food use. At the turn of the century, German researchers iden-
tified palmitic, stearic, oleic, linoleic, and linolenic acids as con-
stituents of citrus seed glycerides (13).1 The same researchers
also determined many of the physical and chemical character-
istics of the seed oils from sour oranges and lemons (41). The
earliest references described the oil as having an intense bitter
taste due to the presence of limonin (33, 35, 41).
 Other early research describes the appearance and proximate
analyses of four varieties of orange and grapefruit seed oils (4)
and some of the oil characteristics such as refractive index,
saponification number, iodine value, and relative viscosity (11).
The protein, fiber, ash, water, and crude fat content of air dried
citrus seeds were reported for three varieties of Japanese
oranges (32). The chemical and physical characteristics of
grapefruit seed oil have been reported by several researchers
(15, 22, 28, 37, 47). Grapefruit seed yields per weight of fruit
have also been studied (19).
 Analyses have been performed on orange seeds and seed oils
to determine component fatty acids of the glycerides (12, 18,
20, 24, 39, 45) and other physicochemical characteristics and
processing methods (21, 27, 48, 51, 53). Mandarin orange seed
oils have been separately characterized (10, 26), as have seed
oils from tangerines (46), Ceylon sweet oranges (54), bitter
oranges (38, 56), and several types of Indian citrus, including
shaddock and calamondins (1, 34, 42). Descriptions of lemon
seed oils have been published (17, 25), and lime seed oil has
been described by Oilar as light-colored oil, desirable as a salad
oil (40).
 Biological and nutritive properties of citrus seeds have also
been studied. Experiments have been performed to ascertain
the germination and viability of citrus seeds (36) and establish
the microscopic structure of grapefruit, orange, lemon, and lime
seeds (52). The nutritive value of citrus seed protein in defatted
meal has also been determined (3), while the processed oils were
described as non-toxic and as digestible as other common seed
oils, such as soybean and cottonseed oil (7, 43).


 CHEMICAL COMPOSITION AND CONSTANTS
 Fatty Acids.-The seed oils of all varieties of citrus are com-
posed of significant amounts of polyunsaturated fatty acids, and
in most cases the extracted oil is liquid at room temperature.
 'Numbers in parentheses refer to Literature Cited.