In the seeds of Hevea brasiliensis, the cyanogenic monoglucoside linamarin (2-b3-D-glucopyranosyloxy-2-methylpropionitrile) is accumulated in the endosperm. After onset of germination, the cyanogenic diglucoside linustatin (2-[6-f8-D-glucosyl-,f-D-glucopyranosyloxyJ-2-methylpropio- In addition, a linustatin-splitting diglucosidase in Hevea is described. From its activity in different developmental stages and in different tissues it is suggested that this enzyme is involved in the metabolism of cyanogenic glycosides. It is deduced that linustatin is a metabolite in the pathway by which linamarin is metabolized and utilized. MATERIALS AND METHODSSeed Drainage. The seed drainage technique is described elsewhere (17). Additionally, some of these seed drainage experiments were run in a gastight system in which a stream of moistened air was used to exchange the atmosphere in the experimental system continuously. By bubbling this air through 5 ml of 1 M NaOH any HCN liberated from the seedling during the experiment was trapped for quantitative determinations.HCN Determination. The HCN was estimated with the Merck

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Cocoa fermentations in Ghana and Trinidad as well as anaerobic fermentation-like incubations of fresh cocoa beans in Germany were carried out under controlled conditions. Samples of beans were taken during the course of these treatments and determinations were made as to acidification (pH, acetic acid content), proteolysis (free a-amino nitrogen, peptide nitrogen and SDS electrophoresis of the protein peptides) and flavour potential (gas chromatography of the highly volatile compounds, in particular isopentanal and organoleptic analysis after thin layer roasting). A positive correlation between acidification, proteolysis and the development of flavour potential during anaerobic fermentation can be demonstrated in principle. However, the flavour potential is increased if the temperature rise is comparatively slow in both normal fermentation and laboratory incubation. Strong acidification and high accumulation of amino acids and peptides were not essential for a good flavour potential. The isopentanal content proved to be a useful indicator of the progress of normal fermentation in the tropics. These findings can be interpreted on the basis of earlier results about germination-like processes in the protein vacuoles, pre-and post-mortem subcellular structures and the special characteristics of acetic acid diffusion. Conclusions which are relevant to the practice of cocoa fermentation are discussed in more detail.

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