PROCESSING OF ORANGE JUICE Effect of Storage Temperature on Quality Factors of Bottled Juice LTHOUGH the quality of canned orange juice available commercially has been improved greatly by the flash pasteurizer and t h e d e a e r a t o r , off-flavors frequently develop which make the product unsatisfactory. Improved processing conditions have been suggested by Chace, von Loesecke, and Heid (W), Heid and Scott (9, IO), Joslyn and Marsh (IS), Tresder, Joslyn, and Marsh (M), Mottern and von Loesecke (19), Heid ( 8 ) , Mottern (18), and others. I n general, they suggested deaeration of the juice, heating to 195-205’ F. (91-96’ C.) in less than 20 seconds, cooling to 175’ F. (79” C,), filling and sealing full or under vacuum or with inert gas. Mottern (18) suggested storage of pasteurized orange juice at 35” F. (2’ C.). Pulley and von Loesecke (26) showed that commercial deaeration is usually very inefficient. Loeffler (16) developed a of deaeration efficiency.
A
H. J. LOEFFLER’ Agricultural Chemical Research Division, Bureau of Agricultural Chemistry and Engineering, U. S. Department of Agriculture, Los Angeles, Calif.
High-temperature pasteurization is recommended to retain the “cloud” in orange juice, followed by rapid cooling to avoid cooked flavors. Quantitative methods using a photoelectric colorimeter have been devised for measuring vitamin C, color, cloud, and amino nitrogen content. These tests indicate that during warm storage of pasteurized orange juice, carbon dioxide is produced, the color darkens, vitamin C is lost, the “cloud” settles (unless a sufficiently high pasteurization temperature has been used), and off-flavors develop. These changes are prevented by cool storage. Appreciable vitamin C may be lost from frozen juice stored at 0’ F. ( - 18’ C.) in the presence of air. rapid and simple measure
Deterioration of Orange Juice CLARIFICATION OF JUICE.Pectic enzymes through hydrolysis may split methoxyl groups from the pectin of the “cloud”; this causes precipitation of a white fluffy powder that is probably pectic acids and leaves a clear supernatant liquid. This powder may congeal to the “curd” frequently encountered in citrus juices. Cruess (3) Suggested that high pasteurization temperatures would inactivate the pectic enzymes and prevent this clarification. Tressler, Joslyn, and Marsh (28) correlated time and temperature of pasteurization with clarification during storage. However, they used a longer heating period than is employed in flash pasteurization. Heid ( 8 ) pointed out that pressure reaming incorporates a proportionately larger amount of pectic enzymes from the peel and makes their inactivation difficult. Parks (24) stated that improper pasteurization is the only factor causing clarification of grapefruit juice. Joslyn, Marsh, and Morgan (14) found the rate of oxidation slightly more rapid in filtered than in cloudy navel orange juice. Hence the retention of cloud may be desirable to prevent oxidation changes2. address, Western Regional Research Laboratory, U. S. Department of Agriculture, Albany, Calif. 1 Present
OXIDATIONAND DARKENOF JUICE. The oxidative changes in orange juice are marked by a loss of reducing substances measured b y the reaction with iodine or 2,6-dichlorophenol indophenol, and possibly by the darkening of the juice. Eddy (6) found a greater amount of oxygen absorbed t h a n w a s i n d i c a t e d by potential reducing substances, as determined by the dye titration of fresh juice. He concluded that (‘8 part of the oxygen was used otherwise than by the primary oxidation of the reducing substances”, suggested that the oxygen may have been used to oxidize oil in juice sacs discovered by Davis (4, and explained that the characteristic off-flavors can develop w i t h o u t l o s s of r e d u c i n g factor. Although tin cans bleached the juice and prevented darkening except at high temretard development of bitter INO
perature, they did not fls.vors. .._ .. Von Loesecke, Mottern, and Pulley (16) believe that darkening is not always accompanied by deterioration in flavor, and that deterioration in flavor is not always accompanied by darkening. Wilson (SO) found a reduction in amino nitrogen and reducing sugar, and suggested that darkening may be due to a Maillard reaction between sugars and amino acids. However, Nelson, Mottern, and Eddy (22) could detect no changes in the character of the nitrogen bases present in orange juice, and thus had reason to doubt Wilson’s theory. Joslyn, Marsh, and Morgan (14) found that browning was marked by a great increase in the red color and a slight increase in the yellow color as judged with the Lovibond tintometer. Joslyn and co-workers (12, 14) found in Valencia orange juice that “browning began to occur when the iodine reducing value of the juice had decreased from 26.0 to 12.9”. They believe that reducing substances must be almost completely destroyed before browning can begin and suggest that the products of oxidation may later undergo a Maillard reaction to form the brown compound. Joslyn and Marsh (12) said that storage a t elevated temperature does increase the rate of browning, but that the
* Since the preparation of this paper, a patent has been granted to the California Fruit Growers Exchange for the use of high pasteuriaation temperatures for the “stabiliaation” of the turbidity of orange juice.
1308
October, 1941
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1309
RANCIDITY.Nolte and von Loesecke (23) found that data are meager. Ferrous ions increased browning, stannous petroleum ether extract of deteriorated canned juice, comions decreased it, while other metallic salts (including ferric, pared to fresh juice, had a rancid rather than fresh odor, a stannic, and copper salts) had no effect. The lack of effect sfty fold higher peroxide number, an eightfold higher of copper casts doubt on the correlation of the darkening acetyl value, positive rather than negative Kreis and Taufel with the loss of reducing factor since that metal catalyzes the ketone test, and other indications of rancidity. oxidation of the ascorbic acid present (6). PRODUCTION OF CARBON DIOXIDE. Wilson (80) reported MEASUREMENT OF REDUCING FACTOR IN ORANGE JUICE. accumulation of carbon dioxide during the storage of sterile The reducing factor in orange juice, mostly ascorbic acid, is orange concentrate, and suggested that it may arise from the usually measured by reaction with iodine or 2,6-dichlorodecomposition of ascorbic acid. However, Eddy (6) detected phenol indophenol. no carbon dioxide formation in his experiments on the oxygen Mottern, Nelson, and Walker (20) reported that iodine absorption of unprocessed orange juice and ascorbic acid was not a good measure of the reducing ability of orange solutions. juice, and that after the reaction with orange juice and OTHER CHANGES. Von Loesecke, Mottern, and Pulley atmospheric oxygen had gone to completion, the juice still (16)showed an increase from 5.54 to 9.41 per cent in invert reduced small amounts, presumably owing to reaction with phenolic glucosides known to be present in orange juice. sugar, a decrease from 6.36 to 1.21 per cent in sucrose, and a drop in pH from 4.02to 3.62,although there was no change Tillmans, Hirsch, and Jackisch (l7) concluded that iodine is in titratable acidity during storage of orange juice for 9 not so specific as the dye. months in tin containers a t 80-100" F. (26.7-37.8' C.), Joslyn, Marsh, and Morgan (14) quoted Szent-Gy6fgyi as finding that iodine-reducing substances other than ascorbic acid are present in orange juice. Harris and Ray (7) found Study of Processing Methods that iodine titration measures an appreciable amount of subIt has been found in this laboratory that California Valstances in fresh orange juice other than vitamin C. They recommended titration of an acid solution of pH 2.5,with an encia juice may be preserved with satisfactory flavor and freedom from off-flavors by a method which includes the unbuffered dye. following successive steps : thorough deaeration, flash pasJoslyn, Marsh, and Morgan (14) found that filtration teurization at 196-200" F. (91-93" C.), rapid cooling to reduced iodine value about 20 per cent. These authors also found variations in titration value with indophenol to be 160" F. (71"C.) or lower, and bottling, vacuum sealing, and dependent on rate of titration. The browning of juice interstoring at 40' F. (4' C.). fered with the titration by either indophenol or iodine, but THOROUGH DEAERATION OF JUICE.We have taken 0.8 cc. they concluded that "the iodine titration is superior to an or less of dissolved gases per 100 cc. of juice as a measure of indophenol titration in practice as it is easier to carry out satisfactory deaeration. Of this quantity, less than 0.10 cc. and can be more readily duplicated". will be oxygen. The juice was passed twice at room temperature through an inverted-flask deaerator such as deJoslyn and Marsh (11) noted that dissolved tin interferes with the iodine titration. They say "increase in iodine scribed by Mottern and von Loesecke (19) with a vacuum of number due to the presence of dissolved stannous salts is about 28 inches (71 om.). The method used for determining responsible for the relatively high iodine reducing number of air and the efficiency of the deaeration are discussed elsecanned juice packed in plain tin cans". where (16). More recently Stevens (96)developed a double back-titraFLASH OR HIGH-SHORT PASTEURIZATION. The minimum tion with iodine. He stated that the results parallel those exit temperature required in our pilot-plant installation to obtained with the indophenol titration on orange juice sufmaintain cloud under the recommended cool storage condificiently for all practical purposes. Bailey and Fisher (1) tions was 193" F. (89"C.) where the time of contact of juice reviewed the literature and concluded that the vitamin C with heat was 16 to 18 seconds. Uniform heating was obcontent of fresh fruit juices, determined by bioassay, is practained by passing the juice through a silver and stainless tically identical with the ascorbic acid content as detersteel coil immersed in a steam and electrically heated oil bath mined by indophenol dye titration. maintained at 221-230" F. (105-110" C.) for rapid heat Lorenz and Arnold (17) suggested standardizing indophenol solutions with ferrous ions; it follows, thereTABLE I. RETENTION OF CLOUD DURING 5-MONTH STORAGE AT 40' F. (4' c.) fore, that ferrous ion dissolved in juices Clear Cloudy cans may affect the from Code Cooling Pasteurized, Heat exCod2 bast:urized, Cooling Heat exindophenol titrations as well as the C . ~ 0 . a temp., C . posure, seo. No. C. temp., C . posure, seo. iodometric. 7 84-86 10 min. l2ABC 79 17.8 12 x 4 87-88 75 13 77-79 19.3 ... More recently Evelyn, Malloy, and 77 14 85-86 74-78 15 ... 94-97 ... 78-83 70-78 16 18 92-95 ... 78-79 15.8 Rosen (6) developed a method for 47 22 13.4 83 20 90-95 78-80 ... determining ascorbic acid in urine by 88-89 47 21 23 90-92 15.2 66-72 86-89 62-65 24 26 13.1-14.0 46 93 means of a photoelectric colorimeter. 86-88 64 25 28 14.0-15.2 72-76 15.8-17.5 92-94 88-90 70-68 28 32 14.3 64 17.5 90-92 They use indophenol dye:but differenti36 84-88 34 38 44 16.3-17.0 90-92 14.3 ate the interfering substances in urine, 70-75 39 83-86 35 89-91 14.0-14.6 15.7 70 40 16.1 62 63 16.6-17.5 87 37 90-91 such as cysteine, by reaction rate. 42 83-86 40 41 14.3-15.2 89-92 64 17.0-18.7 68-70 44 86-87 48 90 ..< AMINONITROGEN.A slight decrease 88 70 49 45 90-93 14.0 in formaldehyde nitrogen during the 70 471G 87-88 53 89 14.3 55 91 decomposition of unpasteurized juices 56 90-91 57 93-99 was noted by Wilson (30) and was cor59 90-91 related with the darkening of the juice. 60 89-91 61 88-90 However, local industrial research 62 90-92 workers claim to have found a definite Each code represents several bottles rather than an individual bottle. increase in amino nitrogen during the b Unsteamed. deterioration of processed juice. O
...
(1
1310
INDUSTRIAL AND ENGINEERING CHEMISTRY
transfer. Since the contact with the silver portion was very brief, the oligodynamic action was insignificant. RAPIDCOOLINGOF JUICEBEFORE FILLING.A cooling coil immersed in tap water was connected directly below the pasteurizing unit so that the juice was in a closed system until filled into bottles. BOTTOMFILLING INTO JUICEBOTTLES. The 12-ounce, clear glass, juice bottles were hermetically sealed with double- or triple-lacquered seals and closed; a current of steam evacuated and sterilized the head space. The green or amber 12-ounce crown-cap bottles were filled full and held about a minute after sealing before immersion in cold running water. The bottles were subjected to a preliminary steaming for about one minute, so that the juice would not have to sterilize the container. The filling with juice occurred in an atmosphere of steam rather than air under such circumstances. The juice for these tests was obtained by hand reaming of California Valencia oranges of standard or juice quality. The seeds and rag were removed by a vibrating screen of No. 30 mesh stainless steel. The necessity for using the minimum pasteurization temperature and time described earlier is illustrated in Table I. From these experiments 193" F. (89" C.) appears to be the dividing line for cloud retention; those pasteurized a t a lower temperature lose their cloud, those at a higher temperature retain it. The time of contact of each particle of juice with heat has been obtained by the equation, Time of contact =
ized at low temperatures became clear and were somewhat insipid, but did not develop stale flavors. Those stored at 60" F. (and a t room temperatures, which ranged from 60" to 80" F.) developed slight off-flavors in 6 months, and were classed as fair. Those stored a t 95' F. developed bad flavors in 2 months. Samples of the deaerated but unpasteurized juices were frozen a t 0" F. as control samples. I n most cases air remained in the head space of these 12-ounce crown-stoppered bottles. These samples retained a good fresh fruit flavor.
Analytical Tests Little quantitative study has been made or published of the changes in pasteurized orange juice during storage at various temperatures. By newly developed quantitative measures, we have followed the changes of dissolved gases, color, cloud, vitamin C, and amino nitrogen. DISSOLVED GASES. The author's method (16) for determining the gases dissolved in orange juice was used. It depends on evacuation of an orange juice sample before and after heating by the slow addition, with agitation, of boiling distilled water. Two typical analyses before deaeration and the range of results after deaeration are given in Table 11. The samples were tested by shaking the bottle to reach equilibrium, removing the cap, and immediately withdrawing a sample from the bottom of the bottle into the evacuation chamber.
(vol. of heating coil) X time of filling individual bottlea (vol. of bottles used)
Those samples heated to a higher temperature were passed more slowly through the pasteurizer; hence the time of contact and the temperature are proportional to each other. Therefore these experiments do not shorn whether time of exposure is equally as important as the temperature reached. The temperatures listed are the exit temperatures and do not indicate that the juice had been a t that temperature during the whole time of contact. Those packs cooled to only 167-176" F. (75-80" C.) before filling (packs 12, 13, 14, 16, 18, 20) had a definite cooked flavor; hence rapid cooling to a t least 160" F. (70" C.) is desirable. This differs from the usual commercial practice where cans are filled a t 175' F. (80" C.), sealed and inverted for 1.5 minutes. Code 24 in Table I shows that a good cloud can be retained despite rapid cooling and cold filling. In codes 22 and 23, low pasteurization temperatures (181-192" F. or 83-89" C.) combined with cooling to 116" F. (47" C.) yielded a clear juice. The same cooling in pack 24 combined with adequate pasteurization (199" F. or 93" C.) yielded a cloudy juice. Incidentally, code 24 had a very fine flavor.
Storage Conditions Samples of orange juice prepared in this fashion have been stored a t 40" F. (4" C.), a t 60" F. (16" C.), a t room temperature, and a t 95" F. (35" C.). Part of those stored a t room temperature were exposed to light from a north window and part were kept in the dark. A portion of those stored a t 60" F. were exposed to strong ultraviolet irradiation. No significant effects due to light could be determined, but the experiment will be repeated with a larger group of samples before definite conclusions will be drawn. The samples stored a t 40" F. for one year retained an excellent fruit flavor and were completely free of any off-flavor. Those pasteurized according to the temperatures and times recommended retained an excellent cloud. Those pasteur-
Vol. 33, No. 10
TABLE 11. EFFICIENCY OF DEAERATION
Total gas
cot
0 2
NZ
-Before Cc./l,OO cc. juice 3.63 1.71 0.52
1.37
Per cent 4+:2 14.3 37.7
DeaerationCc./~OO cc. juice 3.66 1.54 0.48 1.64
Per cent 4i:O 13.1 44.8
Range after Deaeration, Based on 10 Sam les, C c . / 100 Juice 0.5 -0.8 0 . 3 -0.4 0.03-0.09 0.2 -0.4
8,.
VITAMINC CONTENT.Preliminary experiments showed that the double-back iodine titration suggested by Stevens ($6) is time consuming, and the end points are obscure. We have found that the indophenol dye is not specific for ascorbic acid but will react for example with ferrous ion which may be present in canned juice. The result would be a falsely high figure for vitamin C content. We have found that such substances react with the dye a t a slow rate; hence they can be differentiated if present in appreciable amounts. This interference with the dye titration will be detailed in a later publication. It was found that a modification of the Evelyn-MalloyRosen method (6) was the best way of measuring the ascorbic acid in orange juice. The sensitivity was increased by a 20 to 1 dilution of orange juice with distilled water. Filtering the orange juice does not reduce the ascorbic acid content by any significant amount (Table 111). The filtered juice was tested in the colorimeter calibrated with distilled water; the unfiltered sample was tested with the colorimeter calibrated against a diluted solution of unfiltered juice. The insignificant difference and the difficulty of obtaining an aliquot of pulp and keeping it suspended amply justify the use of filtered solutions. The dilution made a correction for the juice cloud unnecessary, except in very turbid solution; hence distilled water can usually be used for the calibration. In the presence of interfering substances, the 5-second reading is more satisfactory for orange juice than is the zero-extrapolated time reading suggested by Evelyn et ul. for liquids of lower vitamin content.
October, 1941
TABLE111.
VITAMIN
Juice
INDUSTRIAL AND ENGINEERING CHEMISTRY
1311
these have been filtered out.
Hence a clear juice, despite
C I N FILTERED AND UNFILTERED ORANGE JUICE
Sample Pasteurized 114N
Sample Pasteurised 115M
cloudy, the turbid elements will reduce the light transmission by dispersion and absorption, or by what might be termed “mechanical” means. The galvanometer readings, which are proportional to the light transmission, are recorded as measures of the turbidity or as the cloud index. A high
Sample Raw 112
Mg. per 100 cc. o j juice-
Filtered
40.6 40.5 39.2 40.6
Unfiltered
38.5 39.2 40.6 40.6
37.8 39.0 39.7 39.1
TABLEIV. The method is as follows: Orange juice is filtered on a Buchner funnel after addition of 2 per cent of Super-Cel. Five cubic centimeters of the filtrate are added to 90 CC. of distilled water and 5 CC. of glacial acetic acid in a stoppered flask. The air in the top of the flaqk !s swept out with carbon dioxide, the flask closed, a n d t h e c o n t e n t s shaken. One cubic centimeter of this diluted filtrate is pipetted into a matched tube and inserted into the Evelyn photoelectric colorimeter, calibrated to read 100 with distilled water and with filter No. 520. The dye solution is added in the same way as in the Evelyn method with urine, where 9 cc. are delivered from a wide-tip calibrated pipet. Readings are taken at 5 , 10, and 30 seconds. The readings for 10 and 30 seconds should be identical in the absence of interfering substances. They are used unless widely different when the 5second reading ‘is used. The ascorbic acid content is calculated according to the formula suggested by Evelyn:
-
Mq. ascorbic acid/100 oc oran e juice filtrate
CLOUD
OR
10.8
(.ti - E)20
Pack No.
CHANGE OF QUALITY FACTORS WITH STORAGE TEMPERATURE Storage Time Day;
Taste
Total Gas
COO
Cc./!OO CC. juzcs
I
31 32
I1
37 51 52
I11
I
56 65 70 72 72F
*... .. .. .. .. .. .. .. ..
.. .. .. .. .. ..
127 127
Good Good
60 70 117
Good Good Good
117 50 114 114 52
Good Good Good Good Good Pasteurized Good Good Good
Packs 0.44 0.59 1.26
.. .. .. .. .. ..
...... .. .. .. .. .. .. .. .. .. .. .. .. ......
0.34
32.0-32.0 35.5 30.7-32.2
60
81
70 34
... ...
94 49 89 90.5 66 68
0.51 0.54 0.53 0.50 0.52
34.3-32.9 32.9-34.0 34.3-36.5 39.7-41.4 42.4-43.5 31.0-32.9
65 62 62 61 62.5 65
44 44 46 69 46 89
Packs Stored a t 15” C. 1.13 0.45 0.39 0.72 0.40 0.94 0.40
... ...
38.2-40.1 32.6-32.6 32.6-34.2
61 60.5
61
99 98 9Q
Good Good Good
0.89 1.53 1.19
0.51 0.87 0.72
0.45 0.34 0.37
38.4-39.4 33.5-34.7 37.7-38.0
59.7 63 61
51.5 52 59
Good Good Good Fair Poor Good Good Good
0.88 1.43 0.80 0.89 0.46 1.19 0.39 0.48
0.41 0.44 0.49 0.44 0.20 0.65 0.14 0.26
0.59
35.5-36.5 33.3-32.7 30.5-30.5 28.1 40.2 32.9-34.0 29.3-27.4 34.7-35.9
62.5 60.2
42 42.5 46.5 58.5
i.04
0.65
63C 670 69C 71A 72A 61A
95 90 91 93 90 87
120 122 122 122 52 120
Good Good Good Good Good Good
1.14
0.74
0.59 0.31 0.47
0.64 0.67
0.34 0.34
3lB 32c 32G
89 88 87
60 60 60
I1
51H 52F 52D
91 91 91
I11
59c 60G 601 66F 66G 66H 68D
90 91 91 91 90 90 90 90
I
25D
93
111
58E 58F 69B 69D 69E 69G 69H 72B 72E 72F
90
90 91 91 91 91 91 92 89 89
I1
3SA 40F 40H 48B
95 87 87 89
75 75 75 35
Pasteurized Bad Bad Bad Bad
111
530 54D 55B 67A 67H 6SF 68G 6SH
89 91 91 89 91 90 90 91
75 75 60 35 75 60 75 35
Bad Bad Bad Bad Bad Bad Bad Bad
Pasteurized Good Poor Fair
. . . . ... ..
0.66
...
...
0.45 0.46
...
... ... ... ...
0.53
...
0.45
Pasteurized Packs Stored a t Room Temperature 800 Fair 1.04 0.60 0.41 38.2-40.1 Go9d Fair Fair Good Fair Fair Fair Fair Fa!r
80
Falr
758
Ultraviolet light.
0
..
82 60 59 62 62 61
0.26 0.70
130 1300 1300 1300 75c 520 , 520 52
29.7
40.6-41.4 34.3-34.7 32 3-32.7 34,3-35.4 38.9-38.9 38.9-39.4
0.47 0.98 1.73
0.48
55 63
0.44 0.49 0.46 0.50 0.34 0.34
Good Good Good Good Good Good
b
62 60
44 38 43
139 137 133 137 120 120
Amber bottle.
30.7-31.4 31.4-31.4
60 61 60.5
87 91 91 89 90 91
600.b 100 60
0.34 0.34
40.6-40.8 39.6-39.6 40.8-42.1
38D 41A 41A 41G 52c 62G
0
73 69.5
Mg./iOO GO. juice filtrate
Stored a t 4O C. 0.26 0.45 0.29 0.41 0.67 0.45
92
6SC
Cloud Index
60
91
I
Color Index
33.0-36.5 28.7-29.8 33.9 31.7-32.2 30.8-32.9
140 140 138
I11
VitaminC
... ...
89
I1
Amino Nitrogen
Packs 8tored a t -18’ C. (without Pasteurization)
20D 21D 28H
TURBIDITY.
The turbidity or “cloud index” is determined by centrifuging a sample of whole orange juice for 10 minutes at 1400r. p. m. Ten cubic centimeters of the centrifugate are placed in a matched tube, and the reading is taken in the photoelectric colorimeter using filter No. 720 calibrated to read 100 with distilled water. This filter allows only orange and red wave lengths to go through; hence the color of the juice centrifugate has no effect on the reading. Orange juice owes its orange color to the absorption of the complementary green wave lengths, and
Code No.
Pasteuriaation Temp., C.
If
it8 color, will yield almost 100 per cent transmission.
Light.
1.13
0.90
1.01 1.13 0.63
0.69 0.90 0.31
i.y7
d.Xl
0.85 0.65
0.15
......
. . . .0.41 ..
0.53 0.53 0.55 0.63
... ... ... ... 0.42
...
Packs Stored a t 35” C . 1.57 1.03 0.41 2.58 1.94 0.47 2.04 1.67 0.49
40.5 48 48
61.2
96
60.8 63 69 49 48.5 48.6 57
83 85 76
63 63.5 57 56 47 64 48.7 65
...
0.34 0.34
29.2 32.9-33.9
1.62 1.37 1.14 0.84
1.16 0.90 0.81 0.65
0.61 0.39 0.51
...
64.5 64 64 5s 63
61
1.46 1.31 0.84
......
65 62
46 94.7 43 37 3s 44 94.2 94
2.05 1.71 1.09
... ...
61
66
31.3-32.3 34.0-33.3 31.0-31.8 31.4-32.2 33.3 35 3-37.4 39.4-40.4 35.3-36.3 40.8 38.6-38.2 31.8-81.9 25.6-26.8 29.3-28.2 32.7
......
57.5 60 63 62
30:iLii.s 28.8-27.3 33.7-33.7 34:3-39.3
59.2 64 66
69.3 61.5 61
94.7 61
7s
89 85
..
93 36 88 96 53
1312
INDUSTRIAL AND ENGINEERING CHEMISTRY I
TABLE V. Pack No.
Time of Temp. Storage C.
I
SUMMARY OF AVERAGESOF PACKS OF ORANGE .JUICE HELDKr VARIOUS TEMPERATURES
-18 4 15
Days
127 139 60 80
Total Gas
COS cc.po0 cc.
% COz
3U2C8
6.Y6
6.40
52.b
Amino Nitrogen
Vitamin C 1100 cc,--
