Standardization of Canned Citrus Juice by the Use of Partial Concentration1

PROCESSING SECTION STANDARDIZATION OF CANNED CITRUS JUICE BY THE USE OF PARTIAL CONCENTRATION1

Edwin L. Moore, C. D. Atkins, results of these taste tests indicated that L. G. MacDowell, and the quality of the orange juice had been Richard L. Huggart improved by partial concentration.

Florida Citrus Commission Experimental University of Florida Citrus Procedure. The oranges used in this Experiment Station work were Hamlins obtained from cer Lake Alfred tain experimental plots at the Citrus Ex periment Station, Lake Alfred, Florida. The object of the work to be reported These grove-run oranges were specially on this afternoon was to find out if a chosen for their low-solids content in an low-solids and low-acid orange juice effort to show what could be done to could be improved in quality by concen standardize as poor a sample as is likely tration. The term "standardization" as to be encountered in a canning opera used here will refer to the partial con tion. The fruit was washed at the Cit centration of orange juice to raise the rus Experiment Station and then trucked Brix and acid to minimums of 10.5 in field boxes to the U. S. Citrus Prod degrees and 0.75 percent, respectively. ucts Station, Winter Haven, Florida, It is possible that if internal grades for where it was held at about 40°F. for 4 fresh fruit are raised, standardization of days before processing on December 31, canned citrus juices by partial concen 1946. tration may offer a possible use for some The juice was extracted using a rotary fruit with solids content under that re juice press, passed through a 0.030 inch quired for fresh fruit. screen, and held in a stainless steel hold Three experimental packs, consisting ing tank until the quantity of juice of a control and two partially concen needed for the packs had been collected. trated juices, were put up in plain tin The juice was then processed further as cans and stored at 40° and 80°F., and follows: examined initially, and at the end of 3 Control pack. A quantity of deaerated and 6 months. After storage for 3 juice was used for the control pack. months at 80 °F., samples of the three Concentrate-added pack. A quantity juices were sent to all Florida citrus of the juice was concentrated under processors for taste comparisons. The vacuum to 55 degrees Brix at a tempera ture of 90°F. This 55 degrees Brix con 1 Paper prepared by Edwin L. Moore and delivered centrate was then added to a quantity of by C. D. Atkins at the 61st Annual Meeting of the Florida State Horticultural Society, West Palm Beach, deaerated juice to adjust the Brix to at Florida, October 28, 1948. This paper is condensed from a previously published article titled, "An Experi least 10.5 degrees. Table 1, calculated ment on Partial Concentration As a Means of Stand ardizing Low-Solids Orange Juice," by Edwin L. from sucrose values (1), gives the gal Moore, L. G. MacDowell, C. D. Atkins, and Richard L. Huggart, that appeared in Fruit Products Journal, lons of 55 degrees Brix solution to add Vol. 27, pp. 72-74 (November 1947), and is reprinted with the permission of Fruit Products Journal. to 100 gallons of a given low-Brix solu-

1948 (201) 202 FLORIDA STATE HORTICULTURAL SOCIETY, 1948

TABLE I

GALLONS OF 55° BRIX SOLUTION TO ADD TO 100 GALLONS OF A GIVEN LOW-BRIX SOLUTION TO OBTAIN A 10.5° BRIX SOLUTION

(BASED ON SUCROSE VALUES)

>>(GIVEN 7.0 7.5 8.0 8.5 9.0 9.5 10.0

10.5 6.4 5.5 4.6 3.7 2.8 1.9 0.9

TABLE 2

GALLONS OF WATER TO EVAPORATE FROM 100 GALLONS OF A GIVEN LOW-BRIX SOLUTION TO OBTAIN 10.5° AND 55° BRIX SOLUTIONS

(BASED ON SUCROSE VALUES)

7.0 7.5 8.0 8.5 9.0 9.5 10.0

10.5 34.3 29.4 24.6 19.7 14.8 9.9 4.9

55 89.6 88.9 88.1 87.3 86.5 85.8 85.0 MOORE, ATKINS, MACDOWELL, HUGGART: CITRUS JUICE 203 tion to obtain a 10.5 degrees Brix solu will be noted that the "Control" juice is tion, and may be used as an approxima low in Brix (7.43 degrees) and acid tion for citrus juices. (0.55 percent), and that the "Concen Concentrated pack. The remainder of trate-added" and "Concentrated" juices the juice was concentrated under vac have been standardized to at least 10.5 uum to at least 10.5 degrees Brix at a degrees Brix and 0.75 percent acid. Also, temperature of 90°F. Table, 2, calcu the high ascorbic acid content of the lated from sucrose values (1), gives the "Concentrate-added" and "Concen gallons of water to evaporate from 100 trated" juices will be noted. gallons of a given low-Brix solution to All three juices stored at 40°F. for 6 obtain 10.5 degrees and 55 degrees Brix months retained about 97 percent of solutions. their initial ascorbic acid content. Dur The "control," "Concentrate-added," ing storage at 80°F. for the same period and "Concentrated" juices were pas of time, all juices retained about 88 per teurized at 200°-205°F., filled at 190°- cent of their initial ascorbic acid con 195 °F. into 9M fluid ounce cans (1.25 tent with no significant differences be hot-dip tin plate), sealed, and cooled. tween the packs. In general, the canned juices showed a After storage for 3 months at 80°F., 9- to 10-inch vacuum and a gross head- coded samples of the three juices, with space of 3/16 to 4/16 inch. some descriptive information, were sent Each of the three packs consisted of to all Florida citrus processors with the approximately 10 cases of 24 cans each, request that the juices be tasted by the and a part of each pack was placed in members of each organization. A ques storage at 40° and 80°F. tionnaire was enclosed to be filled out Results. The initial analysis of the and returned to the Research Depart juice packs for Brix, total acid, and ment of the Florida Citrus Commission. ascorbic acid, is given in Table 3. It Thirty-nine canners, represented by

TABLE 3

INITIAL ANALYSIS OF THE CANNED ORANGE JUICES

CONTROL CONCENTRATE- CONCENTRATED ADDED

•BRIX 7.43 10.65 10.70

TOTAL ACID,% 0.55 0.79 .0.78

ASCORBIC ACID, MG./IOOML 39.8 58.4 59.3 204 FLORIDA STATE HORTICULTURAL SOCIETY, 1948

CONCENTRATE-ADDED

CONCENTRATED

NO PREFERENCE BETWEEN] CONCENTRATE-ADDED ANI CONCENTRATED

CONTROL

20 40 60 80 100

NUMBER OF TASTERS

FIGURE I- PREFERENCES OF TASTERS FOR THE CANNED ORANGE JUICES AFTER STORAGE OF JUICES FOR 3 MONTHS AT 80° F.

210 tasters, generously cooperated in packs were analyzed initially and at the tasting these samples of orange juices end of 3 and 6 months to study partial and returning the questionnaires. These concentration as a means of standard results are presented graphically in izing low-solids and low-acid orange Figure I. Of these 210 tasters, 103 pre juice to improve its quality. ferred the "Concentrate-added" juice, 94 No significant differences in retention preferred the "Concentrated" juice, 8 had of ascorbic acid were found between the no preference between the "Concentrate- packs at the end of the storage periods. added" and "Concentrated" as the best Thirty-nine canners, represented by juice, and 5 preferred the "Control" juice. 210 tasters, cooperated in tasting the From these results on taste tests, it would packs of juices after the juices had been appear that the quality of the orange stored at 80°F. for 3 months. The re juice had been improved by either sults of these taste tests indicated that method of concentration used. the quality of the orange juice had been improved by partial concentration. Summary Reference Three experimental packs, consisting (1) Handbook of Chemistry and Physics. of a control and two partially concen 26th Edition., pp. 1548-1549, (1942) trated juices, were put up in plain tin Chemical Rubber Publishing Co., Cleve cans and stored at 40° and 80°F. The land, Ohio.