Preservation of Orange Juice by Deaeration and Flash Pasteurization HARRYW. VON LOESECKE, H. H. MOTTERN, AND GEORGE N. PULLEY U. S. Citrus Products Station, Bureau of Chemistry and Soils, Winter Haven, Fla. in which the proper amount of sugar sirup and terpeneless orange oil was added, as explained below. In general, deaerat,ion e n t i r e l y successful commercial and extraction of the juice were carried venture because of the poor flavor of out simultaneously, and the juice was in contact with the air for only a comparathe canned product. As c o m m o n l y tively short period. p r o c e s s e d , orange juice rapidly deThe juice m a be p u m p e d u n d e r a teriorates in flavor and soon becomes vacuum from t E e storage c o n t a i n e r , unpalatable. The p r o b l e m of prethrough the pasteurizer, or the vacuum may be broken with an inert gas, such as serving orange juice has been studied nitrogen, and the juice pumped at atmosby Cruess (4), McDermott (9), Chace pheric pressure. No significant difference (2), Irish ( 7 ) , and more recently b y was found b e t w e e n the juice pumped Joslyn and Marsh (8),M o t t e r n a n d t h r o u g h the pasteurizer at atmospheric ' pressure and that under a vacuum. von L o e s e c k e (IO), and others. AlThe pasteurizer (Figure 1 ) consisted of a though the mechanism of the changes block tin tube, flattened into a ribbon, taking place in canned orange juice is formed into a coil, and mounted in a steam n o t fully understood, numerous jacket. The juice flowing from the pasworkers have indicated that oxidation teurizer was maintained a t a temperature of 96" C. (205' F.) by means of an autop l a y s a n i m p o r t a n t role. Mottern matic tem erature controller. It required and von Loesecke (IO)have shown that 5 seconds For the juice to pass through the a palatable canned orange juice could pasteurizer, and therefore the juice was be obtained by deaeration and then exposed to a temperature of 96"C. (205"F.) for less than 5 seconds. flash pasteurization at a temperature If the containers are filled with orange higher than that used b y other investia t the high temperature of pasteurizagators. The present paper summarizes FIGURE1. BLOCKTIN RIBBOS-COIL juice tion, there is danger of developing a cooked PASTEURIZING APPARATUS the results obtained at this station durtaste before the juice can be properly cooled. Therefore, the juice from the pasing the past two years. teurizer passed through a tin coil of similar design immersid in EXPERIMENTAL PROCEDURE water which cooled the juice to 76" to 82"C . (170,"to 180' F.) and filled into the containers. The temperature of filling depends upon Packing-house cull fruit was used throughout these experi- the size and type of container and the sanitary conditions of the ments, Fruit containing less than 1.00 per cent total acidity plant. In one plant where the laboratory apparatus was installed, it was found that the juice could be cooled only to 90" C. (194"F.), was found to be unsatisfactory, the canned product being while in another plant the filling temperature was 77" C. (170'F.); insipid and exhibiting more rapid deterioration. "Sweated" and no loss resulted from subsequent fermentation. fruit, oranges t h a t had been through the coloring rooms or If the juice was filled into cans, they were vacuum-closed. If had been in the warm packing house for a week or more, were vacuum closure was between 12 and 14 inches (30.5 and 35.6 cm.) and the juice had been properly deaerated and was at a temperafound unsuitable. If of proper maturity, Florida Pineapples, ture not higher than 80" C. (176" F.) there was no danger of boilSeedlings, and Temple oranges made as satisfactory a pack as ing and loss of juice. When cooled, the cans showed a vacuum of Valencias. 20 inches (50.8 cm.). The cans were placed on a reel which revolved; at the same Juice was prepared by reaming the halved fruit on a slowly re- time the cane were made to revolve on their own axes (Figure 2). volving (about 60 r. p. m.) burr. Rapid burring is accompanied Thus they were cooled rapidly and efficiently. Juice thus treated by considerable tearing of the fruit and incorporation of air. and stored a t a temperature of 13' to 16' C. (55" to 60' F.) There was no evidence that slow reaming introduced significant was still excellent in flavor after 10 months. Although lacking the amounts of oil from the peel. It has been stated (3) that the full bouquet of fresh fruit juice, it did not possess the disagreeable fruit should be peeled before the juice is extracted, to eliminate all taste of deteriorated juice. Storage a t higher temperatures danger of contamination by oil. After 10 months of storage no lessened the keeping qualities of the juice and, if stored a t temdifference could be found in the taste of juice prepared by slow peratures of 27" to 38" C. (SO' to 100" F.), showed an apparent reaming and that which had been pre ared from the peeled fruit. deterioration in flavor after 3 or 4 months. It was found advantageous to add sugar sirup to the juice Pressing the halved fruit over a pergrated cone incorporates a significant amount of oil and is therefore unsatisfactory. The before pasteurizing. Sirup of 65' Brix was added in sufficient juice and pulp were fed directly to a revolving screen which amounts to increase the total soluble solids-acid ratio to 15.0. Thus, the quantity of sirup added varied with each lot of juice continuously separated the pulp and seeds from the juice. The screened juice was immediately drawn by vacuum from a and depended upon the initial total soluble solids and acidity. receiver to the deaeration a paratus. This consisted of a 12- In the case of grapefruit juice, sirup was added to increase the liter round-bottom inverted $ask into which the juice was forced ratio to 10.0. The addition of orange oil from which most of at a high velocity through a small orifice, where it spread out in a the terpenes had been removed in amounts of 0.003 to 0.005 er thin film containing numerous bubbles. The temperature of the cent, enhanced the aroma of the product. If terpeneless oif is liquid was below the boilin point at the vacuum used (about used, there is no danger of decomposition and the development 25 inches or 635 mm.). Altiough it is not possible to remove all of a turpentine taste. Terpeneless oil does not, however, have the gases, the method is beneficial. Juice containing 2.5 cc. of the full aroma of cold-pressed orange oil, and it is therefore probdissolved gases per 100 cc. of juice before deaeration contained ably desirable to use a concentrated oil which does not contain but 0.5 cc. of dissolved ases per 100 cc. juice after deaeration. terpenes in sufficient amounts to cause off-flavors on oxidation. From the deaerator t f e juice flowed to a stainless steel barrel If the limonene content of the oil is reduced from 95 per cent in also under vacuum. This barrel served as a storage container the original oil to 5 per cent in the deterpenated oil, the resulting
T
HE preservation of orange juice by canning has never been a n
JUICE OUTLET
771
July, 1934
INDUSTRIAL AND ENGINEERING
flash-pasteurized as described in this paper. The results, although somewhat erratic showed a tendency toward a slight diminution (about 1.0 cc.) in reducing power after 9 months of storage a t room temperature. Further work along this line is Contemplated this season. SUMMARY
A method is described for preserving orange juice by slowly reaming the halved fruit, immediately deaerating, pasteurizing a t about 96" C. (205" F.) for not more than 5 seconds, filling into the containers a t 76" to 82" C. (170" to 180" F,), and vacuum-sealing a t a pressure sufficiently high to prevent boiling. Juice thus prepared has been stored for 10 months a t 16" C. (60" F.) and still has a satisfactory aroma and taste. The addition of sugar sirup to increase the ratio of total soluble solids-total acidity to 15.0, and terpeneless orange oil to the extent of 0.003 to 0.005 per cent, has been found to enhance the keeping qualities of the juice. Orange juice, packed as described in this paper, will not retain a satisfactory aroma and taste for mort? than about 3 months if stored a t temperatures in the vicinity of 32" C. (90" F.).
773
Packs in glass darken especially in the absence of significant amounts of tin and if stored a t temperatures of 27" C. (80" F.) or higher. During storage a t temperatures of 32" to 38" C. (90" to 100" F.) there is an increase in reducing sugars (as invert), a corresponding decrease in nonreducing sugars (as sucrose), and a decrease of pH, but there is no change in titratable acidity. Although results were somewhat erratic, orange juice preserved as described in this paper showed a slight diminution in reducing power toward dichlorophenolindoplienol. LITERATUBE CITED (1) (2) (3) (4) (5) (6) (7)
(8) (9)
Florida Pineapple, Seedling, and Temple oranges, if of the proper maturity, make as satisfactory a pack as Florida Valencias. "Sweated" fruit, or that which has been through the coloring rooms, or has stood in the packing house for more than a week does not make a satisfactory pack. Fruit of 10tv acidity is unsuitable for canning.
CHEMISTRY
(10)
Bennett, A. H., and Tarbert, D. J., Bzochem. J.,27, 1294 (1933). Chace. E. XI.. Calif. CitrooruDh. 5. 264 (1920). ' Coons, B. C.,'Canking 14,275 (1933). Cruess, TV. V., Calif. Agr. Expt. Sta., Bull. 244, 157 (1914). Fellers, C. R., and Isham, P. D., J. H o m e Econ., 24, 827 (1932). Hanke, M. I., "Diet and Dental Health," g . 36, Univ. Chicago Press. 1933. Irish, J,' H., Calif. Agr. Expt. Sta., Circ. 313 (1928); revised by W.V. Cruess, 1932. Joslyn, M. A., and Marsh, C. L., Food. Ind., 5, 172 (1933): Canning Age, 14, 229 (1933). McDermott, F. A,, J. IXD. ENG.CHEM., 8, 136 (1916). Fla. Agr. Expt. Sta., Bull. 135, 130 (1917). Mottern, H . H., and von Loesecke, H. W., Fruit Product8 J., 12, 325 (1933); Bnonymous, Glass Pucker, 12, 551 (1933).
Ah,
RECEIVED .4pril 2, 1934. Presented as p a r t of the joint Sympoaiurn on Citrus Fruits before the Divisions of Agricultural and Food Chemistry a n d of Biological Chemistry a t the 87th Meeting of the American Chemical
Society, St. Petersburg, Fla., March 26 t o 30, 1934. search Division Contribution 219.
This paper is Food
Re-
Effect of Respiration on Vegetable Flavor E. F. KOHMANAND N. H. SANBORN, National C a n n e r s Association, Washington, D. C.
A
S A RESULT of the known
susceptibility of vitamin C correlated is available. Data have been presented elsewhere t o oxidation, great care to eliminate atmospheric (3) showing that rough treatment resulting in bruising of oxygen is customary among those engaged in proc- peas and lima beans may be the cause of abnormal flavors essing foods. It is not always realized that each raw vege- in these vegetables after canning. While it was shown that table and fruit has a normal oxygen requirement. If con- the rough treatment in question was generally followed by ditions of h a n d l i n g are such the usual tendency of slightly that the vegetable cell is not increased carbon dioxide Bruising of vegetables has a marked effect on able to secure its normal quota e v o l u t i o n , t h e bruising was respiration. Oxygen consumption is greally of oxygen or if the treatment s h o w n t o b e the cause of a reduced iahile carbon dioxide ecolution generally is such that the functioning of marked decrease in oxygen conincreases although, contrary to the usual opinion, the cell to use its normal quota s u m p t i o n . It has long been it m a y under certain conditions decrease but of oxygen is disturbed, results known that, if the oxygen supply quite as disastrous as oxidation of a vegetable or fruit is limited, not to the same degree a s the oxygen consumpof vitamin C may follow. I n a1 c o h o l and acetaldehyde are tion. I n this connection, raw frozen vegetables other words, abnormal reducing formed as a result of anaerobic m a y be considered to be severely bruised since fhe reactions or conditions may be as respiration. I n the case of the cells are generally ruptured. An explanation undesirable as abnormal oxidizb r u i s e d peas and lima beans is thus afforded for the off--flavors that develop. ing conditions or reactions. referred to, the f o r m a t i o n of I n the normal respiration of a alcohol and acetaldehyde was Alcohol and acetaldehyde are produced in bruised vegetable, the ratio of oxygen demonstrated, but it was eegetables apparently as a normal product of c o n s u m e d to c a r b o n dioxide shown that these were not the anaerobic respiration. These products, however, evolved is close t o unity. Gencause of the off-flavors noted. do not account f o r the off-flavors that develop erally, in b r u i s e d o r i n j u r e d Evidence was presented, howeither in vegetables in which artificial anaerobic vegetable tissue there is a tendever, to indicate t h a t the offency toward increased carbon flavors were a p r o d u c t of anrespiration has been induced or in bruised or d i o x i d e e v o l u t i o n , but, a s aerobic respiration. raw frozen vegetables. T h e manner in which this will be shown, this is not alThe possibilities of anaerobic anaerobic activity is involved in the freezing, ways the case. Little informaactivity a f f e c t i n g t h e flavor refrigeration, a n d handling of vegetables and tion in w h i c h b r u i s i n g and of various vegetable products f r u i t s is discussed. oxygen consumption have been as a result of t h e m a n n e r of
