_ without apparent change for two years or more. Pure nitrogen, hydrogen or methane * 
heavy oni which, upon final ane leaves a thick: crust of crystallize 
surface. Lemon, orange and citron are the principal fruits used for this “purpo: 
There are but few acres of citron in California, principally at Riverside; whil 
production of these groves is prolific, yet attempts to manufacture candied peel ha’ re 
not been altogether successful in.competition with candied citron peel from abroad. 
As secondary products, really by-products of the by-products, Will mentions a few 3 
articles which are not essential to the success of the by-product industry but rather ~ 
a final refinement of processes, useful in the future development of the industry. ~ 
Amongst others, it would be possible by isolating the pectin bodies, to prepare. ac4 
substance capable of serving as a jellifier. Moreover alcohol, as well as vinegar, — 
might be obtained from the fruit. Finally there are three bitter bodies 2z., hesperidin, a 
isohesperidin and aurantiamarin which might possibly be put to some technical use. — 
We may here mention a publication by F. A. McDermott’) on the utilization of 
“culls” from Florida citrus fruits. The by-products to be considered are mainly the 
juice and the volatile oil, the recovery of citric acid forming one of the minor problems. — 
It was found that by pasteurization alone orange and lime juice could not be preserved; = 
the juice does not keep longer than two weeks, after which time it becomes dark : 
-and muddy, a change which is accompanied by a deterioration in flavour which. 
finally becomes offensively acrid. The darkened specimens appeared to be sterile so s 
that the alteration seemed to be due to some chemical action, but though tests were ~ 
made, these failed to indicate as to what change had taken place. It was found, ~ 
however, that the removal of the air dissolved in the juice and that in the container 
above it, followed by pasteurization, was sufficient to prevent deterioration for a con- 
siderable time. In fact all failures which occurred within two years could be traced — 
to air having gained access to the juice. As was to be expected, it was also found ~ 
that it was the oxygen of the air which was responsible~for the change, althoda 
replacing the air with pure oxygen did not produce as rapid a darkening as might — 
have been expected. a 
McDermott observed that the most common organized contamination of the orange — 
juice was a strain of the wild yeast (“Kahmhefe’”’), Willia anomala, and it seems that it is ~ 
this organism which is responsible for the development of the ester odour (apparently <= 
ethyl acetate) which may so frequently be noticed in orange juice which has stood for ~ 
some hours at room temperature. Acetic acid bacteria were also found occasionally. : 
The common blue molds of the peel of the orange, Penicilliiwm italicum and P. oe . 
appeared to be unable to grow on the sterilized juice. - 
The simplest way to remove the air from and above the juice in the containers 
was to replace it by some non-oxidizing gas; carbon dioxide appeared to be the best. — 
A large number of specimens of orange and grapefruit juices were prepared, in whictea 
the juice was charged with carbon dioxide at atmospheric pressure, and the air above - ; 
the liquid replaced with the dioxide; the content of many of these bottles remained — : 
iii Ui BES 
proved equally satisfactory. Nitrous oxide gave results about like those of pure oxygen x 
With hydrogen the flavour of the juice seemed to keep best. Carbon dioxide gave z % 
slightly unnatural tang suggesting incipient fermentation. 
Sealing in vacuo was also tried and eventually proved to be the eet satisfacto 
method of meeting the eerece 
1) Journ. Ind. Eng. Chemistry 8 (1916), 136. 
