Crop description. Prunus communis, P americana, and P. amygdalus— commonly known as almond, amandier, mandelbaum, almendro, and mandorlo (see Fig. 4.20)—belong to the family Rosaceae and grow in temperate Mediterranean areas. Major producing countries are Italy, Spain, Morocco, France, Greece, and Iran. The almond tree grows to a height of 3-8 m. Many varieties of almonds are grown, but they can be

Figure 4.19 Allanblackia stuhl­mannii. (Photo courtesy of Josina Kimottho (ICRAF) [www. worldagroforestry. org/Sites/ TreeDBS/aft/imageSearch. asp].)

broadly divided into two types: bitter and sweet. Bitter almonds contain amygdalin and an enzyme that causes its hydrolysis to glucose, ben — zaldehyde, and hydrocyanic acid, making the fruit nonedible. The bitter almond oil yield is around 40-45%, and sometimes as low as 20% [77, 178]. Major fatty acid composition of oil includes palmitic acid (7.5%), stearic acid (1.8%), oleic acid (66.4%), and linoleic acid (23.5%) [178].

Main uses. Bitter almond press cake cannot be used for feed due to its toxic components [179]. They are pressed at low temperatures, gener­ally at about 30oC, to prevent destruction of the hydrolytic enzyme. The press cake is then used for production of bitter almond oil [77]. Despite the oil content and fatty acid composition, no references about the use of bitter almond oil as a raw material to produce biodiesel have been found so far.