Hastening the coloration of lemons

✍ Scribed by F.E. Denny

• Book ID: 104125036
• Publisher: Elsevier Science
• Year: 1924
• Tongue: English
• Weight: 123 KB
• Volume: 198
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(24)90091-3

✦ Synopsis

SOME commercially mature lemons are green in color when picked.

The desired yellow color must be secured by subsequent treatment.

The change from green to yellow is hastened by the use of the combustion gases that arise from kerosene stoves during the burning of kerosene.

An investigation was conducted in the Bureau of Chemistry to determine the identity of the gaseous constituent responsible for the coloration of the fruit.

After the mixture of gases from a kerosene stove had bubbled through Pettenkofer tubes filled with bromine water, the residual (unabsorbed) gas failed to induce coloration. This suggested that the effective constituent must be among the unsaturated hydrocarbons, Ethylene, even in low concentration, caused green lemons to turn yellow.

Fruit colored in this way differed in no way from similar fruit colored in the usual way with kerosene stoves.

However, attempts to isolate ethylene from stove gas were unsuccessful.

When mixed with air in varying proportions by volume, concentrations of ethylene down to I to 200900 colored lemons in five to eight days. Concentration clown to I to 2,ooo,ooo required six to ten days. The lowest concentration tried (I to 5,ood,ooo) required about fourteen days, indicating that this concentration represents the highest dilution at which the rate of coloring is markedly influenced.

High concentrations appear to retard coloring, since 80 per cent. ethylene for seven days gave only slight coloring.

Absence of oxygen prevented coloration of the fruit by ethylene.

*Communicated by the Chief of the Bureau.