Crop description. Carica papaya L. (see Fig. 4.22)—commonly known as papaya, pawpaw, melon tree, papayier, lechosa, or mamon—belongs to the family Caricaceae and grows in tropical to subtropical areas. Native to South America, now the crop is widely distributed through­out the tropics. Papaya is a short-lived rapidly growing plant (not a true tree) having no lignified tissues. The seeds contain 25-29% oil [77, 179]. The oil contains mainly unsaturated fatty acids, around 70.7%, and may contain toxic components that make it unusable in human foods [75]. Fatty acid composition of the oil includes oleic acid (79.1%) and palmitic acid (16.6%) [179].

Main uses. Papaya is mainly used as fresh fruit, and for the production of drinks, jams, and so forth. In some places, the seeds are used for treat­ment against worms [181]. The green fruit is also a commercial source

Figure 4.22 Caricapapaya L. (Photo courtesy of Barbara Simonsohn [www. barbara-simonsohn. de/ papaya. htm].)

of the proteolytic enzymes papain and chymopapain—the former find­ing use in a wide range of industries, particularly brewing for haze removal, and the latter in medicine. Oil extraction from the seeds could improve the viability of the industry in countries where papaya is cul­tivated for papain production and processing. The seeds constitute around 22% of the waste from papaya puree plants [182]. No references about its use as a biodiesel source have been found so far.