THE PROCESS OF OIL FORMATION AND ACCUMULATION IN THE MACADAMIA

Abstract

In previous investigations of the problem of oil formation in the pecan it has been shown (4, 16) that the fatty acids, and consequently the oil and fats, are formed from carbohydrates, either stored or currently synthesized. The present paper deals with formation and changes in characteristics of the oil in the Macadamia from the young embryo to the mature fruit. The oil present in the mature Macadamia nut (Macadamia ternifolia F.v.M. var. integrifolia Maiden) is very similar to pecan oil (2), consisting largely of the glyceride of oleic acid with small amounts of the glycerides of palmitic, stearic, and myristic acids (3). It has a saponification value of 197.3, an acid value of 0.57, and an iodine number of 75.2. As pointed out above, carbohydrates provide the principal carbon source from which fats are formed, but M'Clen?h?n (9) believed that in the case of black walnuts the oil was derived from tannins; Scubti and Tommasi (13) thought that the higher alcohol, oleanol, was converted into oil in the olive. The formation of limited amounts of fatty acids from hexoses outside of the living cell has been accomplished by Smedley (14) who prepared these acids by first breaking down hexoses into C3 compounds followed by oxidation of the latter into pyruvic acid which was then condensed into acids with longer carbon chains. It is also of interest to note that fatty acids are prepared commercially from the paraffin hydrocarbons (5).