B) Refined neem extracts - AZADIRACHTIN-ENRICHED EXTRACTS (also called two-step extraction plant)

Advantages (according to Ermel, personal communication):

· products can be easily stored (less volume) and have a longer shelf-life

· better quality in terms of azadirachtin content

· easier to fulfil the registration requirements since they contain no oil or additional substances

· easier to formulate

· homogenous quality (do not vary much from batch to batch)

· higher concentration of azadirachtin, which is required to control certain pests

· less phytotoxicity by eliminating undesirable by-products such as wax

· possible use of the extraction plant for other products

Disadvantages:

· higher investment required
· more sophisticated technology
· technology protected by patents and therefore often not available to small entrepreneurs

By applying special extraction procedures or further enrichment steps for alcoholic extracts, e.g. by fluid/fluid extraction, unwanted substances (such as residual oil, sugar, etc.) are separated and azadirachtin(s) and other tetranortriterpenoides are converted in an organic phase which is easy to vaporise. After recovery of the solvents a powder extract remains with an azadirachtin content of up to 20%. The powder can be stored and used on demand to formulate an emulsified extract (EC) with 3 - 5% azadirachtin A.

This sort of production technology is used by most plants processing commercial neem products on a large scale (1000 - 3000 t of neem kernels). In India these plants are often set up in joint ventures with partners of companies offering neem products in industrial countries such as the US.

The company Trifolio has developed a procedure starting from simple water extracts, but continuing with a fluid/fluid extraction with a special combined solvent and formulation liquid, which concentrates the Als of the non-water phase and formulates them for application in the field (Kleeberg 1996).

Other technologies

There are two further technologies which are of importance in relation to neem extraction: