day extraction schedule, present facilities can produce 400 to 500 pounds of chlorophyll per day, depending on grade of alfalfa processed. Products from the Lake Worth plant enter into a variety of applications. Chlorophyll extracted from the alfalfa leaf meal may be purified and marketed as an oil-soluble dye for lubricating oils, paints, and candles. A high purity oil-soluble product, which has had plant waxes removed by acetone extraction, goes into pharmaceuticals, foods, cosmetics, and ointments. Ilowever, over 90% of the chlorophyll extracted a t Lake Worth becomes the water-soluble form, chlorophyllin. The most popular, sodium-potassium-copper chlorophyllin, finds use as a deodorizing agent in toothpastes, soaps, shampoos, candies, mouthwashes, deodorants, and pharmaceuticals. Chlorophyll, in various forms, was reportedly present in 1000 products that consumed 10,000 pounds of the green material per month in 1952. With many of the marginal products now off the market, a more stable 150 items are consuming about 2000 pounds per month in 1954. Extract from the alfalfa leaf meal also contains the yellow carotenoid pigments, carotene and xanthophyll. Carotene, a fatty pigment of lipochrome, occurs in living vegetation in association with chlorophyll. I n fact, an analysis of plant matter for carotene content may be used as an evaluation of its quality for chlorophyll extraction. I n alfalfa, carotene occurs in the form of highly unsaturated isomers, a-carotene and p-carotene, having the formula CNHM. Both isomers are precursors of vitamin A. This has caused commercial interest in carotene as an additive to food products, particularly in margarine, since 1950 legislation removed federal restrictions on marketing of the yellow product. Carotenes are the natural coloring pigments in many yellow vegetables, butter, and eggs. Xanthophylls, the hydroxy, keto, or hydroxy-keto derivatives of carotenes, may also be recovered in carotene purification. Research by the United States Department of Agriculture has stimulated interest in these derivatives as poultry feed supplements ( 5 ) . Poultry fed a rich xanthophyll ration exhibits a healthy appearance of fatty tissue and skin to win good customer acceptance on butchers' shelves. Natural pigments have been isolated from fatty tissue, liver, eyes, blood serum, eggs, skin, and the feathers of fowls. Saponification of chlorophyll or reaction with strong acids splits off the phytyl group from chlorophyll as the unsaturated alcohol phytol, C ~ O H ~ ~ OLaboratory H. quantities of phytol have been obtained by vacuum distillation of crude xanthophyll extract a t November 1954
Lake Worth. Phytol may be markcted as an intermediat.e for manufacture of vitamins I? and I
