Bitter or Sour Orange (Citrus aurantium)

The bitter or sour orange (Citrus aurantium) is not as widely known as other citrus fruit and tends to be localised to Japan. Anyone who has ever bitten into this fruit will have testament to its extremely sour flavour. It would be a very useful citrus fruit for sharp acidic fruit sauces or for salad dressings.

There are a few cultivars including:-

• daidai (C. aurantium Linn. var. Cyathifera Y. Tanaka)
• kabusu (C. aurantium Linn. forma Kabusu)
• konejime (C. neo-aurantium Tanaka)
• tokosu (C. aurantium Linn.).

The daidai is rich in hydrocarbons ( around 97%). The main aroma components are geranial, octanal, linalyl acetate and cis-limonene oxide (Sawamura, 2000).