GEORGE
H.
HART
89
ss tubes or in heavy paper containers
red for 8 weeks in the dark at tempera-
-s of—5 to 5°C. sustained no loss ;
rage for 8 weeks at room temperature
20 to 30° C. resulted in a 30 per cent
s. After 9 days in the dark at 60° and
C. there was 62 and 87 per cent loss,
respectively. He showed that over a 15-
y period the rate of loss of carotene in
alfa leaves was roughly doubled for
ch 10° rise in temperature. The loss in
ole leaves was only slightly less than in
ely ground leaves. The rate of loss in
cns at both 40° and 60° C. was greater
bring the first 3 to 6 days than
absequently.
In storage under practical conditions
sses of carotene were serious during
summer weather, the mean temperature
ing 70° F. or higher. After several
months under such conditions artificially
dehydrated meal might be much lower in
crotene content than freshly prepared
n dried meal produced under favourable
conditions.
Peterson, Hughes and Freeman [1937]
supported a modification of the Guilbert
method of carotene estimation in foodstuffs.
ne methods of carotene estimation have
en examined by the American Associa-
in of Official Agricultural Chemists, and
unsey [1937; 1938] as Associate Referee
made two reports on the" subject. In 1939
ne Report of Sub-Committee A on Reeom-
mendations of Referees [1939] recommen-
ded that the Peterson Hughes method for
estimation of carotene be adopted as
entative, and the spectrophotometer be
used or the 0.1 per cent potassium dichro-
mate reference standard.
Ensiling is an important method of
preserving fresh forage. The usual
method of ensiling results in protein
breakdown and fermentation during which
crotene is destroyed. Virtanen [1938]
modified the method so as to maintain the
idity of the ensiled material below pH 4,
and thereby prevent the destruction of
crotene. The method under the name of
the A.I.V. process has been widely used
and is a practical success.
RELATION OF CAROTENOIDS IN THE FOOD TO T
COLOUR OF MILK AND BODY FAT
Palmer and co-workers [1922] found
carotene was the principal pigment in
blood serum and in the body and milk fat
of cattle and in skin secretions of Guernsey
cattle. The yellow colour in chicken
tissues, including egg yolk, is mainly
xanthophyll. Swine, sheep and goat
tissues do not usually contain an appreci-
able amount of pigment and their body fat
is white. The subject has been studied by
Hirzel [1935] in experiments with rabbits.
In this species, as shown by Willimott
[1928], xanthophyll is the main pigment
in the fat. Xanthophyll also occurs in
the fat of some strains of sheep in
Australia. In the pigmentation of the fat
in both rabbits and sheep in California,
Guilbert [1936] has shown the pigment to
be xanthophyll.
The widespread prejudice against
yellow fat in the beef trade has little to
support it, except for the tendency of the
colour to increase in intensity with age
and thus to be a sign that the meat is from
aged animals. As the carotene furnishes
an important dietary essential it is mis-
chievous to permit trade practices which
result in deprecation of its presence.
Carotene is present in greatest quantity
in the carcases of grass fed animals which
are often lacking in 'finish,' and is parti-
cularly marked in old dairy cows of the
Channel Island breeds. Well 'finished'
cattle which are largely fed on concentrates
with small quantities of roughage have fat
which is relatively white.
Thus colour has become carelessly
used in the meat trade as an index of
quality, but this attitude has barely exten-
ded to the housewife or ultimate consumer.
The grading of beef based upon conforma-
tion, quality and smoothness of the carcase
with the degree of finish or covering with
fat, is sufficient to place all carcases in their
proper class.
Buckley et al. [1930] reported caro-
tenosis in bovine livers, found during meat
inspection. There was parenchymatous