Bulletin 1J5, Utilization of Cull Citrus Fruits


 The distillation method still remained to be tried. It has
long been considered, and so stated in the literature, that
" rectified citrus oils are decidedly inferior in quality. How-
ever, some preliminary work done by Mr. McDermott indicated
that the distillation method contained possibilities, and further
experiments were undertaken.
 The first of the preliminary work was done by distilling in a current of
alcohol vapor (from 50e alcohol). The distillate was a milky emulsion,
with a very pleasant odor and favor of fresh orange oil.
 An apparatus was next arranged in which the ground peel was placed in
a long cylindrical tube which was preheated by being entirely surrounded
by the vapor of the boiling alcohol, thus diminishing condensation in the
peel; 95'; (commercial) alcohol was used in this case. The distillate
consisted of two layers, the upper being' limonene from the oil, and the lower
a dilute alcohol containing' most of the flavorings materials from the oil. At
first this alcoholic layer w as not clear, but on separation from the limonene,
and filtering, thru paper, it became clear. At this pint its taste was iot
entirely pleasant, but oin standing for about two days, a small hnm of oil
separated out, and on -removing this, a clear alcoholic solution remained,
having a very pleasant flavor of orange. About an equal volume of alcohol
was foul to have condensed in the apparatus and this was drained off anid
filtered; it corresponded fairly well to an ordinary alcoholic extract of ich
peel. 1y1 mixing equal volumes of these two extracts, a very good orange
llavorinx' was prepared.
 Distillation with steam under reduced pressure was next tried, using
the apparatus described above, and a good yield of oil of excellent icvality
was obtained.
 The final, most satisfactory method of distillation found
was as follows: A vacuum pan was equipped with a piece of
lead pipe run in thru a tight joint at the side near the top, and
coiled in the bottom, the coiled portion being perforated with
many small holes. A piece of wire gauze was placed over the
coil to protect the holes from clogging, and the ground peel was
placed on top of the gauze. The outer end of the lead pipe was
connected with a small steam generator capable of withstanding
a vacuum; the cover of the vacuum pan was clamped on tight
over a rubber gasket, and the outlet pipe was connected with
a tin coil condenser and receiver. The whole system was ex-
hausted by means of a rotary vacuum pump. As soon as the
vacuum had reached approximately 25 inches, as indicated by
a mercury gauge, heat was applied beneath the steam generator,
and by the time the vacuum had reached 27.5 to 28 inches,
water vapor was coming off regularly from the generator and
shortly afterward had passed thru the column of ground peel
and began to condense and collect in the receiver. The first