K. C. SEN AND P. A.
SESHAN
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Studying the effects of ultra-violet radiations on vitamin-A, it was shown
by biological tests that up to one hour of exposure there was no loss, while
after four hours of irradiation only 1.5 per cent of the original content re-
mained. But the colour test showed that the destruction started at once
and that there still remained 30 per cent after thirty-two hours of exposure
[Norris, 1931]. The vitamin-A content in alfalfa was found to decrease with
age whether kept ground or chopped. Curing alfalfa in cocks in the field
had the same effect as curing in diffuse light of varying intensity. When
this hay was cured in windrows exposed to sunlight, only 2/3rds of the potency
was lost while the hay exposed to sunlight with rain and dew lost 3/4ths
[Hartman, 1931]. Drying alfalfa in the field caused a greater loss of potency,
probably through enzyme action, than when dried by hot air or hot flue gas.
Warmth and moisture favoured the destruction of vitamin-A, whilst cold,
rapid drying or autoclaving hindered it [Hauge and Aitkenhead, 1931]. Alfalfa
hay, protected from the sun while curing, contained four to five times as
much vitamin-A as the hay exposed to the sun and rain [Reed, 1931]. Alfalfa
which was removed from the field as soon as cut and stored in a dark, well-
ventilated room, was compared with exposed ones. Exposure for 2¾ to 6¾ hours
led to a loss of twenty to thirty per cent of vitamin-A but none of the green
colour. Overnight exposure in the field caused a loss of seventy-five per cent of
its content while a week's sun and rain bleached the hay severely and destroyed
about ninety-six per cent of its potency [Smith and Briggs, 1933]. Sun-cured hay
exposed to one inch or more of rain was less potent than that cured in diffuse
sunlight, the vitamin-A content varying from 10 to 60 Sherman units per
grm. of hay. Growth of moulds had deleterious effects on all vitamins
[Douglas et al, 1933]. The vitamin-A and -D contents of hay dried quickly
at 68° C. in two hours were much greater than when slowly dried in meadows
or frames [Rygh, 1934]. Machine dried alfalfa has a higher vitamin-A con-
tent than the field dried ones. Rapid loss of carotene occurred in field curing
in day light. Dried alfalfa, finely ground, could be stored in vacuo at 0° C.
without loss [Russell et al, 1934]. Vacuum dried alfalfa, dried for three hours
at 100° C., had as much carotene as the fresh leaves, while the field cured ones
and the commercially dehydrated ones had the same content of carotene,
25.3 mg. per 100 grm. The vacuum dried alfalfa hay contained 52 mg.
per 100 grm. [Guilbert, 1934]. Vitamin-A potency of freshly cut alfalfa
could be retained if the enzymes were destroyed immediately before drying.
The destruction attributed to sunlight might be attributable to the higher
temperatures produced accelerating the enzymatic activity [Hauge, 1935].
No loss was noticed on vacuum drying but autoclaving and sun-drying caused
considerable losses. In slow drying, enzymic and bacterial action had their
part. Below 5° C. a storage of six months did not show any loss. Tempera-
ture was found to be the most influencing factor in decreasing the vitamin-A
potency of hay [Guilbert, 1935]. When alfalfa was cut and cured in the
cock in fresh condition it had a vitamin-A content of 308±13 units per grm.
On being ground and stored for four months it was 233±20. When exposed
in the swathe for one day before cocking it had 144 ± 10 units per grm., whereas