Schriften zu Genetischen Ressourcen - Genres

Utilisation of plant genetic resources for valuable raw materials
Fig. 1: Synthesis of important basic fragrance materials from a-pinene
Onion and garlic bulbs are very important raw materials and are processed in high
amounts into various products in the food and pharmaceutical industry. Onion juice is
obtained by repeated expression of the plant tissue and subsequent flash heating up
to 160°C and then cooling down to 40°C. The juice contains both flavour and aroma
precursors which are mainly cysteine sulfoxides. In order to get a juice concentrate
the freshly produced onion juice is carefully evaporated to approx. 75 % solids. Solvent
extracts of onions are performed in the flavour industry in order to obtain roast
flavours for meat or instant soups. These dark brown juices may be mixed with sugars
and amino acids or lecithin to yield an oleoresin having a flavour intensity approx.
100 times that of fresh onions. In the US, also garlic juice has some importance as
health product. Last but not least, it has to be mentioned here that numerous garlic
preparations are very successful also in the European market (FENWICK and HANLEY
1990).
Analytical characterisation
188
a-pinene
+HC
H + , H2O
OH
OAc
camphene Isobornyl acetate
a-terpineol
HOAc, H +
camphor
1. OH -
2. [O2]
O