Almonds (bitter as well as sweet) contain about 50% of a fatty oil, which is, though, too expensive to be used for cooking. It is made up of glycerides (80% oleic acid, 15% linoleic acid, 5% palmitic acid).
Bitter almonds contain 3 to 5% amygdalin, a so-called cyanogenic glycoside composed of mandelic nitrile and gentobiose. Vegetative parts of the almond tree accumulate the analogous prunasin (with glucose as sugar component).
On enzymatical hydrolysis of these glycosides by β-glucosidases, the aglycon mandelic nitrile (2-hydroxy-3-phenylacetonitrile) is liberated. A second enzyme (mandelonitrile lyase) converts mandelic nitrile quickly to benzaldehyd (C6H5-CHO) and hydrocyanic acid (HCN, also known as prussic acid). By chance, both compounds are olfactorily similar, but hydrocyanic acid is highly toxic; bitter almonds’ value as a spice is only due to the benzaldehyd.
Almond flower
Hydrocyanic acid is a dangerous poison (about one twentieth of a gram is considered lethal for an adult), but it is also very volatile and susceptible to hydrolysis at higher temperatures. Therefore, significant amounts of hydrocyanic acid are highly unlikely to accumulate in any dish prepared with bitter almonds. On the other side, incorporation of whole raw bitter almonds is fairly dangerous because, in this case, all of its hydrocyanic acid is formed in one’s stomach. Serious poisoning is quite rare with adults, but children may be killed by just a few bitter almonds. Very similar warnings hold for other plants of the genus Prunus, the kernels of which all contain amygdalin: Peach, apricot and, to a lesser extent, cherry and plum. One kernel of bitter almond yields about one milligram of hydrocyanic acid.
It should be noted that bitter almonds can only develop their aroma if both water and the necessary enzymes are present. The two enzymes (called together emulsin) are desactivated by heat; thus, bitter almonds must never be fried nor roasted, for they will not develop almond aroma afterwards.
Sweet almonds are, by centuries of cultivation and breeding, very low in amygdalin and, thus, harmless; however, even sweet almond trees sometimes yield single bitter almonds (up to 1% of total crop), and some sweet almond cultivars still contain traces of bitter almond aroma. This does not apply to Californian almonds, which can be regarded totally destitute of amygdalin.
Principally, sweet and bitter almonds are very different products and can never substitute each other.
Source: Gernot Katzer’s Spice Dictionary
Lizz Wright performed on 15th November, 2004 in a small, but famous Reigen jazz club.The performance was very professional and all musicians were fantastic. Lizz has an incredible voice and is a true professional in using it. Throughout the performance I haven’t caught even one mistake, and yet the band used almost no sheet music and the mood was quite relaxed, not a rigid concentrated jazz performance. Bravo!
