134 Bulletin 135, Utilization of Cull Citrus Fruits

was shown that a temperature of 63 to 65C. for 15 to 30
minutes was the most satisfactory condition for securing com-
plete sterilization, with a minimum of the objectionable cooked
taste.
 These preliminary tests were followed by a more extended series, using
50 cc. quantities in small narrow-mouthed bottles. Several methods of
treatment were tried. The first was to warm the juice slightly in a cur-
rent of the gas with which the test was being made; then while the cur-
rent of gas was maintained, the juice was cooled with ice water, run into
the bottles, the air driven out of the space above the juice with the gas,
the bottles stoppered, the stoppers tied in, and the whole pasteurized.
After pasteurization, the necks and corks were dipped in melted paraffin.
Later tests were made in which the removal of the dissolved air was
effected by means of a vacuum, and also by passing the gas thru the juice
without warming. Usually twelve bottles were prepared in a set; these
were then kept under observation for some time, specimens being occa-
sionally opened and tasted. The details of some of the tests are as follows:
 Series A: Dec. 16, 1911.-Juice heated to 60C. while passing CO2,
cooled to room temperature, bottled in CO,, and set in ice box over night;
next day run into small bottles (previously sterilized), air removed by COz,
bottles closed with paraffined stoppers, tied in, and pasteurized at 60'C. for
20 minutes. Aside from precipitation of suspended matter and a slight
darkening, these specimens had undergone no serious change up to June
24, 1913.
 Series C: Dec. 19, 1911.-Duplicate of Series A, except that a tempera-
ture of 70C. was used both for the initial treatment with CO,, and for
pasteurizing. The juice kept equally well, but the high temperature injured
the flavor.
 Series D: Dec. 20, 1911.-Duplicate of Series C, except that a tempera-
ture of 80'C. was used. The flavor was badly impaired; also after long
standing the color became darker than in Series A, tho not as dark as
specimens pasteurized in air.
 Series F: Dec. 22, 1911.-In this series nitrogen was used containing,
as before stated, about 7% oxygen. Pasteurization was done at 70*C.
Darkening set in after about 4 weeks, and all were quite brownish at the
end of 6 weeks.
 Series G: Dec. 28, 1911.-Juice was saturated in the cold with CO., in
pressure ("soda") bottles, closed when full of gas and pasteurized at 60'
to 65C. for 20 minutes. Had retained good color and taste up to June 24,
1913. The CO., however, gave it a slightly unnatural tang.
 Series H: Jan. 1, 1912.-Juice was heated in an open beaker to 60'C.
and then cooled in ice water in a CO, stream, placed in small bottles, sealed
and pasteurized at 70" to 75'C. for 15 minutes. The samples became some-
what darker than those of Series A, but not as dark as in Series F.
 Series I: Jan. 2, 1912.-The juice was exhausted and the vacuum re-
leased by the admission of hydrogen; container and juice then cooled in ice
water, the juice placed in small bottles, the latter filled with hydrogen, stop-
pered and pasteurized at 70' to 75C. for 15 minutes. Both color and taste
kept very well.